Make sure you have a clean 5V supply. A bit hard to do without a scope but an AC voltmeter should tell you if
there is any ripple to disturb the processor.
Next, check the zener diode D6, this is where the 2,9 V should be found. R90 should hold 3,5 - 3,6V.
The voltage on the processor pin 39 is also interesting since this is the actual CPU reset point.
Anything lower than apprx 2,5V will halt the CPU.

The processor could of course be dead but it is rare to see.

Martin

hi martin!

as far as i can see, the power supply should be o.k. 

i had 4,6V at pin 39, then i replaced  d6, now i have 0,1V at pin 39.

voltage at d6 is 4,9 V, which is obviously too much. so i will check around the reset circuit. 

i already replaced tr5 and tr6, but nothing changed. 

thanks for your help!

greetings from munich!

jens

p.s.: my beogram 6006 runs perfectly with your tachodisc, which i bought on ebay! thanks for this ! 

2D6 is a 2,7V zener. If you have 4,9V across this diode, it's either dead or of a wrong type. Are you sure you mounted a 2,7V zener diode ?

0,1V on pin 39 keeps the processor halted, 4,6V sounds more like the correct voltage here.

Good job on the mounting and thanks for the feedback on the tachodisc, greatly appreciated ! 🤒

Martin

i double checked the zener, it´s a 2V8 zener bzx.

but when i put the old one (the original b&o) back in - surprise,surprise all the voltages went back to  their former values.

so i´ve got 2,9V over D6 and 4,6V on ic pin 39.

but unfortunatly still no reset and no standby.

Probably a dead processor then. A scope would tell if any activity is found anywhere (keyboard scan etc.) but there probably isn't any.

Martin

hi martin!

i guess the ic is no longer available?

it´s a shame, that after all the work and the new parts, i have to give up. 

thanks for your help!

jens

first of all, hello everyone. i am new on this forum, and... please forgive my eventual language mistakes 🙂

jens_m, for your problem, i am sorry but i do not know the answer at this moment :( but, maybe you can help me....

i also have a BM 6000, and i have it for a long time. it was perfect until some stupit did some repairs at the electric cables on the street and connected my house to a 380 voltage. a lot of my electric stuff was damaged, and the BM6000 was also plugged, and now is dead. it's problem is the primary supply transformer, the little one that is sealed. i have a lot of supply transformes, but i do not know the correct voltage for it at this moment, and i do not know wich one fits. it has 2 voltages on the exit. one of them is 15V (the ic2 is a 78-15 supply), but i can not figure the other one, because i have no repair manual for it :(. so please, can you tell me vhat voltages delivers that voltage transformer? AC, and DC on the main capacitors c1 and c10.

i'd be greatfull if you can help me, and .... and, maybe if i can bring it to life, i can help you with some mesurements on mine if you want to compare to yours. DO NOT give up with it, it is a wonderfull amplifier.

nic

Please guys, don't give up too easily. You know why we have the Beoworld forum ? - Namely so that people can help eachother ...

nic, welcome to Beoworld ! 🤒

The transformer; Why do you think it is dead ? If the mains fuse keeps blowing check the capacitors on module 16 (the low voltage power supply inside the cooling tower) and the rectifier(s). I've seen the two large board mounted capacitors short circuit quite often. A full capacitor kit is available but a single cap can also be arranged. I may also have a good used transformer in stock if you need. Is your Beomaster 6000 a 220/240V version ? Check for the part number sticker on the transformer if it's still present - something like 8013258.

The processor; I am not sure if B&O still can supply this part, worth asking I suppose. They do surprise occasionally. If not, I will be happy to help you look for one.

Martin

hi nic!

the two voltages on the transformer should be 10VAC and 20VAC according to the repairmanual. after the rectifier it should be 10.5VDC at c1 and 24VDC at c10. after a regulation circuit the 10.5V go down to 6.5V (plug p41 position 1) and the 24V go down to 15V (plug 42 position 5 and 6).

i suppose, you´ve checked the fuses on pcb 11 (the small board close to the transformer).

i hope the overvoltage did not destroy any ics.... 

good luck for your work!

jens