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AQ160 rejects before play

Posted: Fri May 15, 2015 7:39 am
by ken g
Yes one of the simplest problems ...right .. I spent an hour searching for details on this before i posted here and could not find this . Yes i have worked on 7 or 8 of this model and never ran into this problem .

It loads the record and will play normal 30% of the time . Its very random . What i have done is unhook the ''missing record '' contacts . Unhooked the rear reject switch . Unhooked the front tone arm reject switch . I oiled & freed up the plunger and clutch assembly . It still rejects most of the time . In every other case in the past , one or 2 of the above fixed the problem . Not this time .

Whats left to do ?

Re: AQ160 rejects before play

Posted: Fri May 15, 2015 10:12 am
by Rob-NYC
Does the trip coil feel powered? if you hold down the manual trip lever, does it try to pop up?

Try a --known good-- 2050.

this is one of the peculiar failure modes of that tube in this circuit. It will fire and stay conducting too long.

Check also for the negative bias on the 2050 grid. It should be around -25VDc.

Clutch is the obvious cause. Even if lubed, it may still do this if the yoke bearing on the clutch lifter is gummy.

Rob/NYC

Re: AQ160 rejects before play

Posted: Fri May 15, 2015 4:18 pm
by Ron Rich
Hi Ken,
Unless you have an ASU-1, or a TASU-1, connected, you have NO, "missing record contacts". If either is in use, I would un-plug it before going further, as they both contain an electronic record reject trigger. As Rob said,a "gummy", or frozen clutch yoke pin, can cause this. Also, this can be caused by the plunger stop, in the detent coil--is the brass insert still there ? if not, has it fallen inside the coil sleeve ? Either way, if missing, or broken, it will cause this to intermittently happen. Also, you need to suspect an electrical problem in the 2050 tube/circuit, as mentioned, and that the end of record switch is not re-setting all the time---
BTW--when it "screws up", do you hear the pop meter solenoid "clicking twice" ? If so, the problem is mechanical !
Ron Rich

Re: AQ160 rejects before play

Posted: Sat May 16, 2015 2:15 am
by ken g
Thanks guys . I did not know the 2050 was part of this , i have a new tube to try . I will go back with all of this info and let you know .