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  • Re: First attempt at Beomaster 2400 'refurbishing'

    I thinks this project is almost done. Did a FM tuner check yesterday, reception is surprisingly good, with only a short length of 0.75mm2 wire pushed into the antenna plug Only headphone hum left to fix. Tried two different jack-to-mini-jack converters and 3 different headphone types so an issue with the electronics. Cannot find any shorts or loose ground wires, the Tape-In DIN plug is rock steady in place. Hum increases when i touch the metal end of the electrolytic caps on the sound control board
    Posted to The Workbench (Forum) by jesperb on Tue, Apr 9 2019
    Filed under: Beomaster 1900, beomaster 2400, hum, beomaster 1900-2
  • Re: First attempt at Beomaster 2400 'refurbishing'

    Got a little spare time, which immediately went into the Beomaster 2400 on the kitchen dining-room workbench (no room for guests this week). Looking at the 'volume up mute' issue, where volume would play briefly and then mute for the first 3-4 taps on 'vol up', I measured out 'any and all' voltages around P3 and P5, all voltages matching the values on the diagram. Finally I gave up analyzing the muting diagram, couldn't quite understand it anyways and decided either 3TR3
    Posted to The Workbench (Forum) by jesperb on Sat, Apr 6 2019
    Filed under: Beomaster 1900, beomaster 2400, beomaster 1900-2
  • Re: First attempt at Beomaster 2400 'refurbishing'

    ...i go my lamps from Dillen (too).
    Posted to The Workbench (Forum) by jesperb on Sun, Mar 17 2019
  • Re: First attempt at Beomaster 2400 'refurbishing'

    Honestly ? I don't know. I bought them as a 'Beomaster repair kit' and no markings. Try do a search, lots of discussions about the lamps.
    Posted to The Workbench (Forum) by jesperb on Sun, Mar 17 2019
  • Re: First attempt at Beomaster 2400 'refurbishing'

    Not sure this is troubleshooting progress, but tapping 'vol up' will activate the mute circuit. Can be reproduced from when volume has been off completely and until there is 'a little' voltage out of the counter (3IC1) pins QA-B-C-D. The scope screenshot shows the mute out signal, PCB3 between 3R28 and 3R28a. Far left volume is all the way down, tap 'vol up' slightly and 'mute' goes 'high' or 'on'. Then mute is 'released' when i tap 'vol
    Posted to The Workbench (Forum) by jesperb on Sun, Mar 17 2019
  • Re: First attempt at Beomaster 2400 'refurbishing'

    Not sure this is troubleshooting progress, but tapping 'vol up' will activate the mute circuit. Can be reproduced from when volume has been off completely and until there is 'a little' voltage out of the counter (3IC1) pins QA-B-C-D. The scope screenshot shows the mute out signal, PCB3 between 3R28 and 3R28a. Far left volume is all the way down, tap 'vol up' slightly and 'mute' goes 'high' or 'on'. Then mute is 'released' when i tap 'vol
    Posted to The Workbench (Forum) by jesperb on Sun, Mar 17 2019
  • Re: First attempt at Beomaster 2400 'refurbishing'

    Just as soon as i got the lid back on, new issue : Sometimes the sound mutes, when i turn the volume up. Only if i touch volume up shortly, like nudging a single step up in volume. Keeping the finger on volume up and it works just fine. Volume down doesn't have this issue, at least i have not been able to provoke it. I desoldered and measured all transistors out on the volume PCB (#3), all measures out OK. All diodes too. I have 18V/100kHz at 3C11/C12. Voltages on the 'input' side of
    Posted to The Workbench (Forum) by jesperb on Wed, Mar 13 2019
    Filed under: volume, beomaster 2400, beomaster 1900-2, Beomaster 1900 Beogram 1500
  • Re: First attempt at Beomaster 2400 'refurbishing'

    Having done the no-load adjustments, a bit fiddly without multi-turn potentiometers, heating is practically the same on both sides. So time to call it over & out, thanks to everyone who pitched in with their 2€
    Posted to The Workbench (Forum) by jesperb on Tue, Mar 12 2019
  • Re: First attempt at Beomaster 2400 'refurbishing'

    After the no-signal current adjustment, the Beomaster is playing nicely. However, the left channel with new TIP's is running sligthly hotter than the right. Playing at half volume for about 30 minutes, the cooling fins, for the left channel, are at 32-33 degrees, where the right channel fins, they are at 28-29 degrees. Is this business as usual or should I dig deeper into this ? If not, it is time to dig out - and test - the remote control.
    Posted to The Workbench (Forum) by jesperb on Fri, Mar 8 2019
  • Re: First attempt at Beomaster 2400 'refurbishing'

    After some deliberation, I turned the Beomaster on. It turned itself off immediately and gave a blue puff of smoke. Plus one of the 220VAC fuses blown. Finally i did, what Dillen has told me (and many others) to do from the start : Test/measure all components in the output stage. Nothing seemed to be burnt though. Transistors good, diodes good, all resistors good. I could only think of two things : 1. I had re-used the 'non burnt' TIP 146/IC201 plus a new TIP141 for IC200. 2. I hadn't
    Posted to The Workbench (Forum) by jesperb on Thu, Mar 7 2019
    Filed under: Beomaster 1900, beomaster 2400, beomaster 1900-2
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