Can someone help me fix this TV. I have the schematics and have been trying to get the supply up but can't get B+ to the CN641 block. TIA,

KB

Is there a big heatsink mounted IC on the board?

Sony had issues with one for several years. I saw them on the 20" up to the 35" sets, and I sure hated having to move these sets!!

I dont have any schematics anymore on these. I want to think it was known as IC601? It comes to mind...

When Sony only sold the part, it was over $36. On the parts market now, it is only about $5.

If you can post a pic of the power supply, whole chassis &
the schematic of the power supply we may be able to help.
Hard to remember all the models especially the newer ones
that changed so fast & we didnt see in the #s of older sets.

73 Zeno

http://elektrotanya.com/sony_kv-32s40_50_34sl40_45_35s40_45_37sl45_32v40_65_34vl65 _35v65_37vl65_ch_aa-2d.pdf/download.html

Yes that is the exact board you decribed Holmes and I can't get picture to post.

Zeno hope this works : Homes I already replaced IC-601 and it was bad I think but it still has a problem and I can't get B+ to that connector cn-641 PINS 1 & 2. I'm not sure if I can read it at that connector as a standalone supply or if it has to be connected to the main board before it will deliver the B+ but it's not there either way.


Can't get picture to post can you guys help me out here . Not sure why it won't work I'm not very good at posting pictures

OK I dont know your skills so I will keep it easy.
If IC601 shorts R607 opens. The relay will still click.
You will get no B+ R607 is used as a fuse so use an
OEM part or a flameproof of same value.

IMPORTANT you must be sure there are no shorts on
CN641 1-2 If there is a short you will probably blow IC601
again. I would cut the wires and get the B+ up again first.
Usually Q502 shorts and may be caused by bad T503 flyback
or cold solder around T501. they also go for no reason sometimes.

See what you find and & get back to us BEFORE you hook wires back up.

Good luck 73 Zeno

I'm worryed about blowing IC-601 but am good if I have to get another if I can find the short. The resistor R-607 is good and if I fire the board I get the 341volts to the filter caps but it doesn't get to the CN641 connector and this is with the supply out. I can wire up a 5k resistor to pins 10 and 11 of CN-641 and it will trip the relay but I still get no B+ to CN-641. To be honest I don't think I'm getting 9 volts or the AU voltage either.

Edit : When I 1st started with this set the TV worked but was getting squish horizontally so I took the power supply out and did a visual inspection and found nothing fried and no blown up caps so I put it back in and that's when it wouldn't fire up again but I didn't do anything to the main board at that time.

Do you think the power supply will work right as a standalone if I trip the relay. If I can't get B+ to CN-641 there is no need to put it back in the set unless there is maybe a pulse that sends voltage back from the flyback. Just wondering ?

One of the issues with the IC601 dying was the horizontal width would suddenly get very small. If it stayed that way very long, parts started dying.

Yes I believe it will run alone with pin 11 pulled up.
This basic design has been in some sonys for years. As I remember
Its just a multivibrator, control circuit samples 130 V (pin 1-2)
& loads T603 to effect pulse amplitude to T605. I NEVER had
problems with the control circuit. Shutdown is via the micro chip
& senses beam current, HV & vert sweep. Pin 11 will go low &
the relay drops. But I am not an engineer & thats what I remember
from 15-20 yrs ago. I think it will run without the control ckt
BUT 130 will run high & D648 will short.

For now run separate on the bench, check everything around
IC601 especial R612 & 615, also had a C615 go once but it had
cracks & was shorted. & dont forget you are dealing with 2
separate grounds !

keep us posted
Zeno

Checked all the components and they all checked good. R-615 is at 64k and is higher while supply is still warm. I'm getting the 135 volts at R-607 from gnd on both sides but not sure where it stopping or whats keeping it from getting to that CN641 node.

One of the issues with the IC601 dying was the horizontal width would suddenly get very small. If it stayed that way very long, parts started dying.

