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: how hot should a schottky get?
http://groups.google.com/group/sci.electronics.repair/t/c666fc4f127ae347?hl=en
==============================================================================

== 1 of 2 ==
Date: Thurs, Nov 3 2011 6:50 pm
From: "hrhofmann@att.net"

On Nov 3, 7:40 pm, b <reverend_rog...@yahoo.com> wrote:
> On Nov 3, 8:15 pm, spamtrap1888 <spamtrap1...@gmail.com> wrote:
>
>
>
> > Absolute maximum current is 3A, at a forward drop of 0.5 V, so max
> > power dissipation is 1.5W. The typical thermal resistance is 20C/W, so
> > the max temperature rise should be 30 C. Can you keep your finger on a
> > 55C temp surface?
>
> Thanks for the suggestions guys.
> left it on for a few more hours, and the temp. didn't seem to get out
> of hand. Above calculations noted, many thanks.
> I suspect this is just a poor design, the psu is a tiny crappy circuit
> board, no regulators in sight just crude diodes and caps. Lots of pcb
> area was scorched as things obviously ran hot/at the limits of their
> tolerances from the word go.
>
> Will do some more exhaustive soaktesting and if things deteriorate,
> will check the voltage drop and current as sugested. For now I've just
> got it off the bench for more pressing things.
> regards, B.

If you have any sort of a spare heatsink, it wouldn't hurt ot use it,
might help and can't hurt.

== 2 of 2 ==
Date: Fri, Nov 4 2011 11:30 am
From: Robert Macy

On Nov 3, 5:40 pm, b <reverend_rog...@yahoo.com> wrote:
> On Nov 3, 8:15 pm, spamtrap1888 <spamtrap1...@gmail.com> wrote:
>
>
>
> > Absolute maximum current is 3A, at a forward drop of 0.5 V, so max
> > power dissipation is 1.5W. The typical thermal resistance is 20C/W, so
> > the max temperature rise should be 30 C. Can you keep your finger on a
> > 55C temp surface?
>
> Thanks for the suggestions guys.
> left it on for a few more hours, and the temp. didn't seem to get out
> of hand. Above calculations noted, many thanks.
> I suspect this is just a poor design, the psu is a tiny crappy circuit
> board, no regulators in sight just crude diodes and caps. Lots of pcb
> area was scorched as things obviously ran hot/at the limits of their
> tolerances from the word go.
>
> Will do some more exhaustive soaktesting and if things deteriorate,
> will check the voltage drop and current as sugested. For now I've just
> got it off the bench for more pressing things.
> regards, B.

For every 10 C rise in operating temperature the MTBF for a component
goes to one half, lasts on the average half as long. So, cooler IS
better.

Most of the heat goes out the legs, some out the body.Remember in
convection air te rule of thumb is 1 C rise per watt per 100 square
inches

==============================================================================
TOPIC: Identify make and model of LCD display ?
http://groups.google.com/group/sci.electronics.repair/t/55ef97f8ec432fa5?hl=en
==============================================================================

== 1 of 2 ==
Date: Fri, Nov 4 2011 4:22 am
From: "N_Cook"

12 inch diagonal, 12V dc supply as used here but may originally have had a
ps.
CVBS video input
made 2005 to 2009
Build into an expensive bit of specialised commercial kit and the original
outer case of the display absent.
Main pcb overlay marked "Sharp8 pcb"
main chippery Techwell TW9903
STK6-F3L
LM2576S
STK6005BQPP

== 2 of 2 ==
Date: Fri, Nov 4 2011 4:48 am
From: "N_Cook"

may well be Pyle PLVW ???? and rebadges
like this, just the display section of
http://cf.mp-cdn.net/91/20/a8d68e6ddec4c5c6e23fa9e7d1f1.jpg
flip-down type going by the remnant chassis metal work and shape of control
buttons.
No schema available presumably

