sci.electronics.repair - 24 new messages in 9 topics - digest

sci.electronics.repair
http://groups.google.com/group/sci.electronics.repair?hl=en

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Today's topics:

==============================================================================
TOPIC: OT: Video - I bet she will listen next time!
http://groups.google.com/group/sci.electronics.repair/t/0231af1c6c094716?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Sep 22 2010 11:57 am
From: PlainBill47@yawho.com

On Wed, 22 Sep 2010 10:03:18 -0400, RoadRunner <asdf@aol.com> wrote:

>Don't question it, just watch. How one man deals with a misbehaving
>wife...
>
>http://www.craigboyce.com/Videos/WebFinds/TakingBackThePants.shtml
Some things a man should always remember:
1. If she ever saw 'Something to Talk About' she knows how to make
you very sick.
2. She knows where you sleep.
3. She knows the pillow over your face trick.
4. She knows that duct tape can make it a permanent solution.

PlainBill

==============================================================================
TOPIC: general question: mainboard caps
http://groups.google.com/group/sci.electronics.repair/t/1bf5ee3341246b6a?hl=en
==============================================================================

== 1 of 14 ==
Date: Wed, Sep 22 2010 1:09 pm
From: "Daniel Mandic"

Michael wrote:

> Ok, thanks to everyone who replied. Seems doable... looks like I'm
> going shopping for a vacuum desolderer.

Hi Michael!

Makes repair surely easier :). It's always my advice, but I don't have
an desoldering-iron (vacuum) since then ;-). The 'right' stuff is
expensive....

I have done some boards, desoldering the failing condensators by
changing the soldering-iron from one pin to the other, pulling the
capacitor side (pin) by side (pin), out of its placement.
The new caps I pull into the same way....
Tin-solder I take only a tip..., just to have a better contact to the
origin tin-solder of the mainboard, which can be tricky and sticky :-(.

Some boards are easier, and you can desolder it with desoldering-lace
(flex, cord). Plus, that the standard (yours) tin-solder will be
adopted, too.

--
Daniel Mandic

== 2 of 14 ==
Date: Wed, Sep 22 2010 1:43 pm
From: Jeff Liebermann

On Wed, 22 Sep 2010 18:55:13 +0000 (UTC), Meat Plow
<mhywatt@yahoo.com> wrote:

>On Wed, 22 Sep 2010 11:11:56 -0700, Jeff Liebermann wrote:
>
>> On Wed, 22 Sep 2010 16:31:39 +0000 (UTC), Meat Plow <mhywatt@yahoo.com>
>> wrote:
>>
>>>On Wed, 22 Sep 2010 09:23:21 -0700, Jeff Liebermann wrote:
>>>
>>><snip>
>>>
>>>> I've been soldering for about 50 years, so I suspect I'm sufficiently
>>>> experienced to have made all the usual mistakes (several times). It's
>>>> not the lack of skill.
>>>
>>><snip>
>>>
>>>My first "job" in electronics was in the back room of my barber's shop
>>>who had a little hobby business repairing electronics odds and ends. It
>>>was where I learned how to solder. Especially after being told by one of
>>>the barber's friends that I soldered like his grandmother :) That was in
>>>1971. I was 16.
>>
>> That was a compliment.
>>
>> I started with an Ungar wood burner at about 14 years old. The first
>> lesson I learned is that the power cord of the iron will melt and short
>> when I place the iron on it. It was downhill from there as my father
>> taught me to use a large copper gas fired furnace soldering thing used
>> to make industrial sewing machine attachments. By comparison, the Ungar
>> seemed easy. After several years of doing everything wrong, the high
>> skool electric shop teacher introduced me to flux. Over the years, I
>> learned the basics, like you can hold solder in your mouth, but don't
>> try it with copper wire. Far too many Eico, Heathkit, and Knightkit
>> constructions were great practice.
>>
>> I recently tried to teach a friends 14 year old brat how to solder. He's
>> hopeless, but dedicated, and will eventually learn.

>LOL! We had wood burners but I think I was only 10. I can't imagine the
>politics of selling those thing to children of that age as a child's toy
>these days.

