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hcraig244
SILVER MemberUnclamped the sock and rotated it to remove the kinks…..this is much happier now, never seen this before……will re secure the clamp and look to replace the trimmers.
hcraig244
SILVER Memberduring testing I found that when the tone arm approached the ES position it was slowing down considerably, when moving forward slowly by nudging the tone arm by small increments to simulate a record on the deck, and more often than not actually stopping short.
I noticed that the drive motor was still running and the belt was slipping….watching this a couple of times i spotted this..the cable containment sock was all twisted and lumpy and the carriage was fouling on it at the end of its travel…
Tht
hcraig244
SILVER MemberRemoved 1TR28 and it tested fine! went ahead and tested all 1TR27/1RT26/1TR29…..all proved good…..put them all back and powered up and needless to say everything worked perfectly…..dry solder joint somewhere? temperamental transistor?
hcraig244
SILVER MemberOk….time for a update, according to solderons training notes when FF is operated the collector of 1TR25 should go high (approx 22v) I was getting closer to 14v at this point….still good.
Also said voltage is fed to the Base of 1TR27…still good…and therafter to the Base of 1TR28 thus causing the motor to rotate in the forward direction…..the 14v was not getting out of 1TR28…..so no rotation.
hcraig244
SILVER Memberfollowing re solder of the transport motor connections powered up again and the following happened….Main motor started to run, Neon lamp illuminated, scale illumination lamps came on as did 33rpm lamp….Solenoid didnt pull in immediately which was also good however no movement of the transport motor.
Operating the FWD switch on the control panel did nothing…so wound the transport carriage forward an inch or so and operated the REV switch on the control panel and the transport was driven to the stop position by the motor…..
Hit start again and nothin happened so wound the transport carriage forward again by hand all the way to the 33rpm drop position and the solenoid pulled in…continued winding until the end point and the solenoid de energised and the transport was driven back to the stop position…big improvement,
Clearly an issue with the transport motor circuit…..will have a look.
hcraig244
SILVER Memberspent a little time this morning unsoldering and cleaning the transport slide switches, didnt look bad actually….I think someone may have gold plated these ;¬) but cleaned them to eliminate them from any further considerations.
hcraig244
SILVER MemberHit Start and the neon lamp came on, always a good start….the 45rpm lamp also lit up and the main motor started to revolve….scale lamps also illuminated…all good stuff, however the solenoid energised straight away and the tracking motor sat motionless….a small push inboard did nothing….a small push outboard momentarily powered the tracking motor, the carriage didnt move as the belt to the pully was just slipping too much to get any traction.
So……quite a bit to sort out, I suppose the main good thing is that all the vital components, transformer/motors/solenoid and I did notice the detector arm lamp was lit/ are all healthy…they just seem to have “lost there marbles”.
I will start by examining the slider switches as they often seem to be behind a lot of issues with these decks…..as always comments and advice is welcome ;¬)
hcraig244
SILVER MemberPut the PCB back and got the variac out…….with the meter in series slowly powered up, the multivibrator circuit clicked on and there was no smoke or crackle of unhappy components..current draw was around 20ma…
hcraig244
SILVER MemberQuick look under shows signs of activity….looks like 1TR29 and 1TR30 have been replaced with something else…also the speed control relay has been replaced….
hcraig244
SILVER MemberIts doubtful I would have missed the absence of said screws so im suspecting a third party involvement somewhere…..
hcraig244
SILVER MemberOk…..opened up and a visual inspection prior to power on reveals only one screw holding the main PCB in place….not a very encouraging start.
hcraig244
SILVER MemberBeen here before as can be seen from the Rudi patented laser printed capacitor bracket, and the ne 6v & 24v power supply smoothing capacitors….cant quite remember what else I did in here but I suspect it may have been a replacement of the 24v regulator OTR1….It comes with the description of “misbehaving” in as much as the tone arm is driving inboard and not returning to the stop position when required….I will have a look.
hcraig244
SILVER MemberWell secured and packed…..platter was packed separately and stowed away under the Beogram in foam and cardboard
hcraig244
SILVER MemberLifted out …..
hcraig244
SILVER MemberNot a particularly good image but does show the extent of the protection the chest provides for these delicate machines…given the degree of abuse they would suffer at the hands of almost all delivery companies
hcraig244
SILVER MemberAnd inside the chest was a heavily padded BG4000….
hcraig244
SILVER Membermust be these two fellows………
hcraig244
SILVER MemberFrom your pic I can see the tone arm connector which accepts the cartridge is ruined…..this can be replaced with a lazer printed component available from Rudi the Beolover. This is a quite involved process requiring some very tricky soldering and also some time to achieve, the absence of light from the detector arm may be nothing more than a burned out lamp, also requiring some soldering skills…..these are not tasks to be undertaken by anyone unsure of said abilities…..and if one can find a repair shop willing to take it on, not many will due to the time consuming process, they will charge you a fortune. I have a B&O shop close to me who advised me they charge £150 just to look at a BG4000…..needless to say any repairs on my kit is carried out by myself ;¬)
Tim Jarman is well respected in this forum, though I have never met him, I’m sure he would be more than capable of giving you some guidance.
Craig
hcraig244
SILVER MemberLooks to me like the “upgrade” in question doesn’t cover the more complicated BG4000…..even though the end result is identified as such
hcraig244
SILVER MemberAnd post some pics….always useful ?
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