hcraig244
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Removed 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?
Ok….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.
following 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.
spent 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.
Hit 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 ;¬)
Put 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…
Quick 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….
Its doubtful I would have missed the absence of said screws so im suspecting a third party involvement somewhere…..Ok…..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.
Been 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.
Well secured and packed…..platter was packed separately and stowed away under the Beogram in foam and cardboard
Not 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
From 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
Looks to me like the “upgrade” in question doesn’t cover the more complicated BG4000…..even though the end result is identified as such
Just had a thought, is this the 6000 quad amp, unfortunately I have assumed it is ?
Love these amps…so over engineered it’s untrue, you should consider replacing all the capacitors as a matter of course, however it’s a good idea to resolve the problem you have first so you know your not introducing additional issues as you go along.
you could start by looking at replacing the four output capacitors first, I have found these caused similar problems to the one your having…..and as you should replace them anyway it’s a good place to start, check out my posts in the archives, I’ve done one or two and they may help you out….enjoy ?
