Video stopped working (Sound works) Watson VR3730
 

Hello,
I recently got a Watson VR3730 VCR that was stored away for at least 10+ years, which i want to use to create digital copies of some VHS tapes.
I connected the VCR to my PC via a Video/Audio Grabber and stared recording.
After I finished recording I restarted the Tape and the problems started.
Suddenly the video was black and white, I tried different tapes, reconnected everything and so on.
Then the video disappeared completely and the sound became really bad.
The next thing I tried was opening the VCR and clean everything, this fixed the sound but i still don't have any video, the screen stays completely black.

Any ideas how I can get the video back?
I have some technical knowledge and tools (multimeter) if that helps.

You can't expect a VCR that's been in storage for 10+ years to work properly without servicing it first. Cleaning the VCR won't do much. These devices need to be serviced every 3-4 years.

Hard di diagnose without having the machine on a bench.
I don't know the Watson VR3730, but a couple things might help narrow it down.

You said you are connected to a computer. Does it work connected to a TV?
Does the VCR output a RF video signal that would normally connect to the antenna input of a TV?
Is it connected via s-video or composite?