sci.electronics.repair@googlegroups.com

Today's topics:

* Mopar model 812 car radio, (early 1950's Chrysler product) - 12 messages, 10
authors
http://groups.google.com/group/sci.electronics.repair/t/3135639c17d6af1d?hl=en
* Porcelain thermally conductive insulators ? - 6 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/b69decd6bfa03d8b?hl=en
* Ampeg BA600 - 115 bass amp combo, 6 months old, ROHS - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/bc6178fc14fcf982?hl=en
* minidisc player shows track but won't play tracks - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/305742f0844c5c34?hl=en
* Replacing camera flash trigger MOSFET - 2SK2715 - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/2272695d470a3c81?hl=en
* Uniselector mini project. - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/b7082851ed958781?hl=en
* Where's best source for laptop battery? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/e22e3559f49b976b?hl=en

==============================================================================
TOPIC: Mopar model 812 car radio, (early 1950's Chrysler product)
http://groups.google.com/group/sci.electronics.repair/t/3135639c17d6af1d?hl=en
==============================================================================

== 1 of 12 ==
Date: Wed, Apr 20 2011 12:10 am
From: "N_Cook"

klem kedidelhopper <captainvideo462009@gmail.com> wrote in message
news:a5b8ddea-d0b2-40c4-b137-f151d4146709@r6g2000vbz.googlegroups.com...
> It seems like everything coming in here lately is other than TV
> repairs. But TV's are getting so cheap now and as a consequence things
> are so slow I hate to turn anything away these days.This is a six volt
> positive ground radio out of an early 1950's Chrysler product. Tubes
> light up but vibrator will not buzz. I pulled the vibrator and
> connected the coil terminals up to six volts and it does buzz. Not
> conclusive but at the very least it tells me that six volts is not
> reaching the coil. Does anyone have a schematic for this radio, or do
> you know where I might find one? The owner just bought the car, is
> restoring it and really wants to keep it original, so he'd really like
> to have this radio working. Thanks, Lenny

I have renovated a vibrator, usual pitted contacts problem, robbing contacts
from
a power relay or switch and swaging them into the carrier.

== 2 of 12 ==
Date: Wed, Apr 20 2011 3:56 am
From: "Colin Horsley"

"klem kedidelhopper" <captainvideo462009@gmail.com> wrote in message
news:a5b8ddea-d0b2-40c4-b137-f151d4146709@r6g2000vbz.googlegroups.com...
: It seems like everything coming in here lately is other than TV
: repairs. But TV's are getting so cheap now and as a consequence things
: are so slow I hate to turn anything away these days.This is a six volt
: positive ground radio out of an early 1950's Chrysler product. Tubes
: light up but vibrator will not buzz. I pulled the vibrator and
: connected the coil terminals up to six volts and it does buzz. Not
: conclusive but at the very least it tells me that six volts is not
: reaching the coil. Does anyone have a schematic for this radio, or do
: you know where I might find one? The owner just bought the car, is
: restoring it and really wants to keep it original, so he'd really like
: to have this radio working. Thanks, Lenny

Look here for your vibrator:-

http://www.radiosforoldcars.com/vibrators.htm

Colin in AUS

== 3 of 12 ==
Date: Wed, Apr 20 2011 5:29 am
From: klem kedidelhopper

On Apr 20, 6:56 am, "Colin Horsley" <horsley-s...@westnet.com.au>
wrote:
> "klem kedidelhopper" <captainvideo462...@gmail.com> wrote in message
>
> news:a5b8ddea-d0b2-40c4-b137-f151d4146709@r6g2000vbz.googlegroups.com...
> : It seems like everything coming in here lately is other than TV
> : repairs. But TV's are getting so cheap now and as a consequence things
> : are so slow I hate to turn anything away these days.This is a six volt
> : positive ground radio out of an early 1950's Chrysler product. Tubes
> : light up but vibrator will not buzz. I pulled the vibrator and
> : connected the coil terminals up to six volts and it does buzz. Not
> : conclusive but at the very least it tells me that six volts is not
> : reaching the coil. Does anyone have a schematic for this radio, or do
> : you know where I might find one? The owner just bought the car, is
> : restoring it and really wants to keep it original, so he'd really like
> : to have this radio working. Thanks, Lenny
>
> Look here for your vibrator:-
>
> http://www.radiosforoldcars.com/vibrators.htm
>
> Colin in AUS

Thanks for all the info guys.I don't know for certain yet if I need a
vibrator but I do need to order a schematic. Lenny

== 4 of 12 ==
Date: Wed, Apr 20 2011 10:55 am
From: Meat Plow

On Wed, 20 Apr 2011 05:29:17 -0700, klem kedidelhopper wrote:

> On Apr 20, 6:56 am, "Colin Horsley" <horsley-s...@westnet.com.au> wrote:
>> "klem kedidelhopper" <captainvideo462...@gmail.com> wrote in message
>>
>> news:a5b8ddea-d0b2-40c4-b137-
f151d4146709@r6g2000vbz.googlegroups.com...
>> : It seems like everything coming in here lately is other than TV :
>> repairs. But TV's are getting so cheap now and as a consequence things
>> : are so slow I hate to turn anything away these days.This is a six
>> volt : positive ground radio out of an early 1950's Chrysler product.
>> Tubes : light up but vibrator will not buzz. I pulled the vibrator and
>> : connected the coil terminals up to six volts and it does buzz. Not :
>> conclusive but at the very least it tells me that six volts is not :
>> reaching the coil. Does anyone have a schematic for this radio, or do :
>> you know where I might find one? The owner just bought the car, is :
>> restoring it and really wants to keep it original, so he'd really like
>> : to have this radio working. Thanks, Lenny
>>
>> Look here for your vibrator:-
>>
>> http://www.radiosforoldcars.com/vibrators.htm
>>
>> Colin in AUS
>
> Thanks for all the info guys.I don't know for certain yet if I need a
> vibrator but I do need to order a schematic. Lenny

