sci.electronics.repair - 25 new messages in 10 topics - digest

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

sci.electronics.repair@googlegroups.com

Today's topics:

==============================================================================
TOPIC: MESMARISING VIDEOS&HOT PHOTOS
http://groups.google.com/group/sci.electronics.repair/t/ff5fc5cceeefa201?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 3 2011 12:49 am
From: SAILAJA LOVES U

==============================================================================
TOPIC: I Don't Get It!
http://groups.google.com/group/sci.electronics.repair/t/a367b736ad25687d?hl=en
==============================================================================

== 1 of 6 ==
Date: Mon, Jan 3 2011 2:04 am
From: D Yuniskis

On 1/3/2011 1:01 AM, Ron wrote:
> Okay, the new channel 32.2 has started broadcasting and I get it on
> two of the converter boxes in the house, but on the DTV box in my
> room, all I get is audio and a black screen which says "Audio
> Service." I paid a good deal of money for the DTV converter, so I
> expect it to do everything it's supposed to do. Does anyone know why I
> can't get the proper picture, and what can be done to fix this?

Play with your antenna. You will discover all sorts
of magical, unexplained behaviors just by moving the
receiver (antenna) up, down, rotated, etc.

Ain't DTV fun? We get entirely different channels in
two rooms separated by 30 ft!

== 2 of 6 ==
Date: Mon, Jan 3 2011 2:03 am
From: David Nebenzahl

On 1/3/2011 2:04 AM D Yuniskis spake thus:

> On 1/3/2011 1:01 AM, Ron wrote:
>
>> Okay, the new channel 32.2 has started broadcasting and I get it on
>> two of the converter boxes in the house, but on the DTV box in my
>> room, all I get is audio and a black screen which says "Audio
>> Service." I paid a good deal of money for the DTV converter, so I
>> expect it to do everything it's supposed to do. Does anyone know
>> why I can't get the proper picture, and what can be done to fix
>> this?
>
> Play with your antenna. You will discover all sorts
> of magical, unexplained behaviors just by moving the
> receiver (antenna) up, down, rotated, etc.
>
> Ain't DTV fun? We get entirely different channels in
> two rooms separated by 30 ft!

Yes. And lots of people (most?) think that it's *all* digital (including
the RF parts), and therefore somehow magical and not at all prone to the
kinds of problems experienced with the bad old "analog" TV (ghosting due
to multipath propagation, etc.)

(Well, presumably not most of the people *here*, but ...)

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

== 3 of 6 ==
Date: Mon, Jan 3 2011 4:00 am
From: "William Sommerwerck"

Canon had problems with some of its sensors. I don't know if that applied to
this model.

== 4 of 6 ==
Date: Mon, Jan 3 2011 6:08 am
From: Meat Plow

On Mon, 03 Jan 2011 04:00:56 -0800, William Sommerwerck wrote:

> Canon had problems with some of its sensors. I don't know if that
> applied to this model.

Canon makes a DTV converter?

--
Live Fast, Die Young and Leave a Pretty Corpse

== 5 of 6 ==
Date: Mon, Jan 3 2011 6:49 am
From: "William Sommerwerck"

>> Canon had problems with some of its sensors.
>> I don't know if that applied to this model.

> Canon makes a DTV converter?

Duh... I'm getting old. I must have answered the wrong post.

== 6 of 6 ==
Date: Mon, Jan 3 2011 8:12 am
From: Ron

On Jan 3, 2:04 am, D Yuniskis <not.going.to...@seen.com> wrote:
> On 1/3/2011 1:01 AM, Ron wrote:
>
> > Okay, the new channel 32.2 has started broadcasting and I get it on
> > two of the converter boxes in the house, but on the DTV box in my
> > room, all I get is audio and a black screen which says "Audio
> > Service." I paid a good deal of money for the DTV converter, so I
> > expect it to do everything it's supposed to do. Does anyone know why I
> > can't get the proper picture, and what can be done to fix this?
>
> Play with your antenna. You will discover all sorts
> of magical, unexplained behaviors just by moving the
> receiver (antenna) up, down, rotated, etc.
>
> Ain't DTV fun? We get entirely different channels in
> two rooms separated by 30 ft!

