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Author Topic: Otari MX5050 MkIII-2 (No B) Wiring (not XLR)  (Read 3427 times)

Offline JohnRichard

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Otari MX5050 MkIII-2 (No B) Wiring (not XLR)
« on: October 14, 2014, 12:52:08 PM »
Greetings, so glad to find such useful resources here!  Already learned some things today.

I have purchased the machine in the title (MkIII-2) with no B letter.  The console version.  It's a wonderful machine.

However it came with no cables, and unable to find any I had to make them myself.  That's done, everything mostly works however on the deck, coming out of the 25-pin interconnect, there is a White wire with GREY strip on Pin-18 - I don't know what this goes to.

On the AMP section, there was no wire on Pin-18, and I have no stray lost wires on the amp section for which to connect it.

Can anyone determine what this wire might go to? 

Current issues with the deck:
Stop button doesn't like to work, but sometimes does (likely dirty button)
Edit really doesn't seem to do anything except ignite a green LED
SEL-REP channel 1 (left) doesn't work, no sound on playback
Record channel 1 doesn't work (likely dirty tape path)
Channel 2 fine (likely button issue? or 1/2-1/4 switch) on record AND playback
VU bulbs not lit, VU meters work fine.
I have yet to test out the XLR connections so that just may add other complecations.
Trying to bring this deck back to life.
15ips playback works well.

Mystery pin-18 wire?? +12v to VU bulb?
Need NEW tape!




Offline Listens2tubes

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Re: Otari MX5050 MkIII-2 (No B) Wiring (not XLR)
« Reply #1 on: October 14, 2014, 04:21:40 PM »
I have a MkIII-8. Locate the internal speed switch on the main board. I am not sure why this machine shares this switch with it B2 cousins but it does. Get the deck on it's side and spray contact cleaner (Deoxit) through the switch while working it back and forth 10 or more times. Also spray into the back corners of the front Speed switch and work it 30+ times. This treatment shook out capstan and logic issues on my MkIII-8. Also I have found the Pitch Control can cause wow and occasionally keep the capstan from spinning if dirty. Exercising it On and Off (in/out) 30-40 times has helped there. I wish mine was a 2 track.
Neal - Ampex Fineline F-44, 3 - Otari MX5050BII-2, Revox A77 Mk II , Teac A 4010s, 4070, Sony TC102A, Magnecord 1020, Systemdek IIX/Dynavector Karat 17D2MKII, CEC CD3300 CDP, K Works NanoMax DAC, Van Alsine Transcendence Eight+ tube preamp, Dynaco MkIV amp pair, Paradigm Reference Studio 100 v1