Pull the vibrator out of its case and look for welded contacts. Lots of
times they can be separated and dressed with a relay file or fine emery
nail file. Sometimes you can even bang on the vibrator and loosen the
contacts if they aren't stuck together badly. I ran across this Youtube
video some while back. It will help you immensly

http://youtu.be/Fp6PkRTmb8U

--
Live Fast Die Young, Leave A Pretty Corpse

== 5 of 12 ==
Date: Wed, Apr 20 2011 11:03 am
From: PeterD

On 4/20/2011 1:55 PM, Meat Plow wrote:
> On Wed, 20 Apr 2011 05:29:17 -0700, klem kedidelhopper wrote:
>
>> On Apr 20, 6:56 am, "Colin Horsley"<horsley-s...@westnet.com.au> wrote:
>>> "klem kedidelhopper"<captainvideo462...@gmail.com> wrote in message
>>>
>>> news:a5b8ddea-d0b2-40c4-b137-
> f151d4146709@r6g2000vbz.googlegroups.com...
>>> : It seems like everything coming in here lately is other than TV :
>>> repairs. But TV's are getting so cheap now and as a consequence things
>>> : are so slow I hate to turn anything away these days.This is a six
>>> volt : positive ground radio out of an early 1950's Chrysler product.
>>> Tubes : light up but vibrator will not buzz. I pulled the vibrator and
>>> : connected the coil terminals up to six volts and it does buzz. Not :
>>> conclusive but at the very least it tells me that six volts is not :
>>> reaching the coil. Does anyone have a schematic for this radio, or do :
>>> you know where I might find one? The owner just bought the car, is :
>>> restoring it and really wants to keep it original, so he'd really like
>>> : to have this radio working. Thanks, Lenny
>>>
>>> Look here for your vibrator:-
>>>
>>> http://www.radiosforoldcars.com/vibrators.htm
>>>
>>> Colin in AUS
>>
>> Thanks for all the info guys.I don't know for certain yet if I need a
>> vibrator but I do need to order a schematic. Lenny
>
> Pull the vibrator out of its case and look for welded contacts. Lots of
> times they can be separated and dressed with a relay file or fine emery
> nail file. Sometimes you can even bang on the vibrator and loosen the
> contacts if they aren't stuck together badly. I ran across this Youtube
> video some while back. It will help you immensly
>
> http://youtu.be/Fp6PkRTmb8U
>
>
>

yes, this can work. I've repaired a few over the years by disassembling
and using an auto points file on the contacts. They are usually easy to
take apart, too.

--
I'm never going to grow up.

== 6 of 12 ==
Date: Wed, Apr 20 2011 11:49 am
From: "Ron D."

I think I know who might have solid state one (Antique Electronic
Supply) I built one for an old Blaupunkt 3 band radio laid out in
wavelength rather than frequency for a 73 vehicle. My replacement was
huge though. Threw it together with a few parts from. Radio Shack.

== 7 of 12 ==
Date: Wed, Apr 20 2011 11:53 am
From: spamtrap1888

On Apr 20, 11:03 am, PeterD <pet...@hipson.net> wrote:
> On 4/20/2011 1:55 PM, Meat Plow wrote:
>
>
>
> > On Wed, 20 Apr 2011 05:29:17 -0700, klem kedidelhopper wrote:
>
> >> On Apr 20, 6:56 am, "Colin Horsley"<horsley-s...@westnet.com.au>  wrote:
> >>> "klem kedidelhopper"<captainvideo462...@gmail.com>  wrote in message
>
> >>> news:a5b8ddea-d0b2-40c4-b137-
> > f151d4146...@r6g2000vbz.googlegroups.com...
> >>> : It seems like everything coming in here lately is other than TV :
> >>> repairs. But TV's are getting so cheap now and as a consequence things
> >>> : are so slow I hate to turn anything away these days.This is a six
> >>> volt : positive ground radio out of an early 1950's Chrysler product.
> >>> Tubes : light up but vibrator will not buzz. I pulled the vibrator and
> >>> : connected the coil terminals up to six volts and it does buzz. Not :
> >>> conclusive but at the very least it tells me that six volts is not :
> >>> reaching the coil. Does anyone have a schematic for this radio, or do :
> >>> you know where I might find one? The owner just bought the car, is :
> >>> restoring it and really wants to keep it original, so he'd really like
> >>> : to have this radio working. Thanks, Lenny
>
> >>> Look here for your vibrator:-
>
> >>>http://www.radiosforoldcars.com/vibrators.htm
>
> >>> Colin in AUS
>
> >> Thanks for all the info guys.I don't know for certain yet if I need a
> >> vibrator but I do need to order a schematic. Lenny
>
> > Pull the vibrator out of its case and look for welded contacts. Lots of
> > times they can be separated and dressed with a relay file or fine emery
> > nail file. Sometimes you can even bang on the vibrator and loosen the
> > contacts if they aren't stuck together badly. I ran across this Youtube
> > video some while back. It will help you immensly
>
> >http://youtu.be/Fp6PkRTmb8U
>
> yes, this can work. I've repaired a few over the years by disassembling
> and using an auto points file on the contacts. They are usually easy to
> take apart, too.

Guys, the OP says his vibrator buzzes when he applies 6 volts directly
to it. That argues that the vibrator is not the problem, but that
there's an open circuit between the power supply and the vibrator.

I would suspect that either the socket contacts or the pins on the
vibrator are corroded.

== 8 of 12 ==
Date: Wed, Apr 20 2011 12:19 pm
From: PlainBill@yawhoo.com

On Tue, 19 Apr 2011 19:25:51 -0700 (PDT), klem kedidelhopper
<captainvideo462009@gmail.com> wrote:

>It seems like everything coming in here lately is other than TV
>repairs. But TV's are getting so cheap now and as a consequence things
>are so slow I hate to turn anything away these days.This is a six volt
>positive ground radio out of an early 1950's Chrysler product. Tubes
>light up but vibrator will not buzz. I pulled the vibrator and
>connected the coil terminals up to six volts and it does buzz. Not
>conclusive but at the very least it tells me that six volts is not
>reaching the coil. Does anyone have a schematic for this radio, or do
>you know where I might find one? The owner just bought the car, is
>restoring it and really wants to keep it original, so he'd really like
>to have this radio working. Thanks, Lenny
It looks like most of the other replys totally missed the fact that
the vibrator isn't vibrating in the radio, but does work with DC
applied directly.
I just did a quick check and two terminals of the vibrator are
usually connected directly across the DC input. That should make
troubleshooting fairly simple, even without a schematic.