I don't know who makes the other two converters but they aren't DTV,
and now I wish I hadn't bought this in the forst place but I liked the
timers. Anywho... I tried the antenna and still get zip even at a
signal strength of 86 wich is pretty good even for the stations I do
get.

Ron

==============================================================================
TOPIC: Adjusting scanner focus
http://groups.google.com/group/sci.electronics.repair/t/46e902abed9b7a3f?hl=en
==============================================================================

== 1 of 3 ==
Date: Mon, Jan 3 2011 2:15 am
From: David Nebenzahl

Anyone here ever attempted (or better yet, succeeded at) adjusting the
focus on an ordinary tabletop scanner?

I've got a cheapie (Microtek V6USL), now more than 10 years old, still
works, still as noisy as ever. It works, but it's certainly not a great
scanner, and perhaps is doing the best it ever will do. But I'm not sure
it's in focus. Having stripped down scrapped scanners, I know there's a
focus adjustment, done at the factory and invariably set with some kind
of paint or glue.

Just wondering if it would be worthwhile trying to adjust mine. I
suppose marking the current setting for return in case of problems, and
trial and error could work.

The other annoying thing about the scanner is that it has to be "warmed
up"; the first scan or two are always way too light and washed out. Is
this typical of CCDs of this vintage? I remember seeing this same
behavior with some low-res cameras my company used to use on a CD
printing system we made, to take snapshots of CDs in the printer tray;
our software took two or three shots, threw them away and then took one
for real.

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

== 2 of 3 ==
Date: Mon, Jan 3 2011 2:55 am
From: "Michael A. Terrell"

David Nebenzahl wrote:
>
> Anyone here ever attempted (or better yet, succeeded at) adjusting the
> focus on an ordinary tabletop scanner?
>
> I've got a cheapie (Microtek V6USL), now more than 10 years old, still
> works, still as noisy as ever. It works, but it's certainly not a great
> scanner, and perhaps is doing the best it ever will do. But I'm not sure
> it's in focus. Having stripped down scrapped scanners, I know there's a
> focus adjustment, done at the factory and invariably set with some kind
> of paint or glue.
>
> Just wondering if it would be worthwhile trying to adjust mine. I
> suppose marking the current setting for return in case of problems, and
> trial and error could work.
>
> The other annoying thing about the scanner is that it has to be "warmed
> up"; the first scan or two are always way too light and washed out. Is
> this typical of CCDs of this vintage? I remember seeing this same
> behavior with some low-res cameras my company used to use on a CD
> printing system we made, to take snapshots of CDs in the printer tray;
> our software took two or three shots, threw them away and then took one
> for real.

The 'warmup' is the CCFL. The problem gets worse as they age. Some
change color before they fail, which screws up your white balance.

--
For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!

== 3 of 3 ==
Date: Mon, Jan 3 2011 3:14 am
From: "N_Cook"

David Nebenzahl <nobody@but.us.chickens> wrote in message
news:4d21a1b8$0$30399$822641b3@news.adtechcomputers.com...
> Anyone here ever attempted (or better yet, succeeded at) adjusting the
> focus on an ordinary tabletop scanner?
>
> I've got a cheapie (Microtek V6USL), now more than 10 years old, still
> works, still as noisy as ever. It works, but it's certainly not a great
> scanner, and perhaps is doing the best it ever will do. But I'm not sure
> it's in focus. Having stripped down scrapped scanners, I know there's a
> focus adjustment, done at the factory and invariably set with some kind
> of paint or glue.
>
> Just wondering if it would be worthwhile trying to adjust mine. I
> suppose marking the current setting for return in case of problems, and
> trial and error could work.
>
> The other annoying thing about the scanner is that it has to be "warmed
> up"; the first scan or two are always way too light and washed out. Is
> this typical of CCDs of this vintage? I remember seeing this same
> behavior with some low-res cameras my company used to use on a CD
> printing system we made, to take snapshots of CDs in the printer tray;
> our software took two or three shots, threw them away and then took one
> for real.
>
>
> --
> Comment on quaint Usenet customs, from Usenet:
>
> To me, the *plonk...* reminds me of the old man at the public hearing
> who stands to make his point, then removes his hearing aid as a sign
> that he is not going to hear any rebuttals.

