Beogram 4002 arm movement

17 replies
OR
Offline
orava
Bronze
Posted October 4, 2022 at 06:50 GMT
#1649502
Reason for 4IC1 was bad aglinment.
For slow carriage movement shorted D31 between slow back 3V adjustment and motor feed transistors.
Next problem. Carriage motor wont stop at stop switch, and yes, switch is ok.
Mark-sf
Offline
Mark-sf
Bronze
Posted October 5, 2022 at 01:02 GMT
#1649550
Does the turntable motor keep spinning as well as the lamps stay lit? If so, you still have an active 22.8v rail and OTR1 is not turning off. Is the anode of 1D1 grounded when this occurs?
OR
Offline
orava
Bronze
Posted October 5, 2022 at 15:43 GMT
#1649562
Well, I do not have any 0TR1, I C1 I guess..

As I say on first message newer board and service manual do not equal. Manual says "circuitry is basically identical" although layout and numbering is different. So I have to decode board with almost right circuit diagram.
Mark-sf
Offline
Mark-sf
Bronze
Posted October 5, 2022 at 18:16 GMT
#1649565
No, a TR is not an IC. You will need to trace the circuit but you have the SO switch as a reference. Just follow its high side.
OR
Offline
orava
Bronze
Posted October 6, 2022 at 09:13 GMT
Edited October 10, 2022 at 06:49 GMT
#1649581
Yes

and this is from 551x, so mine is 552x. (1IC1=TIP120)
Mark-sf
Offline
Mark-sf
Bronze
Posted October 6, 2022 at 17:29 GMT
#1649603
IC1 is a voltage regulator and the operation is the same in that it is being turned off by the SO switch grounding the anode of D5. I would confirm that is occurring.
OR
Offline
orava
Bronze
Posted October 10, 2022 at 06:50 GMT
#1649650
oh well, broken trace, things are not allways complicated...

Then mechanical adjutment and re-build
or
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