Of course, if this is point to point wiring, it's probably a rats nest
of wires in there. But no lead free solder!!

PlainBill

== 9 of 12 ==
Date: Wed, Apr 20 2011 12:34 pm
From: PeterD

On 4/20/2011 2:53 PM, spamtrap1888 wrote:

>
> Guys, the OP says his vibrator buzzes when he applies 6 volts directly
> to it. That argues that the vibrator is not the problem, but that
> there's an open circuit between the power supply and the vibrator.
>
> I would suspect that either the socket contacts or the pins on the
> vibrator are corroded.

I did miss that... Likely it is good and there is a supply problem then

--
I'm never going to grow up.

== 10 of 12 ==
Date: Wed, Apr 20 2011 1:14 pm
From: mm

On Wed, 20 Apr 2011 05:29:17 -0700 (PDT), klem kedidelhopper
<captainvideo462009@gmail.com> wrote:

>On Apr 20, 6:56�am, "Colin Horsley" <horsley-s...@westnet.com.au>
>wrote:
>> "klem kedidelhopper" <captainvideo462...@gmail.com> wrote in message
>>
>> news:a5b8ddea-d0b2-40c4-b137-f151d4146709@r6g2000vbz.googlegroups.com...
>> : It seems like everything coming in here lately is other than TV
>> : repairs. But TV's are getting so cheap now and as a consequence things
>> : are so slow I hate to turn anything away these days.This is a six volt
>> : positive ground radio out of an early 1950's Chrysler product. Tubes
>> : light up but vibrator will not buzz. I pulled the vibrator and
>> : connected the coil terminals up to six volts and it does buzz. Not
>> : conclusive but at the very least it tells me that six volts is not
>> : reaching the coil. Does anyone have a schematic for this radio, or do
>> : you know where I might find one? The owner just bought the car, is
>> : restoring it and really wants to keep it original, so he'd really like
>> : to have this radio working. Thanks, Lenny
>>
>> Look here for your vibrator:-
>>
>> http://www.radiosforoldcars.com/vibrators.htm
>>
>> Colin in AUS
>
>Thanks for all the info guys.I don't know for certain yet if I need a
>vibrator but I do need to order a schematic. Lenny

Did you see Spam's first post:
>Do you have six dollars and fifty cents? A NOS Sams Photofact can be
>yours:
>
>http://www.smcelectronics.com/samsauto.htm
>
>MOPAR Models: 812/813/815/816/817 AM Car Radio. - $6.50

When are you going to be back on tv?

== 11 of 12 ==
Date: Wed, Apr 20 2011 3:31 pm
From: David Nebenzahl

On 4/20/2011 1:14 PM mm spake thus:

> On Wed, 20 Apr 2011 05:29:17 -0700 (PDT), klem kedidelhopper
> <captainvideo462009@gmail.com> wrote:

[stuff]

> When are you going to be back on tv?

Well, if that's really him, he doesn't know how to spell his own name.
It's Clem Kadiddlehopper, as anyone who ever saw Red Skelton could tell
you ...

--
The current state of literacy in our advanced civilization:

yo
wassup
nuttin
wan2 hang
k
where
here
k
l8tr
by

- from Usenet (what's *that*?)

== 12 of 12 ==
Date: Wed, Apr 20 2011 3:38 pm
From: Meat Plow

On Wed, 20 Apr 2011 11:53:34 -0700, spamtrap1888 wrote:

> On Apr 20, 11:03 am, PeterD <pet...@hipson.net> wrote:
>> On 4/20/2011 1:55 PM, Meat Plow wrote:
>>
>>
>>
>> > On Wed, 20 Apr 2011 05:29:17 -0700, klem kedidelhopper wrote:
>>
>> >> On Apr 20, 6:56 am, "Colin Horsley"<horsley-s...@westnet.com.au>
>> >>  wrote:
>> >>> "klem kedidelhopper"<captainvideo462...@gmail.com>  wrote in
>> >>> message
>>
>> >>> news:a5b8ddea-d0b2-40c4-b137-
>> > f151d4146...@r6g2000vbz.googlegroups.com...
>> >>> : It seems like everything coming in here lately is other than TV :
>> >>> repairs. But TV's are getting so cheap now and as a consequence
>> >>> things : are so slow I hate to turn anything away these days.This
>> >>> is a six volt : positive ground radio out of an early 1950's
>> >>> Chrysler product. Tubes : light up but vibrator will not buzz. I
>> >>> pulled the vibrator and : connected the coil terminals up to six
>> >>> volts and it does buzz. Not : conclusive but at the very least it
>> >>> tells me that six volts is not : reaching the coil. Does anyone
>> >>> have a schematic for this radio, or do : you know where I might
>> >>> find one? The owner just bought the car, is : restoring it and
>> >>> really wants to keep it original, so he'd really like : to have
>> >>> this radio working. Thanks, Lenny
>>
>> >>> Look here for your vibrator:-
>>
>> >>>http://www.radiosforoldcars.com/vibrators.htm
>>
>> >>> Colin in AUS
>>
>> >> Thanks for all the info guys.I don't know for certain yet if I need
>> >> a vibrator but I do need to order a schematic. Lenny
>>
>> > Pull the vibrator out of its case and look for welded contacts. Lots
>> > of times they can be separated and dressed with a relay file or fine
>> > emery nail file. Sometimes you can even bang on the vibrator and
>> > loosen the contacts if they aren't stuck together badly. I ran across
>> > this Youtube video some while back. It will help you immensly
>>
>> >http://youtu.be/Fp6PkRTmb8U
>>
>> yes, this can work. I've repaired a few over the years by disassembling
>> and using an auto points file on the contacts. They are usually easy to
>> take apart, too.
>
> Guys, the OP says his vibrator buzzes when he applies 6 volts directly
> to it. That argues that the vibrator is not the problem, but that
> there's an open circuit between the power supply and the vibrator.
>
> I would suspect that either the socket contacts or the pins on the
> vibrator are corroded.