I would firstly try 3 test scans with a piece of paper, as normal, stuck
under the doc glass and placed over a piece of glass over the doc glass, to
see if there is a focussing difference

==============================================================================
TOPIC: Tapco Juice J 2500 slave amp, 2007
http://groups.google.com/group/sci.electronics.repair/t/185ab3fdb182c05a?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 3 2011 2:25 am
From: "N_Cook"

How do American repairers get on with PbF boards, not marked as PbF. Is
there an overlay codification meaning PbF or LF ? Has anyone collated
together what USA makers + models for what 21C years definitely had PbF or
definitely had leaded solder? Or putting it another way , what is the
probability of any China manufacturer using leaded solder in 2001/ .../2007/
... ?
This amp made in China in 2007, for USA, exported to UK. Balance of
probabilities from appearance, indentation test etc is probably PbF.
Yet again faced with repairing a "fully working" but intermittant failure
PbF amp
However much tugging and twisting on input and output and pot boards cannot
get either channel to fail, as user contact there, most likely failure
areas. Closely inspecting all boards - no bad-contact solder found. So far
powering to 75 percent mains, noting some mid-amp signal AC and DCs , as
nothing useful out there on this amp. Before upping the mains (may of course
cause a protect failure in one ch from that) . And before seriously
attacking the main amps with engraver tool and nylon bolt as tip ,
monitoring large dummy loads with attenuated phones, to try and make a
failure.

==============================================================================
TOPIC: Canon A420 camera
http://groups.google.com/group/sci.electronics.repair/t/11a9e31849085804?hl=en
==============================================================================

== 1 of 4 ==
Date: Mon, Jan 3 2011 3:28 am
From: adrian@poppyrecords.invalid.invalid (Adrian Tuddenham)

who where <noone@home.net> wrote:

> On Sun, 2 Jan 2011 22:33:02 +0000, adrian@poppyrecords.invalid.invalid
> (Adrian Tuddenham) wrote:
>
> >John Keiser <john.keiser2@hawaiiantel.net> wrote:
> >
> >> Is this in all modes - Auto, Program, etc?
> >
> >It seems to be.
> >
> >Even using it with the manual exposure at its darkest setting gives
> >over-exposure and a coarse 'raster' effect.
>
> Possibly the sudden freeing up of the mode switch is the clue. It may
> be "detached" and stuck in an inappropriate mode.

It seems to switch between modes normally, so at least one section of
the switch is working - but I agree it does seem the first place to
look.

I have found two other references on the Web from people who have
experienced the same fault - but neither of them appeared to have found
a solution.

> Basically with the cost of these device dropping continuously you will
> find - as we have - that repair is not a cost-effective alternative to
> replacement. That said, you have littlle to lose by disassembling it
> (not trivial) and exploring the internals with special attention to
> the mode switch.

That's going to be my first plan of action. I notice there is a camera
repair shop in London which claims to do economically-priced repairs on
this model.

My problem with buying a new camera is that I may not be able to get a
suitable card reader which works with my current Mac OS 8.6 system - and
I cannot change the OS because all my business software runs on it.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

== 2 of 4 ==
Date: Mon, Jan 3 2011 5:49 am
From: "Geoffrey S. Mendelson"

Adrian Tuddenham wrote:
> My problem with buying a new camera is that I may not be able to get a
> suitable card reader which works with my current Mac OS 8.6 system - and
> I cannot change the OS because all my business software runs on it.

Can you be more specific? That would place it as a late Power Mac, or an early
G3.

This is going to become more and more of a problem, as your 10 year old plus
computer starts to fail and parts are no longer available. Besides keeping
lots of backups, you should investigate either alternate hardware or spares.

