Otari MX50

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gamve

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Hi Guys,
Have an old Otari MX50 I am trying to resurrect. Unit powers up and FF and Rewind seem to function OK. Problem I am having is that when I try to play a tape the capstan spins backwards and dumps all the tape from the take up reel. I have searched the web for a user and maintenance manual but no luck so far. Can anyone help?
Cheers and thanks in advance
Graham
 
You might have the tape threaded wrong. Does the capstan spin clockwise, or counterclockwise?

The manual used to be on the German Otari site, but it's gone now and I can't find it on their new site. I have it in PDF, so shoot me a PM and I'll send it to your email. It's only 524 kb in size.
 
Beck said:
You might have the tape threaded wrong. Does the capstan spin clockwise, or counterclockwise?

The manual used to be on the German Otari site, but it's gone now and I can't find it on their new site. I have it in PDF, so shoot me a PM and I'll send it to your email. It's only 524 kb in size.
Click to expand...

Hi Beck,
Can't see how you could thread it wrong, The tape has to go between the capstan and the pinch roller. The capstan is rotating counterclockwise from memory. Have sent a PM on the manual, thanks for that, it's a hard item to find.
 
Had another look armed with the manual from Beck (Thanks Beck). The machine is a MX50N according to the name plate on the back. I made a mistake the capstan is actually spinning clockwise. I noted in the manual that the capstan motor is a DC unit. Could it simply be a connector on the wrong way round. Will investigate this now. I could not see how to get into the machine originally but it appears from the manual that the large circuit board in the back simply hinges down.

Had a look. Connections are OK. Found that fuses F2 and F3 are blown. Will get some more tomorrow and try again.
 
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Otari MX 50 N

Hi gamve!
What is the difference between the 50 and the 5050? Is it as good?
Best regards
persve
 
Could it be an auto reverse deck? I have never dealt with the unit your asking about. It's just a thought.
 
The MX50N is a 1/4" 2 track machine.
I replaced the fuses but no change and both fuses are again dead....bugger
Must be something damaged/shorted on one of the boards
 
gamve said:
The MX50N is a 1/4" 2 track machine.
I replaced the fuses but no change and both fuses are again dead....bugger
Must be something damaged/shorted on one of the boards
Click to expand...

Power supply.
 
RRuskin said:
Power supply.
Click to expand...

Yeah Rick, Will be the best place to start I guess. Seems weird that the capstan motor still turns even though it is in reverse and at full speed. Also noted the Vari speed does not work either. This I assume is due to the capstan control circuits being either shorted or having no power available?
Thanks for the starting point
cheers
G
 
Just a thought, if the deck is equipped with an edit dump feature, it could create some weird symptoms like this. My MX-5050 was so equipped, never really had a use for the edit dump button, but maybe that could be the problem too.
 
Look for my thread on MX5050Bii-2. I had transport issues with it, and it turned out to be either a bad rectifier or capacitor. I replaced both, and fixed hte pwr supply problem. It too was incessently blowing a fuse. If you have a schematic, and it is a blown fuse issue, you may be able to easily locate where the increased current is coming from and the likely fault. Capacitors are always a culprit, and I'm guessing on mine that it may have caused the rectifier to fail by shorting. Also, I have equiv part numbers for some of the relays if that is an issue. Parts are avail from Otari. You talk to a guy named Taka in California, he will help with part numbers if needed. I have a contact number if you need it. Can't seem to google it right now.

https://homerecording.com/bbs/showthread.php?p=3105086
 
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Thanks Blue Jinn for the hints. I am thinking of looking at the caps in the power supply tracing back from the two fuses that are blowing. I have a manual but it does not have circuit diagrams so this will be a bit of a bugger.
 
vincedog3 said:
Just a thought, if the deck is equipped with an edit dump feature, it could create some weird symptoms like this. My MX-5050 was so equipped, never really had a use for the edit dump button, but maybe that could be the problem too.
Click to expand...

Yeah I Thought that as well but I think the tape dump function just stops the take up reel from rotating and the tape dumps out on the right side of the pinch roller. The tape on my machine is dumping on the wrong side as the capstan is spinning full tilt backwards.
 
Made some serious progress with this old girl. Many thanks to the guys on TapeHeads. One of the guys had the same problem and found that the strengthening bar in the base of the deck had been bent up at some time and was shorting on the board resulting in the fuses blowing. The tolerance here if fairly small, so if the deck has had a serious bump or has been dropped, this is the place to check first.
In my case somebody had fitted over length screws which had not only shorted the board but cracked it in both back corners. Removal of the screws has resulted in the fuses now staying intact and the capstan now spins in the correct direction at the correct speed. It looks like it is all going to work. I have movement in both meters and all controls are working properly. Will test for audio once I determine which XLR pin is hot.
Cheers
Graham
 
WOW!!

That is awesome that you found help for what is, in my estimation, an obscure problem, and thanks for following up here. This has got to help somebody else at some point. ;)

I would bet you that pin 3 is hot.
 
Sorry guys forgot to update. This machine nows plays well and the sound quality at 15ips is bloody good to boot. I had a go at recording but no joy. I'm pretty sure my setup was OK, meters were registering signal and the machine was out of safe mode (the Chanel ready lights were on) but nothing went onto the tape!! Will have another look later on. Really want to get this thing recording as the playback is spectacular. The heads are mint unmarked so it should have a long life with my limited use patterns.
BTW you guys are spot on, Pin 3 is hot on the MX50 and The MX55
 
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