Hi Vintage B&O Fans:

I just got myself a Beomaster 1900 with good looks but some malfunction. It does not come out of standby (only the standby light goes off, but nothing else happens when touching any of the inputs). I was wondering what the best way might be to open it for service? Can one simply take off top and bottom to find the board mounted on the plastic frame, or is this more complicated? The exploded drawing in the service manual is a bit confusing on this aspect. Any recommendations for the standby issue are of course also welcome.... Thanks!

Rudy

Rudy,

Sounds like it could be either the SPS5431, one of the selector IC's or an unstable 15V.
Don't get me wrong but if you cannot find out how to get in there, I doubt you will be able do the repair.
Are you familiar with electronics ?
Do you have a standard electronics soldering iron and basic electronic tools and the skills to use them ?

Martin

Hi Martin,

Thanks for the input! My seemingly stupid question about opening the 1900 is rooted in my experiences with my BM8000 where it took me a while to figure out to get in there "in style". You may not recall, but we were in touch via email last year regarding a BG 8000 tachodisk and belts for my BC 9000, and I gave you a quick rapport about my BM8000 "adventures".

In the meantime, I made some progress and built up an electronics lab and enjoyed myself restoring a Revox A78 (which now works again in its old glory, but this is another story for another forum...;-). The BM8000 told me that B&O design is elegant, but that if you do not know what you are doing, it is easy to break 'little plastic things' and other precious irreplaceable items...So, my question regarding the 1900 is, can I simply remove the top part by unscrewing the two screws under the panel and maybe taking off the back panel, or are there any "tricks" like the slide-out metal bar on the BM8000 which conceals the screws for the panels? I am wondering for example about the sliders and the buttons, and how they connect to the potis and switches underneath, if anything needs to be considered during disassembly with regard to being able to put it back together etc...Thanks!

Rudy

Rudy,

I get a lot of emails and PM's but yes, I do remember you now.

There are no hidden shortcuts in the Beomaster 1900.
Remove the rear metal rail (4 screws).
Undo the 2 screws under the top alu lid and lift it right off. The alu lid will come off together
with the underlying plastic panel and the grill over the cooling fins as one piece.
The sliding potentiometers knobs will stay with the top part and
they will have to grip into their respective potentiometers when you put it back together.

Martin

Hi Martin,

I opened it up per your advice. All went well. I plugged it in and started measuring. It seems that the 15 V circuit is coming on. After I touch any of the program inputs TP15 goes to 15V. Also, the standby diode goes off indicating 15V indeed arrive at its other end. However, it seems that the relay RS1 does not switch. After touching an input field, ~14.5 V drop across D55 (the diode parallel to the relay), i.e. the relay should switch, but I think it does not...no clicking, nothing moving inside. Another indicator: TP27 (27V supply) remains at about 0.2V before and after touching a program field...Does this make sense so far? Thanks!!

Rudy