ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
De afstemming op FM1 doet het wel?
The circuit for the source indicator lamps works closely together with the muting circuit, allowing for abrief muting of the sound while switching source.Wrong wattage front panel lamps can leak enough current through the circuit to activate the muting.Check that the lamps are correct.
If some sources work and other don't, you can confirm the diagnosis by swapping the lamps from one that works and one that doesn't.
I can supply correct lamps, if you need.
Martin
Lampjes kan een oorzaak zijn, heb je die vervangen?
Hi Martin, I have some lights from my previous order.
The lamps will light up normally - also if they are wrong wattage.The problem is with the circuit they work in.
If you have some spare lamps from me, try fitting them for the sources that are silent.
If nothing happens when you touch the standby pad, check that the pads bronze contact connects to its pin on the main board.If the relay just clicks when you touch the standby pad, but the Beomaster goes back on when you lift your finger off the pad, check IC9 (SPS5431).
Idle currents to high.Replace the trimmers and adjust.
All Class-B amplifiers needs a little idle current to keep the output stage just opened.It has something to do with the transistors charateristics.Without idle current, you will have cross-over distortion.With to high idle current, the output stage will work hard and run warm, even if it doesn't actually play anything.
The adjustment trimmers go bad and must be replaced.After replacing, the new components must be adjusted to the correct setting.It's all in the servicemanual.