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  • Re: Beomaster8000 repair/resoration

    Hi ALF, I still suspect the volume circuit on the filter and tone control board but to isolate that I suggest taking the preamp board from your other Beomaster 8000 and swapping it in this one. If the problem is the same I think you can eliminate the preamp and those multiplexer devices. If the problem goes away then you just have the preamp board to deal with. Assuming the preamp is good, you are left with the filter & tone control board. You verified the volume control IC was getting signals
    Posted to Vintage Products (Forum) by sonavor on Thu, Apr 11 2019
  • Re: Beomaster8000 repair/resoration

    Hi ALF, I found this relay: Omron G2R-1A-E-DC24 It has a maximum coil voltage rating of 170% of the rated 24VDC coil voltage. That will handle both the requirements for 7RL1 and 7RL2. Looking at the Beomaster 8000 startup circuit schematic The 7RL1 coil voltage can be over 24VDC so the 170% rating of the Omon G2R will work for that. The 7RL2 relay coil should be 24VDC. John
    Posted to Vintage Products (Forum) by sonavor on Wed, Apr 3 2019
  • Re: Beomaster8000 repair/resoration

    Hi ALF, The 7RL1 relay can see more coil voltage than the 7RL2 relay. The coil resistance of the relay is a factor in that. Without any spec sheet on the Schrack relay we don't know what the maximum coil voltage can be. We have the Omron spec though and it shows an 1100Ω coil resistance and a maximum coil voltage of 170% of the rated coil voltage (which is 24V). So the Omron will handle up to 40.80VDC. The voltage across 7RL1 should be less than 30VDC. John
    Posted to Vintage Products (Forum) by sonavor on Wed, Apr 3 2019
  • Re: Beomaster8000 repair/resoration

    This is an interesting issue. I have only replaced these 7RL1 and 7RL2 relays one time and I did it by changing the relays from one Beomaster 8000 spare unit to the one I was repairing. I didn't pay attention to the two relays as they looked the same and I replaced 7RL1 to 7RL1 and 7RL2 to 7RL2. The Beomaster service manual does list the two relays with separate B&O part numbers - 7RL1: 7600053 7RL2: 7600060 I have never found any specifications on them. Today I opened up one of my spare
    Posted to Vintage Products (Forum) by sonavor on Tue, Apr 2 2019
  • Re: Channel bias

    Other than a muting relay there are usually no electronic components between the cartridge and the plug for the preamp. From your description of the problem it sounds like you can manually adjust the arm and get it to play a record correctly. If that is the case then the problem sounds like it is related to tracking force. Is your RX2 tracking force calibrated? In other words, is it actually applying the tracking force it says? You can check that with a tracking force gage. Occasionally I will run
    Posted to BeoGram (Forum) by sonavor on Tue, Mar 26 2019
  • Re: Beomaster 8000 repair for a non-savvy user

    Thank you Martin. I am talking to Francisco via PM now. John
    Posted to Vintage Products (Forum) by sonavor on Sun, Mar 24 2019
  • Re: Beomaster8000 repair/resoration

    If you probe at P76 before plugging it in and there is 5V then lose it on plugging it in then there must be a short there. You said earlier you changed out the microcomputer IC oscillators. Did you remove the microcomputer ICS when you did that? If so, did you make sure the oscillators were shorted while doing the procedure? It is too late to worry about now but in the future one shouldn't really mess with the oscillators unless there are symptoms there is a problem related to it. I do change
    Posted to Vintage Products (Forum) by sonavor on Sat, Mar 23 2019
  • Re: Beomaster8000 repair/resoration

    Hi Alf, Don't try to tackle too many issues at once. Right now it appears your issues are related to the power supply circuits. You need to troubleshoot the relays and see why they are acting the way they are. Determine if the relays are good or if the circuit controlling them is faulty. If you think the voltage regulators are running hotter than expected then check what their incoming voltage levels are. I would go through the power coming in from the transformers through the rectifiers and
    Posted to Vintage Products (Forum) by sonavor on Thu, Mar 21 2019
  • Re: Beomaster8000 project

    Hi Alf, I would inspect the work that was done and continue testing the new unit then. Perhaps one of the startup relays have gone bad. I had to replace a couple before. John
    Posted to BeoGram (Forum) by sonavor on Tue, Mar 19 2019
  • Re: Beomaster8000 project

    It is a good problem to have where your new Beomaster is in great cosmetic shape. That means another future restored Beomaster 8000 can go back into service. I never trust a non-restored Beomaster 8000. They are too old now. I wouldn't risk doing any further electrical damage to it until the capacitors have been replaced, the connections checked out and the power supplies verified. John
    Posted to BeoGram (Forum) by sonavor on Mon, Mar 18 2019
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