ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
I was watching TV last night when I heard a "thump", guessed it was someone shutting a car door outside. Five minutes later I heard it again but louder, this time I went to look and I found my beolab penta 1s powered on but no display in the centre. I then noticed the standby light on the Beomaster was off. Initially it wouldn't power on and then it did, just once. It's now dead, and does not come on by remote or input or front panel.
Guidance, best guesses welcome.
This may or may not be relevant but I have also had an irritating crackle in both speakers, independent of volume for many months but hadn't got around to investigating. Could this be something on its way out which has finally gone.
Odd that it came back to life just once last night.
Open it up and see if something looks suspect - remember to disconnect it from mains.
If you are lucky, it could just be a blown fuse. Otherwise, I would suspect capacitors on the power board first.
A blown fuse would be lovely but it came back on briefly and fuses, once blown, tend not recover.
Really need someone's help. Had it in pieces, power in rectifiers checked out fine, as did main power caps and many of the transistors around the main power in circuits. Decided to put it back together to see if I'd disturbed anything for the good and am still getting no front panel lights but a constant noise from the speakers like very distant machine gun fire or a fast tickover diesel engine.
Can anyone point me in ANY direction
Please !
Bad capacitors in the low-voltage power supplies, dead voltage regulator and/or dead CPU.Some versions have a fuse on the processor board, check it if present.
Martin
There is a fuse but it's ok, still trying to FIND a voltage regulator !
By low voltage circuit I assume you're referring to the 5 volt circuit supplied to the microprocessor board ?
All voltages apart from the ones feeding the amplifiers.
The voltage regulators are on the cooling fins, right side.
On the cooling fins I've got 4 Darlington transistors, which I assume are 2 for each channel, and 4 standard transistors TR5, 8, 13 and 16. If I'm missing something obvious please forgive me.
Does anyone have a full parts list for the beomaster 6500 ? I need to replace TR12 which shows at a BC337 but there are different versions of the BC337 (different gain). I have the service manual and schematics but neither show this detail.
I have a very depressing update on this issue. Early on I tested the low voltage rectifier and it didn't fail in that the internal diodes had readings in the correct direction however, the voltage drop to the pos and neg terminals were different, 0.5v and 0.7v. Stupidly, I ignored this and continued testing components, I've now replaced it and all has now come back to life, except, now I have no sound and I am pretty fed up right now.
All and any suggestions welcome.
No output from the headphone socket either
Are the amplifier sections powered at all?
There was until something popped while I was checking !! Now I've got nothing again.
Before it popped I found 40v on one channel and nearly 80v on the other. No idea what's gone now, both power supply fuses are fine, I now just have '-' on the right side if the front panel.
I've not been able to fix this yet but I have got hold of a BM7000 and something odd has happened. Having used my beolink 1000 and MCP6500 with it neither will now operate my original 6500 equipment.
????
Before you all call me an idiot I've realised the problem is that the BM7000 is not transmitting the instructions to the 6500 equipment.
Anyone know if there is any resolution to this problem ?
Anyone know if I can swoop the microprocessor board over with the dead BM6500
cmsammy: Anyone know if I can swoop the microprocessor board over with the dead BM6500
No.
Is the Beomaster receiving orders from the remote control?Martin
Yes, the BM7000 IS responding to all commands but is clearly not talking to the CD Tape or Phono
Are the Tape/CD etc. connected to the correct sockets? (The sockets are often confused because of the printing).All seven pins present in their respective DIN plugs?
All plugs in the correct sockets, and playing ok, just can't control them remotely. I have simply replaced a BM6500 with a BM7000 so all din plugs are the same as I have been using for the past 5 years
The datalink signal has some protective diodes to ground and power that could have shorted.Worth checking.
D1, 2, 3 and 4 on board 3 I presume, (I'm working from the service manual), I'll check tomorrow, thanks Martin. It's also not retaining any settings or radio presets, I assume the battery on the microprocessor pcb
Battery, most likely.And a bad battery can cause other problems too.I would replace the battery first.
So I can carry in using it while waiting for the new battery can you tell me what type I need, then I won't have to take it apart till it's here.
Forget it, bit of research and it's a CR2450 !
Well this just goes from bad to worse !
Yesterday I plugged in my recent auction win to find it won't talk to the CD etc. and wouldn't retain any settings but at least I listened to music last night.
Today it won't respond to the remote so I cannot use it at all. I will replace the internal battery when it arrives, how much it will resolve, who knows 😔
Stranger and stranger. Despite numerous power on and off yesterday I couldn't get a peep out of the BM7000, with the resulting request for my money back from the auction seller who said it was working, (with no other B&O equipment with which to test it he should have said, lights come on !). Today, power off then on, all has come back. The remote not only works the BM7000 but has now decided to operate the Tape and record decks but still refuses to operate the CD which is a real pain as this unit needs the remote more than the others.
cmsammy:The remote not only works the BM7000 but has now decided to operate the Tape and record decks but still refuses to operate the CD which is a real pain as this unit needs the remote more than the others.
Been using it for the past 5 years with a BM6500 with no problem. I can check inside the plug but it seems unlikely that unplugging it a couple of times would break it, especially a factory fit plug.
Progress !
I have replaced the internal battery and this has restored radio presets and amp settings, vol, bal etc. I can also turn it off without loss of remote access.
One fault remains, remotes operate everything except the CD, I've checked the din plug and used contact cleaner in the socket to no avail, seems odd it operates tape and record deck, neither as important as the CD, typical.
I'm using TP2 for the Tape as I have a Sony minidisc in TP1. I noticed that TP1 and CD datalinks are paired.
Not sure if this makes a difference.
Swopped TP1 and TP2 over and I can no longer operate the Beocord so it looks like the datalink diodes on TP1 and CD as Martin suggested.
This may take a while, anyone know the values of D3 and D4 ? Being a complete novice I have no idea
They are both 1N4148
Having finally got a working BM7000 I've been reluctant to dismantle it again but today I took the plunge and replaced diodes 3 and 4 on the CD and TP1 data circuit, (anyone whose done this know what a pain in the bum it is !).
Still can't remotely operate the CD or TP1, phono and TP2 still work grrrrr, any more ideas ??
Capacitor C16 on the microprocessor board maybe ?
All 7 pins present in the DIN plugs of the CD/Tape products you are connecting?
Yes, and they have worked for years before the BM6500 went wrong. The remote operates the cassette if it's in TP2 but not in TP1.