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[tom_c]

Hello everyone,

I was wondering if anyone could help me with an issue I'm having regarding my JH-110.  I've had an intermittent problem with the take up motor on my machine which is no longer intermittent.  For a month or so, I would turn on the machine and the take up reel would not spin (counter clockwise for tape tension) when I tried to load tape, or go into fast forward or play mode when I put an opaque card in the tape break sensor.  I would then turn off the machine exercise the three molex connectors (power, tach, break)and it would work sometimes.  Other times just turning it off and back on would do the trick.  I've bought two of the 110's at the same time and have swapped out the motor to no avail.  The motor is getting voltage, and when I block the tape break sensor, I hear the break disengage and can turn the reel freely.  If anyone has any ideas of where to go next, I'd really appreciate it.  

Thanks,
Tom

[Brian Roth]

I would guess there's a bad Molex connection on the analog torque board, or perhaps in the motor drive amplifier assembly.

Bri

[tom_c]

Thanks Brian.  That was what I feared it would be.  I've been following the posts on MCI machines and see that both you and John Klett recomended replacing or at least redoing soldering the molex connectors on these boards.  I replaced the chimney assembley with a back up I had and that didn't solve the problem either.  I've got a second analog torque board so I'll try that.  Thanks for your help, I'll keep you posted.

Tom  

[tom_c]

Ok, swapped analog torque boards, take up reel now works, but it's spinning way to fast.  The board I swapped was of a different build than the one originally in the machine.  It's got what appears to be a number of very ugly mods done on it so I decide to pull it out.  This isn't a problem since I figure I've isolated the problem to the torque board.  So I went ahead and desoldered, exercised, and resoldered all the molex connectors on the old torque board, reinstalled it, and...the take up motor doesn't work...again!  Well as a last effort before I finish up for the night, I decide to check the torque and idle adjustment resistors.  I tweek the idle a little clockwise from the starting positions (Marked with a fine point sharpie)and the take up starts to turn at idle.  I then followed the manual to adjust the idle tension, hit play and it works!  I'm still glad I did all the work on the molex connections though, and I got some time to get familiar with my scope.  Thanks for the help Brian!

Tom

[Brian Roth]

Tom, welcome to the wonderful world of older MCI machines <g>.

The "bed of nails" on the transport mother board are a common source of problems.  I suggest that 100% of them be resoldered if any future problems arise.

As for setting up the analog torque board, be sure to do the "offset null" adjustment.

Bri

[tom_c]

Thanks Brian.  Did the offset Null adj. last night when I did the idle.  I'm going to do all of the molex connections and recap all of the boards and power supply over the next week or so.  Thanks for the point in the right direction.

Tom

[Brian Roth]

Tom, I didn't notice if you mentioned whether or not you had those incredibly BAD red-colored IC sockets on your analog torque board(s).  They were an even worse problem than the Molex connectors.

Sometimes, I think MCI stood for:   Much-Connector-Itis

<g>

That said, I currently keep a pair of JH24/24 and a couple of JH-110B/C machines running nicely in my area of the planet, after dealing with the connector issues many years ago.

Bri

[cdr-1]

the dreaded plague of the red sockets...it's like a scary campfire tale for recording geeks...

We replaced them all in my JH-110-B 8 it works very well now. Little quirks here and there, but overall, I love it.

Be through when adjusting the tension and offset null. Also, check the tension often. My B machine actually ate a tape when I let the tension get too out of whack.