I can't recall how old I was when I got the wood burner, so I guessed
on the age. I may have been younger. Mine hand a huge ceramic
heating element, with a diameter about the same as the handle. There
was no way to put it down anywhere without seriously burning what it
touched. The unplated tiny copper screw-in tip was a bad joke that
pitted badly after a few hours of use. The handle got really hot. I
had it for maybe 30 years and used it for cutting and welding plastic.
By todays standards, the old woodburners are dangerous even for an
adult.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 3 of 14 ==
Date: Wed, Sep 22 2010 1:51 pm
From: Jeff Liebermann

On Wed, 22 Sep 2010 11:42:53 -0700 (PDT), Michael
<mrdarrett@gmail.com> wrote:

>I noticed that one of the capacitor leads is connected to what looks
>like a fat copper trace (ground?) The other lead seems soldered to
>just a tiny little circle... if I hadn't looked closely, I might have
>soldered it to ground by mistake too...

Some of the traces and pads are VERY close to nearby grounds and other
traces. Be careful and don't slop too much solder around when you
install the replacement cap.

>I heard that the bulb doesn't work very well. My dad has one.

Steal the bulb, throw it away, and get him a solder sucker. Better
yet, steal just the teflon tip. It fits some solder suckers.

>hey, I play the piano too! Trying to learn how to play George
>Winston's piano solos... The Cradle is pretty straightforward, but, oh
>man, his variations on the Carol of the Bells is extremely tough!

I can't read a note of music and scribble my own. My playing is awful
but given a few centuries practice, it might improve:
<http://802.11junk.com/jeffl/music/>
My Korg DDS-1 synthesizer slowly died over the last month and is
scattered in pieces all over the living room. I can't tell what
failed, but it's making strange noises and the LCD backlighting has
quit. Yet another project. Playing music is the only thing that
keeps me sane, which may explain this months rants on usenet.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 4 of 14 ==
Date: Wed, Sep 22 2010 1:57 pm
From: Michael

On Sep 22, 1:09 pm, "Daniel Mandic" <daniel_man...@hotmail.com> wrote:
> Michael wrote:
> > Ok, thanks to everyone who replied. Seems doable... looks like I'm
> > going shopping for a vacuum desolderer.
>
> Hi Michael!
>
> Makes repair surely easier :). It's always my advice, but I don't have
> an desoldering-iron (vacuum) since then ;-). The 'right' stuff is
> expensive....
>
> I have done some boards, desoldering the failing condensators by
> changing the soldering-iron from one pin to the other, pulling the
> capacitor side (pin) by side (pin), out of its placement.
> The new caps I pull into the same way....
> Tin-solder I take only a tip..., just to have a better contact to the
> origin tin-solder of the mainboard, which can be tricky and sticky :-(.
>
> Some boards are easier, and you can desolder it with desoldering-lace
> (flex, cord). Plus, that the standard (yours) tin-solder will be
> adopted, too.
>
> --
> Daniel Mandic

That reminds me... is it a good idea or a bad idea to solder the new
cap with normal (leaded) solder?

Thanks,

Michael

== 5 of 14 ==
Date: Wed, Sep 22 2010 2:00 pm
From: "Daniel Mandic"

larry moe 'n curly wrote:

> With any iron, a chisel tip, about
> 2mm - 2.5mm wide, works better than a conical tip, and tips are best
> cleaned with curly brass hair or a damp paper towel, not a sponge.

A good watered sponge does work. Good condition solder-tip expected...

So many Tips and Tricks you gave, I don't think Michael will understand
the halve of it ;-)

--
Daniel Mandic

== 6 of 14 ==
Date: Wed, Sep 22 2010 2:22 pm
From: "Daniel Mandic"

Jeff Liebermann wrote:

> I can't read a note of music and scribble my own. My playing is awful
> but given a few centuries practice, it might improve:
> <http://802.11junk.com/jeffl/music/>
> My Korg DDS-1 synthesizer slowly died over the last month and is
> scattered in pieces all over the living room. I can't tell what
> failed, but it's making strange noises and the LCD backlighting has
> quit. Yet another project. Playing music is the only thing that
> keeps me sane, which may explain this months rants on usenet.

Some people do have only one hit in their life, but.
E.g. 'Scatman'. Or...!... 'Born to be Alive'!

With this in mind, play your melodies and enjoy the time. I do so...

[Yamaha AN1-X, KORG DSS-1, Wavestation, .....and some DiY, preferably
analogue, in my mind! ;-) e.g. MiniMOOG, TR-909, Formant Synthesizer,
etc., much work AND high costs....]