Yes if you get it going you cant run it with that width problem.
If you get there look for connections I mentioned & D502,3 & 4
something from the hoz drive through FBT or in the pin or yoke ckts.
Beyond the obvious its to deep to troubleshoot on the internet.

Same with the PS. Things are getting deep.
Dont forget when making measurements anything around IC601
and on that side of the 2 transformers use neg end of C606 for
ground. For the rest of the set use the cold ground pins 3-4
of the connector, or any good chassis ground when you get there.

Good luck Zeno

If you encountered this problem where would you go from here. I have scopes and all types of test equipment just don't know the circuit. Can you give me a way to test the transformers to tell if they are good. I have to start eliminating good components if I can't find bad ones. I've tested meter wise every component on that board and checked traces and all are legit.

That big transformer beside !C601... I've never encountered a bad one. I did have one once that would chirp and sing loudly on bright screen images, but a good re-soldering of the PCB pins took care of that.

Is it possible I could find a replacement. I've combed this board and retouched every solder joint and checked for bridges and there none.

At this point I would see if IC601 is oscillating. Should be large
waveform at primary of T605. IC601 may have been damaged
or defective new. 99% they dead short BUT you never know.
Dont forget this may have been self inflicted so look for things
you dont expect. Dont feel bad it happens to everyone.
So use a scope & ISOLATION TRANSFORMER & get that thing
oscillating............ Then you can fix the real problem.

BTW I had HUGE advantages with a problem like this.
I fixed TV's from 1970 til a few yrs ago. Tens of thousands of
them. We were Sony ASC so I could call Sony. The TV was in
front of me. I could order a board (usually) & return it if need be.
I belonged to a pay site with tips & techs. I had both OEM &
Sams hard copy manuals, PDF manuals SUCK !!! I had training
manuals & went to seminars easily 5 times a year. Top notch
newer test eq. Other techs, if self inflicted this is key.......
Stick with it & let us know how you do

73 Zeno

At this point I would see if IC601 is oscillating. Should be large
waveform at primary of T605. IC601 may have been damaged
or defective new. 99% they dead short BUT you never know.
Dont forget this may have been self inflicted so look for things
you dont expect. Dont feel bad it happens to everyone.
So use a scope & ISOLATION TRANSFORMER & get that thing
oscillating............ Then you can fix the real problem.

BTW I had HUGE advantages with a problem like this.
I fixed TV's from 1970 til a few yrs ago. Tens of thousands of
them. We were Sony ASC so I could call Sony. The TV was in
front of me. I could order a board (usually) & return it if need be.
I belonged to a pay site with tips & techs. I had both OEM &
Sams hard copy manuals, PDF manuals SUCK !!! I had training
manuals & went to seminars easily 5 times a year. Top notch
newer test eq. Other techs, if self inflicted this is key.......
Stick with it & let us know how you do

73 Zeno

Dang that was the good ole days ey:banana:

I've been a Guitar Amp Tech for 25 years now but this ain't tube gear although I understand some of it and work on some monitors every now and then so I get the circuit just never worked on a switching supply this complex. But if you guys hang with me I 'll do what you say. TWbranch brought me here and said he had a lot of respect for you all so it's all good.

I'll post what I find. I have an isolation tranny and will scope the transformer. Where should I set the voltage and frequecy sweep and how large voltage wise am I looking at ?

One thing though that the double transistor IC-601 is not shorted and is diode checking pretty well. The last one I took out wasn't shorted either but was mismatched in resistance from trasistor to transistor. This supply was working when I took it out and not sure what went South when I put it back in but that chip is getting way to hot to run for any amount of time. When I find the problem the heat issue will go away I think or maybe it does run that hot. That is a monster heat sink

Ok I got big AC signal on pin 2 of T-605 with the isolation tranny hooked up and scoped and the only AC signal on the other side was small on 10 & 11 so does that whole other side get rectified for each pair of windings. 5&6 / 7,8(ct)9 and 10 &11 ?

So I should get DC at all of those rectifiers right and the ground reference would be the cold gnd or pins 3 & 4 of connector 641. This whole thing sounds like an open ground because the whole supply at CN-641 has no voltage at all.

