What kind of diode is this?

[stj]

Re: What kind of diode is this?

you probably need to clean the old crap out and re-lube them.

[eccerr0r]

Re: What kind of diode is this?

They are brushless DC motors and they use electronics to synthesize AC. The electronics will automatically generate the correct phasing so that there's no need for the capacitor to do so to generate the other phase (compare to 3-phase AC motors instead of 1-phase AC motors.)

[redwire]

Re: What kind of diode is this?

Rule out mechanical problems before going into the electronics.
I would first clean out the old lube with q-tip and IPA. After 35 years, the original grease and oil is gummed up. The worm shaft for the head stepping motor needs grease, and guide shaft needs oil. The disk motor probably needs oil but should not be stiff as to not start spinning without help.

The disk motor circuit may be the same FC-9 as the later OA-32V pcb 1-609-924-11
I'm not sure what the "FG print coil, 60 pieces" is on CN1, as a tachometer circuit?
It's not like an AC motor with start cap. There's several 1uF,10uF ,100uF caps which could upset the tach. No datasheet on Sony CX-069A it might be a PLL for speed regulation.

For the diode D2 smoking, if the wiring is not shorting and the connector was not put on backwards, I would check the resistance of the stepper motor's four windings, and continuity to the motor case.
A fault to GND on CN5 pin 1 or 2 is what I would see overloads the diode.

[roadrash]

Re: What kind of diode is this?

Thanks for that excellent idea redwire thats something i will check as ive checked and nothing could have shorted in the connectors.

[stj]

Re: What kind of diode is this?

your lucky btw, some old drives have a belt!

[roadrash]

Re: What kind of diode is this?

Well I had the new diodes arrive. I put a new diode in and tested the transistor its connected to, which was ok and then rebuilt the drive again, looking carefuly this time to see what could have caused the short the last time but I still cannot understand where it shorted. Anyway its back together and its working just as it should but like all the other drives, its now not booting any system disks. I only ever did get one of these drives booting when I first restored the computer but now I have 4 drives in nice clean condition, all working but unable to boot a disk. I have no idea what to do now, it might be alighnment but I havent altered that. This drive only stopped working originally after a tried a floppy out of another old apriocot in it. So its crazy all this happed just because of tried a floppy out of another aprocot in it. Oh ho I wish I hadn't.. At least its working again and not smoking.
Just to get it to read a disk again ...

[stj]

Re: What kind of diode is this?

did you clean the heads yet with ipa??

[roadrash]

Re: What kind of diode is this?

I cleaned the heads with Surgical spirit. They are nice and shiny clean..