--
Daniel Mandic

== 7 of 14 ==
Date: Wed, Sep 22 2010 3:14 pm
From: "Daniel Mandic"

Michael wrote:

> That reminds me... is it a good idea or a bad idea to solder the new
> cap with normal (leaded) solder?

Mainboards, AFAIK, are soldered in an solder bath. I don't know the
temperature nor the solder-tin they use. Even that, I would have no
idea what to do with the data ;-)

I do by trying. Believing my skills (can excel to rubbish quality, if I
don't keep the pace regarding IT motherboards) might help.

But you can make some repairs if you dare, and save some money here and
there. (I am starting to rhyme in english... :-))

Keep an eye, as other posters said (take a lens for example!), for
solder- spots/patches/splotches, where they shouldn't be.

By the way. Power capacitors are, I would say, arranged to the bottom
side of the mainboard. The pins of the cap goes through the board.
I have had similar thoughts as you... 8layer, 4layer special
electronic, but, so long as I have had bringing back PC's, I am pretty
sure power caps are to be found on the bottom side (physically on the
top side, off course).

--
Daniel Mandic

== 8 of 14 ==
Date: Wed, Sep 22 2010 6:02 pm
From: Michael

On Sep 22, 2:00 pm, "Daniel Mandic" <daniel_man...@hotmail.com> wrote:
> larry moe 'n curly wrote:
>
> > With any iron, a chisel tip, about
> > 2mm - 2.5mm wide, works better than a conical tip, and tips are best
> > cleaned with curly brass hair or a damp paper towel, not a sponge.
>
> A good watered sponge does work. Good condition solder-tip expected...
>
> So many Tips and Tricks you gave, I don't think Michael will understand
> the halve of it ;-)
>
> --
> Daniel Mandic

Dad always used a sponge (repaired TVs and radios decades ago) for
solder work. I prefer a used tissue personally. (A sponge is such a
waste.)

Michael

== 9 of 14 ==
Date: Wed, Sep 22 2010 8:52 pm
From: "Michael A. Terrell"

Michael wrote:
>
> On Sep 22, 2:00 pm, "Daniel Mandic" <daniel_man...@hotmail.com> wrote:
> > larry moe 'n curly wrote:
> >
> > > With any iron, a chisel tip, about
> > > 2mm - 2.5mm wide, works better than a conical tip, and tips are best
> > > cleaned with curly brass hair or a damp paper towel, not a sponge.
> >
> > A good watered sponge does work. Good condition solder-tip expected...
> >
> > So many Tips and Tricks you gave, I don't think Michael will understand
> > the halve of it ;-)
> >
> > --
> > Daniel Mandic
>
> Dad always used a sponge (repaired TVs and radios decades ago) for
> solder work. I prefer a used tissue personally. (A sponge is such a
> waste.)

Then why is the industry standard for manufacturing? They can be
rinsed out and turned over. Even with heavy use, they have a long
life. Also, it is much easier to keep them damp that a dirty kleenex.
You do not want the sponge to be sopping wet, just damp enough to keep
it from burning. If it is too wet it can cause the iron plating to
crack, and cause the tip to have a very short life.

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

== 10 of 14 ==
Date: Wed, Sep 22 2010 9:38 pm
From: Michael

On Sep 22, 8:52 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:
> Michael wrote:
>
> > On Sep 22, 2:00 pm, "Daniel Mandic" <daniel_man...@hotmail.com> wrote:
> > > larry moe 'n curly wrote:
>
> > > > With any iron, a chisel tip, about
> > > > 2mm - 2.5mm wide, works better than a conical tip, and tips are best
> > > > cleaned with curly brass hair or a damp paper towel, not a sponge.
>
> > > A good watered sponge does work. Good condition solder-tip expected...
>
> > > So many Tips and Tricks you gave, I don't think Michael will understand
> > > the halve of it ;-)
>
> > > --
> > > Daniel Mandic
>
> > Dad always used a sponge (repaired TVs and radios decades ago) for
> > solder work. I prefer a used tissue personally. (A sponge is such a
> > waste.)
>
> Then why is the industry standard for manufacturing? They can be

What? There is still electronics manufacturing in the United States?
8-D

== 11 of 14 ==
Date: Wed, Sep 22 2010 9:40 pm
From: "Michael A. Terrell"

Michael wrote:
>
> What? There is still electronics manufacturing in the United States?