Ok I got big AC signal on pin 2 of T-605 with the isolation tranny hooked up and scoped and the only AC signal on the other side was small on 10 & 11 so does that whole other side get rectified for each pair of windings. 5&6 / 7,8(ct)9 and 10 &11 ?

So I should get DC at all of those rectifiers right and the ground reference would be the cold gnd or pins 3 & 4 of connector 641. This whole thing sounds like an open ground because the whole supply at CN-641 has no voltage at all.
If you have AC on T605 pri you get your B+ UNLESS its to small,
way off freq, or there is a short. I may be wrong but I think they ran
around 30kc with 2oov pulses. I do remember the training manual said
the waveform had to be perfect. You say the IC runs hot, check
for shorts on the secondary especially D648 ( lift it).
Beyond that you may need some outside help & I can give you
some ideas on that.
BTW manual has no waveforms but the Sams manual prob. does.

73 Zeno

I removed T-605 and put a small 10 VAC voltage on the primaries and it blew my 8 amp variac fuse. Do you think it's bad or is my transformer test not a valid one ? All of the trannys I use operate the same way is there something I'm missing.

Pulled D648 and it won't give me a diode drop like it's open I'm reading 3.8M on ohms reading so It's not shorted but could be bad ?

I removed T-605 and put a small 10 VAC voltage on the primaries and it blew my 8 amp variac fuse. Do you think it's bad or is my transformer test not a valid one ? All of the trannys I use operate the same way is there something I'm missing.

Pulled D648 and it won't give me a diode drop like it's open I'm reading 3.8M on ohms reading so It's not shorted but could be bad ?
Good idea BUT switchers run at high freq so if you use at 60hz
it sees a dead short. See if it works with D648 out.
I understand SMPS' are difficult when you have done tube audio. It
was always the hardest thing for me to fix. Some have a wicked high
parts count & near imposable to understand. Add to that Sony is
the only one doing it this way & every one I fixed was an obvious
fix.

You may consider joining repairworld.com. They cover everything
and may help you in your regular work also. Thousands of tips
catagorized by make/model. Also you can post problems.
A few tips will pay for it fast. Dont forget to search similar
models.........

73 Zeno

Good idea BUT switchers run at high freq so if you use at 60hz
it sees a dead short. See if it works with D648 out.
I understand SMPS' are difficult when you have done tube audio. It
was always the hardest thing for me to fix. Some have a wicked high
parts count & near imposable to understand. Add to that Sony is
the only one doing it this way & every one I fixed was an obvious
fix.

You may consider joining repairworld.com. They cover everything
and may help you in your regular work also. Thousands of tips
catagorized by make/model. Also you can post problems.
A few tips will pay for it fast. Dont forget to search similar
models.........

73 Zeno

So even with the tranny out it won't test like a regular transformer ? So if I sent say a 30k 10 volt signal to it then it would work ? How does the transformer know what frequencies it is supposed to see ? Do appreciate the help Zeno and just trying to grasp this concept. ha !

So even with the tranny out it won't test like a regular transformer ? So if I sent say a 30k 10 volt signal to it then it would work ? How does the transformer know what frequencies it is supposed to see ? Do appreciate the help Zeno and just trying to grasp this concept. ha !
DC wise its the same & works the same. You can check continuity
the same. If you know what freq it is designed for yes you could do it
that way. But the farther you go from that freq the more current it
draws & eventually it is seen as a short.......

Look at an amp. Output xfmr made to pass say 20h-20kh.
If you could get say 50kh through it the 6L6's wouldnt like
it & would glow cherry red & meltdown. Same idea. Go to
the secondary & it says "use 4-8-16 ohm spkrs". Use a 400 ohm spkr &
you barely hear it. Its not really ohms DC wise, but impedance. How things behave with AC & complex signals. Beyond that we get into engineering.
I wont go there, its better to look like a fool than prove it to all !!!

Oh yes, how the xfrm knows. its in the core material, windings,
spacing etc...........

