388 playback troubles (too fast... R112 and R212 affecting playback speed? wierd.)

[migrant worker]

Well... I adjusted the FFW and REW speed about a week ago at R112 and R212 (tension roller height adjustment), and things were butter until just today...

I went to record and suddenly lost both the "play" and "record" transport functions.

After verifying all fuses in the top right section under the panel were ok...

And... CHecking that the capstan belt was intact and that the capstan would indeed spin if I lifted the right tension arm...

I'm stumped.

I got the play function back after fiddling with trimpots 212 and 112 again, but adjustment there now affects playback speed.

It's my understanding that this shouldn't be the case.

Anyone got any ideas?

(Thanks in advance for any help!)

Matt


PS: Immediately after the play/record functions stopped working, I noticed that the tape would play if I pushed the pinch roller up some (I think its pressure is set by the right tension roller height though, so this may not be important information).

 

[migrant worker]

Well...

I figured it out...

One of the screws that mount the pinch roller solenoid had come loose (it was actually rolling around in there)... Apparently this allowed the solenoid to pivot so that it didn't exert enough force on the capstan for the play function to work.

It looks like they put small dabs of blue glue on these screws to fix them in there at the factory, but after 30 years or so... I guess it's "un-stuck."

I'll have to go get some med. strength loc-tite tomorrow and anchor them in there well.

Anyway... Just wanted to leave a record of this fix in case the same thing happens to anyone else.


One other unrelated thing I noticed...

When connected to the 388 (but not powered on), the AQ-65 auto locator unit will cause the PLAY, REW, and F.FWD LEDs in the transport to glow green...

Power it on and the LEDs turn off and everything operates normally.

(Just in case this should happen to anyone else, it appears to be normal).


Matt

 

[jpmorris]

If it's like the other machines I've messed with the pinch roller on, the solenoid is mounted by several screws with slots to allow the position of the solenoid to be adjusted and the amount of force that the roller exerts is a function of how near or far the solenoid is to the lever mechanism.
So I'd be a bit leery of trying to glue it into place as you may need to adjust it in the future. IIRC you're supposed to do this after replacing the roller...