Quasar VR-1000

[old_tv_nut]

This is an adjustment to make the free-running head speed approximately match video vertical rate when recording.

Speculation:It could be that some component in the servo loop has drifted, so that you are compensating for that when making this adjustment in record mode. Then when you go to play mode, there is no video input and the offset shows up.

In any case, there must be a malfunction causing it to run at a different speed on playback. You could try adjusting it for correct playback speed (as seen via your USB capture) and see what voltage readings you end up with in this record procedure.

Servos are hard to debug because if there's an error in one part of the loop, another part will compensate until it's so bad you exceed the pull-in limits.

[starbond]

Thanks for the help TV_NUT.
You dont have to of course, but here are all the sheets with adjustments on it. If you have a moment to skim through it, perhaps you might see something that could be adjusted instead? I feel like I'm very close to the end but keep getting caught on the little things

https://www.mediafire.com/file/anwi9...pages.pdf/file

Unfornuately, when I try to upload the individual sheets they are unreadable becuase videokarma compresses it so much

[old_tv_nut]

First thoughts: anything on the FV panel except the top two audio items could be suspect. Anything involving the control pulse or 60 Hz oscillator. I don't know why they have an amplitude check for the "frequency generator" and not a frequency check.

[starbond]

A bit of good news and not so good news. I DID manage to get the monitor colors to sync with the playback colors. so NTSC color bars show properly in monitor mode, and videos play with correct color.
I did recheck the tape speed adjustment and it was exactly where it should be, and yet the capture card still gave me the same issues as before, whether I plugged the VTR right to the card or ran it through the TV and out to the card.
Also TV_NUT, if you notice on all those you mention, there no way to adjust them if they are wrong, it just states "x should be y". I wouldnt know how to correct if I needed to.

[old_tv_nut]

Do you get the same skewing if you are in monitor mode and connected to your USB capture device, or only in tape playback?

[starbond]

If I record a moving image in MONITOR mode, it looks fine on my USB device.

I was going through the adjustments again and I noticed
HORIZONTAL OSCILLATION BIAS - SET TO 4V (with MM)
Now for some reason, I'm only getting about 3.5V if I leave the variable resis. at its location when i started working on the unit. even if turn it to MAX level, I only get about 3.75V Perhaps I should look into this?

Lastly, I recorded the NTSC signal onto a blank tape, and played it back, and god it looks awful, for some reason the picture is too low so theres a horizontal bar at the top, and the color drops in and out at random.

[starbond]

I also found an interesting pattern on the dull side of some of the tapes.

[old_tv_nut]

Scratching my head. I have no idea what the specs of D355 are supposed to be. You could check resistor values to see if anything is open or far off-value. Haven't figured out what's going on with the oscillator feeding back to TR356 either.

Weak/noisy recording is surely something else entirely. Have you checkjed FM record current (VR301)?

[Electronic M]

Originally Posted by starbond

I also found an interesting pattern on the dull side of some of the tapes.

Probably a manufacturing mark (my guess is it rested on chicken wire or some such material with that pattern)...Magnetic tape was probably made in strips a few feet wide then cut to 1/2", 1/4", 1/8" etc before spooling and packaging (same way they make toilet paper, paper towels, electrical tape, etc)...

[starbond]

Well something happened and now I have a major setback, I dont know what happened, but now when I play tapes, I get very bad flagging and the color drops in and out of sync at random. I can hear the tape head whine go up and down as the picture fuzzes in and out. I'm so upset. The tapes were playing FINE and now they are borderline unplayable..

[old_tv_nut]

Check for something related to the control track - maybe just a head cleaning.

[Electronic M]

Also may be a good idea not to store tapes close to the TV since most sets have a degaussing coil that runs Evey power up or down of the TV and is capable of harming magnetic media...

[starbond]

Thanks for the heads up about the tapes, they are no longer near the TV.
As for the picture, nothing I've done has made much of a difference. Control track waveform is showing what it should be. schem says 150pp min and its at 200pp with no adjustment for that one.
I'm feeling pretty discouraged, maybe this unit can't be fixed after all. I'll keep trying but, at least I was able to finally see what was on the tapes.

[starbond]

So perhaps in a foolish state, I purchased another VX1000 off ebay to perhaps mix-n-match parts on. I'm determined to get this working haha.
So far this unit only had 3 major flaws, two have been fixed:
Melted Drive Belt - cleaned and swapped with one from my first unit
Cracked circuit boards on the bottom - swapped from my first unit
7V take up motor does not spin - might be a crack somewhere i didnt see or a bad component. This shouldnt be too hard to fix.
Assuming I get that fixed, this second unit seems to be much less used than my first one. Fingers crossed on this

[old_tv_nut]

Well, you touched the "tarbaby" - no getting loose now!