Otari MX5050 problem...

[macd23]

Hey guys I am new to both the forum and also just getting into tape. I came across a MX5050 BII for 100 bucks on craigslist. The lady that I bought it off of did not know anything about them. The unit itself looks very clean but I do have a problem. I cannot get any of the motors to work. The only time I can get movement is if I hit the edit button and then play. This makes the left motor turn but nothing else happens. FF or RR does not work when in edit. I am thinking it is not likely a one of the motors. Maybe a motor controller? Please let me know what you guys think. Thanks

Darren

[Shawn]

Darren,

Do you have a tape threaded up when you are attempting to play/ff/rew?  If so is the capstan motor spinning? 

If no tape is threaded you need to engage the capstan motor by lifting up on the right tension arm.  If you have done this and are still having no luck try gently turning the capstan by hand while lifting the tension arm (sometimes they need a bit of help to start if the machine has not run in a while).  Also it is possible that the capstan could be in need of some lube.  Let  us know if any of this helps.

Regards,

Shawn

[ironbut]

Hi Darren,

Welcome to the forum.
It sounds like you got a hell of a deal there! Anytime I check out a machine, I do what Shawn suggested. I usually put a little adhesive tape to hold the tensioner up and hit play.
BTW, if you don't already have one, you can download a manual for free here;

http://www.analogrules.com/

[macd23]

Thanks guys for your response. I have tried it with the tape fead and it just makes a big click sound from the left motor trying to turn. The capson is not moving at all. I again get no response when not in edit mode. And no response from the record ff or rr. I tried cleaning out all the connections to see if that would work but still no motion in the right wheel and capson. What should I see when I hit play (not in edit) when no tape threaded and the tension arm is up. Should both wheel motors be turning or only the right? If the right one should be turning also, could we narrow it down to any parts that could have gone bad? What about fuses do should I replace them? Thanks again.

[macd23]

oh sorry guys I mean Capstan not Capson...sorry just learning the lingo haha

[macd23]

I actually just realized that the speed at which that left motor is turning when I hit play in edit mode is extremely fast. Like a ff and rr speed. Hope that helps you guys out.

[ironbut]

When there's no tape to hold the motors back and the switch in the tensioner in engaged, the reel motors should both turn in play. The left one (supply side) should turn clockwise while the right one (take up) counterclockwise (creating back tension).

The capstan should turn when the tensioner is lifted. If it doesn't do this, it could be a problem with the motor control board or the power supply.
I'd start troubleshooting by downloading that manual and being sure that all the setting are correct and check the internal fuses. Be sure that all the editing controls are off. They may actually disable the motors.

Do all the following with the machine turned off. If you don't feel comfortable with electro-mechanical devices, you may want to have someone else do the following.

The easy stuff would be to check to be sure all the multipin connectors are seated correctly. Carefully pull all of them you can easily reach (sometimes you'll need to loosen them with a flat bladed screwdriver,.. careful though, sometimes those circuit boards can become brittle with age and cracking one just increases your problems). Use a light and examine the pins that the connector goes on. If they aren't nice and clean, use a little contact cleaner on a q-tip before you put the connector back on. Take your time and try the machine with each one.
If you can tell which is the power supply board, start there.

I believe that your Otari has edge connectors on some of the circuit boards. You might try wiggling the boards around a little to seat them a little better. When a machine sits around unused for a while, those edge connectors can get oxidized so shifting them around in their connectors can make a clean connection.

While you're in there, try turning the capstan motor by hand. It should only be impeded by the weight of the motor/flywheel.

Well, give those things a try and let us know how it goes.
Also, any descriptions of noises that the machine makes when you try and play a tape might be helpful (does it sound like the motors are trying to turn etc).

[macd23]

Thanks Steve, I have removed all of the multipin connectors. I have not tried to replace any fuses as of yet, I will do that today. When I am not in edit mode, if I hit any command such as rec play rr ff, there will be NO response. There is not a sound present other than the sound of the button. This does lead me to think it could be a power/fuse issue. It does power up nicely with both VU meters working. I can hook up headphones and the test frequency buttons work as well as volume/channel control. This tells me that the amplifier section is working well. I do have reason to suspect that this unit has been sitting for 15 plus years. Can fuses just get old? Thanks again.

[steveidosound]

remote control switch or missing dummy plug? Is this possible with this model?

[ironbut]

I've never had a problem with aging of fuses. As far as I know, they're either blown or good.

I would suspect that maybe the edit button isn't disengaging correctly. Try turning it on and off about 10 times and see if that makes a difference.
Also, one of the other members here has found problems with the "pitch" control button. It pulls to engage and turns to adjust. Try working that on and off and rotating it. The large/small reel and the speed selector switches might be sticky too.
 If you look in the back, I think you'll find that all these controls go to the same circuit board. That's the one that most likely to be giving you problems with edge/multipin connectors.

[macd23]

Could anyone tell me what the board that is located above the capstan and right below the right motor(if you are faceing the front) is called? I just inversed the multipin connector that was connected to this board and i got both of the wheel motors running. Now i get response when i am not in edit mode. The play record ff and rr all work now but both the motors spin at the same speed no matter what command. The speed is like a ff or rr speed. The multipin connector is not meant to fit this way i have it, so im guess that something is wrong with the board. Insight on this would be appreciated. Thank you

[ironbut]

I'm not sure which board it is but you've probably reversed the power input to it. Don't do that again since you don't know the voltages that those different pins carry. You could easily burn out one of the many IC's or transistors that are very likely no longer made. For instance, your machine probably has a 5V line for transistors. It's probably on the same multipin connector as several other voltages that are over 20V to power the reel/capstan motors. Switching those voltages randomly is asking for trouble.

[ironbut]

Darren,
You didn't mention if during your "experiment", the capstan motor worked.
I think that getting the capstan working would be my primary concern at first. The controls for operating the reel motors is quite often preceded by the capstan speed controls or certainly interconnected by some sort of loop. I wouldn't be too concerned about how fast the reel tables move since they only provide back tension and it's the capstan/roller that moves the tape in play.

[macd23]

Hey Steve, thanks for your reply. I have not gotten the capstan to move or make any sound. I am in the process of purchasing a used capstan and board to see if thats the problem.  Let me make sure I understand what you are saying. You are saying that if there is something wrong with the capstan, it could affect the wheel motors also. correct?

[ironbut]

 Well sort of. The capstan speed is usually controlled by pulses generated by an oscillator and compared to the motion of the capstan motor.  Those same pulses are used to control the reel motors . What needs to be controlled in the reel motors are the tensions or torque applied to the tape (depending on tape speed, reel weight and resistance in the tape path).
If you haven't gotten the capstan to turn at all, it could be the control circuitry, a loose wire, or just about anything that sends power to the capstan.

I suggest that you save your money and fool around with looking for bad connections, sticky switches and the like. If you can't stumble across the problem, I'd take it to a repair guy. Buying this or that and not knowing for sure that "that's" the problem is depending on shear luck.
I certainly won't tell you that it's crazy since I do that kind of thing all the time! I enjoy messing around with that kinda stuff.
I just want you to realize that the odds of guessing right are long.