Sony KV32S12

Hi. Does anyone know what all I have to do to get this set going? Both oif the

4834 transistors were blown, the fuse resistor and three of those small condensers also, the HOTr chceks good Could I have Flyback trouble? Thank you for the help Vince.
Reply to
Vince
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Possibly flyback,crt, the power supply VDRs. Look up past postings for the long list of parts to replace and some hints on variac checks. Don't have a variac? Little chance of KNOWING that it is fixed properly.

Best bet is to follow Sony's repair and troubleshooting guide on that smps design.

Reply to
dkuhajda

Sony SP-Kit has 2-2SC4834, 2SD4927, 0.1 ohm fusible resistor. Flyback is fine, rare to go in these units. VDR601 (281K) must be replaced, or it will blow up again. Solder horizontal drive transformer. Rono.

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Rono

Reply to
kip

Rono: Even if all of what you mentioned is replaced there are other parts that can cause immediate and drastic failure..... refer to the Sony factory service literature on this troublesome SMPS design.

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Daniel Sofie
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Reply to
sofie

Flyback is unlikely. If you have not serviced these supplies they can be tricky and if you don't have a scope and a variac you may waste parts and lots of effort. If the HOT is shorted you likely have bad connections on the HDT or a bad cap in the H-drive circuit. If this is the case, you would not likely have had the other parts besides Q601,2 and R607 fail. When you have other parts fail in the PS it is usually due to something in the PS or an external cause such a lightning or a power surge. Basically, every part in the PS primary needs to be tested and the PS needs to be checked as you start it up slowly for operating frequency, transistor duty cycle, and output. If you don't have access to the Sony training material it will be hit and miss. If you try to fix it yourself, make sure to use P rank

2SC4834 transistors, preferably a matched pair. It is not necessary to get them from Sony as many will tell you. Also, check the VDRs carefully. If in doubt, change them if you can't test them, though it is not necessary in all cases (another Sony related myth). I would suspect them in this case, since you noted the additional parts damaged in the PS.

An experienced Sony tech can fix these quickly. We charge $80 labor, plus parts for most of them. Also, the CRT needs to be tested at this age to verify the set is worth fixing.

Leonard

Reply to
Leonard Caillouet

If you have a drawing on this set, I need to know the value of , C 609,610,

Reply to
Vince

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Art

Reply to
Vince

You sound like a tech. Where are you located and what kind of work do you typically do?

Start the PS up slow and as soon as it starts switching note the frequency. If it is below about 50kHz be careful. I have seen these sets with surge damage with bad switching transformers and the tend to run slow from the start. If it does it will blow the PS again in short order. Also note the duty cycle of the transistors, which should be within a couple of percent of

50%. You should really get the training manual on this series of sets if you are going to work on them. Once you get to understand them they are pretty easy repairs.

Check the standby circuit. If VDR601 was shorted, R644 is likely open and you need to check the rest of the standby circuit carefully before trying to start the PS. With external sources of damage I have seen these circuits, and the soft start and protect circuits damaged.

C609-C612 .22uFd 100V R653 1 ohm .25W

BTW, Tritronics has many Sony parts on their search engine and if they don't will do the research for you for free. Other Sony distributors such as Andrews and Fulton will do the same.

Leonard

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Reply to
Leonard Caillouet

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