That's right, missed it. The video I posted can be used to troubleshoot
it further, the circuits are all pretty basic.

--
Live Fast Die Young, Leave A Pretty Corpse

==============================================================================
TOPIC: Porcelain thermally conductive insulators ?
http://groups.google.com/group/sci.electronics.repair/t/b69decd6bfa03d8b?hl=en
==============================================================================

== 1 of 6 ==
Date: Wed, Apr 20 2011 2:16 am
From: "N_Cook"

Baron <baron@linuxmaniac.net> wrote in message
news:iokrbf$ma5$1@dont-email.me...
> N_Cook Inscribed thus:
>
> > Baron <baron@linuxmaniac.net> wrote in message
> > news:iohp6k$bbn$1@dont-email.me...
> >> N_Cook Inscribed thus:
> >>
> >> > 1.8mm slabs of porcelain under TO220 devices.
> >>
> >> I would check that ! Its more likely that they are Beryllium_oxide !
> >> <http://en.wikipedia.org/wiki/Beryllium_oxide>
> >>
> >> > Tried grinding a clearance notch on the side of one
> >> > pad but got nowhere as ceramic.
> >> > Not only that but I had no trouble holding the slab in fingers
> >> > while trying to grind a slot, it was barely getting warm - good
> >> > thermal insulator or small grinding wheel not generating heat as
> >> > not cutting into the material ?
> >>
> >> The dust from grinding or abrading Beryllium_oxide is highly toxic !
> >>
> >> --
> >> Best Regards:
> >> Baron.
> >
> >
> > Unfortunately it would not grind. I assume it was not heating up
> > because the grinding disc was just running over the surface without
> > even rubbing , let alone grinding, so no dust, still the flat edge.
> > Does BeO have that sort of translucent appearance of porcelain?
>
> The surface tends to have the appearance of good quality photocopy
> paper, very smooth with a barely visible grain. A bit like ferrite
> beads.
>
> > I've managed to grind small sections of the ceramic used is high
> > temperature "chock block" connectors, that has a normal solid white
> > appearance. But given its use here then presumably BeO.
> > It was the slightly milky/translucent porcelain-like appearance that
> > convinced me.
>
> Both Aluminum oxide and Beryllium oxide are extremely hard materials. I
> belive that the pink dye was used later to specifically identify
> Beryllium. So its a good chance that the white insulators that you
> have are Aluminum oxide. Even so its not a good idea to try to grind
> them.
>
> Ceramics are also used to machine metals, including some that are so
> tough that only ceramic cutters can be used on them.
>
> --
> Best Regards:
> Baron.

The next time I come across one I'll try passing a laser beam or bright
light through it to see if any light passes through. It was that
translucency appearance, like porcelain , that I noticed.

== 2 of 6 ==
Date: Wed, Apr 20 2011 4:24 am
From: "N_Cook"

I had to get inside that amp again, yet another PbF problem from next to
zero insertion force speaker connector at the PA 4 removal & inserts by me
was enough , only 6 months old.
The slabs pass red laser pointer light, but then on checking but so does the
ceramic of high temp "choc block".
These slabs are more trnasmissive and scatter the light throughout the slab
not just the entry and exit area of the chock block.

== 3 of 6 ==
Date: Wed, Apr 20 2011 2:14 pm
From: Baron

N_Cook Inscribed thus:

> I had to get inside that amp again, yet another PbF problem from next
> to zero insertion force speaker connector at the PA 4 removal &
> inserts by me was enough , only 6 months old.
> The slabs pass red laser pointer light, but then on checking but so
> does the ceramic of high temp "choc block".
> These slabs are more trnasmissive and scatter the light throughout the
> slab not just the entry and exit area of the chock block.

Mmm ! Interesting. I have a small quantity of boxed TO3 BeO
insulators. I'll have to get one out and see.

--
Best Regards:
Baron.

== 4 of 6 ==
Date: Wed, Apr 20 2011 8:32 pm
From: josephkk

On Mon, 18 Apr 2011 17:36:42 +0100, Baron <baron@linuxmaniac.net> wrote:

>N_Cook Inscribed thus:
>
>> 1.8mm slabs of porcelain under TO220 devices.
>
>I would check that ! Its more likely that they are Beryllium_oxide !
><http://en.wikipedia.org/wiki/Beryllium_oxide>
>
>> Tried grinding a clearance notch on the side of one
>> pad but got nowhere as ceramic.
>> Not only that but I had no trouble holding the slab in fingers while
>> trying to grind a slot, it was barely getting warm - good thermal
>> insulator or small grinding wheel not generating heat as not cutting
>> into the material ?
>
>The dust from grinding or abrading Beryllium_oxide is highly toxic !

BeO is very expensive. I would be very surprised to find any in such
application.

== 5 of 6 ==
Date: Thurs, Apr 21 2011 12:16 am
From: "N_Cook"

Baron <baron@linuxmaniac.net> wrote in message
news:ioni74$fk3$1@dont-email.me...
> N_Cook Inscribed thus:
>
> > I had to get inside that amp again, yet another PbF problem from next
> > to zero insertion force speaker connector at the PA 4 removal &
> > inserts by me was enough , only 6 months old.
> > The slabs pass red laser pointer light, but then on checking but so
> > does the ceramic of high temp "choc block".
> > These slabs are more trnasmissive and scatter the light throughout the
> > slab not just the entry and exit area of the chock block.
>
> Mmm ! Interesting. I have a small quantity of boxed TO3 BeO
> insulators. I'll have to get one out and see.
>
> --
> Best Regards:
> Baron.

