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#2
05-10-2013, 09:48 AM
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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. 
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#3
05-13-2013, 08:18 AM
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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
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#4
05-13-2013, 09:14 AM
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http://elektrotanya.com/sony_kv-32s4.../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 Last edited by Ampkat; 05-13-2013 at 09:46 AM.
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#5
05-13-2013, 12:12 PM
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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
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#6
05-13-2013, 12:34 PM
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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 ? Last edited by Ampkat; 05-13-2013 at 12:41 PM.
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#7
05-13-2013, 01:49 PM
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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.
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#8
05-13-2013, 02:25 PM
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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
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#9
05-13-2013, 04:00 PM
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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.
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#10
05-14-2013, 10:13 AM
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Quote:
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
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#11
05-14-2013, 11:41 AM
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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.
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#12
05-14-2013, 12:04 PM
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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.
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#14
05-14-2013, 12:40 PM
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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
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#15
05-14-2013, 02:18 PM
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Quote:
 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 Last edited by Ampkat; 05-14-2013 at 02:23 PM.
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