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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 26th Feb 2005, 4:39 pm   #1
scruffygit
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Default Revox PR99 - Slow or no rewind

Just wondered if anyone has any ideas on this. My PR99 (nearly the same as B77) refuses to rewind tape properly. It's very slow or stopped. Sometimes you can get it going by physically rotating the spool. It seems worse on 10.5 Nab spools than on 7 spools. It plays OK and seems to fast forward OK. It will rewind a bit quicker if I engage the tape dump button. I bought the PR99 on Ebay about 3 months ago, and at that time it was OK, since then it hasn't been used, until now and it's playing up. Any info would be greatly appreciated. Thanks.
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Old 26th Feb 2005, 9:41 pm   #2
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Default Re: Revox PR99 - Slow or no rewind

Hello Scruffygit, !! Although I have couple of Revox recorders I am unable to suggest a cure for the problem with your PR99. You may get more response to your request for info if you put it on the "Vintage tape recorder" section on this website. Hope its soon sorted. Reelguy. Failing that there are a few Reel recorder sites with people who may be able to suggest a cure..
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Old 26th Feb 2005, 10:45 pm   #3
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Default Re: Revox PR99 - Slow or no rewind

I've moved it for you.
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Old 26th Feb 2005, 11:07 pm   #4
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Default Re: Revox PR99 - Slow or no rewind

Hi Scruffygit
I'll have a quick look in my PR99 manual tomorrow and see if I can help.
I have a feeling this machine uses rubber wheels, so we may be talking spring tension, roughing surface with sandpaper etc.
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Old 26th Feb 2005, 11:11 pm   #5
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Default Re: Revox PR99 - Slow or no rewind

Hello,

I have had a similar problem with a ReVox but it turned out to be a burned out motor. First, remove the reels, cover the light sensor then press rewind, see if the supply motor picks up speed quickly you may just have a lubrication problem if its been standing. Another thing it could be is oxide build-up, some tapes leave sticky oxide on the heads and guides causing excess friction on the tape.

Just checking, this will be a thee servo controlled motors, you could check to see if the motor is burned out by checking the impedance of the supply reel against the impedance of the take-up reel if you have a meter.

I shall have a look into my manuals and see if I can find some info on the PR99

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Last edited by reel-to-reel-man; 26th Feb 2005 at 11:19 pm.
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Old 27th Feb 2005, 12:29 pm   #6
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Default Re: Revox PR99 - Slow or no rewind

Hi Guys. Sorry about posting this in the wrong section to start with!
Thankyou for the tips so far. I can't get to look at the PR99 today (Sunday) but hopefully I'll get a chance tomorrow and I'll report back. Thanks once again....I'dreally like to fix the beast as it looks like minimum repairs are in the region of £125.00 and I'm sure that it can't be that serious. I have tried rewinding with no spools and covered the sensor. The supply motor picks up speed quickly....about the same as the takeup motor if FF ing. One thing though is that the pickup motor is running in the opposite direction when the supply motor is rewinding........I'm not sure but is this to give tape tension? This is only evident when there are no spools.
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Old 27th Feb 2005, 1:44 pm   #7
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Default Re: Revox PR99 - Slow or no rewind

The take up reel moving in the opposite direction whilst rewinding is perfectly normal, if you think the motors are picking up speed equally then I would have a look at the heads and guides. If you can see black deposits on the rollers and heads this will cause the tape to stick making it hard for the recorder to move. Clean the guides with pure alcohol or something with a high alcohol contents (Vodka )Just checking, does this recorder have a switch for spool size, most machines have a 7" and 10.5" switch, I think that the newer machines like the A807 and onwards didn't though.

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Old 27th Feb 2005, 8:20 pm   #8
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Wink Re: Revox PR99 - Slow or no rewind

Are the motors induction, capacity start split phase? check caps for leakage.
If leaking , motors will run on reduced power. Replacement caps can be found at Radio Spares. (Do not use electrolics)
Harold

Last edited by scotty29; 27th Feb 2005 at 8:27 pm.
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Old 27th Feb 2005, 9:46 pm   #9
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Default Re: Revox PR99 - Slow or no rewind

Hi Scruffygit
Had a butchers at my PR99 manual as promised, but is only the circuit diagrams, no pysical layouts or mechanical info.
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Old 27th Feb 2005, 10:53 pm   #10
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Default Re: Revox PR99 - Slow or no rewind

Quote:
Originally Posted by scotty29
Are the motors induction, capacity start split phase? check caps for leakage.
If leaking , motors will run on reduced power. Replacement caps can be found at Radio Spares. (Do not use electrolics)
Harold
I thought about the cap idea yet wouldn't the motor stop all together if a phasing capacitor went, or the motor would lock up?

Just checked my info, you have a switch under the splice block for the reel size, when the machine is in play mode, press this button and see if the two tension arms either side of the headlock move, if they don't this would indicate a fault.

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Last edited by reel-to-reel-man; 27th Feb 2005 at 10:57 pm.
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Old 28th Feb 2005, 7:50 am   #11
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Default Re: Revox PR99 - Slow or no rewind

Just found this on Ebay

http://cgi.ebay.co.uk/ws/eBayISAPI.d...754131996&rd=1

Just in case the motor or its controller is faulty, the PCB's may not go into the PR99 but they may have the spares you want

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Old 28th Feb 2005, 9:37 am   #12
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Default Re: Revox PR99 - Slow or no rewind

Had this problem recently with a Sony TC252 machine would play at half speed, but would not run in forward or reverse unless given some help by turning the spools. Changed motor cap, fault gone.
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Old 1st Mar 2005, 2:02 pm   #13
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Default Re: Revox PR99 - Slow or no rewind

Ok.....thankyou to everybody. My problem is solved!!!!
It appears that some of my old Ampex tapes are shedding a nasty sticky mess. Most of these tapes are on 10.5 nab spools, and once one of these has been on the PR99 it struggles to rewind. A really good clean of the transport and all is well until a bad tape goes back on. I'm pleased that all is OK with the PR99 but it's a shame that I've probabley lost the recordings on the Ampex tape.
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Old 1st Mar 2005, 3:03 pm   #14
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Default Re: Revox PR99 - Slow or no rewind

Some old tapes, notably some particular types of Ampex, were notorious for becoming a sticky mess. Many master recordings were made on this sort of tape and have been retrieved by a rather hairy process involving baking the tape. This gave you just one chance to play it and copy the material.
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Old 1st Mar 2005, 3:51 pm   #15
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Default Re: Revox PR99 - Slow or no rewind

Thought it was the tape, I have had this problem before. Now have tried the technique of baking a tape in the oven, I had a Sony Video recorder which the 1/2 inch tape went sticky, I placed my tape in the oven at a low temperature for about 3/4 an hour and it appeared to work but this was 1/2 inch and not 1/4 inch.
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Old 1st Mar 2005, 6:45 pm   #16
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Thumbs up Re: Revox PR99 - Slow or no rewind

I've just been reading about the baking process!
Here's the link.....some may find it useful.
http://www.tangible-technology.com/tape/baking1.html
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