MCI JH-110 down for the count!

CurtZHP · Post by **CurtZHP** » Mon Nov 07, 2011 5:17 am

I fired up my JH-110 last night to record something (for lack of a better thing to do). Threaded up the tape on the take-up side, hit rewind, immediately noticed something wasn't quite right. Hit FF. Nothing happened -- except for tape spilling all over the place. Got it rethreaded, hit FF. Nothing. Hit Play. Nothing. The buttons light up, but no forward motion whatsoever. Not even when hitting Record. Occasionally, when hitting Play, the Play and Stop buttons will light simultaneously. The take up side doesn't even do that little forward "creep" to keep tension on the tape when stopped.

At first blush, one would think the motor was shot, but I'm hoping that's not the case. It's not like this machine gets used every day. (It's been months since I used it last.) And the previous (original) owner was easy on it too.

I did a visual check of the transport electronics, and nothing is visibly crispy. I didn't see any of the infamous red chip sockets down there. The ones I found in the audio drawer have been stricken from the machine.

Has anyone else seen any such thing?

themagicmanmdt · Post by **themagicmanmdt** » Mon Nov 07, 2011 7:42 am

sounds to me like something on a control card, relay voltage line, or associated etc got sprung.

now's the fun part - troubleshooting!

i personally couldn't help unless the schematics and machine was in front of me - but randy blevins does his 'over the phone' help, since he knows MCI machines like his own...well...pants.

the good news - it's servicable! you don't have to throw the whole machine out!

CurtZHP · Post by **CurtZHP** » Mon Nov 07, 2011 7:47 am

Fortunately, I've got the tech manual with schematics, so I'm not flying blind. I was just seeing if anyone else had the same problem and could say, "Oh, yeah! Here's what to do."

You're right. Troubleshooting can be "fun."

The Scum · Post by **The Scum** » Mon Nov 07, 2011 8:23 am

Common MCI hangups:

Verify that all of the fuses are good.

Clean & reseat all of the Molex connectors.

CurtZHP · Post by **CurtZHP** » Mon Nov 07, 2011 4:10 pm

Cleaning, and also resoldering, the Molex connectors is on tap for tonight. I'll also check fuses.

Would I be safe in assuming that a supply rail feeding the supply reel motor and capstan motor also feeds the take up motor? Trying to rule out the power supply itself.

cjmnash · Post by **cjmnash** » Fri Nov 18, 2011 8:47 am

i'm reading this while eating cheerios, so pardon if i missed anything in your original post.

get some more info- if the motor does nothing in any state (play, ff, idle) it's most likely the power supply, if it works in some modes and not others, could be logic.

if you're still stuck on it - i do troubleshooting via skpe!

-chris mara
www.welcometo1979.com
www.nobraineraudio.com

CurtZHP · Post by **CurtZHP** » Fri Nov 18, 2011 9:20 am

I managed to track the problem down to the motor drive control on the power supply. It was so caked up with dirt that had been sucked through the supply by the fan that the dirt was actually shorting out connectors. (Probably had tape particles mixed in.)

This is probably the first time in this machine's life that the power supply was ever opened, so there was 30 years worth of dirt in there.

A good cleaning and all is well.

cjmnash · Post by **cjmnash** » Fri Nov 18, 2011 11:04 pm

awesome!

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MCI JH-110 down for the count!

MCI JH-110 down for the count!

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