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ARCHIVED FORUM -- March 2012 to February 2022
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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022

 

Justin's BG4000

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Craig
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And the 45rpm

 

Craig
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All done and ready for shipping back.......I just hope it survives the one day in transit Surprise

 

chartz
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chartz replied on Wed, Apr 28 2021 4:56 PM

Nice!

By all means, pack the platter separately.

Jacques

Craig
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Well....despite my best efforts the Beogram didn't arrive at its destination intact, so annoying! non the less Justin has sent it back with the suggestion that he collects in person when its back up and running....the central key of the control panel has been dislodged.

 

Craig
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Not a major issue as they are fairly easy to put back into place....Rudy can provide a couple of laser printed tools to assist in this endevour, I prefer to remove the front panel complete with all the keys and, using the holes in the back that im sure are there for that purpose, carefully press the leaf springs back into place....

 

Craig
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Bit fiddly but I suspect its easier than going in from the front...

Craig
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That was the easy part....additionally the voltage selector switch has been bashed in and one retaining screw mounting has been destroyed....difficult to get a good picture bit the corner mounting is damaged, i think i can repair it with a machine screw and bit of doner plastic.

 

Craig
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These are the bits that fell out upon inspection....

Craig
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And it keeps on getting worse.......the voltage regulator OTR1 and its associated zener diode OD2 are also kaput....the insulator is broken, but i think i can repair that.....new parts on order ;¬)

 

Craig
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As we know these parts live in the chassis in order to keep them cool.....im wondering what else has suffered downstream on the 24vdc side with this component flooding the circuit with too much power......im sure i will discover that in the fullness of time.

 

BeoBeo95
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BeoBeo95 replied on Wed, May 12 2021 5:29 PM

Hey,

your love of challenges reminds me of a film I watched last time. It was really interesting. You definitely have to watch it. You can find some information about it here Smile

 

 

 

 

Ein Leben ohne B&O ist zwar möglich, aber sinnlos Wink

Craig
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Also in the frame is the 24vdc reed relay, the relay responsible for illuminating the display on start....when the contacts get fused the panel lights come on before the start switch is activated.....with one wire disconnected the switch measured closed with a meter.

Craig
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This is a delicate job as the hair fine coil connectors are close by....wires unsoldered and on tab bent back allows the switch to be withdrawn, one end needed snipping off also.

Craig
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The replacement reed relay is a lot smaller than the original but are rated 0.5A, I have used these in the past and they seem to be a good replacement.....the annoying thing was once removed I re tested the switch and it had gone open circuit...... 

Craig
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Un deterred I have gone ahead and replaced it...im sure it will bear scars from its ordeal that will likely result in it sticking closed again in the future..

Craig
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Ok....following on from a Bilateral Inguinal Reductable Hernia procedure I am getting back to this machine, in order to take the pressure off I installed all of the laser printed parts Justin acquired into one of my good BG4000 units and Justin has collected that machine in person.....this gives me the pleasure of chasing down the issues on this unit at my leisure, after all who wants a fully functional machine when a challenge is open?

I know.......crazy englishman.....none the less the 24vdc voltage regulator parts arrived.

 

Craig
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And as yesterday was wet and horrible I have installed said parts, along with a set of capacitors to replace those removed. Ready to roll....

Craig
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Craig replied on Wed, May 26 2021 10:26 AM

Powered up and this is what transpired:

  • unit sat powered up with no actions
  • upon hitting Start the platter drive started up at 33rpm
  • the panel ilumination lamps came on
  • the 33rpm speed selector lamp cam on
However the transport drive motor didn't run, I could change the speed from 33rpm to 45rpm but no other functions responded. Time to look at the circuit diagrams...... 

Craig
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This is what I found....the following components where shot:

  • 1D11 Diode
  • 1TR33
  • 1TR31
  • 1TR30
  • 1TR32

All of the components on the opposite side of the motor tested good.

 

Craig
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Craig replied on Wed, May 26 2021 10:40 AM

Replaced the above from my stock of parts and with the transport drive belt removed, along with the transport slide, I powered up again....I was rewarded by the rotation of the transport motor once Start was activated, operation of the back/forward switches on the control panel reversed the direction of rotation......this was very rewarding, this feeling was to be short lived I'm afraid.

 

Craig
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Following the re installation of the slider assembly I ran the same test, expecting the platter motor to run, the transport motor to drive the pickup assembly in to the first drop point followed by the solenoid latching in and the arm dropping down.....not so.

What occurred was all of the above up to the pickup arm moving to the first drop point, slider moved over the switches fine, i was treated to a sudden crack and distinctly saw a spark in the area identified in the picture.....the unit died at this point ;¬(

 

Craig
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Craig replied on Wed, May 26 2021 11:00 AM

I have no doubt that I spotted a spark flash in the location above.....almost looked like something went to ground around that point, but there's no components nearby that can be suspect?

I removed the slide transport switch activators and could find no distinct evidence of arcing.....though there is a very slight mark the looks suspect. Powered up again and found the 24vdc came straight back on prior to start being pressed.....reed relay again, fortunately I bought 2 so was able to replace the fused switch straight away, powered up once more and the platter motor runs at 33rpm, the transport drive motor also runs in both directions, so im back to where I was before i replaced the slider switch actuators......good news, next step is to go over the operation of the unit without the slider switch actuator in place and see what happens......I'm thinking the slider actuator is shorting something on its travels.....  

Craig
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Following on I have powered up and pressed start, everything is running as it should, no slider plate in place, when 25/30 switch is pressed manually the transport motor stops, but the tone arm doesnt drop, the solenoid isnt pulling in as it should, the logic signal Q1 is switching from High to Low when i carry out this operation, I tried it a couple of times....so I know the logic is asking for the solenoid to be energised.

checked out the following:

  • 1D3
  • 1TR10
  • 1TR11
  • 0TR4
  • 6D1
  • 7R1
  • Solenoid coil

All the above tested fine

 

 

Craig
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This puzzled me......im getting 35v at the solenoid terminals when its disconnected so it should be pulling in......had a closer look at the set of contacts responsible for opening when the solenoid pulls in to drop the current from pull in current to holding current, although the contacts looked closed they also looked out of line, it looked like the spring wasn't hitting the stud connector fully ....thinking if i soften the solder at the point where the spring is held onto the small circuit board i would be able to get it back into alignment to make a better contact....and the spring promptly fell apart, looks like this has broken in the past and someone has repaired it by soldering it back together.....

 

Craig
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Salvaged a switch from a doner beocord 500 I bought some time back in order to get mine up and running, however the spring length is a little short, needs to be long enough for the actuator to open the switch when the solenoid energises, to achieve this I have soldered a piece of the broken spring onto the back of my replacement to give it the required length......making sure its a good strong solder connection, mechanical strength is important for this switch.....wouldnt do to have it drop off ;¬)

Its makes a nice firm connection now with the stud, im not sure this is the sole cause of the problems but it certainly wouldn't be helping things

 

Craig
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Result.....powered on and hit Start

  • platter runs
  • transport drive motor runs

hit 25/30 switch maunally

  • transport drive stops
  • solenoid pulls in
  • tone arm drops

hit SO switch

  • everything turns Off

Will check out the other functions tomorrow......for now its a glass of wine ;¬)

 

Craig
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Tested all the other functions i could without the slider actuator plate in place and all was well, fitted the plate and the plater and belts and gave it a go, one hand on the power socket......performed flawlessly ;¬)

 

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