Yes, just not $10 radios or $20 TVs.

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

== 12 of 14 ==
Date: Wed, Sep 22 2010 11:06 pm
From: Jeff Liebermann

On Wed, 22 Sep 2010 13:57:28 -0700 (PDT), Michael
<mrdarrett@gmail.com> wrote:

>That reminds me... is it a good idea or a bad idea to solder the new
>cap with normal (leaded) solder?

No. It's highly likely that the motherboard uses RoHS blessed
unleaded solder. Mixing solder types results in a rather dull looking
cold solder joint. However, if you suck away all of the solder on the
pad, you can probably get away with switching solder types, but I
wouldn't bother. Just get the right solder.

Incidentally, I have two soldering irons on my bench... one for each
type of solder.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 13 of 14 ==
Date: Wed, Sep 22 2010 11:15 pm
From: Michael

On Sep 22, 9:40 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:
> Michael wrote:
>
> > What? There is still electronics manufacturing in the United States?
>
> Yes, just not $10 radios or $20 TVs.
>

Will wonders never cease... ok, I'm taking half of my wife's
dishwashing sponge then...

Michael

== 14 of 14 ==
Date: Wed, Sep 22 2010 11:35 pm
From: stratus46@yahoo.com

On Sep 21, 6:51 pm, Jeff Liebermann <je...@cruzio.com> wrote:
> On Tue, 21 Sep 2010 11:28:35 -0700 (PDT), Michael
>
> <mrdarr...@gmail.com> wrote:
> >Ok, thanks to everyone who replied. Seems doable... looks like I'm
> >going shopping for a vacuum desolderer.
>
> While a proper vacuum desoldering station is nice, you can get away
> with using a solder sucker.
> <http://www.amazon.com/SOLDER-SUCKER-DESOLDERING-DESOLDER-REMOVAL/dp/B...>
> It requires some practice at both using and cleaning. I use one when
> I'm too lazy to fire up the desoldering station.
>
> Someone suggested using solder braid. I disagree. I've lifted so
> many traces and pads from the board with solder braid, that I won't
> use it unless I'm depserate.
>
> Don't forget the stainless steel needle or pin for cleaning the hole.
> --
> # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
> # 831-336-2558
> #http://802.11junk.com je...@cruzio.com
> #http://www.LearnByDestroying.com AE6KS

I'm with you on the braid but it _is_ good for cleaning surface mount
pads before installing the new component. A Metcal with an STTC-126
tip is about the best if you _don't_ have a vacuum desoldering
station. The small tip can fit partway into the hole after the
component is out and then you can use an old fashioned solder sucker
with excellent results.

G²

==============================================================================
TOPIC: fix for toyota clock.
http://groups.google.com/group/sci.electronics.repair/t/14010c2072017f5a?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Sep 22 2010 1:56 pm
From: "Ron D."

Remove battery positive cable. Put ignition in on position. Short
pos cable to ground for 1 min. Turn ign. Off. Reconnect. Worked for
me.

==============================================================================
TOPIC: Computer tech in Queens, NY area?
http://groups.google.com/group/sci.electronics.repair/t/0ab48031718a21a1?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Sep 22 2010 2:00 pm
From: "David Farber"

A friend of a friend has a Dell 1100 Inspiron. It shuts down (overheats?)
and is not as fast as it once was. Can anyone recommend a tech in the
Queens, New York area that can give this laptop the once over? The owner
uses it to teach senior citizens how to use computers so she needs it for
work but cannot afford a new one.

Thanks for your reply.

--
David Farber
Los Osos, CA

==============================================================================
TOPIC: pleasant surprise from MCM
http://groups.google.com/group/sci.electronics.repair/t/a4c659409064c74d?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Sep 22 2010 5:25 pm
From: "Mark Zacharias"

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:i7a90p$jr4$1@news.eternal-september.org...
>> They can afford it. Their prices probably average at least
>> 20% higher than they need to, and their freight and handling
>> charges are inflated.
>
> I usually check prices among dealers before buying anything. The $24
> (each)
> these items cost seemed reasonable, and shipping /was/ "free". MCM's
> prices
> on their "house" items (of which this one) do seem to bounce around,
> sometimes quite a bit, so it makes sense to wait for a "sale".
>
> There is no "free lunch". But it's nice to have decent customer service
> for
> a change. You can't have that, and the lowest price, at the same time.
>
> PS: It's so easy to complain about bad service, that I thought it
> appropriate to compliment good service. This group's responses have
> generally had an implied tone of "You're really an idiot", which I don't
> appreciate.
>
>

Just to be clear - if anyone suggested you were an idiot, it wasn't me.
Certainly no such was intended.