==============================================================================
TOPIC: Any TV experts here? Maybe an aerial specialist too.
http://groups.google.com/group/sci.electronics.repair/t/ad793e4d0dda11c6?hl=en
==============================================================================

== 1 of 2 ==
Date: Fri, Nov 4 2011 7:33 am
From: ~BD~ <~BD~@nomail.afraid.org>

Arfa Daily wrote:
> <snip>
>
>>
>> All your comments are most helpful, Thank you so much for taking the
>> time and trouble to advise me.
>>
>> Have a great day! :-)
>>
>> Thanks again, 'Arfa' (great nym!)
>
> Interestingly, a friend rang me this morning, to say that he was at the
> house of a work colleague, and he was having a similar problem to you
> with a Sammy 32". It actually kept reporting "Weak Signal" on the
> screen, apparently.
>
> I suggested that he did a complete 'new install' retune, to see what
> happened. he rang back a couple of hours later to say that it was all
> now sorted and working fine with quote "hundreds of channels". The only
> problem that he had was that he reckons that he could not find a new
> install option in the tuning sub-menu, so he did a bit of thinking
> outside the box, and selected a 'wrong' country setting, and then asked
> it to do a retune. This, he claims, caused it to find nothing, which
> cleared out the tuning memory, so that when he set it back to "UK" and
> repeated the procedure, it found all the correct multiplexes for where
> the antenna was pointing.
>
> I was a bit sceptical about there not being a total reset option buried
> somewhere 3 or 4 menu levels down, but whatever. His method did the job,
> even if it was a bit around the houses ...

With nothing to lose, I tried that. I got great ITV pictures and no BBC!

So - I reset to factory condition and then retuned.

Right now I've got good pictures on *all* channels! <rolls eyes>

There's *nothing* worse than an intermittent fault! Grrrr!

> OK on the nic. It is of course my tongue-in-cheek tribute to the great
> George Cole, and one of my favourite characters of his, Arthur Daley
>
> Arfa

Gottcha! 8-)

== 2 of 2 ==
Date: Fri, Nov 4 2011 8:14 am
From: amdx

On 10/31/2011 9:41 PM, bill wrote:
> On 10/31/2011 3:21 PM, ~BD~ wrote:
>> Any TV experts here?
>>
>> I'll post my question if there are!
>>
>> This TV: Sony Bravia KDL 32EX503U
>
> I got quite good on repairing Philco 16 inch, black,and white, TVs back
> in 1950s
>
> Bill K7NOM

Nowadays, aren't most TV's a computer driven monitor.
Mikek :-)

==============================================================================
TOPIC: Store that sells ceiling fan capacitors?
http://groups.google.com/group/sci.electronics.repair/t/4792acac41b3eaae?hl=en
==============================================================================

== 1 of 1 ==
Date: Fri, Nov 4 2011 8:20 am
From: amdx

> But the usual suspects don't seem to carry them. Not appliance part
> stores or electrical supply stores. I couldn't find them listed at
> Home Desperate or Louse. There were only a couple of online ceiling-
> fan-part-only outfits, which I try to avoid: I like to show the
> counter guy what I need, have him give it to me, pay, go home, and
> replace.
>
> Any ideas? If I must buy online I must, but I would really rather not

I don't see the part listed a Lowes.com, but I have bought one there
before.
Mikek

==============================================================================
TOPIC: Toshiba D-R160 DVD recorder, 2009
http://groups.google.com/group/sci.electronics.repair/t/5ef69f3de1c23bd1?hl=en
==============================================================================

== 1 of 2 ==
Date: Fri, Nov 4 2011 8:28 am
From: "Arfa Daily"

