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MCI Tape Machine Question
Old 10th January 2014
  #31
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analogtodd's Avatar
 

Jonathan is right, the cables will work, but the connectors will do nothing for you.
Best thing to do would be to get 6 tuchels and wire them up to 2 90-pin pigtails.

Again, no disrespect, but I've bought machines that the heads were said to be in great shape, only to find out channel 24 was dead. Thats a worse case, but you usually end up dealing with uneven wear and having to fight the machine to get it cal'd. An inspection from JRF will save you hours of frustration.
Old 10th January 2014
  #32
Quote:
Originally Posted by analogtodd View Post
Jonathan is right, the cables will work, but the connectors will do nothing for you.
Best thing to do would be to get 6 tuchels and wire them up to 2 90-pin pigtails.

Again, no disrespect, but I've bought machines that the heads were said to be in great shape, only to find out channel 24 was dead. Thats a worse case, but you usually end up dealing with uneven wear and having to fight the machine to get it cal'd. An inspection from JRF will save you hours of frustration.
Todd is VERY correct here, I forgot to add to the chorus in my earlier post. John French will let you know the state of your art, and can make sure that your geometry is correct. Heads and motors are subject to all kinds of failures. The heads are more catastrophic, as the motors can be easily rebuilt. Common motor problems include bad brushes, and worn bearings. Power supplies should be rebuilt and the whole thing should be cleaned. As a search of MCI JH-24 threads here will reveal, the molex connector will not be your friend...lol

Best-
Jonathan
Old 20th May 2014
  #33
Here's a question...and forgive me if it's a n00b question, I've tried to find some answers and keep running into dead ends. Regarding the Tuchel connections on the back of these machines... Is there any reason that I couldn't solder XLR connections onto the other ends of the cables on the harness, or do they need to be connected to an elco/edac connector? For instance, a harness that looks like this:

Tape machine ins/outs (tuchel connectors on one end) -> harness tails for in/out (XLR on the other end).

I see a lot of harnesses that are Tuchel -> Elco/edac, and then Elco/edac -> XLR or hardwired to a patchbay. Is there any reason that I couldn't have a tuchel -> XLR harness for a machine like this? Thanks for the help.
Old 20th May 2014
  #34
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Bob Olhsson's Avatar
 

Quote:
Originally Posted by mharmon1 View Post
...Is there any reason that I couldn't have a tuchel -> XLR harness for a machine like this?
I and a lot of people did that. The Elcos were so that you could easily move a machine between studios and quickly plug everything into the wall. This became common with 3M machines during the '70s.
Old 23rd March 2016
  #35
Here for the gear
 

Hello! Hoping to restart this thread with some people who know about JH16 machines.

I have a JH-16 with a JH100 transport. The transport has no movement. It died when the Supply reel started slowing down and made a strange straining noise. I've replaced voltage regulators on either side of the motherboard chassis. I've recapped the power supplies and analog torque board. Before I did all of this I had a molex plug 1 pin off and I burned an IC on the torque board. I replaced all parts nearby including the sockets and the ICs /resistors/transistors nearby. I have no red sockets. I must have burned the supply motor too as I had a tech come in and find out the motor was fried, so I had it rebuilt. I've also replaced some funky voltage regulators in the transport power supply. Still no luck.

I've reflowed the entire mother board, recapped the mother board (a couple electrolytic caps and the string of 0.01uf ceramics along the bottom) and I'm getting proper voltages all along the motherboard, all within 1V variance of specified voltages. When I have daughter boards connected I find proper voltages on all test points and connection pins to the PCBs.

EXCEPT for one of the small PCBs that control solenoids. I have no schematics for these identicle PCBs but 4/5 have exactly the same voltages going to the same pins, and the one controlling a "Z Roller" is different. I can't figure out what a "Z Roller is...

Most of the lights (RW,FW, PLAY, REC, SHEILD, but not EDIT) work, and the capstan and pinch roller seem to function perfectly, maintaining pressure and varying speed according to 15/30 ips, and along with the varispeed knob.

The only strange bit of functionality I can figure out is that the transport does not respond to anything at all, and the tape sensor takes a few tries before it releases the brake (though it lowers the shield 1st try every time) as in i have to trigger it 3-4 times before the solenoid fully engages, but I can hear it trying each time I trigger the sensor.

SO..

What's a Z Roller?

does anybody have any clue what could be going on with this machine?

below is a photo showing the PCB layout with the "Z Roller" solenoid board

View image: Screen Shot 2016 03 23 at 4 49 37 PM
Old 23rd March 2016
  #36
Gear Guru
 
drBill's Avatar
It would be great if I could just spout off the perfect answer for your question, but in reality, IMO, MCI's are so quirky that it's worth it to have a professional on your side. In my experience it's beyond worth it, it's life or death (of the machine).

The best thing I could advise you :

Blevins Audio Exchange - Other Service Sources
Old 25th March 2016
  #37
Here for the gear
 

Fair enough! Thanks for the advice.
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