Hello everyone!

I've just bought a Beomaster 8000.

Everything seemed to work fine, although it was sold as partially defective.

The amp section just works fine. I haven't checked any values yet but it doesn't get hot and sounds fine.

I also thought the tuner was fine, tuned to 94.4 stereo, my favourite station, but then I realized that there's nothing past 97 MHz!

When I tune back to 94.4 the sound doesn't come back at once, goes thud-thud a bit, but then back to normal and the setting holds.

I can't store any radios either. What can I do?

When testing the microprocessor I get TP.

Thanks.

Is it the same situation in both Aut. Tune and Man. Tune ?
Check the "Signal condition" pin on the CPU.

Martin

Thanks.

Dillen:

Is it the same situation in both Aut. Tune and Man. Tune ?

Yes. 

Should I try to adjust 2R38 then? Or what? 

 

Don't adjust anything.

Does it show correct frequency when tuning below 97MHz ?
And above ?
Is there static noise above 97MHz or just silence ?

Martin

Yes, it shows correct frequency all the way to 97 MHz. Above too, with correct steps, up to 108 MHz, but I indeed only get static after 97 MHz (FM typical hiss).

It sounds as if, past 97 MHz, it goes straight to 108, because I think I can hear very briefly all the stations between 97 and 108 before it goes into white noise only. A bit like when you switch off an analogue tuner: while the PSU discharges you can hear briefly all the radio stations one after another before silence. That kind of thing.

And when I dial down, I can also hear this. So it's got to be voltage-related somehow...

Could be a bit missing somewhere.
I agree, monitor the tuning voltage while you tune up and down.

Martin

Good morning!

Well nothing is missing anywhere. It is not very dusty and nothing leaks or smell! 

This receiver has a strange behaviour. When no aerial is plugged, it invariably displays 87.5 MHz at startup, whatever PX I choose. With some aerial, it starts at the old P settings (not mine). I can't store any new preselections, although the programming procedure appears to run normally: for instance I program 94.4 as P1. Ok, P1 flashes then stop flashing (showing VOL P1 94.4), as if it was stored. Then I press, say P2 (nothing there!), and back to P1 and the old preselection (set by the previous owner I guess) reappear.

Second problem, I tried playing with the two connectors linking PC1 and PC2 and this had the curious effect of triggering the protections (but display still working, just no amps). I had to unplug the Beomaster, wait one minute at least, then plug again for it to come to life again.

I tried to measure the tuning voltage but it won't go over 6 or 7 volts, basically showing any old value from 0.3 V or thereabouts. But it is stable when tuned in.

Oh, and the volume preset won't work either, this also keeps the previous owner's setting and I can't change it.

Otherwise, the rest works normally, and the sound is fine. RC works too.

Once again, the processor test passes fine.

Thank you...

 

 

Hi Jacques

Have a look at some of the previous threads on the BM8000.  There was one entitled "BM8000 standby only" where the memory problem was related to failed "through platings".  You might have to fix those up before you get much further.  The thread gives all of the details of what is involved.

Just a guess but it might help

Regards

Geoff  

Thanks Geoff, but my board is totally different.

It is possibly a revised version.

However, I fixed the presets (PX and volume), the memory chip has two folded pins underneath! Oh dear! 

Still nothing after 97 MHz.

Right then.

On Tim Jarman's advice and after speaking to Richard (aka Richtoy) who had the exact same symptoms, I have ordered a new U264B. Are these kind of fragile? Should I use a holder?

How the hell do you get this processor board out???

Hello Jacques

Can you post a photo of your display and processor board as I cannot visualise how your unit is different to mine. 

From what I remember, the processor board was fairly easy to remove - I am not sure at what stage you are at so some photos would be very useful.

Regards

Geoff

Geoff, It is different. For now the Beo is back together, but I will post a piccy when I have it apart again. Components are just not at the same place as yours, or as the service manual shows for that matter!

Interesting to see these differences... Interesting tuning system in this radio...

Have you seen a piccy of my processor board on my 8000 thread Jacques? Removing the can was fiddly and resulted in some damage to the very fragile copper foil, but nothing too serious. I suspect the warning about Return for Repair is to do with adequate thermal bonding either that or extreme static sensitivity so bear both in mind while working / re-assembling!

It is a lovely amp (haven't you already got one of these?) but a little too big for me personally!

Hi Olly,

Yes my PCB9 is the same as yours. So the mods aren't applicable here, it must be a revised, later board.

(Edit: the SM says there are indeed two versions, our PC9 is the 8002493 ref., the older one (which needs the mods) is the 8002401 ref.)

Since the can had already been removed (unsoldered) it came out easily.

Contrary to what we see here on your piccy ('hope you don't mind my using it):

The tags remained in place, I unsoldered the can only. So the copper didn't suffer at all. I will publish a photo later on.

It's my first BM8000, but I love my Beomaster 6000 and it shouldn't sound too different! I like the filters off option which is missing on the BM6000.

Any further advice welcome Olly, but so far so good, everything works except for that tuner above 97 MHz. I hope a new prescaler will do it!

