Restoring a Pioneer RT-909 Reel-to-Reel

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Hi Rich,
I like to ask you if you have some original switches of the tension arms.
It is not important if they have bad contact, I can clean the contacts inside and bring them back to new.
I would need arround 6-8 pcs if you have some left from your previous restoring works where you replaced them.

Regards,
Vlad
 
Thanks Rich! Great and Informative post. This Needs to be A Sticky P L E A S E!!!
 
Hi Rich,
I like to ask you if you have some original switches of the tension arms.
It is not important if they have bad contact, I can clean the contacts inside and bring them back to new.
I would need arround 6-8 pcs if you have some left from your previous restoring works where you replaced them.

Regards,
Vlad
I replace the switches with new. Old ones are rejected.

Good luck.
Rich P
 
Rich,

I finished rebuilding my tension assemblies last night by your procedure. Much smoother operation and tape handling. It's amazing how many small parts they put into those things.

I want to try and rebuild/repair my capstan motor in my "parts" 909. It runs in both directions, but is very weak and easily stopped with the fingers. Compared to the motor in the operating deck, it has practically no torque. It exhibits this same performance even run off a battery, so I know it's not the servo board.

Is this a conventional DC motor with brushes and an FG tach wheel of some sort? Have you ever taken these apart for servicing? If so, is it anything like the CT cassette motors you have outlined in other servicing threads?

Thanks for any advice on this motor.

David
 
Rich,

I finished rebuilding my tension assemblies last night by your procedure. Much smoother operation and tape handling. It's amazing how many small parts they put into those things.

I want to try and rebuild/repair my capstan motor in my "parts" 909. It runs in both directions, but is very weak and easily stopped with the fingers. Compared to the motor in the operating deck, it has practically no torque. It exhibits this same performance even run off a battery, so I know it's not the servo board.

Is this a conventional DC motor with brushes and an FG tach wheel of some sort? Have you ever taken these apart for servicing? If so, is it anything like the CT cassette motors you have outlined in other servicing threads?

Thanks for any advice on this motor.

David
It's an FG servo, but you will be blazing new trails with this one. Take careful notes and pics, in case you are successful. Good luck...

Enjoy,
Rich P
 
It's an FG servo, but you will be blazing new trails with this one. Take careful notes and pics, in case you are successful. Good luck...

Well, I sort of succeeded. I got the motor running again, but I was using to high a voltage to test it (using a 14 volt cordless drill battery) and I released the dreaded white smoke. Smelled like a resistor, and there is one in the end cap in series with the brushes. That was stupid of me. I think this motor usually runs on around 9 volts.

Here's what I found out:

1. The outer shell comes open with three screws The internal motor is held in place by both a front and back silicon vibration extrusion. There is no mu-metal shield, I guess the outer shell serves this function.

2. This exposes the internal motor, which also has its' end cap held in place by three screws. The motor power wires go into the motor through the end cap. The FG wires go down to the front (taped to the motor outer shell) and into the motor near the front on the side. BTW, no part number on the internal motor case.

3. With the end cap released, the motor easily comes apart. The fg coil is attached inside the case up at the front between the front of the can and the magnets. There is another magnet wheel mounted on the shaft (on the front side of the windings that spins inside the FG coil assembly when the motor is assembled).

4. The motor is a standard, 2 brush, commutator DC motor. There is a small electrolytic cap across the brushes, and a resistor in series with the motor power wires.

5. Looks like about 8 or 10 segments on the commutator. It was really black and burned looking.

6. The rear bearing is a cup bearing in the end plate, with a nylon washer and a flat oil retaining felt washer.

I had no problem putting the armature in my handy variable speed drill and using a burnishing tool (I didn't have any emery cloth or really fine sandpaper) cleaned up the armature. It looked pretty good after that. (I had a couple of dead spots in the rotation before I started).

The brushes are a little worn, and there was a lot of brush dust in the end cap. I cleaned that out with canned air, lubed up the bearings, and re-assembled the unit in reverse order.

The motor ran much stronger until I released the smoke. I'm going to take it apart again tomorrow and see if I burned up that resistor. It was already so burnt when I first opened the motor that I couldn't see what value it was. (I think it is a resistor)

After the smoke, the motor was completely dead. I figure at this point I've nothing to lose.

