Toshiba TV29C90 problem; Image fades to black...

[android]

"market" <email2market@gmail.com> wrote in message
news:1176767123.942101.299110@y5g2000hsa.googlegroups.com...

Find information on RFID companies, RFID equipment, and the medical
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Alright

At first I was surprised
http://click.adultsingles.com/partner/click.asp?id=72473&site=ads&typ=click

Honestly I THINK it's wrong

 

[Michael A. Terrell]

android wrote:

Honestly I THINK it's wrong

Reported to: abuse@t-com.hr


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[runderwo@mail.win.org]

On Apr 14, 1:55 am, meow2...@care2.com wrote:

GFCIs protect against L-E shocks and shorts, which have nothing to do
with the risk that ali wiring posts. Al oxidises at joints, heats up &
catches fire. A gfci doesnt make the remotest difference to that. An
AFCI however would.

I'm under the impression that current AFCIs don't protect against the
type of arc faults Al joints are prone to.

I'm not installing GFCIs to mitigate the Al risk, it's to mitigate the
general risk of operating electrical devices near water.

I'm not that familiar with US practices, but I dont expect many modern
electrical parts will have al compatible connections.

Switches and outlets do, actually, but GFCI outlets seem to be an
exception.

AFCIs arent perfect, but they do reduce risk quite a lot.

Do you have any references that show currently marketed AFCIs to
reduce the risk of bad Al connections?

 

[runderwo@mail.win.org]

On Apr 14, 6:06 pm, "Coyote" <nom...@frontmed.com> wrote:

If in doubt you could make a short jumper. If your circuit conductor is #
12 or #10 alum. use a copper
#12 conductor spliced to the circuit conductor using a copper/alum. butt
splice A compound such as peremetx
could also be used to coat the conductors. Permitex is a paste like
compound that contains both copper and
aluminum metals.

I read that the butt splice method is not a good idea and that is why
the COPALUM pigtail splice exists. Same deal with the Ideal purple
wire nuts vs Scotchlok wire nuts that are spring loaded. In both
cases the latter exerts more force on the aluminum wire keeping it
from loosening as it inevitably expands and contracts.

 

On 17 Apr 2007 08:02:29 -0700, "runderwo@mail.win.org"
<runderwo@mail.win.org> wrote:

On Apr 14, 6:06 pm, "Coyote" <nom...@frontmed.com> wrote:

If in doubt you could make a short jumper. If your circuit conductor is #
12 or #10 alum. use a copper
#12 conductor spliced to the circuit conductor using a copper/alum. butt
splice A compound such as peremetx
could also be used to coat the conductors. Permitex is a paste like
compound that contains both copper and
aluminum metals.

I read that the butt splice method is not a good idea and that is why
the COPALUM pigtail splice exists. Same deal with the Ideal purple
wire nuts vs Scotchlok wire nuts that are spring loaded. In both
cases the latter exerts more force on the aluminum wire keeping it
from loosening as it inevitably expands and contracts.

There is a new device out there called Alumiconn by King Innovation
that is as good as Copalum and you don't need any special tools or
training.
It is a small terminal block with set screws in an insulating jacket.

http://www.kingsafety.com/products/alumiconn.html

 

On 17 Apr, 15:32, "runde...@mail.win.org" <runde...@mail.win.org>
wrote:

On Apr 14, 1:55 am, meow2...@care2.com wrote:

AFCIs arent perfect, but they do reduce risk quite a lot.

Do you have any references that show currently marketed AFCIs to
reduce the risk of bad Al connections?

no, I didnt realise they were parallel only. Where I am in the world
we dont have AFCIs.


NT

 

[Coyote]

<runderwo@mail.win.org> wrote in message
news:1176822149.197370.206240@p77g2000hsh.googlegroups.com...

On Apr 14, 6:06 pm, "Coyote" <nom...@frontmed.com> wrote:

If in doubt you could make a short jumper. If your circuit conductor is
#
12 or #10 alum. use a copper
#12 conductor spliced to the circuit conductor using a copper/alum. butt
splice A compound such as peremetx
could also be used to coat the conductors. Permitex is a paste like
compound that contains both copper and
aluminum metals.

I read that the butt splice method is not a good idea and that is why
the COPALUM pigtail splice exists. Same deal with the Ideal purple
wire nuts vs Scotchlok wire nuts that are spring loaded. In both
cases the latter exerts more force on the aluminum wire keeping it
from loosening as it inevitably expands and contracts.