It maybe a function of thickness, these being 1.8mm thick slabs rather than
wafers

== 6 of 6 ==
Date: Thurs, Apr 21 2011 12:15 am
From: "N_Cook"

josephkk <joseph_barrett@sbcglobal.net> wrote in message
news:e79vq6lnae2qp2p36p8dskjftl2bsmb4ad@4ax.com...
On Mon, 18 Apr 2011 17:36:42 +0100, Baron <baron@linuxmaniac.net> wrote:

>N_Cook Inscribed thus:
>
>> 1.8mm slabs of porcelain under TO220 devices.
>
>I would check that ! Its more likely that they are Beryllium_oxide !
><http://en.wikipedia.org/wiki/Beryllium_oxide>
>
>> Tried grinding a clearance notch on the side of one
>> pad but got nowhere as ceramic.
>> Not only that but I had no trouble holding the slab in fingers while
>> trying to grind a slot, it was barely getting warm - good thermal
>> insulator or small grinding wheel not generating heat as not cutting
>> into the material ?
>
>The dust from grinding or abrading Beryllium_oxide is highly toxic !

BeO is very expensive. I would be very surprised to find any in such
application.

++++

These were not made for the job. They have a hole for either TO220 or TOP66
maybe size transistors . So too wide for this use and the hole is not used
. The layout does not mean they have to be 1.8mm thick , any thickness from
mica up could have been accommodated. Normally you would go for the thinnest
of insulators.

==============================================================================
TOPIC: Ampeg BA600 - 115 bass amp combo, 6 months old, ROHS
http://groups.google.com/group/sci.electronics.repair/t/bc6178fc14fcf982?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Apr 20 2011 7:44 am
From: "N_Cook"

Do Ampeg make bass amps? There will be loads of returns of this model.
Any large lump inside a bass amp is likely to vibrate if inadequately
secured. That 2 x 2 x 1 inch lump is only secured by its screening can at 2
pointsplus inductor ends soldered. That was the main problem , proper solder
would be hard pushed but PbF only lasts 6 months like this. By a daisy
chaining cable ties between made anchor point at the ps , round the L1 can
and out through the cable hole and tightened after the ps+pa screening case
is back over.
Also PbF failing on the speaker socket, would not have been so bad if they'd
used the 4 pole connection like farther down the speaker line. Plus the
absence of star washers on the pots. Ignoring the absent h/s bolt.

==============================================================================
TOPIC: minidisc player shows track but won't play tracks
http://groups.google.com/group/sci.electronics.repair/t/305742f0844c5c34?hl=en
==============================================================================

== 1 of 2 ==
Date: Wed, Apr 20 2011 10:03 am
From: Ron

On 20/04/2011 02:01, Arfa Daily wrote:
>
>
> "Meat Plow" <mhywattt@yahoo.com> wrote in message
> news:pan.2011.04.19.16.48.43@lmao.lol...
>> On Tue, 19 Apr 2011 02:07:09 +0100, Arfa Daily wrote:
>>
>>> "willywainwright" <ww10@mac.com> wrote in message
>>> news:1360b0ff-dfc8-4fd6-
>> b13b-18a3c0ca4f95@a21g2000prj.googlegroups.com...
>>>> On Apr 17, 5:38 pm, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:
>>>>> "willywainwright" <w...@mac.com> wrote in message
>>>>>
>>>>> news:25afe1d0-f5ec-423f-ae7c-
>> a22b29f43c59@q40g2000prh.googlegroups.com...
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> > On Apr 16, 12:23 pm, a7yvm109gf...@netzero.com wrote:
>>>>> >> On Apr 16, 12:10 pm, willywainwright <w...@mac.com> wrote:
>>>>>
>>>>> >> > hello, I have a number of sony minidisc players that suddenly
>>>>> >> > won't play the track for no apparent reason. I've tried batteries
>>>>> >> > and plug in power with no difference. Powers up fine, shows
>>>>> >> > spinning icon in window, track number shows but I can't get the
>>>>> >> > units to play the disc.
>>>>> >> > I've tried it in all positions, even upside down and sideways but
>>>>> >> > still no playing of disc
>>>>> >> > any ideas?
>>>>> >> > willy
>>>>>
>>>>> >> 1) Try lens cleaner disc.
>>>>> >> 2) Now toss the whole shebang in the garbage 3) Get a free cell
>>>>> >> phone, even they'll come with a MP3 player.
>>>>>
>>>>> >> Minidisc is over. It's dead, finished, kaput. And I'm speaking as
>>>>> >> someone who bought a MZ-1 when they first came out.
>>>>>
>>>>> > maybe a lens cleaner disc would work. wonder if I can find one. I'll
>>>>> > give it a try. Garbage is full of my cassette tapes and players and
>>>>> > all my 8-track tapes. Willy
>>>>>
>>>>> Never ever use 'cleaner' discs - not that I recall ever seeing one for
>>>>> a mindisc anyway. They invariably never do anything to help, and in
>>>>> the case
>>>>> of DVDs, I've seen them cause expensive damage where the little
>>>>> 'brush' hairs embedded in the disc, have caught in the lens
>>>>> suspension, and mangled
>>>>> it as the disc has then rotated. I used to do a lot of work on Sony MD
>>>>> players, when a guy that I did work for was a regional service centre.
>>>>> For
>>>>> the most part, failure to play discs is down to a worn out laser.
>>>>> Sometimes,
>>>>> you can get around that for a while, by resetting the laser parameters
>>>>> via
>>>>> built in diagnostic software, but it is a complex and tricky procedure
>>>>> to do. Another thing to check is that when the disc is loaded, it is
>>>>> free to rotate. I had many examples where the turntable had been
>>>>> pushed down on the
>>>>> motor shaft, until it jammed the motor. Another very common problem
>>>>> was 'crap in the works'. The sled drive comprises gears with *very*
>>>>> fine teeth.
>>>>> The slightest bit of contamination in them, is enough to stop the
>>>>> gears from
>>>>> turning. The contamination in question, often seemed to be very fine
>>>>> sand,
>>>>> but I guess that it could have been 'pocket grit'. Just one grain in
>>>>> one of
>>>>> the gear teeth, will jam the mech and stop the laser from homing,
>>>>> which will
>>>>> result in the disc failing to spin up, and the TOC not being read.
>>>>> Finally,
>>>>> I suppose you do actually see the display come up and hear the disc
>>>>> loading
>>>>> as though it's about to do everything normally ? I have had cases
>>>>> where the
>>>>> door-closed sense switch has caused problems. A word of warning
>>>>> though. You
>>>>> need to have the patience of a saint to work on these things, and some
>>>>> very
>>>>> fine tools, including a quality set of Philips jeweler's screwdrivers,
>>>>> and
>>>>> pointed tweezers. Magnetize the screwdriver first. The tiny little
>>>>> screws are no bigger than an ant, and easily lost. Work on a large
>>>>> sheet of paper,
>>>>> and use a strong light, and a magnifying glass. And you need to be
>>>>> able to
>>>>> hold your breath pretty well, also ... d :-|
>>>>>
>>>>> Arfa
>>>>
>>>> Thank you Arfa, great reply, full of good info. Don't know that I will
>>>> attempt the fix but at least I want to be sure it's not something I've
>>>> overlooked,like the hold switch set to on. In this case I guess these
>>>> things just wear out after awhile. Would you, or anyone, know of a good
>>>> repair shop to send these units to? And also, would you be able to tell
>>>> me about how much you guys used to charge for repairs. Hourly? just
>>>> curious.
>>>> Willy
>>>
>>> My going rate for this sort of stuff is around 22 UKP ( $35 ) an hour.
>>> It's not really a true reflection of the complexity / fiddly nature of
>>> the work, but it's about the most that these jobs will stand. Any more
>>> than an hour plus parts, effectively writes them off.
>>>
>>> Arfa
>>
>> Most of the time unless the customer is willing to pay it's just not
>> worth it to repair these things. I've had a couple apart and they are
>> complex and difficult to work on because of the size. Those that I have
>> repaired I had to use my 20x stereo magnifier visor and hold my face
>> about 4 inches from the piece while working on it.
>>
>>
>
> Yep. Pretty much par for the course. I would guess it's probably been a
> couple of years now since I last worked on one. MP3 players killed them,
> really. In actual fact, I think that I would have to think hard before
> really getting into one these days. It was ok when I was doing them on a
> virtually daily basis. You get so used to them that you can pull them
> down with your eyes shut. My eyes are nothing like as good now as they
> were a couple of years back, so that wouldn't help either. I also have a
> stereo headband magnifier, and I find that I am using it more and more
> for 'standard' sized electronics, let alone surface mount stuff. Oh to
> be young again, eh Meat ?
>
>Arfa