I was given a beige G3 the other day, cleaned it up and gave it to a friend
who uses one for his daily writing. His is starting to fail and now he has a
"hot spare". The cost was zero to him, and the owner was glad to see it not
end up in the recycle bin.

Cost of full refurbishement, which I did not do, would have been a $10
battery, and a new(er) floppy drive. Most just need to be taken apart, cleaned
and lubricated, but this one has an electrical problem too, so I would have
to get one from another less functional computer.

I do this as a "good deed" and I'm sure you could find someone who would be
able to help you in your area.

Note that there is a program called SheepShaver that will run on a modern
Mac and let you boot MacOS in a "virtual machine". You can boot your OS 8.6
under it and run your software.

While you are asking around for spares, you may want to ask about that too.

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
Those who cannot remember the past are condemned to misquote it.

== 3 of 4 ==
Date: Mon, Jan 3 2011 7:30 am
From: adrian@poppyrecords.invalid.invalid (Adrian Tuddenham)

Geoffrey S. Mendelson <gsm@mendelson.com> wrote:

> Adrian Tuddenham wrote:
> > My problem with buying a new camera is that I may not be able to get a
> > suitable card reader which works with my current Mac OS 8.6 system - and
> > I cannot change the OS because all my business software runs on it.
>
> Can you be more specific? That would place it as a late Power Mac, or an early
> G3.

The system runs on a collection of beige G3s linked by Appletalk. The
main business workhorse is ClarisWorks 4.

> This is going to become more and more of a problem, as your 10 year old plus
> computer starts to fail and parts are no longer available. Besides keeping
> lots of backups, you should investigate either alternate hardware or spares.

I have a shed full of spares and a lot of backup drives.

> Cost of full refurbishement, which I did not do, would have been a $10
> battery, and a new(er) floppy drive.

You can use a stack of much cheaper coin cells if you machine up a brass
slug to fill the remaining space in the battery holder. These G3s have
ATA drives as well as the original SCSI ones. so replacements are no
problem.

> Note that there is a program called SheepShaver that will run on a modern
> Mac and let you boot MacOS in a "virtual machine". You can boot your OS 8.6
> under it and run your software.

I do have an Intel iMac which would take Sheepshaver, but I have been
told it still wouldn't allow me too use Pub&Sub, which is what links all
my sales software together. No only that, but the iMac won't work on an
Appletalk network, in the past I have had to transfer files to it using
FTP. It sits in a corner, switched off and effectively useless, while
the G3s do most of the work.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

== 4 of 4 ==
Date: Mon, Jan 3 2011 7:33 am
From: adrian@poppyrecords.invalid.invalid (Adrian Tuddenham)

Phil Allison <phil_a@tpg.com.au> wrote:

> "Adrian Tuddenham"
>
> >
> > I have re-set the camera by removing both power and memory batteriea,
>
>
> ** The camera has no memory battery.

This one does, it is a 1220 coin cell in a little plastic clip at the
opposite end from the main battery door.

> > Any other suggestions?
>
>
> ** Try resetting the camera to all defaults.

Tried it - no difference.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

==============================================================================
TOPIC: Where to find (affordable) Oven Set Control G.E.
http://groups.google.com/group/sci.electronics.repair/t/1cb36c021a0afb59?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 3 2011 3:35 am
From: "Arfa Daily"

"Vacillator" <user132384@aol.com> wrote in message
news:0ae25a1a-63e6-43cb-b094-00512e8e2364@l8g2000yqh.googlegroups.com...
>
>>
>> The wonders of modern technology!
>>
>> You haven't indicated what type of "control" it is
>> (pot, optical encoder, rotary switch, etc.) -- hard
>> to guess for someone not owning a similar oven!
>>
>> Also, are you sure the problem is in the "knob"
>> and not in some bit of electronics that the knob
>> "talks to"?
>>
>> E.g., if it wwas *my* oven, I would try swapping
>> the connections for that "knob" with those of
>> a similar knob and see if the problem "moves"
>> with the knob or stays in place regardless of
>> the change. Likewise, follow it back into the
>> bowels of the oven and swap things *there*
>> (i.e., the controls for the actual heating elements)
>> until you have positively isolated the source
>> of the problem. Else you are likely to spend
>> all that cash on the wrong part...
>
> Thanks. The switch is a rotary mechanical switch. There isn't any
> similar knob (switch behind the knob, actually) available on my stove.
> I need to buy one and try it out. It's acting like the connections are
> dirty or worn or both. Rotating the knob 360 degrees fixed the problem
> last night. But eventually I will have to replace it, I think. May end
> up ordering a used switch from eBay and hoping I get a good one.
> Apparently they can be had fo about $16 plus shipping. Thanks to
> other poster for that info.
>
> Thanks again.

