Working on this same Sony #KV32TS35. Both switching regulators Q601 and
Q602 shorted, along with the Hot and fuse. Replaced Hot, and subbed
Q601/602 with NTE2582's. Set powered up for 5 seconds, dead again. New
NTE's shorted and fuse blown. Hot OK.
Does anyone know if these (Q601/602) transistors must be
replaced with Sony parts? I haven't found any other faulty components
in the primary. My next step is replace the transistors, pull the Hot,
and use a variable transformer to slowly increase supply voltage while
taking measurements. I am still a beginner and would like to know if
this is a solid approach to my problem. Quick history - I blew these
transistors trying to check pins of jungle ic for vertical/horizontal
waveforms. Accidently touched 2 pins at once. Was troubleshooting loss
of vertical. Thanks again group.

"Golf" wrote in message
oups.com...
Working on this same Sony #KV32TS35. Both switching regulators Q601 and
Q602 shorted, along with the Hot and fuse. Replaced Hot, and subbed
Q601/602 with NTE2582's. Set powered up for 5 seconds, dead again. New
NTE's shorted and fuse blown. Hot OK.
Does anyone know if these (Q601/602) transistors must be
replaced with Sony parts? I haven't found any other faulty components
in the primary. My next step is replace the transistors, pull the Hot,
and use a variable transformer to slowly increase supply voltage while
taking measurements. I am still a beginner and would like to know if
this is a solid approach to my problem. Quick history - I blew these
transistors trying to check pins of jungle ic for vertical/horizontal
waveforms. Accidently touched 2 pins at once. Was troubleshooting loss
of vertical. Thanks again group.


My shop has seen lots of these caused by bad solder connections at the
horizontal drive transformer.

Mark Z.

On a Sony SMPS and horizontal output you absolutely must use exact
components. Q601/602 even are of different types and that rating is
also very important, mp,mnp,etc.

Given that you shorted some pins together, you may have some other
failure now that is putting the loads on the smps way out of tolerance.
Might be time to get a hold of Sony's training manual for that chassis
and the SMPS training guide given out at school for that SMPS and
follow the 18 or so steps to fixing the set.

"Golf" wrote in message
oups.com...
My next step is replace the transistors, pull the Hot,
and use a variable transformer to slowly increase supply voltage while
taking measurements.

That won't be enough protection I'm afraid. Using a variac means you can
ramp up the voltage slowly, but the current is still potentially destructive
if there's a fault. By the time the power supply kicks in and draws
excessive current due to a fault, it's all over in a microsecond and your
new semicondictors become 'fullyconductors'!

My advice is to use a 100W light bulb in series with the supply to limit the
current to safe levels while faultfinding. If it lights brightly and the
TV's PSU fails to start, you know there's still a problem and it gives you a
second chance to remove the fault.

As you shorted two pins together on the jungle IC, I suspect there's
something blown and loading the PSU, possibly the jungle IC itself.

Dave

You should be using original Sony parts. I am sure that the HOT is also
damaged. We have had a fair number of cold solder connections at the
horizontal scan drive transformer that feeds to the HOT. If the HOT looses
proper drive, it can go shorted, and take out the main power supply and a
few support components with it.

It is very important to make sure that there are no caps that are off value
or high in ESR in the area. It is also possible that the bias resistors in
the power supply that bias the switching drivers are off value. It is also
possible that the flyback transformer is giving problems.

--

JANA
_____


"Golf" wrote in message
oups.com...
Working on this same Sony #KV32TS35. Both switching regulators Q601 and
Q602 shorted, along with the Hot and fuse. Replaced Hot, and subbed
Q601/602 with NTE2582's. Set powered up for 5 seconds, dead again. New
NTE's shorted and fuse blown. Hot OK.
Does anyone know if these (Q601/602) transistors must be
replaced with Sony parts? I haven't found any other faulty components
in the primary. My next step is replace the transistors, pull the Hot,
and use a variable transformer to slowly increase supply voltage while
taking measurements. I am still a beginner and would like to know if
this is a solid approach to my problem. Quick history - I blew these
transistors trying to check pins of jungle ic for vertical/horizontal
waveforms. Accidently touched 2 pins at once. Was troubleshooting loss
of vertical. Thanks again group.

