Problem with Tascam Portastudio 464 pitch control

[Manu]

You can skip all the connectors, switches and pots if you just connect a 1.5k resistor between A and B and disconnect the small speed/pitch board at the connector. If the motor runs steady and relatively on speed(it will not be exact, just ball park, since disconnecting the speed/pitch connector disconnects the speed calibration trimmer also. The voltage will vary slighting across the resistor with varying load such as from one end of tape versus the middle or using an old tape with tape lube worn out of the tape backing. If your connect that resistor and the voltage across it is very low like some of the values you posted, (0.07 etc) I will bet a pint the problem is a bad motor.

Alright, so I did exactly what you wrote : I disconnected the pitch control board, placed a 1.5k resistor between A and B.
With this setup, when I run the portastudio, the voltage between A and B starts around 0.45V ; then at some point it jumps to approximately 0.20, later to 0.10, then back to 0.20, etc... Very sudden jumps, and then it keeps stable around a value until the next jump.

So, bad motor, eh...

I still suspect a broken connection in the speed circuit.

Is there a way that I can spot what's wrong in this motor, and maybe find a way to repair it ? I opened the back of the motor, then removed the neoprene ring ; at this point I can't find a way to remove the circuit. I don't want to risk breaking it in two!

[km6xz]

There is a circuit board inside that has the speed regulator. I never bothered to try to repair one when the motors were readily available. Tascam might still have those, that is where I would start. It definitely the motor, the failing speed regulation was a typical symptom. A source to consider would be looking for a junker for $10 in the bone yard of a Tascam repair shop or music store. In the 90s and early 2000s they were very popular. The same motor is found in many of the same era PortaStudio models. One model had the same motor but the terminals 12AB were reversed but the connections are labeled. The 424 and 488 were more popular so you might find a motor easier from one of them.
Here is a whole working 464 for cheap: Tascam 464 Portastudio | eBay

Good luck!

[g1]

There is probably a generic number on the motor, something like SHU2L or SHL2L, if you search for that number, it may be easier to find online. You will need to reuse the original pulley as there are many different pulley sizes and the motor may or may not have a pulley on it.

Edit: It's an EG-530KD-2B motor.
Here's one:
http://www.ebay.com/itm/MOTOR-EG-530...item2a57775ebb

[olddawg]

Usually there are just a couple of points where the leads from the motor windings stick up. Usually you can lift the board out after they are unsoldered. A picture would help. I've repaired motors like this before. You also might have oxidation on the armature or the rear bearing may be dry. If you take your time they can be made to work. Could be a dry cap on that board or something else drifting. The smart thing to do is replace the motor. But with obsolete stuff you have to be creative. Are you sure you have the right belt on it? A tight, loose or improperly shaped belt can cause all kinds of weird problems.

[dai h.]

some links I've found FWIW (some pics of the motor disassembled in the bottom links) :

Synth Hacker: Portastudio - Voltage Control of Speed

No644

No644�@‚»‚Ì2

TASCAM�@234

TASCAM�@234‘±‚«

[Manu]

Well, I found the two points to unsolder to be able to remove the board. It's simply the two biggest ones, square shaped. But after doing that, when I tried to remove the board (as gently as I could !), it broke in two..! This thing is quite fragile, if anyone tries to do the same, be very careful !
So I guess I will find a new one. Thanks g1, for the ebay link ! It looks like you can also find one there :
Main Electronics Motor Page
I am waiting for an answer from these guys, I will confirm you if they still have some or not.
Thanks all of you for your help, anyway !

[bsco]

There is probably a generic number on the motor, something like SHU2L or SHL2L, if you search for that number, it may be easier to find online. You will need to reuse the original pulley as there are many different pulley sizes and the motor may or may not have a pulley on it.

Edit: It's an EG-530KD-2B motor.
Here's one:
Motor EG 530KD 2B 12VDC Mabuchi No Roller New | eBay

These motors are available at www.mainelectronics.com.....over in Vancouver......Canada......I think they are $15.75 Canadian....should be practially free in US funds.....Lol....

