trouble shooting an MCI JH-110B

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jmpizzoferrato
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trouble shooting an MCI JH-110B

Post by jmpizzoferrato » Mon Oct 09, 2006 11:23 pm

i recently picked up a jh-110b 1/2" 4 track for dirt cheap. tonight i went to fire it up and...

three of the four modules look like they pass signal. i threw up a reel and the brake clicked when it went through the sensor: a good sign, i though. i tightened up the reel and tried to rewind. nothing happed. the rewind and ffw buttons lit up but not the play, stop, record, or edit. the motors seem to be at a stand still. i'm wondering if there might be a problem with the molex connectors. everything looks clean as a whistle inside, which doesnt really mean anything, i suppose.

one thing is that the power suppose doesnt seem to turn on or off if i flip the switch. i have to unplug it to turn it off. i also noticed that there is nothing plugged into the 'servo' plus on the deck. don't know if i need to deal with that or not..

this deck is a total crap shoot but now that i have it, i really want to get it working. i guess my question is: where do i begin to trouble shoot?

thanks!

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brianroth
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Post by brianroth » Mon Oct 09, 2006 11:34 pm

First the easy one...the power toggle switch often craps out on those, and you're lucky it's "stuck on". Replace the toggle switch.

As for the other problem...are you saying that BOTH the RW and FF buttons light up when you attempt to go into either fast wind mode?

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jmpizzoferrato
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Post by jmpizzoferrato » Tue Oct 10, 2006 12:06 am

yes. both buttons light up.. it's just that nothing happens. play, stop, record, and edit DO NOT light up, however.

i'm hoping it's a dirty molex..

jmpizzoferrato
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Post by jmpizzoferrato » Tue Oct 10, 2006 10:14 pm

any ideas anyone?

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brianroth
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Post by brianroth » Tue Oct 10, 2006 11:32 pm

I would first try reseating all of the cards under the transport. There are four, IIRC, that have female molex connectors that sit down onto a "bed of nails" of male molex pins attached to the motherboard.

BE CAREFUL that you get the molex pins correctly aligned when you reinstall a card. It is very easy to be "offset" from left to right, especially with the analog torque board (the big one on the left).

Of course, power the machine "off" before removing/installing any of the cards! <g>


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ladewd
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Post by ladewd » Wed Oct 11, 2006 5:14 am

Sounds like it may be in locate mode. Try unplugging the RTZ processor board under the deck. If that doesn't clear it up, there may be a problem on the control logic board. Either way, you probably should get a tech out to look at it.

CA

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thanks!

Post by jmpizzoferrato » Wed Oct 11, 2006 10:54 am

thnks guys. im planning a romantic evening with the deck tomorrow night.

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brianroth
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Post by brianroth » Sat Oct 14, 2006 12:18 am

Did MCI sell an autolocator/ "RTZ" for the 110b? I've seen them on 110C machines....

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ladewd
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Post by ladewd » Sat Oct 14, 2006 9:12 am

The latter 110B's had RTZ processors which were identical to the JH24 AL3 boards except for the ROMs, and a suboard on the earilier AL3 processor boards. By the time the C's came out the boards were pretty much the same except for the EPROMs and a few added components and jumpers. I believe the AL3 that you see on some 110c's could be retrofitted on a 110B as well, provided it has the buffered capstan tach for the vari-speed functions. I believe if you see the 4 locate posistion switches on the deck, you have a processor based RTZ.

At least that's the way I remember it. A lot of these details are becoming fuzzy as time goes on. You don't use it you lose it. I have made a concerted effort not to work on MCI machines over the past 10 years. My experience is you tend to become married to them, which may or may not be a good thing, depending how you look at it.

:D

CA

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brianroth
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Post by brianroth » Sat Oct 14, 2006 11:28 pm

Cool...I missed the intro of the RTZ for the 110B machines; and only saw them on 110C decks.

Indeed, "RW and FF both lit at the same time" is the mode for an AL III (and similar) when in seek mode.

As many of the MCI decks that used to be around here, I woulda thought that I should have encountered a 110B with a locator! <g>

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