Hi and welcome to the joy of working on the Beomaster 8000. I mean that in a good way :-)

This unit is notorious for presenting all sorts of confusing problems. There is really no way to take in symptoms as you have presented and diagnose the specific problem. I can tell you that the majority of issues are connection problems. That includes solder joints and ground connections. I have seen problems with the display acting up that later went away. Those are likely due to the Microcomputer board to Display board connectors. However, your symptoms are more than just a bad display connection. Check the +5 VDC power on the Microcomputer board and reflow solder joints on the connectors as well as the grounding vias (the solder pads that connect ground on the component side to the trace side).

In going through the Microcomputer board I have experienced suddenly fixing one problem where the whole board starts working again to cases where things start working again one by one. So be patient with the process. I have had some really quirky issues where the Microcomputer board was acting up after I had reworked the board (multiple times). On one particular case I was down to one problem where not all of the sources would switch on. The problem there ended up being a three pin connector between the Microcomputer board and the Display board. It measured good in continuity checks but a key signal was missing when the Beomaster was on. I replaced that connector and the Microcomputer board worked again. That is a rather strange occurrence but not an uncommon type of problem with this board.

Be sure to understand that I don't mean there can't be problems with faulty components. Those type of problems can occur as well but they are less likely the problem compared to connection and solder joint problems. I have seen faulty and strange behavior of the Microcomputer board when the crystal oscillators are failing. Replacing those are not too difficult but you must take care not to damage the two processor ICs. I can send you a link on an example of that repair.

-sonavor

Hi Sanovar and thank you for the reply. Yes that's what I was afraid of. I have seen the Beolovers blog and the change of the crystals in the microprocessor board. I will order them (and the corresponding caps) and make the change. If you have any pointers how to remove safely  the two microprocessors from the socket that would be super appreciated. 

I have a eternity BM8000 project on my workbench (one output just wont come alive) but it is the newer version (Possessor board metal cover not soldered but with metal clips), are these interchangeable? The one that's acting up has soldered metal covers - one of the reasons I did not opened it up in fear of damaging the pcb board. I did re-flow on the display pcb connectors as well the same connectors on the Microprocessor  board did not re-flow the other for some reason.

Its funny I'm writing this and in background the BM8000 with the fault sounding and working excellent... I'm trying it one more time and then let it be on standby ant see if the fault presents its self again.

Regards Egon

Hi,

When removing the processor ICs from their sockets make sure you have an anti-static wrist or ankle band and have it grounded. I connect mine to the ground of my home and also to the ground of the B&O board. The ICs are usually pretty tightly in their socket so I use a small, flat-head screw driver to pry them out. Obviously very carefully. Gently raise one end of the IC then the other in very small increments. Besides getting the IC out the goal is to not bend or damage the pins. Re-inserting them later will also require care. The pins will not be perfectly aligned to go right back where they came out. Just use patience and make sure all of the pins are in their slots before the final push to re-seat the device.

The first series BM8000 Microcomputer board and the later boards are interchangeable if that is what you meant. The metal shield covers are not interchangeable between boards however. The functionality of the boards are the same but they have slightly different layouts.

-sonavor

Well the BM has been performing very well and no fault has presented its self after the first one. I think that still re flow and change of the crystals is necessary in near point n the future. If a fault has presented it self it will come back sooner or later I think. 

Thats so great that microcomputer PCB boards are interchangeable in all the BM 8000 line.

E.

Leave your working Beomaster 8000 in the service position for a while. If it continues to function without any faults you can remove power (unplug it) and swap Microcomputer boards. That way you will know that any faults that occur in the Beomaster at that point have to be a result of the second Microcomputer board. That helps on the diagnosis.

With the first Microcomputer board functioning properly I would not do anything more to it until I had the second board also working 100%.

-sonavor