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  #1  
11-21-2022, 06:16 AM
MrPete MrPete is offline
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(My current adventure began with F04 tape loading error. I'm now deep into Panasonic K Mechanism alignment (AG-5710/1980.)

I'm seriously thinking my Pinch Cam is misaligned or not assembled correctly. I've yet to discover a video or written explanation in any detail of this aspect of the Panasonic K Mechanism.

Symptom: the pinch roller doesn't go up and down properly AFAIK. When I turn the pinch cam gear, it doesn't go up/down even though I see the plastic spiral. I can manually move it up/down a little by lifting/turning... yet even that seems inadequate.

Progress:
  • I've removed the pinch roller assembly from the top of the pinch cam.
  • I've now got the inner gear+spiral axle (white plastic), and outer yellowish plastic housing that apparently should ride up and down the spiral.
Problem: while the outer housing is loose, it absolutely will not lift off of the inner gear/spiral.

QUESTIONS:
  • Any pointers to descriptive info / video on how this ought to function?
  • Any ideas on disassembly?
Thanks muchly!
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  #2  
11-21-2022, 06:34 AM
dpalomaki dpalomaki is offline
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From the AG-1980 FSM

Error F04
Cause Mechanism locks during tape unloading
Remedy/Check
1. Check the loading motor drive circuit.
3. Check the mechanism phase alignment.

Do you have the K-mechanism service manual?

May or may not apply but there is a small plastic coupling on the shaft of the loading motor that acts as sort of a clutch with the worm gear on the loading motor that often cracks causing slippage and failures to load/unload properly. There are separate threads about that somewhere here.
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  #3  
11-21-2022, 09:58 AM
MrPete MrPete is offline
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Right. The loading motor works, and I'm in the middle of mechanism phase alignment. I'll upload a video showing the exact issue I am having.
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  #4  
11-21-2022, 10:30 AM
MrPete MrPete is offline
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Here's a brief video demonstrating what isn't working -- it's the "pinch arm unit" (VXL2246 - roller and outer shell) which mounts on the "pinch cam gear" (VDG0886). i have found both online. I don't see any reason why they would be stuck together like this. ... then again, I've never taken this apart before.


Attached Files
File Type: mp4 2022-11-21 08.29.46.mp4 (15.51 MB, 10 downloads)
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  #5  
11-21-2022, 10:35 AM
MrPete MrPete is offline
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BTW, Quasipal posted a *private* Youtube video several years ago that demonstrates several failure modes etc. It shows a different version of the pinch cam assembly. Here's a link to the original post here... not easily found! https://www.digitalfaq.com/forum/vcr...html#post49715
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  #6  
11-21-2022, 12:13 PM
latreche34 latreche34 is offline
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You are going to have to remove both the white gear at the bottom and the top cam follower or whatever is called and inspect them outside the mechanism, spry some oil between the parts to ease the disassembly, I also noticed that the parts are dry, did you clean up the old grease or was it dry like that?

https://www.youtube.com/@Capturing-Memories/videos
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  #7  
11-21-2022, 01:03 PM
MrPete MrPete is offline
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I had cleaned up old grease. You're exactly correct on there being no way to resolve in place. Just finished working it out:
  • The only way to separate was to remove the P5 base / P5 stopper, which on this K mechanism has a tiny hold down for the cam gear
  • With that removed, I was able to remove both the cam gear and the rest together.
  • Only then could I gently take the two apart with careful wiggling.
  • Turns out, the cam gear has a correct place for the guide pin, and an incorrect place, which is where it somehow got stuck: unable to fully rise or fully drop.
  • I'll upload a short video after I can shrink it to size, showing the issue.
NO idea how this VCR got in such a state.
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  #8  
11-21-2022, 01:20 PM
latreche34 latreche34 is offline
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Sudden shock, broken tapes, foreign objects fall in the gaps, Excessive wear and lack of lubrication, These are all potential causes for mechanisms miss alignment, That's why VCR's have service schedules back in the day just like cars.

https://www.youtube.com/@Capturing-Memories/videos
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The following users thank latreche34 for this useful post: MrPete (11-21-2022)
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