Minidisc is still used extensively in touring theatre, preferred by many
companies over cd and laptop for sound cues.

I haven't repaired a huge amount, but IMO Sony players seem to suffer
from either contaminated switches on the mech[1], or the tiny 'levers'
on the mechanisms which engage the switches.

I`ve seen a few with mangled heads, no doubt due to 'finger trouble'

[1] If I recall correctly, the contamination comes from the flexible
mounts of the mechanism, and can sometimes be seen as a brown 'stain' on
the metal work.

Ron

== 2 of 2 ==
Date: Wed, Apr 20 2011 11:06 am
From: Meat Plow

On Wed, 20 Apr 2011 02:01:49 +0100, Arfa Daily wrote:

>
> "Meat Plow" <mhywattt@yahoo.com> wrote in message
> news:pan.2011.04.19.16.48.43@lmao.lol...
>> On Tue, 19 Apr 2011 02:07:09 +0100, Arfa Daily wrote:
>>
>>> "willywainwright" <ww10@mac.com> wrote in message
>>> news:1360b0ff-dfc8-4fd6-
>> b13b-18a3c0ca4f95@a21g2000prj.googlegroups.com...
>>>> On Apr 17, 5:38 pm, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:
>>>>> "willywainwright" <w...@mac.com> wrote in message
>>>>>
>>>>> news:25afe1d0-f5ec-423f-ae7c-
>> a22b29f43c59@q40g2000prh.googlegroups.com...
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> > On Apr 16, 12:23 pm, a7yvm109gf...@netzero.com wrote:
>>>>> >> On Apr 16, 12:10 pm, willywainwright <w...@mac.com> wrote:
>>>>>
>>>>> >> > hello, I have a number of sony minidisc players that suddenly
>>>>> >> > won't play the track for no apparent reason. I've tried
>>>>> >> > batteries and plug in power with no difference. Powers up fine,
>>>>> >> > shows spinning icon in window, track number shows but I can't
>>>>> >> > get the units to play the disc.
>>>>> >> > I've tried it in all positions, even upside down and sideways
>>>>> >> > but still no playing of disc
>>>>> >> > any ideas?
>>>>> >> > willy
>>>>>
>>>>> >> 1) Try lens cleaner disc.
>>>>> >> 2) Now toss the whole shebang in the garbage 3) Get a free cell
>>>>> >> phone, even they'll come with a MP3 player.
>>>>>
>>>>> >> Minidisc is over. It's dead, finished, kaput. And I'm speaking as
>>>>> >> someone who bought a MZ-1 when they first came out.
>>>>>
>>>>> > maybe a lens cleaner disc would work. wonder if I can find one.
>>>>> > I'll give it a try. Garbage is full of my cassette tapes and
>>>>> > players and all my 8-track tapes. Willy
>>>>>
>>>>> Never ever use 'cleaner' discs - not that I recall ever seeing one
>>>>> for a mindisc anyway. They invariably never do anything to help, and
>>>>> in the case
>>>>> of DVDs, I've seen them cause expensive damage where the little
>>>>> 'brush' hairs embedded in the disc, have caught in the lens
>>>>> suspension, and mangled
>>>>> it as the disc has then rotated. I used to do a lot of work on Sony
>>>>> MD players, when a guy that I did work for was a regional service
>>>>> centre. For
>>>>> the most part, failure to play discs is down to a worn out laser.
>>>>> Sometimes,
>>>>> you can get around that for a while, by resetting the laser
>>>>> parameters via
>>>>> built in diagnostic software, but it is a complex and tricky
>>>>> procedure to do. Another thing to check is that when the disc is
>>>>> loaded, it is free to rotate. I had many examples where the
>>>>> turntable had been pushed down on the
>>>>> motor shaft, until it jammed the motor. Another very common problem
>>>>> was 'crap in the works'. The sled drive comprises gears with *very*
>>>>> fine teeth.
>>>>> The slightest bit of contamination in them, is enough to stop the
>>>>> gears from
>>>>> turning. The contamination in question, often seemed to be very fine
>>>>> sand,
>>>>> but I guess that it could have been 'pocket grit'. Just one grain in
>>>>> one of
>>>>> the gear teeth, will jam the mech and stop the laser from homing,
>>>>> which will
>>>>> result in the disc failing to spin up, and the TOC not being read.
>>>>> Finally,
>>>>> I suppose you do actually see the display come up and hear the disc
>>>>> loading
>>>>> as though it's about to do everything normally ? I have had cases
>>>>> where the
>>>>> door-closed sense switch has caused problems. A word of warning
>>>>> though. You
>>>>> need to have the patience of a saint to work on these things, and
>>>>> some very
>>>>> fine tools, including a quality set of Philips jeweler's
>>>>> screwdrivers, and
>>>>> pointed tweezers. Magnetize the screwdriver first. The tiny little
>>>>> screws are no bigger than an ant, and easily lost. Work on a large
>>>>> sheet of paper,
