Was given this TV in non-working order. It is dead. No response to any of
the front-panel buttons (no remote came with it).

There's one obvious relay on the AC circuit, closing this relay by soldering
leads together makes the tube come on, green with light-green line
horizontal-ish lines, but no power to any of the logic components, no
response to any button pushes.

There is an area on the PCB that looks as if it's gotten a bit too hot
around it. I de-soldered the IC at the epicenter of the black area and it's
a Sanken STR-D1005T "hybrid voltage regulator". According to the datasheet
(which, btw, looks as if it was typed on my old 1955 Royal typewriter
comlete with white-out blobs) reference circuit, it converts rectified AC at
~140-180VDC to 12VDC in conjunction with a transformer.

I've done a bit of electronic repair and have never run into such a beast,
can't make heads or tails of the circuit, but then I never really have
understood SMPS's.

Does anybody have a source for this part? I've checked all the usual
suspects, i.e. via findchips.com and am striking out. There are a few
distributors who'd gladly sell me 1000 or more but that would certainly go a
long ways towards negating the value of my "free" television.

Any help greatly appreciated.

Dave

A bit more info:

As an aside, the main filter cap is a 200V 470uF electrolytic. Just to avoid
painfully shocking myself I was going to discharge it prior to messing
around. Right after powering off the set this cap only read 400mV on my
meter! I shorted the cap with a resistor, then tested using my DMM set on
20M resistance scale expecting to see zero resistance slowly rising to
infinite resistance. What I got was infinite resistance right away, like an
open circuit.

Is this cap likely bad, or should I lift one lead for a better test? If
this cap WERE bad, would it keep the set from powering up? I had heard that
the filter cap could lose as much of 75% of it's capacity before you'd
likely see any problems. Also, anybody know how I might test the STR-D1005T
I removed from the circuit?

Dave wrote:
A bit more info:

As an aside, the main filter cap is a 200V 470uF electrolytic. Just to avoid
painfully shocking myself I was going to discharge it prior to messing
around. Right after powering off the set this cap only read 400mV on my
meter! I shorted the cap with a resistor, then tested using my DMM set on
20M resistance scale expecting to see zero resistance slowly rising to
infinite resistance. What I got was infinite resistance right away, like an
open circuit.

Is this cap likely bad, or should I lift one lead for a better test? If
this cap WERE bad, would it keep the set from powering up? I had heard that
the filter cap could lose as much of 75% of it's capacity before you'd
likely see any problems. Also, anybody know how I might test the STR-D1005T
I removed from the circuit?

Leave the regulator alone for now. Not sure if this chassi has it but,
look for a 33uf@160 volt cap in the power supply. If that dried out,
it'll make the set deader than a stump.

www.techdata-kicksass.net

"Tech Data" wrote in message
oups.com...


Leave the regulator alone for now. Not sure if this chassi has it but,
look for a 33uf@160 volt cap in the power supply. If that dried out,
it'll make the set deader than a stump.

www.techdata-kicksass.net


I'll have a look. It's chassis TAC8807.

Thanks a lot for your help.

Dave

Dave wrote:
"Tech Data" wrote in message
oups.com...


Leave the regulator alone for now. Not sure if this chassi has it but,
look for a 33uf@160 volt cap in the power supply. If that dried out,
it'll make the set deader than a stump.

www.techdata-kicksass.net


I'll have a look. It's chassis TAC8807.

Thanks a lot for your help.

Dave

The closest I can come in a TAC8806 which may be close enough. Check
C887 which is the filter for the 115 volt B+. This has a feedback loop
that monitors the B+. If it's being dragged down, the hot side of the
power supply will shutdown also.

www.techdata-kicksass.net

Dave wrote:
A bit more info:

As an aside, the main filter cap is a 200V 470uF electrolytic. Just to avoid
painfully shocking myself I was going to discharge it prior to messing
around. Right after powering off the set this cap only read 400mV on my
meter! I shorted the cap with a resistor, then tested using my DMM set on
20M resistance scale expecting to see zero resistance slowly rising to
infinite resistance. What I got was infinite resistance right away, like an
open circuit.

Is this cap likely bad, or should I lift one lead for a better test? If
this cap WERE bad, would it keep the set from powering up? I had heard that
the filter cap could lose as much of 75% of it's capacity before you'd
likely see any problems. Also, anybody know how I might test the STR-D1005T
I removed from the circuit?

Check the following components: c840 16v330, c841 50v22, q802 str-d1005

If you don't have an ESR meter you may have to replace these 2 caps
to be sure that they are good.

Good luck

Dave wrote:

Was given this TV in non-working order. It is dead. No response to any of
the front-panel buttons (no remote came with it).

There's one obvious relay on the AC circuit, closing this relay by soldering
leads together makes the tube come on, green with light-green line
horizontal-ish lines, but no power to any of the logic components, no
response to any button pushes.

There is an area on the PCB that looks as if it's gotten a bit too hot
around it. I de-soldered the IC at the epicenter of the black area and it's
a Sanken STR-D1005T "hybrid voltage regulator". According to the datasheet
(which, btw, looks as if it was typed on my old 1955 Royal typewriter
comlete with white-out blobs) reference circuit, it converts rectified AC at
~140-180VDC to 12VDC in conjunction with a transformer.