Later.

==============================================================================
TOPIC: Music Man Sixty Five
http://groups.google.com/group/sci.electronics.repair/t/b6026a75cd412799?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Sep 22 2010 5:53 pm
From: "Arfa Daily"

"Meat Plow" <mhywatt@yahoo.com> wrote in message
news:pan.2010.09.22.18.35.40@hahahahahahahah.nutz.I.am...
> On Wed, 22 Sep 2010 18:13:49 +0100, Arfa Daily wrote:
>
>> Just had one of these lovely old amps across the bench, and was
>> extremely surprised to see a plate voltage of 730 on the two 6CA7 / EL34
>> output pentodes.
>
> That's what they run em at. What did you need to know about them, I used
> to own a 112 combo 65/35 watter. Probably very similar.
>
>
>
Nothing particularly. Their website has all the schematics for free
download, and I fixed all the problems on this one. I was just interested to
see if anyone had any stories about them - or the manufacturer in general -
as it's not a brand commonly seen here.

Arfa

==============================================================================
TOPIC: Fender Showman from 1963
http://groups.google.com/group/sci.electronics.repair/t/04710c995b7d7066?hl=en
==============================================================================

== 1 of 3 ==
Date: Wed, Sep 22 2010 6:18 pm
From: "Arfa Daily"

"Jeff Layman" <jmlayman@invalid.invalid> wrote in message
news:i7dh7q$uq6$1@news.albasani.net...
> On 22/09/2010 17:39, N_Cook wrote:
>
>> Closer look and the cotton covering to the wiring between the output
>> heaters
>> is "perished", crumbling to dust, and needs replacing. Strange having a
>> load
>> of Mullard, Brimar and Z&I Aero valves to test
>
> Z&I Aero!!! I haven't heard that name for over 40 years. That was when
> their shop in Tottenham Court Road was worth visiting, followed by a
> stroll to Proops, and then onto Lisle Street. Are there any surplus
> places worth visiting today?
>
> --
>
> Jeff

I still have a Z&I Aero (Zaerix) glossy covered catalogue / data book in
near pristine condition. It has data on lovely old things like VCR97 'scope
tubes, and has all the prices in pounds, shillings and pence ! Oh those
lovely old days of skiving off school for the day and jumping on the train
to London to go to Tottenham Court Road and Lisle Street. Into Henry's Radio
... I bought my first 'hifi' amplifier in Proops. It's a Teleton SAQ-307.
It's here in the computer room with me, and I'm looking at it right now.
Still works as good as the day it was bought. Only about 8 watts per channel
as I recall, but punched way above that weight. It drives my EMI 13 x 8 cabs
with 7 x 5 mids and Eagle dome tweeters. The EMIs came from Henry's and the
Eagles from Maplin I think, but might have been Tandy (Radio Shack). I also
have the matching Teleton GT-203 tuner, and then the Nikko ND-790 cassette
deck. Remember those ? All together, it was the classic "poor man's" hifi
rig of the early 70s.

I think most of the wonderful old junk shops have pretty much gone now, but
I think that Anchor Supplies up in Nottingham is still going. Remember AH
Supplies ? They used to advertise every month in Practically Witless
magazine, and I bought a lot of ex WW2 radios like 19 sets and an R1392 and
a Wavemeter D from them. I have a feeling that they might still be going in
one form or another. I'm also pretty sure that Birketts over in Lincoln
somewhere are still going too. Then there was John's Radio, and Bull
Electrical. Happy days ... Blimey. I've just looked up John's Radio, and
they are still going !