I had the exact same problem on a cooker of mine here in the UK, which was
used every day to cook shedloads of bacon for one of my wife's cafes. The
switch was readily available at a reasonable price, but was going to take a
week to order in from the manufacturer's spares agent, so in the meantime, I
took the faulty one out (very easily removed with two screws through the
front panel, and pull-off spade tags.) Once removed, it was easy to see the
switch elements. These were simply heavy duty 'leaf' types with tungsten or
similar contact inserts in their ends - much as you might see on a heavy
duty relay. They were operated by individual cams moulded onto the shaft
that ran through the whole switch. There was a contact set for the oven
light, another for the fan, another for the oven element, and another for
the grill element. As expected, the contact set for the grill, was in less
than 'perfect' condition. I guess this is caused by whacking the temperature
knob up first, and then engaging the grill switch, causing it to 'hot
switch' the element, resulting in contact arcing. Much better to set the
function first, then turn up the grill 'stat, as the contacts on that, are
designed to hot switch. Anyways, the contact set was easily removed from the
switch body, which then made resurfacing the contacts with a piece of very
fine wet n dry paper, a doddle. Once the switch was reassembled, and
refitted to the cooker, it worked absolutely fine - and continues to do so
some six or more months later. The new switch duly arrived, but is currently
sitting in a drawer in my workshop as a spare. I see little point in fitting
it at this time, whilst the original switch continues to give normal
service.

I'm not sure that I understand why anyone would have a problem with cleaning
a set of contacts such as these. I have done it all my (long) working life
on everything from high power contactors to medium power switches and relays
, and it has never caused any problem. Obviously, it's not something that
can be done to restore switches with plated contacts, but that is not what
is generally employed in these types of power switching applications.

Arfa

==============================================================================
TOPIC: CD optical block shorting links
http://groups.google.com/group/sci.electronics.repair/t/c6b70c559f40bbab?hl=en
==============================================================================

== 1 of 3 ==
Date: Mon, Jan 3 2011 3:48 am
From: "Arfa Daily"

"Samuel M. Goldwasser" <sam@repairfaq.org> wrote in message
news:uzkrw6uvb.fsf@repairfaq.org...
> "N_Cook" <diverse@tcp.co.uk> writes:
>
>> Samuel M. Goldwasser <sam@repairfaq.org> wrote in message
>> news:uei994ivz.fsf@repairfaq.org...
>> > "N_Cook" <diverse@tcp.co.uk> writes:
>> >
>> > > First time for years (no salvaged one on hand) I replaced old with
>> > > new
>> but
>> > > had forgotten about those antistatic shorting links, wasting time
>> > > trying
>> to
>> > > find the short. Nothing on the box about the shorting link, only
>> > > graphic
>> > > showing use antistatic wrist strap for assembly
>> > > Do they all have these solder-across semicircle land pairs?
>> > > This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
>> > > Is there something in the laser assembly that is especially prone to
>> static
>> > > damage?
>> >
>> > Yes, the laser diode. There's generally very little circuitry between
>> > the
>> > cable and laser diode and it can be damaged by any number of things
>> including
>> > ESD.
>> >
>> > --
>> > sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
>>
>> But is a CD laser diode any more susceptible to ESD damage than a bulk
>> standard red LED or a 1N4148 say, in otherwise the same poor handling
>> circumstances?
>
> YES! A 1 ns current spike with a peak just above the laser diode's
> maximum
> rating can destroy it. Accidentally connecting a charged 0.01 uF 5 V cap
> across a laser diode will destroy it. Etc., etc. Look at it the wrong
> way.....
>
> --
> sam

