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MCI JH-110B Capstan Problem
Posted: Wed Nov 20, 2013 6:00 pm
by kerble_Archive
Hey Matt!Welcome aboard, I'm going to move this to the Tech Room, as it's more populated, and you might get a better response. cheers, and good luck.
MCI JH-110B Capstan Problem
Posted: Wed Nov 20, 2013 6:00 pm
by mattjhuber_Archive
Okay -- so, someone gave me an MCI 2-track RTR; I am so excited to step into this world!So, of course, I power it on I run into an issue...Fast forward / rewind work perfectly...everything seems to be running smoothly on that end...HOWEVER...play and record result in no movement of the tape. I cannot, under any circumstances, get the capstan to run. When I press play, the capstan makes contact with the pinch roller, as it should. The play switch works properly (at least, the light comes on when pressed)Any idea where to start? Could this be a result of the infamous Molex issues? And if so, where should I start?Thanks so much, my friends!
MCI JH-110B Capstan Problem
Posted: Wed Nov 20, 2013 6:00 pm
by mattjhuber_Archive
You guys are amazing...thanks for giving the question more exposure.Definitely excited to get this thing running.
MCI JH-110B Capstan Problem
Posted: Wed Nov 20, 2013 6:00 pm
by numberthirty_Archive
Quoted your post in the "Little Tech Questions From Your Day" thread -http://www.electricalaudio.com/phpBB3/viewtopic.php?f=5&t=43703You might get a few more bites there.
MCI JH-110B Capstan Problem
Posted: Thu Nov 21, 2013 6:00 pm
by greg_Archive
Let's keep the thread alive here so we don't lose it in unrelated discussions, and it will be easy to search. It could be any number of things starting at the logic/command board to the capstan PLL board, to power supply, and motor amplifier. It's kind of too big an issue to diagnose over the interwebs. You will need all the schematics, manual, oscilloscope, and some know-how that is more than the average bear. Not to discourage you, but see if you can hire a tech for the afternoon, and hang out while he looks at it, ask questions.For now, I'd recommend gently reseating all the boards sitting on the giant mother board under the transport. Keep an eye out for what pins appear where in case you pull a board completely out. It is possible to have something pluged in a whole pin off, which will cause all sorts of headaches (to put it mildly). If your ICs are seated in big rectangular sockets with little slits for the legs to fit in that's bad news. They are usually colored red, but sometimes black. The good sockets have circular holes for the IC legs to fit, and are about the hight of the IC itself. Google "machined pin IC sockets" to see what the good ones look like. They will be white or black. If you have those, that removes a swath of possibilities.Even if you get this to wake up I recommend getting a tech to check the whole transport out and shoot the shit with y'all about it. It will give you a running start on a good life with this...Good luck and post when you find a solution please,gREG
MCI JH-110B Capstan Problem
Posted: Thu Nov 21, 2013 6:00 pm
by mattjhuber_Archive
Any thoughts on my issue? I am not getting a voltage reading at the motor...so, it appears to be an issue before the motor itself.Also, I've re-seated all of the Molexes, and haven't noticed any intermittence issues. All of the connectors are very clean -- no corrosion.
MCI JH-110B Capstan Problem
Posted: Thu Nov 21, 2013 6:00 pm
by numberthirty_Archive
I noticed Adam commented in the "Little Tech Question" thread. Maybe posting your newest details there for him to see might be the play?