J
Jumbaliah
- Jan 1, 1970
- 0
Hi,
I recapped my powersupply with panasonic FC series (low esr 105deg)
electrolytics in my JVC HR-S4700U about a month ago. I have used the
tuner since then without problems. My problem now is that the VCR
doesn't work well with tapes. I've got the service manual and I've
recently replaced the following:
Loading belt
Pinch roller
Mode Switch (didn't realize I could have cleaned my original)
Capstan Gear (original had cracked but still seemed fine - better to
change it)
In the manual there is a procedure to check the main deck without the
cassette housing. Once the housing is out of the way (unobstucted
view of the main deck) you have to disable the End-Sensor with an
opaque cover (I used heat shrink). Then connect pins 2 and 3 on the
Deck-Terminal board connector 3 (CN3). I used a computer jumper to
short these pins. Then it says I should be able to select a mode of
operation. It cautions that if I try a reverse direction it will stop
after a few seconds because of the reel sensor.
After setting up the above (without vhs tape) and powering on the VCR
the mode motor spins the worm clutch so the control cam rotates CCW -
about 90 degrees. This causes the Pinch roller to start to drop into
place. It only moves down slightly then stops and the mode motor
reverses direction. The mode motor forces the control cam to rotate
CW until part of it hits the stop on the half loading gear. The
loading belt then just slips on the worm clutch for a second or so and
the VCR powers off.
When I replaced the loading belt I made sure the alignment holes
though the cam/gears matched as well as the half loading and guide arm
assemblies and plate assembly under the main deck.
When I tried testing with the cassette housing and a real vhs tape (no
jumper and heat shrink used) it will either:
1) Load tape. Play the tape but the take up reel doesn't seem to work
as the tape starts snaking it's way all over the place after the
capstan/pinch roller. I quickly hit stop and eject to save the tape.
2) Load tape. Play fine and even play with forward search. As soon as
I hit rewind search it started to pile up tape then sensed something
wrong and shut off.
3) Load tape. I then just hit eject (no attempt to play) and it
doesn't fully reel in the tape and it ejects the cassette.
I looked at the idler gear and it seems fine. The teeth on it and the
clutch assembly both appear fine. The timing belt looks good. I can
rotate the capstan motor and it spins the idler gear via the clutch.
I'm new to fixing VCRs but I've learned a lot more on how they work.
Just not enough to get mine running smoothly. Anyone have any
suggestions?
Thanks,
burnboy
I recapped my powersupply with panasonic FC series (low esr 105deg)
electrolytics in my JVC HR-S4700U about a month ago. I have used the
tuner since then without problems. My problem now is that the VCR
doesn't work well with tapes. I've got the service manual and I've
recently replaced the following:
Loading belt
Pinch roller
Mode Switch (didn't realize I could have cleaned my original)
Capstan Gear (original had cracked but still seemed fine - better to
change it)
In the manual there is a procedure to check the main deck without the
cassette housing. Once the housing is out of the way (unobstucted
view of the main deck) you have to disable the End-Sensor with an
opaque cover (I used heat shrink). Then connect pins 2 and 3 on the
Deck-Terminal board connector 3 (CN3). I used a computer jumper to
short these pins. Then it says I should be able to select a mode of
operation. It cautions that if I try a reverse direction it will stop
after a few seconds because of the reel sensor.
After setting up the above (without vhs tape) and powering on the VCR
the mode motor spins the worm clutch so the control cam rotates CCW -
about 90 degrees. This causes the Pinch roller to start to drop into
place. It only moves down slightly then stops and the mode motor
reverses direction. The mode motor forces the control cam to rotate
CW until part of it hits the stop on the half loading gear. The
loading belt then just slips on the worm clutch for a second or so and
the VCR powers off.
When I replaced the loading belt I made sure the alignment holes
though the cam/gears matched as well as the half loading and guide arm
assemblies and plate assembly under the main deck.
When I tried testing with the cassette housing and a real vhs tape (no
jumper and heat shrink used) it will either:
1) Load tape. Play the tape but the take up reel doesn't seem to work
as the tape starts snaking it's way all over the place after the
capstan/pinch roller. I quickly hit stop and eject to save the tape.
2) Load tape. Play fine and even play with forward search. As soon as
I hit rewind search it started to pile up tape then sensed something
wrong and shut off.
3) Load tape. I then just hit eject (no attempt to play) and it
doesn't fully reel in the tape and it ejects the cassette.
I looked at the idler gear and it seems fine. The teeth on it and the
clutch assembly both appear fine. The timing belt looks good. I can
rotate the capstan motor and it spins the idler gear via the clutch.
I'm new to fixing VCRs but I've learned a lot more on how they work.
Just not enough to get mine running smoothly. Anyone have any
suggestions?
Thanks,
burnboy