Kid Squid
Well-known member
Bore Da Chaps,
Was up my mate's studio the other morning, and we got talking about his MTR-90, well, it's not working right.
aparently, a while ago, on switch on, the capstan motor spins off out of control !, so he fired it up, and the capstan spins off, at a rate of knots :shock:
Anyway, It turns out, that he had an ' Otari' guy in, to have a look at it, and he thought the problems were around the drive motor power transistors.
what happens next is a bit of a oopsy :roll:
aparently, he changed one of the drive transistors for a wrong type (npn for pnp), and blew a hole out of the back of the replaced transistor :green:
anyway, there were a few phonecalls, one big red face, and a disappearing tape machine guy..........
So, I thought I'd try to have a look at it. - replaced drive transistors Q9, Q10, as these were blown, switched on, .... and capstan runs off.
checked Q9,Q10 again, these were blown ( not with catastrophic guts bow out , tho !)
shorted from base to collector to emitter etc,etc., all otherpower transistors on heatsink tested ok. didn't have time to have a look at the smaller transistors, on inside of heatsink, on board PB9A449, had to pick the missus up from shopping :wink:
Have any of you come across this before,
Any schematics lying around ?, I've checked the link for the manual here, but it's not letting me see it! needs authorization.
BTW. here are the transistors, they are not cheap !
http://www.precisionmotorworks.com/shop/enter.html?lang=en-us&target=d2.html&lmd=39157.739375
Any Info is much appreciated,
Steve :thumb:
Was up my mate's studio the other morning, and we got talking about his MTR-90, well, it's not working right.
aparently, a while ago, on switch on, the capstan motor spins off out of control !, so he fired it up, and the capstan spins off, at a rate of knots :shock:
Anyway, It turns out, that he had an ' Otari' guy in, to have a look at it, and he thought the problems were around the drive motor power transistors.
what happens next is a bit of a oopsy :roll:
aparently, he changed one of the drive transistors for a wrong type (npn for pnp), and blew a hole out of the back of the replaced transistor :green:
anyway, there were a few phonecalls, one big red face, and a disappearing tape machine guy..........
So, I thought I'd try to have a look at it. - replaced drive transistors Q9, Q10, as these were blown, switched on, .... and capstan runs off.
checked Q9,Q10 again, these were blown ( not with catastrophic guts bow out , tho !)
shorted from base to collector to emitter etc,etc., all otherpower transistors on heatsink tested ok. didn't have time to have a look at the smaller transistors, on inside of heatsink, on board PB9A449, had to pick the missus up from shopping :wink:
Have any of you come across this before,
Any schematics lying around ?, I've checked the link for the manual here, but it's not letting me see it! needs authorization.
BTW. here are the transistors, they are not cheap !
http://www.precisionmotorworks.com/shop/enter.html?lang=en-us&target=d2.html&lmd=39157.739375
Any Info is much appreciated,
Steve :thumb: