The Workbench

Re: updated: BM8000 won't start up any more

Premiumverum — Tue, 17 May 2011 02:36:54 GMT

A fellow member reminded me I never posted the solution to my tuner/radio problem.

Resoldering the broken wire on L2 solved the tuning problem, there was nothing wrong with the U264B.

It gave the same symptoms as a broken U264B chip. Worth checking out before ordering one!

Re: updated: BM8000 won't start up any more

Dillen — Thu, 31 Mar 2011 09:46:36 GMT

Well done !
The quiet tuner is probably a cable running to the processor board, pulled out from the tuner module.
That happens easily and unnoticed.
Enjoy that Beogram 8002 !

Martin

Re: updated: BM8000 won't start up any more

Premiumverum — Thu, 31 Mar 2011 08:45:43 GMT

Problem solved!

The readings didn't really look like there was anything wrong in module 6 as far as I could make out, so I thought, maybe I'd start all over again. I rechecked all the connectors again, and this time I spotted a small solder bridge I probably made redoing the connectors! I must have missed it the first time as it was really small and the weather is kinda grey and dark at the moment here in the Netherlands. Removed the bridge and the beomaster starts again!

Put everything back together and it works, except for the radio that won't give any sound at all. Probably a connector that I forgot, I don't care. For now after all this stress I am first going to enjoy all the beautiful functions that do work, in particular a new BG8002!

Re: updated: BM8000 won't start up any more

Premiumverum — Thu, 31 Mar 2011 06:57:21 GMT

6TR11: collector (pin marked C on PCB 6) has 0.01V when Standby, 14.99V when On.

Checked the base (pin marked B on the PCB ) too, has 0.70V when Standby, 0.07V when On. Service manual says it should be 0.043V.

Re: updated: BM8000 won't start up any more

Dillen — Thu, 31 Mar 2011 05:45:46 GMT

If you have more than 1V on the base of transistor 6TR11, it's dead.
Can you tell me the voltages in Standby and On on the collector pin of 6TR11 ?

Martin

Re: updated: BM8000 won't start up any more

Premiumverum — Wed, 30 Mar 2011 05:03:45 GMT

Thank you gentlemen!

@Step1: yes there is -22.3 V on both sides of the relay coil, one of them should become ground and the relay will energize? This means the relay is fine then, the switch just isn't made to turn the relay on.

@Dillen: I'll check the traces between processor and display when I have more time this evening. For now what I managed to find out is that the relay on signal gets to R36 after P48-5 on module 6, so no broken traces there, but it is 1,16V in standby and 0,07V when on, instead of the 5V and 0V mentioned in the service manual. There is 4,8V in R56 where according to the service manual should be 5V.

Any thoughts on this?

EDIT: just tested the traces of the processor and display boards/connectors: all of them are fine.

Re: updated: BM8000 won't start up any more

Dillen — Tue, 29 Mar 2011 11:57:34 GMT

L2 is a tiny transformer working with the frequency readout circuit.
It will obviously need a repair but it is not the reason for the main problem.
That will most likely be a broken copper trace near a solder pad at the connectors
between the processor board/display board or a similar missing connection elsewhere.
Check f.e. the "Relay out" signal from the processor (P76-6) and follow it to P48-5 on module 6.
A low signal here should activate the amplifier power supply relay(s).

Martin

Re: updated: BM8000 won't start up any more

Step1 — Tue, 29 Mar 2011 11:11:47 GMT

I don't know this model (although would really like to get my hands on one!) you need Martin. which side is the relay energised there might always be -22v with a switched ground so you need to check this. Is the -22 on both sides of the relay coil for instance? Did you sort the broken coil out and can you show a picture? I would say the inductor would have something to do with logic / processor supply maybe?

Maybe worth going over every plug and socket also checking for bad joints / wires etc...

updated: BM8000 won't start up any more

Premiumverum — Mon, 28 Mar 2011 10:40:36 GMT

Hi all,

Had the afternoon off so decided to solder in the U264B I recently received in the hopes of getting my beomaster 8000's radio working again.

When I put everything back together the beomaster wouldn't start up anymore. Stand by works, you can turn it on and the displays work, the processor test delivers 'TP' but the amplifiers do not come on. There are no relay clicks whatsoever.

I did the wire bridges modification and all capacitors have been replaced except for the four big ones in the amplifiers PSU.

Where should I start looking?

PS: found something odd. On the processor PCB one wire of L2 (a litte coil-thingy) is broken. The resistor parallel to this coil (R62) has some wire wound around it. is this (the broken wire) normal?

UPDATE: checked the relay board. When in TP1 I measure -22V opposed to ground on the coil of RL2, nearly as expected from the service manual, but it doesn't click. Took RL2 out and tested it with 2 9V batteries, worked fine. When I put it back in the BM nothing happens.