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Magnavox VCR schematic or help needed

D

Don Wall

Jan 1, 1970
0
The VCR is a Magnavox VR601BMG23, the symptoms are: when plugged in, the
power led and cassette in led illuminate, even though there is no
cassette in the unit. It will not load a cassette if one is inserted,
and if the carrier is manually loaded, either empty or with a dummy
cassette, it will not eject it. The loading motor will try to run, and
if the belt is taken off, it will run. After a few seconds, the power
led will go out, and the cassette in led will flash. I could use a
schematic to troubleshoot, or if anyone has seen this problem and can
suggest a fix, I'd appreciate it very much!

Don Wall
 
O

Ol' Duffer

Jan 1, 1970
0
The VCR is a Magnavox VR601BMG23, the symptoms are: when plugged in, the
power led and cassette in led illuminate, even though there is no
cassette in the unit. It will not load a cassette if one is inserted,
and if the carrier is manually loaded, either empty or with a dummy
cassette, it will not eject it. The loading motor will try to run, and
if the belt is taken off, it will run. After a few seconds, the power
led will go out, and the cassette in led will flash. I could use a
schematic to troubleshoot, or if anyone has seen this problem and can
suggest a fix, I'd appreciate it very much!

I am writing from home, so don't have service manual handy.

"The loading motor will try to run" sounds like the mechanism
is stalled. Many of these have a "kick pulley" that engages
a pawl to snap the brakes on when going from FF or REW to
PLAY or STOP so you don't get tape spill. It takes a pretty
good amount of torque to drive this, and it is not uncommon
for the loading belt to slip with age, especially in a smoker
or greasy environment. Once the pawl is jammed against the
pulley, the machine will not recover until enough torque is
generated to finish the stroke. Often, you can give it a
push with your finger and it will then appear to function
normally for awhile, but will happen again if the belt does
not have enough traction. The cure for this is to replace
the belt and clean the pulleys.

Another scenario is that if the mode switch gets oxidized
badly enough, the machine will not be able to find home
position. Motor will run all the way to end of eject and
continue trying to run until it times-out. The cure for
this is to clean the mode switch and lubricate it with an
anti-oxidant oil or grease.

And the opto source and tape end sensors can cause some
odd problems. IR LED in the middle of the tape gets
weaker with age, tape end mirrors get foggy, sometimes
light pipe alignment was poor to start with.

Loading mechanism, mode switch, and opto sensors are the
sources of an overwhelming majority of problems. When I
break out a service manual, it's usually to look up part
numbers, and it's rare to unfold a schematic page.
 
M

Mark D. Zacharias

Jan 1, 1970
0
Ol' Duffer said:
I am writing from home, so don't have service manual handy.

"The loading motor will try to run" sounds like the mechanism
is stalled. Many of these have a "kick pulley" that engages
a pawl to snap the brakes on when going from FF or REW to
PLAY or STOP so you don't get tape spill. It takes a pretty
good amount of torque to drive this, and it is not uncommon
for the loading belt to slip with age, especially in a smoker
or greasy environment. Once the pawl is jammed against the
pulley, the machine will not recover until enough torque is
generated to finish the stroke. Often, you can give it a
push with your finger and it will then appear to function
normally for awhile, but will happen again if the belt does
not have enough traction. The cure for this is to replace
the belt and clean the pulleys.

Another scenario is that if the mode switch gets oxidized
badly enough, the machine will not be able to find home
position. Motor will run all the way to end of eject and
continue trying to run until it times-out. The cure for
this is to clean the mode switch and lubricate it with an
anti-oxidant oil or grease.

And the opto source and tape end sensors can cause some
odd problems. IR LED in the middle of the tape gets
weaker with age, tape end mirrors get foggy, sometimes
light pipe alignment was poor to start with.

Loading mechanism, mode switch, and opto sensors are the
sources of an overwhelming majority of problems. When I
break out a service manual, it's usually to look up part
numbers, and it's rare to unfold a schematic page.

Good suggestions. I would add that maybe the load carriage timing is wrong
with regard to loe lower mechanism. Happens all the time, especially if
someone has been into it.

Mark Z.
 
I have an old Magnavox VCR that began having a strange problem.
I unplugged and re-plugged all connectors (must have been over
35 connectors). Problem disappeared. Apparently a bad connection
formed over the years.
 
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