>>>>> and use a strong light, and a magnifying glass. And you need to be
>>>>> able to
>>>>> hold your breath pretty well, also ... d :-|
>>>>>
>>>>> Arfa
>>>>
>>>> Thank you Arfa, great reply, full of good info. Don't know that I
>>>> will attempt the fix but at least I want to be sure it's not
>>>> something I've overlooked,like the hold switch set to on. In this
>>>> case I guess these things just wear out after awhile. Would you, or
>>>> anyone, know of a good repair shop to send these units to? And also,
>>>> would you be able to tell me about how much you guys used to charge
>>>> for repairs. Hourly? just curious.
>>>> Willy
>>>
>>> My going rate for this sort of stuff is around 22 UKP ( $35 ) an hour.
>>> It's not really a true reflection of the complexity / fiddly nature of
>>> the work, but it's about the most that these jobs will stand. Any more
>>> than an hour plus parts, effectively writes them off.
>>>
>>> Arfa
>>
>> Most of the time unless the customer is willing to pay it's just not
>> worth it to repair these things. I've had a couple apart and they are
>> complex and difficult to work on because of the size. Those that I have
>> repaired I had to use my 20x stereo magnifier visor and hold my face
>> about 4 inches from the piece while working on it.
>>
>>
>>
> Yep. Pretty much par for the course. I would guess it's probably been a
> couple of years now since I last worked on one. MP3 players killed them,
> really. In actual fact, I think that I would have to think hard before
> really getting into one these days. It was ok when I was doing them on a
> virtually daily basis. You get so used to them that you can pull them
> down with your eyes shut. My eyes are nothing like as good now as they
> were a couple of years back, so that wouldn't help either. I also have a
> stereo headband magnifier, and I find that I am using it more and more
> for 'standard' sized electronics, let alone surface mount stuff. Oh to
> be young again, eh Meat ?

When I first started out and for maybe 25 years after I was pretty proud
not to need glasses for reading or working. Evermore so since all my
siblings wore glasses and contacts from a very early age. Now I need a
350 diopter pair to work close up and 150 just for general reading.
Really intricate things require the visor. I can say though that I've
repaired some bad solder joints on PC boards by inspecting them using the
visor and a bright light. Normally with even 20-20 vision some of these
you aren't able to spot unmagnified. So I've been using the visor long
before my need for reading glasses.

--
Live Fast Die Young, Leave A Pretty Corpse

==============================================================================
TOPIC: Replacing camera flash trigger MOSFET - 2SK2715
http://groups.google.com/group/sci.electronics.repair/t/2272695d470a3c81?hl=en
==============================================================================

== 1 of 3 ==
Date: Wed, Apr 20 2011 11:56 am
From: Peabody

While the pop-up flash on my Canon XT camera works fine, the hot
shoe doesn't work. So I took it apart, and found a discrete
transistor near the hot shoe, with one lead going to the hot shoe
center-pin connector, one going to ground, and the third going off
into the circuit bowels.

So I'm hoping this transistor is bad, and that's what's causing
the problem. The number on it is K2715P, which I assume is
2SK2715, a 500V N-channel MOSFET. That would make perfect sense in
this application.

But the problem is that the transistor is soldered onto that amber
flexible plastic stuff that passes for a PC board these days. I've
never attempted to desolder or resolder anything to that stuff. I
have a 30-watt iron. Can anyone give me advice on that?

An alternative would be to wire in the replacement in in parallel
with the existing part, probably just soldering to the old part
leads and trying to stay away from the plastic PC board as much as
possible. If I have room to do it that way.

And finally, this transistor appears to be pretty obscure, and
while Mouser carries it, it would be nice if I could use something
I'm more likely to find locally - an NTE part perhaps. It wouldn't
really have to have a 500V DS rating. As a practical matter, I
think 50V would be plenty - modern flashes don't go over 12V. So if
anybody knows of a common N-channel MOSFET that might work, please
let me know. But it has to be small. The body of the old one is
6.5mm wide.

Thanks for any help.