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:j8trfi$faj$1@dont-email.me...
> Probably a generic DVD mechanics question.
> One motor for sledge , optical deck up/down and drawer open/close.
> Transported by courier and would not accept DVD when received at the other
> end - box must have been jarred. Try pushing the drawer in and it knocks
> the
> spinner motor assembly which is in the up / play position. The repair
> manual
> only says replace the DVD unit in this situation. Removed this sub-unit,
> N78E3CBN no info found. Delatched the drawer and removed , turned cogs and
> Z
> track etc until only the drawer motion cog moved with no movement of
> sledge
> or Z-rack and reintroduced the tray and optical unit in eject position. Is
> this a standard approach to this symptom for direct coupled ie no drive
> bands? Seems to work now - but just temporary or fixed proper for normal
> use? No cracked /broken cogs/racks or free-floating pieces found.
> The drawer seems very flimsey, I assume it flexed and a guide peg got on
> the
> wrong side of a rail. Common problem? with a recognised correction of
> beefing up somehow?
>
>

Generally speaking, there's no 'magic' involved. In my experience, if you
are not familiar with the manufacturer's recommended starting positions for
the gears and deck, then the method that you adopted is as good a starting
point as any. As a general rule of thumb, if it closes and opens without
catching or graunching on anything when you've finished, then you have the
timing correct. Incidentally, your 'spinner motor' is more correctly known
as the spindle motor, and the little platter on the top, as the turntable.

Arfa

== 2 of 2 ==
Date: Fri, Nov 4 2011 9:16 am
From: "N_Cook"

Arfa Daily <arfa.daily@ntlworld.com> wrote in message
news:FwTsq.13089$z92.4370@newsfe07.ams2...
>
>
> "N_Cook" <diverse@tcp.co.uk> wrote in message
> news:j8trfi$faj$1@dont-email.me...
> > Probably a generic DVD mechanics question.
> > One motor for sledge , optical deck up/down and drawer open/close.
> > Transported by courier and would not accept DVD when received at the
other
> > end - box must have been jarred. Try pushing the drawer in and it knocks
> > the
> > spinner motor assembly which is in the up / play position. The repair
> > manual
> > only says replace the DVD unit in this situation. Removed this sub-unit,
> > N78E3CBN no info found. Delatched the drawer and removed , turned cogs
and
> > Z
> > track etc until only the drawer motion cog moved with no movement of
> > sledge
> > or Z-rack and reintroduced the tray and optical unit in eject position.
Is
> > this a standard approach to this symptom for direct coupled ie no drive
> > bands? Seems to work now - but just temporary or fixed proper for normal
> > use? No cracked /broken cogs/racks or free-floating pieces found.
> > The drawer seems very flimsey, I assume it flexed and a guide peg got on
> > the
> > wrong side of a rail. Common problem? with a recognised correction of
> > beefing up somehow?
> >
> >
>
> Generally speaking, there's no 'magic' involved. In my experience, if you
> are not familiar with the manufacturer's recommended starting positions
for
> the gears and deck, then the method that you adopted is as good a starting
> point as any. As a general rule of thumb, if it closes and opens without
> catching or graunching on anything when you've finished, then you have the
> timing correct. Incidentally, your 'spinner motor' is more correctly known
> as the spindle motor, and the little platter on the top, as the turntable.
>
> Arfa
>

This looked more like a button rather than motor and platter, it was so
tiny.
At one time with CD decks there were transit screws like vinyl decks. Did
some change do away with that requirement for CD and presumably DVD decks.
Was it just a change of suspension? originally great floppy springy things
and then somone realised you only needed to stop audio feedback, so in came
little soft grommet like things .

==============================================================================
TOPIC: Good sound; intermittent picture.
http://groups.google.com/group/sci.electronics.repair/t/45ba5bddf76a0064?hl=en
==============================================================================

== 1 of 2 ==
Date: Fri, Nov 4 2011 9:59 am
From: micky

On Fri, 04 Nov 2011 11:26:48 +1100, Sylvia Else
<sylvia@not.here.invalid> wrote:

>On 3/11/2011 3:49 PM, micky wrote:
>> On Tue, 01 Nov 2011 18:59:27 +1100, Sylvia Else
>> <sylvia@not.here.invalid> wrote:
>>
>>> On 1/11/2011 5:54 PM, micky wrote:
>>>> Can a tv input signal connection at the input coax connector affect
>>>> only the picture and not the sound??
>>>>
>>>>
>>>> I have a 25" Sharp TV, CRT, that often loses its picture, but never
>>>> the sound. (Other than that, the picture and sound are very good.
>>>> It's analog and I only use channel 3 and a separate tuner.)
>>>
>>> If by "loses its picture" you mean that the picture abruptly and
>>> completely dissappears, with no effect at all on the sound, I'd say "no".
>>
>> Boy, am I stupid. Ifnore my first answer. I thought you described
>> the problem here. I thought that was the problem when I first posted.
>>
>> But in reality, maybe the picture is still there. It's just so dark
>> often nothing can be seen but little blue and red hyphen-shapped
>> lights blinking on for an est. 20th of a second, and then bliniking
>> on somewhere else around the screen. Hundreds of them at any one time.
>>
>> At the same time, when closed captioning is on, it looks perfect,
>> white and bright and the letters fully formed.
> >
>
>You said the previous owner of the television was seeing the same
>behaviour. Did he also have what is now your DVDR unit connected?

My own exact DVDR? No. He was a stranger who gave the TV to me via
Freecycle. He just said the picture went out peroiodically and he
got it back by moving the cable that went into the TV.

>It's not clear what role the DVDR unit is playing here. If it's tuning
>an analogue channel,

I have no analogue channels, just over the air channels.

>and just frequency shifting it, then the closed
>captioning would have to be generated by the TV. In that case, there is
>clearly a fault somewhere in the between the TV's own tuner, and where
>the closed captioning gets superimposed on the picture.
>
>On the other hand, if the DVDR unit is tuning a digital channel, and
>providing an analogue output, complete with closed captioning, then it's
>hard to see that there can be anything wrong with the TV at all, with
>the problem lying in the DVDR unit, which is, after all, connected to
>the other end of the coax that you waggle.

Yeah, but I have 3 other TVs I watch daily that never have problems

The bad one is in the basement, the good ones in the bedroom, the
bathroom, and the kitchen. The DVDR is in the bedroom.and the
bedroom tv gets the signal first. Then the basement TV with the
problem, after after that the signal goes to the kitchen TV which has
no problems.

(There's an amplified splitter that sends the signal to the bathroom
and the bedroom/office, but the computer is broken so I spend a lot of
time in the basement trying to fix it and using a basement computer)

>
>> Not tonight, but I recall that sometimes the picture can almost be
>> seen, like it is night time, with most of it black and maybe part,
>> maybe the background, very very dark blue or very very dark red,
>> barely one shade lighter than black. I guess when the real color
>> isn't blue or red, it just looks like black.
>
>That really sounds to me as if the DVDR unit is just frequency shifting
>an analogue channel, and that there's a faulty connection or dry joint
>in the video signal path in the TV - a small amount of the signal gets
>through by the capacitance of the failed connection.

What I can do to test this is try to watch a movie on the VCR, which
sits next to the DVDR and is connected in parallel by an A-B switch.

I also have a digital conversion set-top box feeding the VCR, so maybe
I'll just watch television via the box/VCR. I'll do that tonight.

>Sylvia.

Thanks a lot.

== 2 of 2 ==
Date: Fri, Nov 4 2011 10:03 am
From: micky

On Thu, 03 Nov 2011 10:53:34 -0700, PlainBill@yawhoo.com wrote:

>On Tue, 01 Nov 2011 02:54:51 -0400, micky <NONONOmisc07@bigfoot.com>
>wrote:
>
>>Can a tv input signal connection at the input coax connector affect
>>only the picture and not the sound??
>>
>>
>>I have a 25" Sharp TV, CRT, that often loses its picture, but never
>>the sound. (Other than that, the picture and sound are very good.
>>It's analog and I only use channel 3 and a separate tuner.)
>>
>>The picture can be restored by bending the co-ax TV input cable one
>>way or the other. Sometimes this lasts for days at a couple hours
>>each day. Other times it lasts for 10 seconds. I have a string
>>attached to the cable. Usually pulling the string, pulling it
>>tighter, or letting the string go makes the picture come back. I wrap
>>the string around a drawer knob on my workbench (beyond which is the
>>tv)., sort of like roping a calf and tying the lasso to the saddle
>>pommel. This is the closest I've gotten to being a cowboy.
>>
>>Is it possible that the problem is the co-ax input cable connector or
>>some part or connection near to that???? I don't see how a bad
>>connection that early on can interrupt the picture and have no effect
>>on the sound.
>>
>>Or is it just a locational coincidence, and the problem has to be
>>somewhere in the main circuity, after the sound and picture are
>>separate????
>>
>>Or in the high voltage? although I would think if it were the high
>>voltage, I would see the picture start out small, maybe as a pinpoint,
>>and enlarge when I pulled on the string and restored the picture.
>>Instead it just appears on the entire screen at once.
>>
>>Thanks for any help you can give.
>If I recall correctly, as the modulation gets stronger, the picture
>gets darker. Of course the tuner/IF system had AGC, which will try to
>maintain an adequate signal output as the strength of the input signal
>changes. And some sets were designed to blank the screen (or put up a
>blue screen) if the input signal was below adequate levels. However,
>I can't see any reason to believe that that is happening in this case.
>
>By far, the most likely situation is that there is a bad solder joint
>in the video processing area AFTER the audio subcarrier is extracted.
>Given the level of integration in modern TVs, the tuner and IF strip
>could be integrated into a single mackage. As such, it is unlikely
>that replacing the RF input would fix anything.
>
>By the deacription, it's unlikely it's the high voltage.
>
>There are a number of sources for schematics and even complete service
>manuals online. One of the better ones is Elektrotanya.com.

I noted each point you made, both exclusions and leads. . I didn't
knjw about Elektrotanya.

Thanks!
>
>PlainBill

==============================================================================
TOPIC: Anybody have a schematic for the SMPS for this laptop?
http://groups.google.com/group/sci.electronics.repair/t/e6610aea87e5a35c?hl=en
==============================================================================

== 1 of 8 ==
Date: Fri, Nov 4 2011 10:11 am
From: Robert Macy

Anybody have a schematic for this simple SMPS?

AC to DC Adapter for the IBM Thinkpad T22
16V 3.36A

On the unit itself is
Battery Technology, Inc.
IB-PS365
09000000106991

from that I found:
Battery Technology, Inc.
16500 East Gale Avenue
City of Industry, CA 91745-1712
Tel: 626-336-6878
Fax: 626-336-5657
http://www.batterytech.com

but, they don't answer their phone, nor does their website 'find' any
refrence to this model?!
the 800 number from their own website comes up disontinued.

Anybody have a schematic? Especially interested in the input section
= AC mains up to the rectifiers and fusing.

== 2 of 8 ==
Date: Fri, Nov 4 2011 11:05 am
From: mike

Robert Macy wrote:
> Anybody have a schematic for this simple SMPS?
>
> AC to DC Adapter for the IBM Thinkpad T22
> 16V 3.36A
>
> On the unit itself is
> Battery Technology, Inc.
> IB-PS365
> 09000000106991
>
> from that I found:
> Battery Technology, Inc.
> 16500 East Gale Avenue
> City of Industry, CA 91745-1712
> Tel: 626-336-6878
> Fax: 626-336-5657
> http://www.batterytech.com
>
> but, they don't answer their phone, nor does their website 'find' any
> refrence to this model?!
> the 800 number from their own website comes up disontinued.
>
> Anybody have a schematic? Especially interested in the input section
> = AC mains up to the rectifiers and fusing.

Don't have the schematic, but tracing out the input part from the board
oughta be trivial.
Anything particular you're trying to determine?

