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  • Re: Beomaster 4000 addiction in the making

    Finally.............after what has seemed like a lifetime I have bottomed this out, 2 failed components TR52 and TR54 on the left channel. Two failed components caused me considerable confusion.....I suspect TR54 went down and in turn burned out TR52, I'm probably wrong there but not to worry. One thing I have learned is that replacing capacitors on a working machine and fault finding down to component level are two completely different things....this has been a war of attrition, and all for
    Posted to The Workbench (Forum) by Craig on Sat, May 21 2016
  • Re: Beomaster 4000 addiction in the making

    progressing through the output board swapping the transistors over one at a time and checking for the healthy signal at the wiper of the emitter idle voltage pot on both channels I find that in each case the right channel continues to deliver a healthy signal with the transistors from the left channel.......until I reach left channel TR53, when swapped with TR42 on the right the right channel fails to give the signal and it appears on the left channel.....great I thought, cracked it! however after
    Posted to The Workbench (Forum) by Craig on Fri, May 20 2016
  • Re: Beomaster 4000 addiction in the making

    Ok....got the power supply capacitors changed out and confirmed everything was back to where I started prior to detecting the leaking cap, powered up ok and still gives the same readings on each channel.....I will now systematically swap each output transistor from the good side to the bad side and see what happens.
    Posted to The Workbench (Forum) by Craig on Fri, May 20 2016
  • Re: Beomaster 4000 addiction in the making

    Yes Sonavor I have seen Rudi's BLOG regarding this exercise, and your right it is quite an expensive enhancement. I myself noticed a leak on one of my big smoothing capacitors last night as I was exploring my failed channel, the big 5000uf 80v piece....I have some replacements so will swap all three out this evening, I don't think this is my issue however. I will continue to pursue this by exchanging each component from the right channel to the left channel until I bottom it out.....I have
    Posted to The Workbench (Forum) by Craig on Wed, May 18 2016
  • Re: Beomaster 4000 addiction in the making

    Got back to it today........removed both transistors TR41 and TR52 and replaced them in reverse, powered up and still the right channel works fine and the left is still not playing ball. Well at least TR41 is eliminated from the list of potential suspects.
    Posted to The Workbench (Forum) by Craig on Sun, May 15 2016
  • Re: Beomaster 4000 addiction in the making

    I was able to trace this signal, varying the amplitude via the volume slider, and varying the frequency via the sig generator all the way to the base of both transistors TR41 and TR52.....however I am loosing the signal at the wiper of the emitter bias trim pot 569 on the left channel, the signal is still good at this point on the right channel 479. So my fault is upstream of the bias on TR52.....unfortunately our garden gate fence post has been blown down in the wind......so I will have to leave
    Posted to The Workbench (Forum) by Craig on Sat, May 14 2016
  • Re: Beomaster 4000 addiction in the making

    Ok... Been a while but I've finally got my hands on an old dual beam oscilloscope! its a vintage CRT job that lacks lots of modern day refinements but I'm hoping to use it to follow the incoming signal on the functioning right channel and compare this at the same points on the failed left channel. Tested the scope with its own 1v ptp square wave test signal and both channels work ok...however it came without a probe so I have ordered one up.....should be interesting ;¬)
    Posted to The Workbench (Forum) by Craig on Wed, May 11 2016
  • Re: Beomaster 4000 addiction in the making

    Looks like someone in the past has had a go, notice the replaced capacitor and the odd pair of series resistors in position 570 on the left channel. looking at the values of both resistors (one at 170 ohm and the other at 180 ohm) they have been used to replace the original 330 ohm component. I don't see any outward signs of frying or damage.....however I have contacted Martin and requested a full capacitor kit and a recommended set of components for this rogue channel......I will post pics as
    Posted to The Workbench (Forum) by Craig on Wed, May 4 2016
  • Re: Beomaster 4000 (2406) An unexpected journey

    Well....the latest acquisition was sourced from ebay at £41...said one channel was down but cosmetically looks reasonable, I'm hoping to bring it back up to spec with some replacement components, still looking for an outer case for the one I got from Steve. It strikes me that there are quite a few of these systems out there that people simply cannot get repaired these days and therefore sell them on very cheaply, I know in my part of the UK there is nowhere anyone could take such a piece
    Posted to The Workbench (Forum) by Craig on Fri, Apr 29 2016
  • Re: Beomaster 4000 (2406) An unexpected journey

    Well.....finally received the replacement power supply capacitors from HiFicollective, took them over a week to deliver and I was not impressed. However fitted them and boxed everything up.....I have to confess I gave up on the 2 capacitors hidden alongside the transformer...just couldn't get to them!.......hooked up an IPad to tape 1 and had a listen, sounds incredible! it's easy to see why people paid so much for this kit back in the day. I know this will sound a bit glib, but I feel as
    Posted to The Workbench (Forum) by Craig on Wed, Apr 27 2016
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