Arfa

== 2 of 3 ==
Date: Wed, Sep 22 2010 6:29 pm
From: Engineer

On Sep 22, 2:17 pm, Jeff Layman <jmlay...@invalid.invalid> wrote:
> On 22/09/2010 17:39, N_Cook wrote:
>
> > Closer look and the cotton covering to the wiring between the output heaters
> > is "perished", crumbling to dust, and needs replacing. Strange having a load
> > of Mullard, Brimar and Z&I Aero valves to test
>
> Z&I Aero!!! I haven't heard that name for over 40 years. That was when
> their shop in Tottenham Court Road was worth visiting, followed by a
> stroll to Proops, and then onto Lisle Street. Are there any surplus
> places worth visiting today?
>
> --
>
> Jeff

Tottenham Court Road... Proops... Lisle Street...
Brings back memories!
Cheers,
Roger
(in Canada since 1970...)

== 3 of 3 ==
Date: Thurs, Sep 23 2010 12:22 am
From: "N_Cook"

Meat Plow <mhywatt@yahoo.com> wrote in message
news:pan.2010.09.22.16.47.04@hahahahahahahah.nutz.I.am...
> On Wed, 22 Sep 2010 17:39:27 +0100, N_Cook wrote:
>
> > Meat Plow <mhywatt@yahoo.com> wrote in message
> > news:pan.2010.09.22.15.17.33@hahahahahahahah.nutz.I.am...
> >> On Wed, 22 Sep 2010 15:23:05 +0100, N_Cook wrote:
> >>
> >> > Known history with this , from its purchase in Germany onwards,
> >> > including its original set of valves (not in there and used now, but
> >> > will test out of curiosity). What are the main potential
> >> > safety/reliability issues with an amp of this age? All the cotton
> >> > covered wiring looks good but is there some test/procedure more
> >> > convincing as to insualting value? Bakelite brittleness in the valve
> >> > bases? metallurgical failure of springiness of valve contacts?
> >> > Someone modified to 3 core mains cable and made an earth point, for
> >> > 240V land, at some point in its history. Numerous caps replaced in
> >> > 1991 and 1997 and some carbon R replaced with MO at some point. I've
> >> > not checked the main caps yet.
> >>
> >> No known safety issues other than mains wiring. These were pretty
> >> reliable amps. I own a 1970 Showman USA model. Someone tried to turn it
> >> into a 100 watt model by replacing the iron and adding two octals to
> >> the already blanked out chassis. I ripped all that stuff out and put
> >> new output iron in it. It's not worth much but it does sound sweet.
> >>
> >>
> >>
> >> --
> >> Live Fast, Die Young and Leave a Pretty Corpse
> >
> >
> >
> > Closer look and the cotton covering to the wiring between the output
> > heaters is "perished", crumbling to dust, and needs replacing. Strange
> > having a load of Mullard, Brimar and Z&I Aero valves to test
>
> Since the heater wiring is twisted it would be a good idea to replace if
> it is that poor of a state. I don't recall ever seeing the LV wiring in
> any Fender of that era in that state and the state of all the wiring is
> what I usually inspect first on any P2P wired vintage amp.
>
>
>
>
> --
> Live Fast, Die Young and Leave a Pretty Corpse

The conductor size, under the insulation, is only 0.7mm presumably not
enough for the current plus localised heating. Will replace with silicon
sleeved wire with "Refrasil" glass sleeving over that , dulled down with
dark green permanent ink felt tip pen, gives a very convincing contemporary
look, and surprisingly does not wipe off the glass

==============================================================================
TOPIC: Cassette tape component
http://groups.google.com/group/sci.electronics.repair/t/11d09b6898cd0cae?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Sep 22 2010 7:55 pm
From: Puddin' Man

On Wed, 22 Sep 2010 02:02:10 +0100, "Arfa Daily" <arfa.daily@ntlworld.com> wrote:

>>>Have you managed to bypass the tape presence switch ?
>>
>> I dunno which it is. There are 3 for which I cannot trace the circuitry.
>> But I confirmed that all switch circuits were closed except for the
>> sensor for plate height (head position). When I short that
>> one, the solenoid actuates.
>
>With no tape in place, the deck should do nothing - no clicks, no motor
>movement, zip, zilch, nada. Now, if you press each switch up in turn with a
>finger tip, one of them should get the deck doing something - even if it's
>just the solenoid clicking behaviour. The switch that you had to press to
>get that, is the tape presence switch.