All absolutely agreed. However, to answer one of Mr Cook's earlier
questions, given that they do have this extreme static sensitivity,
curiously, the answer is no - not all replacement optical blocks *do* have
the laser diode shorted for transit. As well as shorting blobs on the pcb,
other methods of shorting that may be found are a thin metal plate in the
ZIF connector that some have, and a tiny switch that I have seen fitted to
some DVD optical blocks. And of course the solder blobs on the flexiprint
tail rather than on the board, and the 'snip-off' piece of flexiprint (two
varieties) to be found on some Panasonic lasers.

Arfa

== 2 of 3 ==
Date: Mon, Jan 3 2011 4:57 am
From: "Mark Zacharias"

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:5IiUo.37568$E44.36579@newsfe30.ams2...
>
>
> "Samuel M. Goldwasser" <sam@repairfaq.org> wrote in message
> news:uzkrw6uvb.fsf@repairfaq.org...
>> "N_Cook" <diverse@tcp.co.uk> writes:
>>
>>> Samuel M. Goldwasser <sam@repairfaq.org> wrote in message
>>> news:uei994ivz.fsf@repairfaq.org...
>>> > "N_Cook" <diverse@tcp.co.uk> writes:
>>> >
>>> > > First time for years (no salvaged one on hand) I replaced old with
>>> > > new
>>> but
>>> > > had forgotten about those antistatic shorting links, wasting time
>>> > > trying
>>> to
>>> > > find the short. Nothing on the box about the shorting link, only
>>> > > graphic
>>> > > showing use antistatic wrist strap for assembly
>>> > > Do they all have these solder-across semicircle land pairs?
>>> > > This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
>>> > > Is there something in the laser assembly that is especially prone to
>>> static
>>> > > damage?
>>> >
>>> > Yes, the laser diode. There's generally very little circuitry between
>>> > the
>>> > cable and laser diode and it can be damaged by any number of things
>>> including
>>> > ESD.
>>> >
>>> > --
>>> > sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
>>>
>>> But is a CD laser diode any more susceptible to ESD damage than a bulk
>>> standard red LED or a 1N4148 say, in otherwise the same poor handling
>>> circumstances?
>>
>> YES! A 1 ns current spike with a peak just above the laser diode's
>> maximum
>> rating can destroy it. Accidentally connecting a charged 0.01 uF 5 V cap
>> across a laser diode will destroy it. Etc., etc. Look at it the wrong
>> way.....
>>
>> --
>> sam
>
> All absolutely agreed. However, to answer one of Mr Cook's earlier
> questions, given that they do have this extreme static sensitivity,
> curiously, the answer is no - not all replacement optical blocks *do* have
> the laser diode shorted for transit. As well as shorting blobs on the pcb,
> other methods of shorting that may be found are a thin metal plate in the
> ZIF connector that some have, and a tiny switch that I have seen fitted to
> some DVD optical blocks. And of course the solder blobs on the flexiprint
> tail rather than on the board, and the 'snip-off' piece of flexiprint (two
> varieties) to be found on some Panasonic lasers.
>
> Arfa

And some models like the KSS-240 have the power limiting circuit built in;
no shorting required.

Mark Z.

== 3 of 3 ==
Date: Mon, Jan 3 2011 5:09 am
From: "Arfa Daily"

