I have an *old* top-loader, beta format VCR I am trying to resuscitate.
Everything works, but when I play storebought movies, I get audio wow and
flutter, and snow across the screen about once each second. When I play
back tapes I recorded long ago at the machine's slowest speed, the flutter
and snow occur less frequently.

I've replaced the idler and belt, and the pinch roller. I've lubricated
everything, and cleaned the tape path and heads. I did receive a suggestion
that the problem could be the capstan motor. I hope not, as I don't know
where I'd find such a part for a 23-year old VCR.

Any suggestions as to diagnosis, or leads on parts would be appreciated.
The model number is VCR-3900II.

Many thanks.

I'm assuming this is old enough were the capstand and the capstand
motor are not the same. Make sure to oil both.
With the age you may have weak filter capacitors in the power supply
causing ripple and poor regulation on the DC supply for the capstand.
Another possibility may be the upper and lower cylinder on the head
assembly.
These do not turn and sometimes the tape hangs or sticks to them
causing problems.You may want to do a google search on burnishing beta
heads.
You have to be real carefull as not to do the actual head disk.
Doug

"Comcast News" wrote in message
...
I have an *old* top-loader, beta format VCR I am trying to resuscitate.
Everything works, but when I play storebought movies, I get audio wow and
flutter, and snow across the screen about once each second. When I play
back tapes I recorded long ago at the machine's slowest speed, the flutter
and snow occur less frequently.

I've replaced the idler and belt, and the pinch roller. I've lubricated
everything, and cleaned the tape path and heads. I did receive a
suggestion
that the problem could be the capstan motor. I hope not, as I don't know
where I'd find such a part for a 23-year old VCR.

Any suggestions as to diagnosis, or leads on parts would be appreciated.
The model number is VCR-3900II.

Many thanks.



Make sure the audio/control head is well cleaned.


Mark Z.

On 27 Mar 2005 20:04:11 -0800 "Doug"
wrote:

You may want to do a google search on burnishing beta
heads.
You have to be real carefull as not to do the actual head disk.

I did the search that you recommended and came up empty handed. Can
you recommend anywhere in particular to look?

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

Try Googling "MisterBetamax"...he has a website that could be of assistance
and he answers emails. He has information on other brands of Beta decks and
he helped me ID the one I had. He also had links to eBay Beta related
auctions the last time I looked.

"Jim Adney" wrote in message
...
On 27 Mar 2005 20:04:11 -0800 "Doug"
wrote:

You may want to do a google search on burnishing beta
heads.
You have to be real carefull as not to do the actual head disk.

I did the search that you recommended and came up empty handed. Can
you recommend anywhere in particular to look?

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

You may search thru the folllowing
Also do a search on Zenith Beta as they used Sony

http://www.diyvcrparts.com/index.html
http://www.tutorgig.com/t/VCR
http://www.fixer.com/dbase/

Electrolytic capacitors have probably dried out and went bad in the capstan
or drum servo control circuits. When they go bad the servos can't compensate
for tape speed variations resulting in sound wow and flutter and snow lines
moving up and down the screen every few seconds. Usually the picture will be
fairly clear in fast forward and rewind modes since servo lock isn't needed,
but poor in regular play mode. The tracking control also becomes dead and
useless since the servos are way too far out of spec to compensate for.
Early 80s Sony Betamax units were notorious for this problem and Sony
capacitor repair kits were popular up until just a few years ago. You can
get a schematic and try to find out what electrolytics exist in the servo
control circuits and replace them. You can also try adjusting various pots
in those circuits to see if it will come back into spec as is, but you'll
still have big problems trying to watch tapes recorded from other machines.

You can buy totally reconditioned Beta machines by professional techs via
Ebay, but sometimes going for $200+ they're not cheap. The Sanyo 3900 was
far from a high quality machine.

"Comcast News" wrote in message
...

Any suggestions as to diagnosis, or leads on parts would be appreciated.
The model number is VCR-3900II.