There are 6 leaf switches on top of the tape slot. 5 of these look identical
and have plastic covers, the other is shorter and is exposed (no plastic
cover). This last one senses the head-plate being raised. It fires the
solenoid when jumped. None of the other 5 seems to actuate anything with the
manual test you described. I tested on both units.

>>>Have you tried 'working' the deck by hand i.e. press the solenoid plunger
>>>in
>>>with a small screwdriver tip. You should see the cam gear 'unlock'.
>>
>> I can't see the gear without dis-assembling the drive components (again).
>>
>>>Then rotate the forward capstan (left as you look at the back) clockwise
>>>(viewing from the back). This should cause the cam gear to rotate to the
>>>next
>>>phase and relock.
>>
>> I can hear it click.
>>
>>>Probably "fast forward", but might be
>>>"play". You should be able to do that for all four phases, and make sure
>>>that the deck is doing what it should be mechanically at least.
>>
>> Not sure I follow that.
>> When I continue to rotate, I get additional clicks. After 2, the cassette
>> won't come out. After another click it will.
>
>
>You don't need (or want) a tape in place to work the deck by hand. You don't
>want any power applied either. The cam gear should have four phases. That is
>"stop" or neutral, "FF", "Play" and "Rew". The periphery of the cam gear has
>four positions with missing teeth that correspond to each of these phase
>positions, and four raised latch catches on the surface, which also
>correspond. The lever worked by the solenoid, catches on these latch
>positions in turn. The cam has a bias spring to keep it pressed against the
>latch lever. Suppose the cam has the deck in the "stop" position. The
>missing teeth in the cam gear periphery which correspond to that position,
>will be over the drive gear which is at the centre of the forward capstan.
>So the capstan can freely rotate, without driving the cam gear. When the
>solenoid is activated to select a transport mode - say "FF" - the latch will
>disengage, and the bias spring will start to rotate the cam gear, until the
>tooth-free area has moved around, and the next section which has teeth, has
>engaged with the gear at the centre of the capstan. By this time, the motor
>should be running, and driving the capstan. This, in turn, will drive the
>cam gear round until it reaches the next area where teeth are missing. This
>will stop the cam in the new position, and the solenoid latch will drop onto
>the catch at that position on the cam gear surface, and hold the gear at
>that position, again against the bias spring. At this time, various levers
>running in grooves under the gear, will have moved their positions to work
>what ever bits of mech that they have to i.e. moving reel idlers into place
>and disengaging reel brakes etc.

Thanks. That helps a bit. I still can't see it happen, but your description
seems to "cover the bases".

>> Major (weird) news. You'll recall I have 2 RS-TR255's, call 'em A. and B.
>> I've been working on A. Thought to check something on B. to see if it
>> was same as A., pulled the cover, tested playback, and it worked. It
>> failed
>> per A. less than a week ago. Also does reverse play, FF, etc.
>>
>> There are 4 gold screws on the drive plate on B. that are absent on A.
>> Looks like they just keep the big wheel from coming off (but it's shaft
>> does that). I thought to install the 4 screws on the A. unit, but it
>> wouldn't take 'em: screw holes *look* the same, but they aren't
>> threaded as on B. I double-checked, both A. and B. are RS-TR255's.
>>
>> Strange, eh? Well, at least I won't be chucking B. in the garbage for
>> a while. I even got readings on the vu, so I guess it's working (for now).
>
>That is odd. The 255 does not appear to be a model that was valid in the UK,
>so I can't get data for it off the Pan engineering website. There is a 155
>on there, which might be pretty similar. Have you checked for voltage at the
>"+" terminal of the motor when it should be running ? The motor should have
>4 terminals. "-" is common to chassis, "+" should have switched 12v on it,
>and "A" and "B" are the speed control terminals

I measure ~12v dc from the chassis to one of the contacts when I 'play'
a tape.

>Just checked. The service manual for the 155 is the same as for the 255

If it is available and doesn't cost a bundle, would appreciate a link
to where I can find it.

Thanks,
P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

==============================================================================
TOPIC: Recovering deleted answering machine email
http://groups.google.com/group/sci.electronics.repair/t/d063e26958de9442?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Sep 22 2010 10:03 pm
From: Jesse Graybill

I have an AT&T answering machine that I accidentally deleted a message
on.

AT&T has told me there's no official way to get the message back.

Is there any way to pull this off the hardware directly?

Thanks!

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