I've done a bit of electronic repair and have never run into such a beast,
can't make heads or tails of the circuit, but then I never really have
understood SMPS's.

Does anybody have a source for this part? I've checked all the usual
suspects, i.e. via findchips.com and am striking out. There are a few
distributors who'd gladly sell me 1000 or more but that would certainly go a
long ways towards negating the value of my "free" television.

Any help greatly appreciated.

Dave


There is nothing wrong with the strd1005 change the cap from pin 1 to
ground and then chenge r840 it has opened do to a shorted cap that str
is a very strong regulator Im' working on that set as we speak so if
anyone has the delfelction diagram please send it to me at

"David Naylor" wrote in message
. ..
There is nothing wrong with the strd1005 change the cap from pin 1 to
ground and then chenge r840 it has opened do to a shorted cap that str
is a very strong regulator Im' working on that set as we speak so if
anyone has the delfelction diagram please send it to me at


Thanks Dave, I thought as much when I noted that the regulator is rated to
800V. The resistor was likely the source of the smoke.

"Dave" wrote in message
news:ZKeNg.2510$cz3.1135@edtnps82...

Can somebody give me the voltage rating of C841 (22uF electrolytic) on an
8805/8806 chassis? Mine seems to have vaporized.

Dave wrote:
"Dave" wrote in message
news:ZKeNg.2510$cz3.1135@edtnps82...

Can somebody give me the voltage rating of C841 (22uF electrolytic) on an
8805/8806 chassis? Mine seems to have vaporized.

50 volts.

www.techdata-kicksass.net

Well, boys, I must say I am disappointed. Got her all back together last
night and fired her up with the series light bulb and... nothing. No click,
no lights, no Wheel of Fortune. Exactly the same as before I started. Now
I'm into it for $7 so I am damned and determined to make this sucker work.
Here's what I did.

Replaced the following:

c822 100 microfarad 16v
c841 22 microfarad 50v
c820 33 microfarad 200v
c842 100 microfarad 6.3v
c840 330 microfarad 16v
c887 (well, actually I did this one last after I did the others with no
success, replaced it with the 33uF 200V that I had removed from C820)
r840 910 ohm 1/2-watt flameproof resistor

I don't have an ESR meter but none of the caps tested open or shorted with a
DMM (well, except the 22uF 50V which had exploded). What feeds c840 that
might have toasted this cap? The 910-ohm resistor tested 860 ohms so it was
still okay too.

I tested the regulator out of circuit as per the data sheet diagram of
internal components and it seems just fine. Not sure that the regulator is
coming in to play here anyway as I'm not even getting a click.

As near as I can see there's a single transformer in the SMPS with two sets
of primaries and two sets of secondaries, one of which is center-tapped..
There's another smaller transformer nearby with no markings on it. None of
the windings on the big transformer are open or grounded. Dunno' what's
what on the other transformer to test. I'm guessing that if I can short the
AC relay and get the tube to light up, the SMPS is basically working
although I have no idea where or how my B+ is generated... that's what seems
to be missing.

Can anybody suggest my next step? I could really use a service manual at
this point.

Dave

On Fri, 15 Sep 2006 14:14:30 GMT, "Dave"
wrote:

Well, boys, I must say I am disappointed. Got her all back together last
night and fired her up with the series light bulb and... nothing. No click,
no lights, no Wheel of Fortune. Exactly the same as before I started. Now
I'm into it for $7 so I am damned and determined to make this sucker work.
Here's what I did.

Replaced the following:

c822 100 microfarad 16v
c841 22 microfarad 50v
c820 33 microfarad 200v
c842 100 microfarad 6.3v
c840 330 microfarad 16v
c887 (well, actually I did this one last after I did the others with no
success, replaced it with the 33uF 200V that I had removed from C820)
r840 910 ohm 1/2-watt flameproof resistor

I don't have an ESR meter but none of the caps tested open or shorted with a
DMM (well, except the 22uF 50V which had exploded). What feeds c840 that
might have toasted this cap? The 910-ohm resistor tested 860 ohms so it was
still okay too.

I tested the regulator out of circuit as per the data sheet diagram of
internal components and it seems just fine. Not sure that the regulator is
coming in to play here anyway as I'm not even getting a click.

As near as I can see there's a single transformer in the SMPS with two sets
of primaries and two sets of secondaries, one of which is center-tapped..
There's another smaller transformer nearby with no markings on it. None of
the windings on the big transformer are open or grounded. Dunno' what's
what on the other transformer to test. I'm guessing that if I can short the
AC relay and get the tube to light up, the SMPS is basically working
although I have no idea where or how my B+ is generated... that's what seems
to be missing.

Can anybody suggest my next step? I could really use a service manual at
this point.

Dave




Sometimes the regulator chip dies when all these parts fail also there
is a resistor in series with the b+ to this chip that can open. (
This is the regulator that supplies the low B+ to the upc. ie. the one
with no heatsink.) Chuck