Hi hermenex. Sorry for misleading you with my previous voltages for F, G & H. I took new voltage readings with another DMM and these are now much closer to spec. F: 3.4V / 3.56; G: 8.05V / 8.85V; H: 24.82V / 24.77 (Left / Right). Using my signal injector things seem OK up to the Balance control, so I eliminated the non-working channel from the volume

Thanks tournedos and hemenex for your input. Much appreciated. I didn't know that transistors can "age" (much like valves)! Today I changed the other 3055 (SGS) to match the other one. On tournedos' suggestion I cleaned the bass, treble and volume controls. In the case of the volume slider pot I opened it and cleaned it. There was

Did some more work on my B&O3000 today and it has been quite fruitful, although the R ch is still dead. I have a basic signal injector which I used systematically to test each transistor stage. A very effective piece of equipment that saves a lot of time checking the individual components, both passive and active. About 4 or 5 transistors were replaced

I've been working on and off and there are a few things I'd like to talk about but it's best to move one step at a time. Armed with Gunther's copy of the layout diagram I took voltage readings at several points but to be honest I couldn't make head or tail about where the problem/s lie/s. In the end I decided to replace the 4 transistors

THAT IS EXCELLENT -- SUPER !!! That will help me identify the test points. No I don't have anything like it. Points 2 & 3 : 0.6V on the working side; 2.7V o n the non-working side, with HI and LO filter buttons in the upper position (deactivated). I just checked it to confirm. Many thanks, Gunther. Joe

<< Yep. But I seem to have the channels mentioned wrongly. C461 is the RIGHT channel, C549 the LEFT.>> Right, it's the Right Channel which is faulty - the one with "pure" colours. I'll print a copy of the upper part of the schematic so we'll be referring to same component number. Yes, there are voltages on my schematic

Hi Gunther, you're a great support, for which I am very grateful. Quote: <But I'm pretty sure you mean those 2 black wires going to the temperature PTC which would be fine with your mentioned 0.8V on the working channel.> I attach a photo. Where exactly is this PTC located - under the output 3055 cover? I don't have the schematic supplied

Thanks hemenex for your thorough reply. I will try to answer your questions and introduce some new results from my work these last couple of days. As you said pins 1 and 2 are connected and I have 57V on both sides (left & right channels). Good you identified the pins 1 to 7. The voltage readings on the remaining pins are as follow: (Working) /

Today I had some time to look into the current problem of output from one channel only. I took voltage readings at the pins leading to the output transistors. I attach a photo taken from the front. I hope it gives a good idea of the area where I took these voltages. There are 22 pins at the end of the main amp pcb. At the centre there are 2 wires -

Thanks all for your interest and encouragement. I have now changed all electrolytics on the pre-amp and main amp boards. I have also made a significant step forward !!! - Volume from FM is now STRONG. Problem was due to broken connections on the balance slider. However, there is still another problem: With the TEST switch down (ie in test position)