73 Zeno

DC wise its the same & works the same. You can check continuity
the same. If you know what freq it is designed for yes you could do it
that way. But the farther you go from that freq the more current it
draws & eventually it is seen as a short.......

Look at an amp. Output xfmr made to pass say 20h-20kh.
If you could get say 50kh through it the 6L6's wouldnt like
it & would glow cherry red & meltdown. Same idea. Go to
the secondary & it says "use 4-8-16 ohm spkrs". Use a 400 ohm spkr &
you barely hear it. Its not really ohms DC wise, but impedance. How things behave with AC & complex signals. Beyond that we get into engineering.
I wont go there, its better to look like a fool than prove it to all !!!

Oh yes, how the xfrm knows. its in the core material, windings,
spacing etc...........

73 Zeno

Thanks Zeno and yes the EE part is mind-boggling tstl when you start getting into the formulars in the complex domain. Transformer lingo can get as hairy as you want to make it and I've seen and done a tad and it's not any fun but to an EE may be but I'm not one of those and don't want to be !!

I'll try to get to that site and see if those cats can help me out. TIA,

KB

Thanks Zeno and yes the EE part is mind-boggling tstl when you start getting into the formulars in the complex domain. Transformer lingo can get as hairy as you want to make it and I've seen and done a tad and it's not any fun but to an EE may be but I'm not one of those and don't want to be !!

I'll try to get to that site and see if those cats can help me out. TIA,

KB

When you go to repair world remember they are mostly like us
making a living at it. So a quick intro is in order otherwise if you
say something wrong you will get bitch-slapped & many wont help
you.
Start the question from original problem & keep things in order &
simple.
And keep that tube stuff going, its all I will use for HiFi. Especially
appropriate since I got nothing but 50's records.....
Good luck & let us know what happens.

73 Zeno

When you go to repair world remember they are mostly like us
making a living at it. So a quick intro is in order otherwise if you
say something wrong you will get bitch-slapped & many wont help
you.
Start the question from original problem & keep things in order &
simple.
And keep that tube stuff going, its all I will use for HiFi. Especially
appropriate since I got nothing but 50's records.....
Good luck & let us know what happens.

73 Zeno

Your a class act Zeno thanks I'll let you know what happens. It will be Monday before I start as a busy weekend ahead.

Tubes are definitely the way to go and I'm also in a band and play guitar so yeah it's all tubes haha!

Your a class act Zeno thanks I'll let you know what happens. It will be Monday before I start as a busy weekend ahead.

Tubes are definitely the way to go and I'm also in a band and play guitar so yeah it's all tubes haha!
Class act ! Never been accused of that before.......
Give my parents the credit, not me.

BTW One other thing to keep alive. You used the term "cats"
I thought I was the only one using it left. Once my son had a few
pals over aged 18ish. I was chewing them out about something
( beer prob ) & said "you cats bla bla.... They were baffled &
laughed at me. Then one of them started insulting my Fisher
stereo tube amp. Not a good idea hooligan punk. I whipped out a mint DJ copy of Anisteen Allens " Fujiyama Mama" ( capitol 1955) & played it LOUD.
They were awe struck. Never heard audio like it.............
I guess I showed them cats !

73 Zeno

Class act ! Never been accused of that before.......
Give my parents the credit, not me.

BTW One other thing to keep alive. You used the term "cats"
I thought I was the only one using it left. Once my son had a few
pals over aged 18ish. I was chewing them out about something
( beer prob ) & said "you cats bla bla.... They were baffled &
laughed at me. Then one of them started insulting my Fisher
stereo tube amp. Not a good idea hooligan punk. I whipped out a mint DJ copy of Anisteen Allens " Fujiyama Mama" ( capitol 1955) & played it LOUD.
They were awe struck. Never heard audio like it.............
I guess I showed them cats !

73 Zeno

I got an old Fisher SA300 that I put UL OT's in and it sounds awesome and just so unique and warm. The new gear has better quality and cleaner but the tone from those amps is stunning especially when you crank it . Glad you set those cats straight !!