Need Help With Sony GV-8 Video Walkman

Hi, all. I have a Sony GV-8 Video Walkman unit. Like all Sony products
from the late 80s and early 90s, it had the classic leaky electrolytic cap
problem. I replaced all the caps a year ago, and it worked fine. (That was
a beastly job!!) Then I put it away for about 6 months. When I took it out
again, everything seemed to work, but it's recording only in b/w.
On-screen pic during record is color, and playback of older recordings is
color, but new recordings are b/w.

I'm quite familiar with the color under recording process, and I'm
guessing that the conversion oscillator might not be running, or that the
converted subcarrier might not be getting mixed in at the record amp. I
don't have service data for the machine, though, and it's hard as hell to
reach much of what's in there. There are several shield cans that are
quite hard to pry off without breaking the board. I don't know where the
conversion oscillator is. Also, when the machine is monitoring the
picture, is that direct e-e (as they used to call it), or has the signal
gone through the color under process and then been reconstituted? If so,
that would indicate that the conversion is working and the problem must be
at the head amp. If not, it could be the conversion oscillator.

Anybody know these units? It'll be a shame to have to junk it after all
the work I put in refurbing it a year ago. Any help is appreciated.

Thanks!!

Michael

 

Try cleaning the heads to start with. Beyond this, it would take some
troubleshooting to find where the failure is without guessing at what is
probable.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
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Hi, all. I have a Sony GV-8 Video Walkman unit. Like all Sony products
from the late 80s and early 90s, it had the classic leaky electrolytic cap
problem. I replaced all the caps a year ago, and it worked fine. (That was
a beastly job!!) Then I put it away for about 6 months. When I took it out
again, everything seemed to work, but it's recording only in b/w.
On-screen pic during record is color, and playback of older recordings is
color, but new recordings are b/w.

I'm quite familiar with the color under recording process, and I'm
guessing that the conversion oscillator might not be running, or that the
converted subcarrier might not be getting mixed in at the record amp. I
don't have service data for the machine, though, and it's hard as hell to
reach much of what's in there. There are several shield cans that are
quite hard to pry off without breaking the board. I don't know where the
conversion oscillator is. Also, when the machine is monitoring the
picture, is that direct e-e (as they used to call it), or has the signal
gone through the color under process and then been reconstituted? If so,
that would indicate that the conversion is working and the problem must be
at the head amp. If not, it could be the conversion oscillator.

Anybody know these units? It'll be a shame to have to junk it after all
the work I put in refurbing it a year ago. Any help is appreciated.

Thanks!!

Michael

 

Hi, Jerry. The heads are clean as a whistle. And, as I mentioned, color
playback is fine; it just won't record in color.

I'm an ex-VCR tech and good at it. I just don't think it's worth spending
for a service manual for this thing. I was hoping somebody might have some
experience with this particular problem or at least know where the chroma
section is. I do see a 4.something MHz ceramic resonator, but I'm not sure
if it's for sound or chroma. In any event, it has signal on it. The 3.58
xtal is running too.

Guess I'll have to just poke around and see if I can find it. I've run
into many older gadgets that had crystals that got balky when they got
older. Usually, a few pf from one terminal to ground will get them started
again. I had to do that to a Panasonic color LCD and it fixed the problem.
This darned video walkman is just so hard to work on.

Sincerely,
Michael