== 2 of 3 ==
Date: Wed, Apr 20 2011 1:06 pm
From: "Gareth Magennis"

"Peabody" <waybackNO746SPAM44@yahoo.com> wrote in message
news:20110420-185604.674.0@news.astraweb.com...
> While the pop-up flash on my Canon XT camera works fine, the hot
> shoe doesn't work. So I took it apart, and found a discrete
> transistor near the hot shoe, with one lead going to the hot shoe
> center-pin connector, one going to ground, and the third going off
> into the circuit bowels.
>
> So I'm hoping this transistor is bad, and that's what's causing
> the problem. The number on it is K2715P, which I assume is
> 2SK2715, a 500V N-channel MOSFET. That would make perfect sense in
> this application.
>
> But the problem is that the transistor is soldered onto that amber
> flexible plastic stuff that passes for a PC board these days. I've
> never attempted to desolder or resolder anything to that stuff. I
> have a 30-watt iron. Can anyone give me advice on that?
>
> An alternative would be to wire in the replacement in in parallel
> with the existing part, probably just soldering to the old part
> leads and trying to stay away from the plastic PC board as much as
> possible. If I have room to do it that way.
>
> And finally, this transistor appears to be pretty obscure, and
> while Mouser carries it, it would be nice if I could use something
> I'm more likely to find locally - an NTE part perhaps. It wouldn't
> really have to have a 500V DS rating. As a practical matter, I
> think 50V would be plenty - modern flashes don't go over 12V. So if
> anybody knows of a common N-channel MOSFET that might work, please
> let me know. But it has to be small. The body of the old one is
> 6.5mm wide.
>
> Thanks for any help.
>

Can't you just snip off the body and solder the correct transistor (quickly)
to those leads? Clamp something on the leads as a heatsink first.

p.s. There is no way I would ever substitute a 500v rated component for a
50v one.

Gareth.

Gareth.

== 3 of 3 ==
Date: Wed, Apr 20 2011 10:53 pm
From: "larry moe 'n curly"

Peabody wrote:
> While the pop-up flash on my Canon XT camera works fine, the hot
> shoe doesn't work.

> 2SK2715, a 500V N-channel MOSFET. That would make perfect sense in
> this application.
>
> But the problem is that the transistor is soldered onto that amber
> flexible plastic stuff that passes for a PC board these days. I've
> never attempted to desolder or resolder anything to that stuff. I
> have a 30-watt iron. Can anyone give me advice on that?
>
> An alternative would be to wire in the replacement in in parallel
> with the existing part, probably just soldering to the old part
> leads and trying to stay away from the plastic PC board as much as
> possible. If I have room to do it that way.
>
> And finally, this transistor appears to be pretty obscure, and
> while Mouser carries it, it would be nice if I could use something
> I'm more likely to find locally - an NTE part perhaps. It wouldn't
> really have to have a 500V DS rating. As a practical matter, I
> think 50V would be plenty - modern flashes don't go over 12V. So if
> anybody knows of a common N-channel MOSFET that might work, please
> let me know. But it has to be small.

Any luck finding a substitute in a power supply, such as one for a
PC? 500V MOSFETs are common in them.

I think you have to use a 500V transistor for the 12V flash for the
same reason vehicle ignition systems use transistors rated for
hundreds of volts on the 12V side of the ignition coil -- big voltage
spikes.

You could practice soldering the flexible circuit boards of junked PC
keyboards. I think they're made of mylar polyester, while that brown
flexible plastic in your camera is probably kapton, a plastic with a
much higher melting point.

==============================================================================
TOPIC: Uniselector mini project.
http://groups.google.com/group/sci.electronics.repair/t/b7082851ed958781?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Apr 20 2011 5:15 pm
From: josephkk

On Sat, 16 Apr 2011 22:50:29 +0100, T i m <news@spaced.me.uk> wrote:

>Hi all,
>
>I would like to use a uniselector (got) to step to its next position
>upon connection to a mains supply (through 'X' circuitry). This will
>probably be at one_per_day time intervals.
>
>Ideally said circuitry would consume as little energy itself as
>possible.
>
>What I'm actually trying to do is 'cycle' an intelligent low current
>(.5A) but quite expensive charger to a range of smallish 12V lead acid
>batteries. Once each battery is actually charged (probably elsewhere)
>it will be kept topped up by said project applying said charger once
>every Y days (where Y could be 25 as I think it's a 25 way selector).
>
>I could use (make) a 240 ac to 50V DC PSU (assuming the uniselector
>was designed to run at that) and then create a suitably long one shot
>pulse on power-up (charge cap?). I could probably even just use one
>mains digital time switch, energising the uniselector 'step' cct for
>one minute, again via a suitable charge cap (so the coil isn't left
>energised for longer than needed)?
>
>Ideally though both the charger and the stepper sides would be power
>cycled at the same time (to ensure the charger was reset). Or the
>charger de-powered when the selector is pulsed (so the selector isn't
>actually switching the charge current).
>
>Ideas welcome please. ;-)
>
>Cheers, T i m
>

Sounds like a great application for a stepping relay. Typical specs: 10,
20, 25, 40, 50, and up to 100 steps; 2 to 10 poles; 250 V, 2 A.

Next; trying to find one.

New ones can be had, but are spendy:
http://www.surplussales.com/switches/SWLedex-1.html

==============================================================================
TOPIC: Where's best source for laptop battery?
http://groups.google.com/group/sci.electronics.repair/t/e22e3559f49b976b?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Apr 20 2011 8:08 pm
From: Robert Macy

Where is the best source for a laptop battery?

You've been through the battles and know where to get a laptop battery
[inside US]
10.8V 3600mAH
02k6627
for the IBM Thinkpad

==============================================================================

You received this message because you are subscribed to the Google Groups "sci.electronics.repair"
group.

To post to this group, visit http://groups.google.com/group/sci.electronics.repair?hl=en

To unsubscribe from this group, send email to sci.electronics.repair+unsubscribe@googlegroups.com

To change the way you get mail from this group, visit:
http://groups.google.com/group/sci.electronics.repair/subscribe?hl=en

To report abuse, send email explaining the problem to abuse@googlegroups.com

==============================================================================
Google Groups: http://groups.google.com/?hl=en