Toshiba M-641 VCR powers on, but doesn't work?

[gronke]

See subject. I picked up a Toshiba M-641 VCR that appeared to be in great condition. However, after plugging in, the only thing that happens when I press the power button is that it illuminates red. Nothing comes on the panel, it won't accept a tape, etc. Basically seems stuck in "standby" or something? I popped open the case. There are two fuses near the power supply, but both appear to be good (checked with a dmm). Where should I start to try to diagnose this? Thanks!

[dpalomaki]

A first step would be to try find a factory service manual.

Won't accept a tape. Does that meany you can insert a tape in the slot but it doesn't load the tape?
When powered on does the head spin briefly then stop?

[gronke]

I can't find a service manual, which has been a first major problem that's led me here.

Correct, it does not load the tape, as in there is no power to the tape loading mechanism.

The head does not spin when powered on. The only thing that happens when the power button is pressed is the power button led light comes on and remains on until pressed again. That's it.

[dpalomaki]

Without a service manual you are running close to blind.

https://www.stereomanuals.com/man/rep/toshiba/toshiba_manuals_m_xx.htm
might have one available for a fee.

First thing I would check is to see if the power supply is putting out voltage to the other boards in the box.

But given the very limited information available on it, that it is VHS, it may not be worth trying to fix. Looking clean on the outside does not assure it will work, just means its case was not abused or handled with dirty hands.

[gronke]

I did continuity testing along the board, and the only spot that doesn't work is going over or from the transformer that sits next to the power supply. That seems the likely culprit, no?

[dpalomaki]

If there is no continuity where there should be, that sounds like a problem.

I gather that there is no output from the power supply.

[gronke]

There is, because the LED on the power light is able to be turned on and off.

[dpalomaki]

That means is that the power to the LED works. If you get no other display beyond a pilot light; e.g., blinking time or mode indication...

VCR power supplies often provide a variety of power output voltages/connections so one may find that some are working and others are not. For example, the power supply in a a Sony VCR I have has five different power outputs from the power supply.

Without the schematic diagram, or a known working model for comparison, you are trusting to luck.

BTW: what is your electronics technician skill level?

[gronke]

Quote:

Originally Posted by dpalomaki

BTW: what is your electronics technician skill level?

Beginner, but I have a degree in Physics. I'm learning!

[lordsmurf]

The bigger issue is that this VCR isn't worth fixing for any sort of real-world usage scenario. It's somewhat crappy for VHS transfer, and you shouldn't play tapes outside of transfer anyway.

You'll just waste time and funds on this.

A comparable/identical Toshiba deck will be under $50 on eBay.

Sure, 20+ years ago, I mentioned it was okay. Not great, not the best, just okay. Late 90s Sharp and early 2000s Sony are far better units. It's been many years since I've had one of these in-hand, and there's a reason for that.

If this is just for funsies, good luck ... I guess. (Not my idea of fun, sounds like work.)

[waldo9555]

Hi gronke, I'm just curious to know if your VCR problem is resolved? because I got exactly same problem as you, but mine is Toshiba M-647 VCR.

I use mine to convert VHS to mp4. But today, like you, no display at all (no hour showing), and the red led lit when I power ON. Impossible to put a tape in it, it don't want.

I can see that there is no 33 volts at the harness that goes from the power supply to the motherboard. But I don't know under what circumstances this should be the case.

I did not find service manual on the web. Do you?

Thanks