You are correct...CP/AL spring loaded nuts could be used.
I used Scotchlock spring loaded nuts for years and never had a problem

 

[runderwo@mail.win.org]

On Apr 17, 10:30 am, gfretw...@aol.com wrote:

There is a new device out there called Alumiconn by King Innovation
that is as good as Copalum and you don't need any special tools or
training.
It is a small terminal block with set screws in an insulating jacket.

http://www.kingsafety.com/products/alumiconn.html

Yeah, that looks like a good product and it's even UL listed. But
it's not listed by CPSC as an approved repair method (yet). This
might be the best way to go in the end, the product makes sense and is
not that expensive.

 

[runderwo@mail.win.org]

On Apr 17, 1:41 pm, "Coyote" <nom...@frontmed.com> wrote:

You are correct...CP/AL spring loaded nuts could be used.
I used Scotchlock spring loaded nuts for years and never had a problem

Do you have a suggestion where I could find such a nut? All the
Scotchlok nuts I have found on their site say Copper connections
only... though it certainly seems that CO/ALR spring nuts do exist
somewhere.

 

On 17 Apr 2007 14:11:09 -0700, "runderwo@mail.win.org"
<runderwo@mail.win.org> wrote:

http://www.kingsafety.com/products/alumiconn.html

Yeah, that looks like a good product and it's even UL listed. But
it's not listed by CPSC as an approved repair method (yet). This
might be the best way to go in the end, the product makes sense and is
not that expensive.

CPSC is not a nationally recognized testing lab, it is a political
entity.

 

On 17 Apr 2007 14:21:29 -0700, "runderwo@mail.win.org"
<runderwo@mail.win.org> wrote:

Do you have a suggestion where I could find such a nut? All the
Scotchlok nuts I have found on their site say Copper connections
only... though it certainly seems that CO/ALR spring nuts do exist
somewhere.

The only NRTL listed CU/AL wirenut is the purple Ideal #65

 

[Michael A. Terrell]

I love spam?

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Chuck]

On Tue, 24 Apr 2007 02:54:12 -0300, Randel Chiffiald <no@email.net>
wrote:

I need to replace a 2.2 mfd 160 V cap, but I don't know which type
of capacitor,(electrolytic, tant, mica, poly... etc.) it is, and I haven't
opened the set yet because although it has a problem, it is still watchable
and I'd like to find out the type of cap so I can buy it before hand and
swap it at the same time I first open it up for service as not to
inconvenience the customer, (who happens to be my ex, and you KNOW how
touchy that situation can be right? She's my ex for a very good reason
vbg&gt And obviously, seeing as who it is, you know it's going to be a
"government job" Know what I mean?

SO, if anyone maybe has the parts list, schematic, anything that
will tell what kind of cap it is, I'd REALLY appreciate it if you would let
me know

BRAND : NEC
MODEL OR CHASSIS : CT-2505A
PART NEEDED : C414. 2.2 MFD @160 VOLTS.

Thanks a lot everyone.
Randy
It's a polarized 105 C electrolytic capacitor.

 

[Michael Black]

Randel Chiffiald (no@email.net) writes:

I need to replace a 2.2 mfd 160 V cap, but I don't know which type
of capacitor,(electrolytic, tant, mica, poly... etc.) it is, and I haven't
opened the set yet because although it has a problem, it is still watchable
and I'd like to find out the type of cap so I can buy it before hand and
swap it at the same time I first open it up for service as not to
inconvenience the customer, (who happens to be my ex, and you KNOW how
touchy that situation can be right? She's my ex for a very good reason
vbg&gt And obviously, seeing as who it is, you know it's going to be a
"government job" Know what I mean?

HOw in the world can you know that it's a specific capacitor without

having opened the tv set?

Either you're guessing at what it might be, or you've done the old
"I took it to a repairman, but they wanted $200 to repair it, so I'm
going to do it myself. But I need to know, what's a capacitor?".

Anyone who really had an idea would be able to make a very good guess
on what type of capacitor.

Michael

 

[Randel Chiffiald]

On 24 Apr 2007 13:58:37 GMT, et472@FreeNet.Carleton.CA (Michael Black)
wrote:

Randel Chiffiald (no@email.net) writes:
I need to replace a 2.2 mfd 160 V cap, but I don't know which type
of capacitor,(electrolytic, tant, mica, poly... etc.) it is, and I haven't
opened the set yet because although it has a problem, it is still watchable
and I'd like to find out the type of cap so I can buy it before hand and
swap it at the same time I first open it up for service as not to
inconvenience the customer, (who happens to be my ex, and you KNOW how
touchy that situation can be right? She's my ex for a very good reason
vbg&gt And obviously, seeing as who it is, you know it's going to be a
"government job" Know what I mean?

