Sony KV32S40


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Sony KV32S40

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crawdaddy
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Apr 18, 2008, 12:18 PM

Post #1 of 9 (1874 views)
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Sony KV32S40	Can't Post

Hey everyone...haven't posted for awhile, been out of the game, so to speak....what I have is a Sony KV32S40, which had been power surged, I was able to restore operation by replacing the IC 601, (the MX 0841B), the 0.1 ohm fusible resistor, and the horizontal output..I brought the line voltage up in 5 volt increments with the variac, and all was well for a few days. Now there is no video, although there is HV, , audio and the horizontal waveforms look good on the scope, however there is no G2 voltage from the flyback...I'm thinking the voltage divider is probably shot, and the cost of replacing the original flyback is just not woth it, the set is 10 years old. Has anyone ever used a replacement flyback from HR Deimen for this set, and is there anything else I can look at as the root cause of the missing G2? I'm going to try drilling a hole in the casing of the flyback, around the screen control, big enough to fit the straw from a can of cleaning spray as a last ditch effort to clean the contact area, but I'm not too hopeful of this actually working, although I have had some limited success with it, if anyone has any thoughts on this, I love to hear from you.........thanks for hearing me out!

techchris
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Apr 18, 2008, 3:45 PM

Post #2 of 9 (1865 views)
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Re: [crawdaddy] Sony KV32S40 [In reply to]	Can't Post

its not a good idea to make holes in the flyback transformer. check theree is no short circuit on the G2 line going to the crt.sometimes there is a cap on the crt base that goes or the crt could be faulty.is there any G2 volts at all?

crawdaddy
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Apr 18, 2008, 4:08 PM

Post #3 of 9 (1864 views)
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Re: [techchris] Sony KV32S40 [In reply to]	Can't Post

thanks for the shout back.....the G2 reads less than a volt...about 0.275v

crawdaddy
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Apr 18, 2008, 4:11 PM

Post #4 of 9 (1863 views)
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Re: [crawdaddy] Sony KV32S40 [In reply to]	Can't Post

techchris, if your right about the crt , then the voltage would return if the set ran with the crt board disconnected?

techchris
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Apr 18, 2008, 7:33 PM

Post #5 of 9 (1855 views)
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Re: [crawdaddy] Sony KV32S40 [In reply to]	Can't Post

yes,pull the base off the crt and switch on.from memory there was an old sony which had a diode in series with the G2 and a 1K resistor which went faulty but i dont know if your chassis was one of them as i have no circuit diagram

crawdaddy
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Apr 19, 2008, 12:07 PM

Post #6 of 9 (1849 views)
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Re: [techchris] Sony KV32S40 [In reply to]	Can't Post

Yes, it's referred to as the 1k video line ...I'll try that and post back with the outcome. I have the service manual for this set if you ever need it.....is covers a few inn the KV series....

crawdaddy
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Apr 19, 2008, 5:01 PM

Post #7 of 9 (1844 views)
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Re: [crawdaddy] Sony KV32S40 [In reply to]	Can't Post

Voltage still less than zero with crt board removed....looks like the flyback is toast, found a replacement from HR Diemen for about half the cost...never used one before..if anyone has any experience, good or bad with these flybacks, it'd be great to hear from you...we all know how fussy Sony equipment can be with generic parts.............and a big thanks to techchris for a fresh perspective...

rrobor
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Apr 24, 2008, 8:39 AM

Post #8 of 9 (1805 views)
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Re: [crawdaddy] Sony KV32S40 [In reply to]	Can't Post

Sounds to me you have done all you can in the horizontal, so I suggest you check your supply. Not knowing the set I cant tell you the correct part to use but its an R2K diode strapped across the B+ line. There are several types, from 120V to 200V , they are zener type Ics, once they zener they go dead short and protect all the rest R2KY=130V, R2KN =140V, R2k= 175V and RY23= 200V

crawdaddy
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Apr 25, 2008, 1:46 PM

Post #9 of 9 (1792 views)
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Re: [rrobor] Sony KV32S40 [In reply to]	Can't Post

Thanks for the new idea, rrobor, I'll check the service manual, and see what is used for that purpose in this set...I have found a replacement flyback at a good price, so I'll install it when it arrives, and creep the voltage up a little at a time again. These sets feature a fusible 0.1 ohm resistor R607, in series with IC 601, a double transistor array, with built in zeners across the base\emitter, and they are really touchy about having the full line voltage applied, when the set has been down for awhile. Anyway, I'll soldier on, and again, thanks for taking the time to share information with me...

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