 

 

If the frequency readout is correct, I'm sure the prescaler is fine.
Check the tuning voltage and the plugs/connectors related to it.
Check also the interconnecting plugs/connectors between the two tuner boards.

Regarding the prescaler, I recommend using an original TFK U264B component.
The newer so-called "replacements" doesn't always work.

Martin

I found there was a slight increase in clarity with the 8000 flat, but this was eliminated by setting the BM6000 to just under +1 treble and a little tiny bit of bass. Not surpirsed with the difference in pre-stages tbh.. The BM6000 has Nichicon KW audio caps (although not bedded in ) and the BM8000 with originals but I suspect they are still ok. Would be interested in hearing your views when everything is running well!

I use a pair of DPDT switches which enables me to switch between amps with the same set of speakers and after the above adjustment I could not tell any difference in sound when switching!

Can't offer you a great deal of advice Jacqes the best People are helping you and I wouldn't have a great deal to add atm! I do hope the prescaler helps but can't see this being the root of your actual tuning probs atm? If so I would have to conclude the processor uses the output of this to help with tuning or is it just for display purposes?? Martin?

Anyone got access to the technical explanation manual that is mentioned in the service manual? I thought I had downloaded but as my main puter is knackered (again, like my Escort lol!) I cannot check and there is nothing on the main site... so maybe I imagined doing so!

 

Dillen:

If the frequency readout is correct, I'm sure the prescaler is fine.
Check the tuning voltage and the plugs/connectors related to it.
Check also the interconnecting plugs/connectors between the two tuner boards.

Regarding the prescaler, I recommend using an original TFK U264B component.
The newer so-called "replacements" doesn't always work. 

Thanks Martin.

I checked all the connectors again, they are fine. Tim Jarman says in his notebook:

"Faults in the FM tuner section can normally be resolved by linking across each pin of 2P6 and 2P7 (the two connectors that join PCBs 1 and 2) with short lengths of stiff wire. In one case the fault, a normal display but no control over the actual tuning with stations coming and going by themselves, was not cleared by adding these links, instead 9IC5 (U264B) inside the microcomputer can was found to be defective."

The U264B I ordered is an original TFK one. This is what I bought—I hope it's not a fake, but the pins on this IC have a particular shape:

That's funny because two people are telling me they have the correct frequency display with the same symptoms as mine. I double-checked all connections, and I still can't get more than 6 or 7 volts. 

 

 

 

That's the correct part !

Popular speaking:
The prescaler basically sets the starting point for the CPU to count.
The prescaler counts the first batch of pulses up to the point where it gets interesting, something like
the first 75-80 millions or so (remember the 74.8 MHz readout from Beomaster 6000 with a dead prescaler)
and the CPU will then take over the count from there.

Two versions of CPU boards exists for the Beomaster 8000 (and Beomaster 6000).
The main difference is the counting. The first Beomasters counted very fast but it took a lot of
CPU power to do and a divider (piggy-back board with a 4013 IC) was introduced to lower (divide) the
frequency fed to the CPU to a level that was not so labor intensive for the CPU to count.
The processor coding was changed accordingly.
Processors are not interchangeable between the versions (or between BM6000 and BM8000).
I am not sure what happens if you try, though. Maybe you have the answer in front of you.

Martin

Dillen:

Maybe you have the answer in front of you.

Martin

I'm not sure what you mean, Martin!

 

Maybe the processor is not correct for the board version.

Martin

Dillen:

Maybe the processor is not correct for the board version.

Martin

Ah, right. That's supposing some so-called tech fiddled with it then, and returned it non-functional!

Can you tell the year of production with the serials? 

PC9 is tagged 3279021 and the Beomaster SN is 2275014.

Have you read what Tim, the English B&O guru, says? (I edited my U264 post).

 

Thanks Martin.

 

Yes, I read that.
I have the deepest respect for Tim, he is extremely skilled and I'm sure he's right.
I never saw that symptom with a dead prescaler myself which is why it wasn't part of
my advice but of course, just because I haven't seen it doesn't mean that it cannot happen.
I suppose that IC can fail in different ways and I suggest you go ahead and try.
Based on Tims advice, I would.

Martin

Like you, Martin, Tim helped a number of times. He isn't to be found in any forum but he always nicely answers my emails!

 

So I have Tim's advice. I'll try it anyway, since the chip is on its way—and your own analysis.

I'll keep the two of you informed of course!

What next?

Oh dear!

I was testing at the wrong connector... It must be my wife's cancer getting on me... Not even funny.

Anyway, the tuning voltage is progressive until 97 MHZ then it goes straight up to 23 volts, but the display remains at 97. When I dial backwards it takes some time to unlock from 23V to get back to the lower frequencies. I can hear radio stations briefly while voltage is going up and down!

Dillen:

If the frequency readout is correct, I'm sure the prescaler is fine.

 

Martin, when I disconnect the prescaler (P84 on the μPC board), the display frequency readout is still correct, manual tuning or with the preselections.

But then I don't get any radios at all (of course).