HOw in the world can you know that it's a specific capacitor without
having opened the tv set?

Simple, it's a common, well documented malady with this particular
model. The set displays the exact same condition described by the numerous
sources of common technical problems with certain TV models. In the
description of the capacitor however, the various sources of this
information fail to provide specific information about exactly what type the
capacitor is. An educated guess would be that it is canned electrolytic, but
there is also the possibility that they have used a tantalum cap in this
circuit. It would make a difference.

Either you're guessing at what it might be, or you've done the old
"I took it to a repairman, but they wanted $200 to repair it, so I'm
going to do it myself. But I need to know, what's a capacitor?".

You couldn't be further from the truth. I am a disabled, (and
obviously semi-retired because of it) former R&D engineering tech and I also
had a repair business myself. Because of the limitations posed by my
disability, I had to quit and only work on personal and "friends" equipment.
Most of my test equipment and documentation was either stolen, given away,
or lost since then.

Anyone who really had an idea would be able to make a very good guess
on what type of capacitor.

Michael

You're absolutely right Michael, but as I explained above, a guess
isn't always right, and I was hoping someone would have the information that
would cinch it so I could do the repair in one visit. I have a difficult
time getting around, and wouldn't be doing this repair at all if it weren't
for the fact that my daughter lives with her mother and asked me if I would
do this repair for her. I figure I'd at least try to do this while I still
can. BTW, the RCA transistor I requested info on in another post is for my
own set.

 

[Randel Chiffiald]

On Tue, 24 Apr 2007 08:26:29 -0500, Chuck <ch@deja.net> wrote:

On Tue, 24 Apr 2007 02:54:12 -0300, Randel Chiffiald <no@email.net
wrote:

I need to replace a 2.2 mfd 160 V cap, but I don't know which type
of capacitor,(electrolytic, tant, mica, poly... etc.) it is, and I haven't
opened the set yet because although it has a problem, it is still watchable
and I'd like to find out the type of cap so I can buy it before hand and
swap it at the same time I first open it up for service as not to
inconvenience the customer, (who happens to be my ex, and you KNOW how
touchy that situation can be right? She's my ex for a very good reason
vbg&gt And obviously, seeing as who it is, you know it's going to be a
"government job" Know what I mean?

SO, if anyone maybe has the parts list, schematic, anything that
will tell what kind of cap it is, I'd REALLY appreciate it if you would let
me know

BRAND : NEC
MODEL OR CHASSIS : CT-2505A
PART NEEDED : C414. 2.2 MFD @160 VOLTS.

Thanks a lot everyone.
Randy
It's a polarized 105 C electrolytic capacitor.

Thanks you very much! That's a big help.

Randy

 

[Michael A. Terrell]

moguiyingzi wrote:

spam

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Dave]

"DaveM" <masondg4499@comcast99.net> wrote in message
news:i8GdnTImqOkC6qrbnZ2dnUVZ_qiqnZ2d@comcast.com...

Since, by your own observations, the subsonic filter switch could be the
problem, or something in the immediate vicinity of the switch. What kind
of switch is it (slide switch, toggle switch, rotary switch)? If you can
easily disassemble it to get at the contacts, you might find that they are
very tarnished or even corroded; caused by airborne contaminants.

It's a plastic push-button PCB-mounted switch, not easy to disassemble at
all. I'd worry about breaking the plastic parts which are, I'm sure, quite
irreplaceable. Not particularly accessible either as there is a display
controller board above the tone control board where the switch is located.

Also sounds like the volume pots are still dirty. Use a cleaner that
lubricates as well as cleans. A tip... when you spray the cleaner into
the pot, turn the set so that the residual cleaner can drain back out.
That allows the cleaner to float out any contaminants as it drains.

I was using zero residue cleaner, I'll pick up some lubricating contact
cleaner and give it another go. There appears to be a hole in the back of
each pot where you can see the shaft turn, plus a small (1-1.5mm) hole on
one side. Maybe a blast of compressed air after cleaning wouldn't hurt
either...

I have also found transistors to cause that exact problem. I surmise that
the wire bond from the external leads to the silicon inside breaks and
becomes extremely intermittent, and can be very difficult to find if you
aren't wary of this kind of fault. Lightly tap on each semiconductor in
the area and see if the audio is affected.
Actually, just about all types of components can become intermittent
(microphonic) in this manner, so using an insulated tool such as a plastic
or nylon tuning wand, tap components and circuit board to see if that
affects the audio.

