Sony Karaoke VCR Dim VFD

[Ed in Tx]

Originally Posted by centralradio

I remember at the shop years ago when RCA/GE send out a supplement to put into the service manuals and had a kit to fix their VCRs with dim displays.

That could cover a LOT of models! There were the Hitachi-made VCRs with either discrete components in the DC-DC converter circuit, or had the DC-DC conv. module, either would fail from bad caps. Then there were the Samsung-made RCA-GE units with capacitors failing in the power supply. Thompson issued a rebuild kit for those. The driver transistor would often fail in those too. I would take that out and check the gain of the transistor since it wouldn't actually go open or short and read fairly normal with simple testing with a meter, and replace it as needed.

[centralradio]

Originally Posted by Ed in Tx

That could cover a LOT of models! There were the Hitachi-made VCRs with either discrete components in the DC-DC converter circuit, or had the DC-DC conv. module, either would fail from bad caps. Then there were the Samsung-made RCA-GE units with capacitors failing in the power supply. Thompson issued a rebuild kit for those. The driver transistor would often fail in those too. I would take that out and check the gain of the transistor since it wouldn't actually go open or short and read fairly normal with simple testing with a meter, and replace it as needed.

Thanks Ed for the details.It was awhile back and could not remember all the info .On the Sony VCRs I had several issues when those transistor look alike circuit protectors blown out. At first It took me on the loop troubleshooting it until I read up on it and found out what they were..The Sony SLV-KH3 is will worth it to fix it.

[Findm-Keepm]

Originally Posted by Ed in Tx

That could cover a LOT of models! There were the Hitachi-made VCRs with either discrete components in the DC-DC converter circuit, or had the DC-DC conv. module, either would fail from bad caps. Then there were the Samsung-made RCA-GE units with capacitors failing in the power supply. Thompson issued a rebuild kit for those. The driver transistor would often fail in those too. I would take that out and check the gain of the transistor since it wouldn't actually go open or short and read fairly normal with simple testing with a meter, and replace it as needed.

For the Hitachis, they made two kits - one early and one later - here's the later.

For the Samsungs, there were so many Goldenrods about them, they made a booklet identifying the changes that were to be made. Rectifiers, caps, spacer on a gear, and a check of the mode switch type. I have the booklet here somewhere, a freebie from RCA that came with our service lit subscription. All of the goldenrods I have are on microfiche, so not easily transcribed. Last time I printed from a microfiche, the ODU library was getting 70 cents a page...

The later VCRs with the VEPSXXXXX power supply modules, we got the kits from MAT or RCA, save for warranty work, where RCA made us swap supplies. The duds went back to RCA, so we had some fun and marked them with a small knife. After rebuild in Mexico, they were issued as new stock - proof that even RCA passed used goods off as new stuff. No reconditioned stickers like the modules and tuners - just a sealed bag with a rebuilt power supply. They paid 0.7 hours labor to replace the supply and more than that for "processing" the claim. Good money for an easy fix. Lightning killed them all - but RCA honored the warranty.

[Findm-Keepm]

OP/MIPS, I checked my Sony ESI library CDs (23 of them...) and haven't found a service manual. Odd unit, or too new for my stuff, which ended in 2005. A google search turned up the usual manual sellers, none of which showed a front page of the manual - handy to search with, as the Sony part number (9XXXXXXX number) is usually on the front page.
Union Electronics or Encompass might still have one if you need a manual, but they charge $$$$ for most Sony manuals.

[MIPS]

I am in the process of saving my pennies right now for the service manual for an unrelated Pioneer LC-V300.