== 3 of 8 ==
Date: Fri, Nov 4 2011 11:24 am
From: Robert Macy

On Nov 4, 11:05 am, mike <spam...@gmail.com> wrote:
> Robert Macy wrote:
> > Anybody have a schematic for this simple SMPS?
>
> > AC to DC Adapter for the IBM Thinkpad T22
> > 16V 3.36A
>
> > On the unit itself is
> > Battery Technology, Inc.
> > IB-PS365
> > 09000000106991
>
> > from that I found:
> > Battery Technology, Inc.
> > 16500 East Gale Avenue
> > City of Industry, CA 91745-1712
> > Tel: 626-336-6878
> > Fax: 626-336-5657
> > http://www.batterytech.com
>
> > but, they don't answer their phone, nor does their website 'find' any
> > refrence to this model?!
> > the 800 number from their own website comes up disontinued.
>
> > Anybody have a schematic? Especially interested in the input section
> > = AC mains up to the rectifiers and fusing.
>
> Don't have the schematic, but tracing out the input part from the board
> oughta be trivial.
> Anything particular you're trying to determine?

pigtail fuse size [can't read without removing]

any potential parts that may have zapped when the liquid hit it while
powered.

== 4 of 8 ==
Date: Fri, Nov 4 2011 11:36 am
From: spamtrap1888

On Nov 4, 10:11 am, Robert Macy <robert.a.m...@gmail.com> wrote:
> Anybody have a schematic for this simple SMPS?
>
> AC to DC Adapter for the IBM Thinkpad T22
> 16V 3.36A

This is a "fat snake" right? Can these be repaired? I always thought
they were completely potted with epoxy. I've never seen one that was
screwed together.

== 5 of 8 ==
Date: Fri, Nov 4 2011 11:48 am
From: mike

Robert Macy wrote:
> On Nov 4, 11:05 am, mike <spam...@gmail.com> wrote:
>> Robert Macy wrote:
>>> Anybody have a schematic for this simple SMPS?
>>> AC to DC Adapter for the IBM Thinkpad T22
>>> 16V 3.36A
>>> On the unit itself is
>>> Battery Technology, Inc.
>>> IB-PS365
>>> 09000000106991
>>> from that I found:
>>> Battery Technology, Inc.
>>> 16500 East Gale Avenue
>>> City of Industry, CA 91745-1712
>>> Tel: 626-336-6878
>>> Fax: 626-336-5657
>>> http://www.batterytech.com
>>> but, they don't answer their phone, nor does their website 'find' any
>>> refrence to this model?!
>>> the 800 number from their own website comes up disontinued.
>>> Anybody have a schematic? Especially interested in the input section
>>> = AC mains up to the rectifiers and fusing.
>> Don't have the schematic, but tracing out the input part from the board
>> oughta be trivial.
>> Anything particular you're trying to determine?
>
> pigtail fuse size [can't read without removing]
>
> any potential parts that may have zapped when the liquid hit it while
> powered.

Every thinkpad supply I've seen has been free of vent holes. You'd have
to drop in a puddle and leave it there to get much liquid in.

You gotta take out the fuse to replace it. If it's not marked, you can make
a guess based on the input current numbers on the sticker.

As for failure, when you fill it up with liquid, the input circuit
is not the weakest link. With a new fuse, you should measure continuity
between the input connector and the diodes. Check the diodes.
That's about all you can do.

More likely, liquid got into the switcher and smoked the main switch
transistor blowing the fuse. Check resistance source to drain on the
FET.

Depending on what liquid, how long before it got throughly neutralized
and thoroughly
dried, you may want to find a dumpster.

It's not extremely likely, but if some bit of corrosion grows and causes
the output voltage to increase to levels lethal to the thinkpad, you'll
be looking for a slightly bigger dumpster. If it catches fire and burns
down your house, you'll need a REALLY BIG dumpster.

The risk is critically dependent on whether the liquid was
clean water dried immediately or cat pee left for a month.