BTW, on my "parts" deck, I found the Control B problems and replaced a regulator, NPN pass transistor, and a 24 volt zener diode. The machine now works except for the capstan. Oh, and looks like I'm going to need a new reel motor. The supply side has significant wobble, I guess due to shipping damage. It's not very bad. I may take the rubber mallet to the shaft and see if I can straighten it, but I know this is probably a lost cause.

The deck plays audio (in both directions) if you spin the reels by hand (I don't have any pinch rollers on it right now), though the speed is highly irregular in "finger capstan mode". :D

David
 
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Hi David,

great post. Seems to be a good idea to rework the capstan motor too when reworking an RT-909.
Cleaning of the brushes and contacts can be done with brass polish.
After cleaning is good to apply some pro-gold or an very thin film of oil otherwise they run dry and wear the brushes faster.
I did such an rework for the motor in an AKAI GX-F71 and after cleaning it had again the spinnig power like new.

I also have an RT-909 with bended reel motor shafts. Have replacement motors so there's no problem.
I'm just wondering how it was possible to bend the shafts of the motors, because there was no damage or any dent or scratches on the whole front. Also the reel tables and reel locks are absolutely scratch free.

Vlad
 
Vlad,

I'm going to make another attempt on the motor tonight, and see if I can figure out the value of that resistor. I made some measurements of the motor's resistance before I initially took it apart, measuring around 100 ohms on most of the poles. I did not measure it after cleaning, so I'm not sure of the exact value. I may just bypass the resistor and put one externally for experimentation.

This motor is really easy to take apart. The screws make it much easier than if it had "divits". The screws are also "slot and dot" type screws, so one doesn't have to worry as much about stripping them as with a phillips head.

More later as details develop. I would take some photos, but my camera can't focus anywhere near close enough to make good pictures, and I haven't found my closeup lens kit since I moved.

David
 
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Well, the motor is pretty much a doorstop. I think it has some shorted windings, as all of the windings read 4-5 ohms except one which reads about 1 ohm. Also, could not identify that resistor; in fact, I'm not sure whether that was actually a resistor or a fuse. On a 9 volt power supply, it draws about 1.5 amps, and still turns really slow. When hooked up to the deck, it drags the power supply way down, and barely runs.

So, now I'm in the market for a capstan motor, which are about as rare as hen's teeth. About the only place I can purchase a new one is from Teac parts, and they want $135.00, and are currently on backorder, according to the email I got back from Teac parts. This is supposedly the same motor as used in many Teac's X series and the 909.

But, on the good side, the heads on this parts deck are almost pristine; only minimal wear, so I think I'll move them to the other deck and sent those in for re-lapping.

My budget is forcing a slowdown on this project.
 
Well, the motor is pretty much a doorstop. I think it has some shorted windings, as all of the windings read 4-5 ohms except one which reads about 1 ohm. Also, could not identify that resistor; in fact, I'm not sure whether that was actually a resistor or a fuse. On a 9 volt power supply, it draws about 1.5 amps, and still turns really slow. When hooked up to the deck, it drags the power supply way down, and barely runs.

So, now I'm in the market for a capstan motor, which are about as rare as hen's teeth. About the only place I can purchase a new one is from Teac parts, and they want $135.00, and are currently on backorder, according to the email I got back from Teac parts. This is supposedly the same motor as used in many Teac's X series and the 909.

But, on the good side, the heads on this parts deck are almost pristine; only minimal wear, so I think I'll move them to the other deck and sent those in for re-lapping.

My budget is forcing a slowdown on this project.

Take a look in the yellow pages for electric motor repair places, maybe you can get yours rewound pretty cheap...i.e. less than half a new motor.
 
But, on the good side, the heads on this parts deck are almost pristine; only minimal wear, so I think I'll move them to the other deck and sent those in for re-lapping.

My budget is forcing a slowdown on this project.

You should think about to relap both head assemblies.
From time to time you can find in the auction site, capstan motors and other assy parst, and they are relatively cheap, because some guyes sells the RT in parts.

Vlad
 
Take a look in the yellow pages for electric motor repair places, maybe you can get yours rewound pretty cheap...i.e. less than half a new motor.