"Mark Zacharias" <mark_zacharias@sbcglobal.net> wrote in message
news:4d21c7a5$0$13466$c3e8da3$38634283@news.astraweb.com...
> "Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
> news:5IiUo.37568$E44.36579@newsfe30.ams2...
>>
>>
>> "Samuel M. Goldwasser" <sam@repairfaq.org> wrote in message
>> news:uzkrw6uvb.fsf@repairfaq.org...
>>> "N_Cook" <diverse@tcp.co.uk> writes:
>>>
>>>> Samuel M. Goldwasser <sam@repairfaq.org> wrote in message
>>>> news:uei994ivz.fsf@repairfaq.org...
>>>> > "N_Cook" <diverse@tcp.co.uk> writes:
>>>> >
>>>> > > First time for years (no salvaged one on hand) I replaced old with
>>>> > > new
>>>> but
>>>> > > had forgotten about those antistatic shorting links, wasting time
>>>> > > trying
>>>> to
>>>> > > find the short. Nothing on the box about the shorting link, only
>>>> > > graphic
>>>> > > showing use antistatic wrist strap for assembly
>>>> > > Do they all have these solder-across semicircle land pairs?
>>>> > > This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
>>>> > > Is there something in the laser assembly that is especially prone
>>>> > > to
>>>> static
>>>> > > damage?
>>>> >
>>>> > Yes, the laser diode. There's generally very little circuitry
>>>> > between the
>>>> > cable and laser diode and it can be damaged by any number of things
>>>> including
>>>> > ESD.
>>>> >
>>>> > --
>>>> > sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
>>>>
>>>> But is a CD laser diode any more susceptible to ESD damage than a bulk
>>>> standard red LED or a 1N4148 say, in otherwise the same poor handling
>>>> circumstances?
>>>
>>> YES! A 1 ns current spike with a peak just above the laser diode's
>>> maximum
>>> rating can destroy it. Accidentally connecting a charged 0.01 uF 5 V
>>> cap
>>> across a laser diode will destroy it. Etc., etc. Look at it the wrong
>>> way.....
>>>
>>> --
>>> sam
>>
>> All absolutely agreed. However, to answer one of Mr Cook's earlier
>> questions, given that they do have this extreme static sensitivity,
>> curiously, the answer is no - not all replacement optical blocks *do*
>> have the laser diode shorted for transit. As well as shorting blobs on
>> the pcb, other methods of shorting that may be found are a thin metal
>> plate in the ZIF connector that some have, and a tiny switch that I have
>> seen fitted to some DVD optical blocks. And of course the solder blobs on
>> the flexiprint tail rather than on the board, and the 'snip-off' piece of
>> flexiprint (two varieties) to be found on some Panasonic lasers.
>>
>> Arfa
>
>
> And some models like the KSS-240 have the power limiting circuit built in;
> no shorting required.
>
> Mark Z.

Yes indeed. And talking of 240's, have you had problems with some players
which use one - particularly Sonys themselves - just not liking the generic
replacements, and suffering all sorts of playability problems after
replacement ? Whenever I had a Sony in that needed a 240, I always used to
quote for a genuine original part ordered from Sony, but it seems that they
are now no longer available from them. I have just picked one up for repair
from one of my feeder shops, and he has asked me to try a stock 240 in it,
but based on experience, I'm pretty sure that it's not going to provide
acceptable performance. I wonder why this should be, given that there
doesn't seem to be a problem with generic replacements in any other Sony
models, or problems using a generic 240 in any non-Sony players ?

Arfa

==============================================================================
TOPIC: RCA VCR VR651HF Loading Motor Source
http://groups.google.com/group/sci.electronics.repair/t/bb7ed9b3e718935b?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 3 2011 4:43 am
From: Whome

I have those motors in stock for 9.75 plus shippinhg

On Fri, 10 Sep 2010 07:35:13 -0400, jaugustine@verizon.net wrote:

>Hi,
>
> RCA VCR model VR651HF
>
> I am looking for a source to order a loading motor (front loader).
>My RCA parts sources told me this motor is "no longer available".
>Note: I don't have SM, therefore I don't have the RCA part number.
>
> I found one site on the web that claims to have it, but there is
>a $300.00 minimum order.
>
> Here are numbers on the motor:
>
> MDH2B
> 62YK1418A
>
> Thank You in Advance, John
>
>PS, Remove "ine" from my email address
>

==============================================================================
TOPIC: UPS battery life
http://groups.google.com/group/sci.electronics.repair/t/b73fd839ce17fb50?hl=en
==============================================================================