This amp is totally discrete and there are no soldered wire connections (all
wound) , so I think (hope) the fact that BOTH channels are messed up
indicates a simple dirty pot problem... I did check voltages at maybe a
dozen transistors, both left and right channel from PS through the pre-amp
and amp and they were all really close to expected at idle. I don't know if
+/- 1V is significant on a 43VDC rail or not... anyway there are quite a
few transistors but nothing unmanageable and as there are no proprietary,
obscure, or out of production IC's in this dog, whatever I did is completely
fixable. I just hope that it doesn't take me 30 or 40 hours to figure it
out.

I may try just bridging the "open" pair of contacts on the subsonic filter
switch with a jumper wire and see if that helps.

Thanks for your help

Dave

Good luck...

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters
in the address)

Life is like a roll of toilet paper; the closer to the end, the faster it
goes.

 

[Steve]

Sounds like you'll be doing some very basic HPIB
work. Consider getting an old HP-85 computer. These
have HPIB, a monitor, keyboard, printer, and BASIC
language built in. Nice small package as well. Been using
mine for years. Be sure to get the books.

Steve

 

On 1 May, 18:49, "Dave" <dspear9...@yahoo.delete.com> wrote:

"DaveM" <masondg4...@comcast99.net> wrote in message
news:i8GdnTImqOkC6qrbnZ2dnUVZ_qiqnZ2d@comcast.com...

Since, by your own observations, the subsonic filter switch could be the
problem, or something in the immediate vicinity of the switch. What kind
of switch is it (slide switch, toggle switch, rotary switch)? If you can
easily disassemble it to get at the contacts, you might find that they are
very tarnished or even corroded; caused by airborne contaminants.

It's a plastic push-button PCB-mounted switch, not easy to disassemble at
all. I'd worry about breaking the plastic parts which are, I'm sure, quite
irreplaceable. Not particularly accessible either as there is a display
controller board above the tone control board where the switch is located.

Also sounds like the volume pots are still dirty. Use a cleaner that
lubricates as well as cleans. A tip... when you spray the cleaner into
the pot, turn the set so that the residual cleaner can drain back out.
That allows the cleaner to float out any contaminants as it drains.

I was using zero residue cleaner, I'll pick up some lubricating contact
cleaner and give it another go. There appears to be a hole in the back of
each pot where you can see the shaft turn, plus a small (1-1.5mm) hole on
one side. Maybe a blast of compressed air after cleaning wouldn't hurt
either...

I have also found transistors to cause that exact problem. I surmise that
the wire bond from the external leads to the silicon inside breaks and
becomes extremely intermittent, and can be very difficult to find if you
aren't wary of this kind of fault. Lightly tap on each semiconductor in
the area and see if the audio is affected.
Actually, just about all types of components can become intermittent
(microphonic) in this manner, so using an insulated tool such as a plastic
or nylon tuning wand, tap components and circuit board to see if that
affects the audio.

This amp is totally discrete and there are no soldered wire connections (all
wound) , so I think (hope) the fact that BOTH channels are messed up
indicates a simple dirty pot problem... I did check voltages at maybe a
dozen transistors, both left and right channel from PS through the pre-amp
and amp and they were all really close to expected at idle. I don't know if
+/- 1V is significant on a 43VDC rail or not... anyway there are quite a
few transistors but nothing unmanageable and as there are no proprietary,
obscure, or out of production IC's in this dog, whatever I did is completely
fixable. I just hope that it doesn't take me 30 or 40 hours to figure it
out.

I may try just bridging the "open" pair of contacts on the subsonic filter
switch with a jumper wire and see if that helps.

Thanks for your help

Dave



Good luck...

The still bad switch probably needs disassembling & reassembling, or
else replacing the individual switch or switch block. Rows of
pushbutton things on PCBs were a standard design around for many years
in the 70s & 80s, so finding a replacement from some scrap item is
likely.

The pot is either still dirty, probably not, or else is worn out or
cracked, or possibly the rivet at the end of the track is loose.

Replacing the pot is most likely the solution, you've already cleaned
it. Is its an oddity, rivets can be squashed, and worn out tracks can
be painted, tho this would unbalance the volume L-R tracking,

Re the off balance, there are reasons amps have balance controls. If
yours has none you can fit a potential divider in the channel with the
higher output, and set it up and replace the covers. If youre lcky and
the amp has external connections between pre and power sections, you
can put what you want between those 2, such as a new volume & balance
control.


NT