CED VideoDisc and Player Discussion

[olePigeon]

Hello. I purchased a RCA VKP-950 VCR described as "just needs new belts." Someone else had obviously worked on it, and I inherited their garbage. So I've been trying everything to get it working. It originally wouldn't turn the supply or pickup reels. The supply reel was grinding on something, but I managed to fix it (see below if interested.)

https://www.youtube.com/watch?v=p0-bo35GMm4

Turns out it was missing a washer or two and was too low, so it was grinding against the metal frame.

So after adding a couple washers to get it the correct height, I solved the grinding issue. I then discovered the sensor on the back left near the play head had completely detached from the circuit board. Re-soldered that back on.

I installed new belts, new pinch roller, and new idler. Apparently the takeup reel's teeth were just too worn out, so even a new idler wasn't engaging. See below if interested:

https://www.youtube.com/watch?v=3-kpkLLzMGs

So I cut a balloon stem and it's on the idler wheel snugly. That gave it just a bit extra width and grip, so now it grips super tight.

During all this, the power was intermittent. The 5v was all over the place with anything connected (fluctuating 1v to 6v), and nearly 6 volts when nothing connected. The VCR would appear to work fine for a few minutes, then the power would go out.

So I replaced the voltage regulator, and that fixed the fluctuating power issue.

Except now the VCR is stuck with the "VCR" and "CHARGE" lights permanently on. The clock does not turn on. Pressing the power button the VCR unit will make it turn on temporarily, then turn off immediately.

It used to do this when the power was initially failing, but would eventually switch over to regular operation (before the power would wonk out.) Now that I have a steady 5v, it's permanently stuck with the two LEDs on. They're very bright, which is reassuring compared to before where they were very dim, but I can't get the VCR to work.

I checked the voltages, and the 5v and 10v are steady and solid.

I've also replaced all the caps just incase that was the issue (including the 5.5v super capacitor.) The regulator board had some pretty bad capacitor leakage. Unfortunately, that didn't fix anything. I've also replaced the op amp.

I have not replaced the thyristor or the IC to the right of the CPU. I'm thinking I might as well, since that would mean I've replaced 100% of the parts on the thing, save for the transformer (which seems fine.)

Does anyone have any suggestions before I buy those parts?

Thanks,

oP

[olePigeon]

Forgot to mention. The 2 lights are on regardless if the VCR is docked. So it's not a battery thing.

[olePigeon]

Well, I just went ahead and purchased a 5444 SCR thyristor. Apparently it's a part that's replaced enough times that RCA sold it as a replacement.

The only parts I will have not replaced will be the CPU itself and the HA17339A comparator.

So if this fixes it, then my VCR will be literally as good as new, save for the reels.

Incidentally, does anyone have any new old stock takeup reels for the RCA VKP-950 (or similar models?)