== 6 of 8 ==
Date: Fri, Nov 4 2011 12:07 pm
From: mike

spamtrap1888 wrote:
> On Nov 4, 10:11 am, Robert Macy <robert.a.m...@gmail.com> wrote:
>> Anybody have a schematic for this simple SMPS?
>>
>> AC to DC Adapter for the IBM Thinkpad T22
>> 16V 3.36A
>
> This is a "fat snake" right? Can these be repaired? I always thought
> they were completely potted with epoxy. I've never seen one that was
> screwed together.
I've never seen one potted.
Clamp it in a vise and whack the seam with a wood chisel.
With practice, they snap apart relatively easily.

== 7 of 8 ==
Date: Fri, Nov 4 2011 2:22 pm
From: PlainBill@yawhoo.com

On Fri, 4 Nov 2011 11:36:26 -0700 (PDT), spamtrap1888
<spamtrap1888@gmail.com> wrote:

>On Nov 4, 10:11�am, Robert Macy <robert.a.m...@gmail.com> wrote:
>> Anybody have a schematic for this simple SMPS?
>>
>> AC to DC Adapter for the IBM Thinkpad T22
>> � 16V 3.36A
>
>This is a "fat snake" right? Can these be repaired? I always thought
>they were completely potted with epoxy. I've never seen one that was
>screwed together.
I've seen them glued together and held together with screws. Usually
they are a simple SMPS, and quite simple to troubleshoot.

PlainBill

== 8 of 8 ==
Date: Fri, Nov 4 2011 4:24 pm
From: Robert Macy

On Nov 4, 11:36 am, spamtrap1888 <spamtrap1...@gmail.com> wrote:
> On Nov 4, 10:11 am, Robert Macy <robert.a.m...@gmail.com> wrote:
>
> > Anybody have a schematic for this simple SMPS?
>
> > AC to DC Adapter for the IBM Thinkpad T22
> > 16V 3.36A
>
> This is a "fat snake" right? Can these be repaired? I always thought
> they were completely potted with epoxy. I've never seen one that was
> screwed together.

Actually, two cables and a plastic box. The box is a 'snap apart' by
gently inserting tool along the separation edges.

==============================================================================
TOPIC: caps for mobo
http://groups.google.com/group/sci.electronics.repair/t/a27d517b2e2829d8?hl=en
==============================================================================

== 1 of 4 ==
Date: Fri, Nov 4 2011 10:44 am
From: "Tom Del Rosso"

Of all the types of electrolytics at Digikey or Mouser, which do you favor
for replacement of bulging mobo caps?

Reply in group, but if emailing add one more
zero, and remove the last word.

== 2 of 4 ==
Date: Fri, Nov 4 2011 11:37 am
From: amdx

On 11/4/2011 12:44 PM, Tom Del Rosso wrote:
> Of all the types of electrolytics at Digikey or Mouser, which do you favor
> for replacement of bulging mobo caps?
>
>

I used Rubycon,

Here's where I got mine, He has other brands too.

http://badcaps.net/

I didn't get the kit, just replace the bulging caps.
The computer worked a couple years, then the HD died.

Just fired up a new computer build yesterday.
Mikek

== 3 of 4 ==
Date: Fri, Nov 4 2011 11:39 am
From: spamtrap1888

On Nov 4, 10:44 am, "Tom Del Rosso" <td...@verizon.net.invalid> wrote:
> Of all the types of electrolytics at Digikey or Mouser, which do you favor
> for replacement of bulging mobo caps?
>

This website is a gold mine of such information:

http://badcaps.net/forum/index.php

== 4 of 4 ==
Date: Fri, Nov 4 2011 2:05 pm
From: "Michael A. Terrell"

Tom Del Rosso wrote:
>
> Of all the types of electrolytics at Digikey or Mouser, which do you favor
> for replacement of bulging mobo caps?

Digikey, Panasonic FM series is what I use.

--
You can't have a sense of humor, if you have no sense.