[bsco]

Well, I found the two points to unsolder to be able to remove the board. It's simply the two biggest ones, square shaped. But after doing that, when I tried to remove the board (as gently as I could !), it broke in two..! This thing is quite fragile, if anyone tries to do the same, be very careful !
So I guess I will find a new one. Thanks g1, for the ebay link ! It looks like you can also find one there :
Main Electronics Motor Page
I am waiting for an answer from these guys, I will confirm you if they still have some or not.
Thanks all of you for your help, anyway !

http://music-electronics-forum.com/n...reply&p=397202

You got it...I just checked their site as well and left a message......I also need one.....I couldn't get that board out for fear of breaking it......
Cheers

[bsco]

http://music-electronics-forum.com/n...reply&p=397202

You got it...I just checked their site as well and left a message......I also need one.....I couldn't get that board out for fear of breaking it......
Cheers

I got that board out after...Shorted power transistor in there....burnt up the board.....

[olddawg]

As long as the board isn't charcoal you should be able to repair it. They aren't that complicated. You just jumper the broken traces with tinned wire of the appropriate size. It will stay together when remounted. If you are anal a drop of epoxy will make it ridged. You can also remove the board altogether and build a new circuit on a piece of perfect board outside the motor. There are only a few parts on it. I've done both. Like I said. With obsolete stuff you get creative.

[bsco]

As long as the board isn't charcoal you should be able to repair it. They aren't that complicated. You just jumper the broken traces with tinned wire of the appropriate size. It will stay together when remounted. If you are anal a drop of epoxy will make it ridged. You can also remove the board altogether and build a new circuit on a piece of perfect board outside the motor. There are only a few parts on it. I've done both. Like I said. With obsolete stuff you get creative.

I realize that........I can get the motor so it would be better to replace it......if however, the motor was no longer available, then yes....I would have to go a route similar to what you suggest.........Thanks for the advice....
Cheers....

[dustartist]

I'm going to jump in here with a similar situation, maybe we can figure it out together. I have a 424 MkII that had a dead capstan motor. I got a replacement from Main Electronics, it's the EG530KD2B, probably same one as you need. I installed it and it spins, so good news there. My problem is that the normal speed now runs slightly fast, even with the trim pot adjustment, and the fast speed runs too slow. I have tried two different new motors and they behave the same way, so I am pretty sure it is something in the speed control circuit outside of the motor. Curious to hear about your progress on fixing yours.

[Enzo]

Does your new motor have a small hole on the rearend cover plate?

Also, does the new one have the exact same pulley on the shaft?

Are the speed controls just resistors and pots? In which case, can you not extend the adjustment range by changing a resistor in each speed circuit?

[bsco]

I'm going to jump in here with a similar situation, maybe we can figure it out together. I have a 424 MkII that had a dead capstan motor. I got a replacement from Main Electronics, it's the EG530KD2B, probably same one as you need. I installed it and it spins, so good news there. My problem is that the normal speed now runs slightly fast, even with the trim pot adjustment, and the fast speed runs too slow. I have tried two different new motors and they behave the same way, so I am pretty sure it is something in the speed control circuit outside of the motor. Curious to hear about your progress on fixing yours.

I received the motor a few days ago so I never got a chance to install it....I also had to change the belt so the speed might be slightly off in the unit but I won't know till I install the motor....which will be early next week...I will let you know how i make out with it.....the motor that I received does NOT have an adjustment hole in the rear plate of the motor....many of the tape deck cassette motors that I have seen does have this adjustment slot but this particular one that I have does not have that feature....there is a small ckt board in behind this metal rear cover but there is no adjustment pot there...just a transistor and a few support components....I'll let you know how I make out and if you get your issue resolved please let me know...I would be very interested to hear about it.....

[bsco]

Does your new motor have a small hole on the rearend cover plate?

Also, does the new one have the exact same pulley on the shaft?

Are the speed controls just resistors and pots? In which case, can you not extend the adjustment range by changing a resistor in each speed circuit?

Hi Enzo. The motor that I received didn't come with a pulley....as far as I know the pulley is not available....