Ampex VPR-80 analog 1"

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Archivist
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Joined: Tue Nov 26, 2019 5:22 pm

Ampex VPR-80 analog 1"

Post by Archivist » Tue Nov 26, 2019 6:25 pm

Does anyone know a place I can take this machine for tune ups (preferably within an easy drive of Northern Montana. The machine is running and has a good picture but has servo problems the longer it runs.

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PID_Stop
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Re: Ampex VPR-80 analog 1"

Post by PID_Stop » Wed Nov 27, 2019 8:53 am

The people who really know these machines (I am not one -- my expertise is with Sony BVH-2000s) are getting hard to find, since the machines are typically 30+ years old, and the people who maintained them are pushing retirement age.

Having said that, here are some general ideas that might help you solve the problem yourself. These are not in any particular order, and I would say #2 is the most probable.

1) Since you say that the servo problems develop the longer it runs, that suggests that the electronics are basically okay, though you could be having trouble with dried out capacitors that drift as the machine warms up. If you can open up the machine to let it cool down (maybe with the help of a fan), that would help narrow down a thermal problem.

2) Another potential cause of servo problems that escalate as you approach the end of the tape is the tape slipping between the capstan and pinch roller. This could be caused by excessive holdback tension, but given the age it's pretty likely that your pinch roller is glazed and/or hardened. Take some medical grade isopropyl alcohol (not the stuff with lots of water) and a lint-free wipe, and give the rubber roller a really good scrubbing until it is no longer shiny and has some "bite" to it. Also make sure that the mechanical linkage for the pinch roller isn't bound up (I've seen this very problem on Sony machines, where the grease sets up... and the result is indeed servo problems). Giving it a good cleaning so that everything moves freely will let the solenoid pull the roller completely against the capstan.

3) If your environment is unusually dry, it's possible that static is building up and causing the tape to stick to the tape path surfaces more than usual.

4) Really old tapes that have not been played in a long time can deteriorate, and layers can stick to each other coming off the reel. Try fast-forwarding the tape to the end, rewind it completely, clean the tape path thoroughly, and try again.

5) Is the supply reel damaged? A reel flange that's rubbing the tape can create trouble like this.

Best of luck, and a happy Thanksgiving to you!

-- Jeff

Archivist
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Re: Ampex VPR-80 analog 1"

Post by Archivist » Wed Nov 27, 2019 1:28 pm

Thank you Jeff
I did a thorough cleaning of the pinch roller before posting and it didn't have any effect. The pinch roller seems in pretty good shape.
I am in a very dry environment but the machine has worked well up to this point.
The same tapes that give problems will play fine the next day so I'm sure the tape isn't the problem. There is also plenty of rf showing.
The take up reel is in good shape.

I'll pull all the boards and look for capacitor problems or loose ic's. Thanks for the suggestions.
I have 75 tapes to transfer and 1 per day will take a while but worst case scenario - 2 1/2 months and I'll be done.

Happy Thanksgiving to you too.

kcbooboo
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Re: Ampex VPR-80 analog 1"

Post by kcbooboo » Thu Nov 28, 2019 5:28 am

"The same tapes that give problems will play fine the next day so I'm sure the tape isn't the problem."

See Jeff's item 4 above, assuming the tapes are in good enough condition to survive FF and REW once or twice.

Bob M.

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