I wasn't aware that anyone would rewind motors this small. There used to be a place here years ago. I don't know if they are still in business.

I decided to obtain my replacement motor by purchasing a Teac X-3 deck, fully functional, from eBay. I'll use the capstan motor for my RT-909, and then probably part out the machine to make some money to apply to my head re-lapping. I can also use it for spares for my TR-3000.
 
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Rich
I got a rt909 with a weird performance
both motors run inwards regardless of forward play or reverse play
the same thing happens with fast forward and fast rewind.
The stop switch functions in the fast forward mode but not in the fast rewind

any advise?
 
Sounds like normal operation when there is no tape loaded. The reels each only drive in one direction. The difference between the selected directions is the amount of torque each reel is driven with. If you will notice, in foward direction, the right reel has alot of torque (take-up), while the left reel has only a small amount (back torque). In the other direction, the torque amounts are reversed, left to right, but the spin directions will be the same.

Now for the not stopping...In fast mode (or any mode), the tape presence sensors (in the tension rollers on each side) will stop the deck if they are allowed to relax, immediately, using the reel brakes. However, this deck implements, by control logic, the practices of tape professionals, in that to stop from fast mode, the deck is switched to the opposite direction fast mode to use the reels motors as brakes, until the reels come to almost a stop, then the stop button is pushed to drop the brakes. This method is the most gentle on tape. This deck does that automatically, by watching the tape counter signal. When you push stop, the drive and back-torques will immediately switch sides, and the brakes will drop only when the reels slow to almost a stop. If there is no tape loaded and the tension rollers are being held up, you will not notice any response to the stop switch, and because the reels do not slow down, the brakes will not drop. In such a case, push one of the tension roller arms down to relaxed position, and the brakes should drop and stop the reels.

I hope that helps...

Enjoy,
Rich P
 
I installed the capstan motor that I obtained from a Teac X-3 machine. The motor is an exact match, so we now have an active source for these motors from Teac, although expensive.

After installing the motor, I still had a few problems. Of course the tension arm switches are bad. I bypassed them to continue testing. The new motor would not run in the deck, so I started back tracking on the Control "B" board, and finally found two cracked traces in the board near a screw hole. These two paths just happened to be the control signals for the reversing bridge for the capstan motor. I repaired the cracks with jumpers, and now the motor runs like a champ.

On to more refurbishing. Looks like I'm going to have two operable RT-909's soon. Another set of tension arms and switches to repair! Oh, Boy! :D

Dave
 
I installed the capstan motor that I obtained from a Teac X-3 machine. The motor is an exact match, so we now have an active source for these motors from Teac, although expensive.

After installing the motor, I still had a few problems. Of course the tension arm switches are bad. I bypassed them to continue testing. The new motor would not run in the deck, so I started back tracking on the Control "B" board, and finally found two cracked traces in the board near a screw hole. These two paths just happened to be the control signals for the reversing bridge for the capstan motor. I repaired the cracks with jumpers, and now the motor runs like a champ.

On to more refurbishing. Looks like I'm going to have two operable RT-909's soon. Another set of tension arms and switches to repair! Oh, Boy! :D

Dave

Dave,
I found an method to refurbish the original tension arm switches.
I don't agree replacements, because there is no one with that low action force like the originals.
If you want, I can make your original switches like new - just send these to me and I do it for free.

Vlad
 
Thanks for the offer, Vlad, but I've already thrown out the switches from the first 909. I've bought replacement switches, since they are still available, and have some new ones on hand for the other deck.

I could send you the ones I'm taking out of the second deck for you to keep, especially if you are having trouble locating replacements. PM me your address if you are interested.

Dave
 
I have an RT-909, oiwned it since new, use it only occasionally. Replaced belts a few years ago. Works fine mechanically, but has an audio problem. Left channel is fine, in either direction, but right channel has low volume and almost no highs, in either direction. Would seem to be an electronics, not a head problem. Same result when plugging headset directly into deck, so it isn't an external amp problem, either. Need someone to advise which pc card to pull, and want to send it to someone to repair or replace it. Not equipped to do that sort of thing myself any more. Can you help? Thanks!

Frank Weikel (Orange County, CA) fhweikel@juno.com 714-898-7209
 
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