==============================================================================
TOPIC: Crate 4x12 Speaker Cabinet Partition for Stereo Use Model BV412SB
http://groups.google.com/group/sci.electronics.repair/t/f1251b6ff1268bb7?hl=en
==============================================================================

== 1 of 1 ==
Date: Fri, Nov 4 2011 4:42 pm
From: "Wild_Bill"

Thanks, I appreciate the informtion.
I had read that Crate specifically chose birch plywood for the cabinet due
to it's particular resonance characteristics, but I admit that a tuned
cabinet is way beyond what I know about acoustics or enclosures.

--
Cheers,
WB
.............

"spamtrap1888" <spamtrap1888@gmail.com> wrote in message
news:19cf23e5-ce42-4e96-9f4b-89363c4936f5@u24g2000pru.googlegroups.com...
On Nov 2, 1:58 pm, "Wild_Bill" <wb_wildb...@XSPAMyahoo.com> wrote:
> Would anyone know of a good reason to not install a partition between the
> left and right pairs, when using the cabinet for a stereo input?
>
> As it is now, there is just open space inside the cabinet.
>
> All four speakers are identical (16 ohm) and there is a switch at the rear
> to select mono (4 or 16 ohm) or stereo (2x8 ohm).
>
> There aren't any baffles, ports or stuffing in the box, just bare inside..
> and I was contemplating installing a wood or wood/foam separator.

From fundamentals: A loudspeaker in a box is a spring-mass-damper
situation. The mass is the mass of the diaphragms, voice coils, and
part of the surround and spider. The spring is the air in the
enclosure, which provides a restoring force to the diaphragms. This
gives a certain fundamental resonance, which is the low frequency
corner that the speaker can reproduce.

Now, if you put a partition in the middle, you halve the moving mass,
but you also halve the air volume. Intuitively the fundamental
resonance should not change, because the two factors cancel out. I
would verify this by finding the resonance with and without the
partition using an oscillator, AC voltmenter, and resistor.

==============================================================================
TOPIC: Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of
Charge
http://groups.google.com/group/sci.electronics.repair/t/9cb107f86fe5df92?hl=en
==============================================================================

== 1 of 1 ==
Date: Fri, Nov 4 2011 5:15 pm
From: "Wild_Bill"

Charge state indicators are used on professional rechargeable packs, and
give a quick indication of when they're not suitable for service/need
recharged.

LED charge indicators would be useful for sealed lead-acid types and other
rechargeable types.

The charge state voltage is what causes intelligent chargers to start and
stop charging, or switch to trickle charging.

I don't know about the newer chemistry types, but I spotted a comment a
couple of days ago that claimed one type can't be recharged if discharged
below a specific level (don't recall if it was lithium or poly-something).

NICD and NIMH types shouldn't be used when discharged to a point below
approximately 80% of full charge, some manufacturers claim the limit should
be about 0.8V per cell.

SLA types should also be limited to specific discharge levels, or
approximately 10.8V for a 12V battery.

So.. if a user can quickly, easily and reliably detect when a battery or
pack needs to be recharged, and cautioned wrt further discharge.. they can
avoid taking low batteries out in the field and finding themselves without
portable power.
Additionally, keeping charge levels above minimum levels will result in
longer battery life. (ideally, one would take a vehicle out in the field and
a charger that would operate from the vehicle's 12V source).

The other option would be to keep all SLAs and rechargeable packs on trickle
chargers or automatic maintenance chargers.

Rechargeable batteries wouldn't be very economical if owners needed to own
enough chargers for every battery or pack that they might own.

--
Cheers,
WB
.............

"mike" <spamme9@gmail.com> wrote in message
news:j8si40$1kh$2@dont-email.me...
>>
>> ** No way it will work with rechargeable cells like NiCd or NiMH.
>>
>> Only good for non-rechargeable like alkaline.

> This is contrary to my expectation. Please enlighten...

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

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

Electronics

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

No Response to "sci.electronics.repair - 25 new messages in 10 topics - digest"

Post a Comment

Blog Roll

Blog Archive