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Discussion Starter #1
I wasn't sure where to put this but was thinking it would get more exposure here. Feel free to move this,Tisenberg or other Mods. Thanks



I have an old Denon DR-M33 Cassette deck. It is 3 head model with a closed loop dual capstan. A decent cassette deck in it's day. I bought it around '86 or '87.

I had not played a tape in it for quite some time. When I try to play a tape it seems only one hub spins, so the tape starts loading up on the right side spool. I also notice the FF and Reverse strain and hardly turn.

What should I look for when I take it apart? Could it be belt slippage or a gummed up motor? Is there a conditioner for the belts or will they most likely have to be replaced?

I'd hate to trash it, as I plan on keeping most of my old Audio equipment. I haven't opened it up as it will be a job getting the unit out, as I have 8 audio and video components zipped tied together. Any help in advance would be appreciated.
 

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Could be that a belt broke or the old grease is dried up and not letting it turn freely. Could need just a good cleaning might have alot of dirt built up in it.
 

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Discussion Starter #3
Originally posted by jodyand
Could be that a belt broke or the old grease is dried up and not letting it turn freely. Could need just a good cleaning might have alot of dirt built up in it.
I'll dig into it when I get the nerve to undo all my neat and fancy cabling work behind the cabinet. :eek:
 

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Mow, awhile back I had an old Marantz tape deck do something similar. I ended up opening up the deck and found that a belt had twisted and poped of one of the pulley spools. I straightened up the belt (looked more like a very thin rubber band) and reinstalled it on the pulley spools and it works great. I was kinda uneasy about opening up the tape deck too but I figured it did not work any longer and I had nothing to loose.
 

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Curt,
After you open the unit up be sure to use the 'right' kind of solvent if it turns out that grease is the problem. Many electronic cleaners can be too harsh for the plastics used in 'home' electronics.

Oh, and FWIW, lithium greases are the hardest to clean up. I've found that by removing as much of the old manually (w/a q-tip/whatever) means less mess. Radio Shack has a 'plastic-safe' cleaner that I've use with pretty good success in the past.
 

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It could be several things. Hopefully cleaning out the fuzz and freeing up the mechanism will take care of it. Finding parts if needed will be hit or miss due to the age. I checked a 1995 PRB (Projector Recorder Belt) cross reference but it did not list any idlers or belts for that model. Most of the suppliers for parts like that have disappeared. Since it is running the motor should be OK. There might be an idler arm assembly that swings back and forth between the two reel posts that could be bound up. It may have a small rubber tire or it may be a gear drive with a slip clutch. Seen them both ways. The tires will either glaze and crack or turn gummy. Sometimes the belt(s) will turn gummy and the pieces will stick to the pulleys. The supplier in the link below shows some parts still available. Just enter your model number into their look-up engine.

Tritronics Inc.

PRB Line

Mark
 

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Discussion Starter #8
Thanks for all the suggestions, guys. I've got the unit out and popped the lid off. Nothing obvious so far. I'm going to have to remove the tape drive assembly to be able to see anything. I hope to get to that later in the week.

You can see the tape transport in the upper right of the pic:

<img src=http://www.homepage.mac.com/userosx/.Pictures/csst.JPG>
 

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Before you pull it apart you might make sure your getting a DC voltage to the white motor. I'm assuming that is the one driving the reel posts. Or, on second thought it may be driving a group of gears to set the mechanism mode of operation. I think the other one is probably driving the capstan posts. Probably a pulsed DC but should read something on a volt meter. My experience is with the Zenith, RCA, Magnavox and Lloyds units of that era. Being lower quality they used one motor to drive the mechanism. (In other words I'm guessing.:D) We'd always get a bunch of them into the shop starting this time of year. The people would try to play their holiday music after the unit had set all year without being used. Most of the time the turntable was gummed up or the capstan flat belt had turned to gum in the cassette or 8-track deck.

Mark
 

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Incidently, I also have a 3 head cassette deck, a Pioneer. I haven't used it in quite a few years. It's amazing how far we have come with computers and music.
Only one hub is supposed to spin. The tape is transported through the heads with powered rollers. If you open the door, there should be two maybe 1/16 dia posts that spin the same time the hub spins. If one of these is not moving, it will likely cause the problem you describe.
 

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Discussion Starter #11
The metal pins or capstans are spinning. The tape spindle really labors when you press play. It spins maybe a revolution and a half, and stops for about a half second. I'm thinking some kind of belt slippage or a deformed belt.
 
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