MCI Calibration help

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Jonkraft

Member
Joined
Apr 27, 2005
Messages
5
Location
Orlando, FL
Hey,

Does anyone know what the tape tension (oz.) is supposed to be for a JH-16/JH-100. Also, where are the adjustments for it? I have, what seems to be a complete "JH-16 manual" AND a second "JH-100 manual" that contains electrical cal and board layouts ONLY(no mechanical. cal). The problem is that when the "complete" manual references specific pots and whatnots, the numbers are incorrect. (Maybe it is for an older or newer transport?) When I look at the board layouts from the second manual, the numbers correlate to the actual markings on the analog torque board.

If this helps? The serial number tag says; its #178, and was manufactured on 10-30-74...


Please beware that this is my first tape machine...
Maybe someone knows of a good calibration resource that would help out a new guy...


Thanks!

Jon
 
Hi,

you should get in touch with Blevins Audio;
blevinsaudio.com

They're pretty much the go-to MCI experts, and have a good rep.

good luck
 
Try the forum at http://www.recordingconsoles.net/consoles/consoles.htm

Category "recording consoles and equipment"

Look for the thread named "Same offer I gave to Tape-Op"

Jakob E.
 
I'll bet it's a JH100 transport. DC capstan and AC reel motors. I think you have to use spring scales like the JH10 transport which was AC all the way.
I have a JH100 manual...I'll check it out
 
You just need a spring scale...like the type for weighing fish. Loop a peice of string around the end, and tie it on to a reel (do it at the hub, otherwise you'll get the wrong tension). I don't remember the exact values, but it depends on tape speed and width.

Tape machine setup is an inexact science....especially with MCI's....

Cheers,

Kris
 
I know that I need a spring scale. My problem is more specific.

I do not:

a. know where the adjustment points are on the board. (the pots/ calibration points)
b. know for certain, what the weights are supposed to be. I think they are 10oz and 6oz.


Thanks!

Jon
 
OK...I found my manual on this machine.

First, are you having a specific problem with the tape path or do you just want to check the tension? If the tape is riding up or down at the outgoing guide (to the right of the play head) a tension adjust may not do the trick.
Everything in the path affects tape travel .Worn heads, guides, ect. makes it tough or impossible to set the deck up properly.
With that said here is the setup procedurefrom the manual:

ANALOG TORQUE BOARD ADJUSTMENTS:

(a) D.C. Offset null adjustment

1. Unplug Reel motors, block photo cell with opaque material
2. Clip negative lead of DC voltmeter to chassis, positive lead to TP-1 and adjust R-11 for DC Null (0 VDC) Repeat to TP-2 with R-13
3. Plug in reel motors

(b) 50/60 Cycle ADJUSTMENT

1. Connect oscilloscpoe to left torque motor test jack on front apron of deck chassis.
2. With no tape loaded, block photo cell and push REWIND button.
3. Display 2 cycles and adjust left 50/60 hz control R-124 for a perfect sine wave as possible.
4. Repeat for right torque motor, adjusting R-129

(c) TENSION ADJUSTMENT

1. Install a reel or hub on each turntable; attach a cord to a 0-36oz spring scale; block photo cell with opaque material.
Secure and wrap cord 2 or 3 times around the supply reel.
2. With deck in PLAY mode, turn test switch S-1 to "ER" and adjust left empty reel control R-61 for 6 oz tension; turn S-1 to "FR" and adjust left full reel control R-56 for 12 oz. Interaction occurs between controls, so they must be alternately readjusted to obtain 6 and 12 ounces.
3. Repeat with scale attached to take up reel and adjust R-62 and R-68 for 6 and 12 ounces of tension respectivly.
4. Remember to return switch S-1 to the "Operate" position when finished.


All the adjustment pots and the DC Null test points will be located on the torque board (largest board on the left)

The test points for the 50/60 cycle adjustment are on each end of the deck apron below the mounted transistors.

Hope this helps
 
Thanks, I really appreciate the info..

Ok, more issues.

When I place the machine into the ER or FR modes and a place card into brake sensor, the reels(there is no tape on the machine of course) spins extremely fast. Fast enough to where Im in danger of loosing an arm, the fish scale, or even worse, damaging the machine or other gear in the room. The reels will only stop spinning if I place the machine back into OP mode. Removing the card or pressing stop does nothing.

I'm assuming this is abnormal.

Any ideas?

Thanks!

Jon
 

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