First, thankyou to all that replied. Lots of great advice. I am hearing
that I definitely should replace with Sony originals. Could this be the
sole problem with Q601/602 (NTE subs), disregarding that I caused them
to fail originally? I can do the lightbulb trick, but not exactly sure
where to insert. If I install in supply, and problem is downstream of
this, wouldn't the faulty component still demand the current regardless
of this load in the supply? Should I remove the HOT, insert light bulb
here, and disconnect the other 135V B+ sources? I just don't want to
sacrifice any more components, especially if I buy Sony replacements. I
will follow all advice, and post feedback when I get the components in.
Thankyou all again.

"Dave D" wrote in message
...

"Golf" wrote in message
oups.com...
My next step is replace the transistors, pull the Hot,
and use a variable transformer to slowly increase supply voltage while
taking measurements.

That won't be enough protection I'm afraid. Using a variac means you can
ramp up the voltage slowly, but the current is still potentially
destructive if there's a fault. By the time the power supply kicks in and
draws excessive current due to a fault, it's all over in a microsecond and
your new semicondictors become 'fullyconductors'!

My advice is to use a 100W light bulb in series with the supply to limit
the current to safe levels while faultfinding. If it lights brightly and
the TV's PSU fails to start, you know there's still a problem and it gives
you a second chance to remove the fault.

As you shorted two pins together on the jungle IC, I suspect there's
something blown and loading the PSU, possibly the jungle IC itself.

Dave

I'd suggest doing some Googling. These power supplies and this problem have
been discussed to death and there is lots of info on them. for the record,
Dave, a variac is the better method for these. Most of these supplies will
start switching at just a few volts and it is there that you check the duty
cycle and the switching frequency. Dave's suggestion to follow the Sony
training manual is good advice if you don't understand how they work and
fail.

Leonard

Using the Sony supplied parts is bad advice. The original Sony parts will
cost many times what you would pay for the same parts from other
distributors. The key is to use a higher gain rated version, match the
pair, and troubleshoot the rest of the circuit completely. For someone who
does not know these supplies, buying Sony part is a great waste of money
because they will blow those just as easily as any other parts. Now the NTE
subs may be a problem. You never know what they are giving you. Just use a
P rank 2SC4834 from a good reliable supplier like B&D, Tritronics, or ACME.

I did extensive testing on these transistors and found (with the help of the
suppliers listed) that there was similar variance in the Sony parts as
others, in fact more, and that the gain rating mad more difference than what
distributor the parts came from. Sony is just another distributor, not the
OEM. The notion that Sony has tighter QC or matches the pairs is untrue, as
verified by testing on several dozen transistors acquired in batches and at
separate times.

I just buy the P rank transistors from the supplier that has them cheapest
in batches of 10 and match the pairs. I can buy 10 pieces cheaper than a
pair from Sony and get better QC.

It is very rare to have a bad flyback causing these failures, but not
unheard of. I had two sets a few years ago that come in within a period of
a couple of weeks that made us crazy with these failures and they were
finally fixed by replacing the flybacks. I have done many dozens that were
just bad connections at the HDT causing the problem.

Leonard

"JANA" wrote in message
...
You should be using original Sony parts. I am sure that the HOT is also
damaged. We have had a fair number of cold solder connections at the
horizontal scan drive transformer that feeds to the HOT. If the HOT looses
proper drive, it can go shorted, and take out the main power supply and a
few support components with it.

It is very important to make sure that there are no caps that are off
value
or high in ESR in the area. It is also possible that the bias resistors in
the power supply that bias the switching drivers are off value. It is also
possible that the flyback transformer is giving problems.

--

JANA
_____


"Golf" wrote in message
oups.com...
Working on this same Sony #KV32TS35. Both switching regulators Q601 and
Q602 shorted, along with the Hot and fuse. Replaced Hot, and subbed
Q601/602 with NTE2582's. Set powered up for 5 seconds, dead again. New
NTE's shorted and fuse blown. Hot OK.
Does anyone know if these (Q601/602) transistors must be
replaced with Sony parts? I haven't found any other faulty components
in the primary. My next step is replace the transistors, pull the Hot,
and use a variable transformer to slowly increase supply voltage while
taking measurements. I am still a beginner and would like to know if
this is a solid approach to my problem. Quick history - I blew these
transistors trying to check pins of jungle ic for vertical/horizontal
waveforms. Accidently touched 2 pins at once. Was troubleshooting loss
of vertical. Thanks again group.