== 1 of 4 ==
Date: Mon, Jan 3 2011 5:49 am
From: PeterD

On Sun, 02 Jan 2011 18:23:31 -0500, "(PeteCresswell)" <x@y.Invalid>
wrote:

>Per nesesu:
>>At work we had a very large UPS that used 600V of gel-cell 12V
>>batteries each about the size of a largish car battery. In the 15
>>years or so that it was in use, there were, perhaps, 5 power failures
>>and the UPS failed every time even though all the routine maintenance
>>and testing was observed. Other than the first time when it was only a
>>month or so old and the inverter blew up [linerally] all the rest of
>>the failures were due to battery failure.
>
>This begs a question that's been bugging me for years: why
>doesn't somebody make a UPS that hooks up to a 12-v non-vented
>automobile battery?
>
>Automobile batteries are available at many different
>price/quality points, they're pretty much a universal standard,
>the capacity is there in spades, public knowledge about
>maintaining/replacing them is widespread, and push-comes-to-shove
>in an extended outage, the battery in somebody's car can be
>swapped in for a few more hours working time.
>
>I guess there has tb a reason... but what?

Automotive batteries are not well suited to long, continous drains
that the UPS would require. Using a deep cycle battery (such as a
trolling battery, or an RV battery, would work, but not optimal.)

== 2 of 4 ==
Date: Mon, Jan 3 2011 6:22 am
From: "(PeteCresswell)"

Per PeterD:
>Automotive batteries are not well suited to long, continous drains
>that the UPS would require. Using a deep cycle battery (such as a
>trolling battery, or an RV battery, would work, but not optimal.)

Is that to say with the first power outage and running the
battery to near-exhaustion (assuming there is a means to control
how far down it goes) that the battery would be damaged?
--
PeteCresswell

== 3 of 4 ==
Date: Mon, Jan 3 2011 6:40 am
From: Jeffrey Angus

On 1/3/2011 8:22 AM, (PeteCresswell) wrote:
> Per PeterD:
>> Automotive batteries are not well suited to long, continous drains
>> that the UPS would require. Using a deep cycle battery (such as a
>> trolling battery, or an RV battery, would work, but not optimal.)
>
> Is that to say with the first power outage and running the
> battery to near-exhaustion (assuming there is a means to control
> how far down it goes) that the battery would be damaged?

In a word, possibly.

The construction of the plates in automotive vs marine (RV)
batteries are different. The Automotive battery is designed
to deliver large amount so f current for short periods of
time.

The marine batteries are designed to for a long term steady
and considerably lower) current draw.

Jeff

== 4 of 4 ==
Date: Mon, Jan 3 2011 8:19 am
From: "Michael A. Terrell"

Jeffrey Angus wrote:
>
> On 1/3/2011 8:22 AM, (PeteCresswell) wrote:
> > Per PeterD:
> >> Automotive batteries are not well suited to long, continous drains
> >> that the UPS would require. Using a deep cycle battery (such as a
> >> trolling battery, or an RV battery, would work, but not optimal.)
> >
> > Is that to say with the first power outage and running the
> > battery to near-exhaustion (assuming there is a means to control
> > how far down it goes) that the battery would be damaged?
>
> In a word, possibly.
>
> The construction of the plates in automotive vs marine (RV)
> batteries are different. The Automotive battery is designed
> to deliver large amount so f current for short periods of
> time.
>
> The marine batteries are designed to for a long term steady
> and considerably lower) current draw.

The 12V batteries made for CATV UPS duty are made for high current
and deep cycle loads.

--
For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!

==============================================================================
TOPIC: SMD 1 percent resistor markings - aide memoire?
http://groups.google.com/group/sci.electronics.repair/t/c52c0c1e4db26587?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 3 2011 6:49 am
From: "N_Cook"

Confronted by resistor marking 75B translates as 5K9, anyone have an
approximate ie 10 percent conversion technique?
to avoid table lookup, eg
http://talkingelectronics.com/projects/ResistorsMadeEasy/SMD-Resistors-EIA-M
arkings.html

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

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