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
Hi there!
First post and of course I'm asking for help!
I have been at work changing all the caps and lights in my Beomaster 1900. (Thanks to Martin for supplying this great service of partskits!) I also fixed the sliders for bass treble and balance.
I test run the unit on the bench disassembled and everything worked perfectly. It's like new again! So I put it together and run it again. Plug it in, standby light lights up. I press "tape" and the the only light that light up is the volume buttons, I think at full brightness, but can't remeber clearly, and the lights for the sliders.
I find this odd, so I turn it off, starts removing panels and try again, still the same problem. After the third time I don't turn off as quick since I was thinking I could measure out the problem. This is when the magic smoke leaves from under the control-board and the unit goes black. I have marked the general area where I saw the smoke come up. I have tried to find any components that are fried but no luck yet. I however found that two wires were touching on the transformer/power board. it's the orange and the orange/white marked in the second picture. Could this cause this problem?
Ok, cut to today, and why I post here. I desoldered the volume lights from the board (black yellow red) and started it again. Now I get no standby-light but I can start it and switch between all the programs. Try to put sound through it but the volume is way way down, but you can hear it at least. The unit is not completely dead! But whenever I connect the light-board for the volume I can't start the unit again, it does not respond to any input.
I believe this could help my find the problem from you guys, the ones who have seen alot of stuff! please? with butter on top?
The smoke could come from anywhere, really.Often the emitter resistors in the output stage can fry if the idle current is too high but it usually doesn'tcause other things to stop working.Check that no speaker outputs or output stage transistors are shorted.Check power supply voltages.
Martin
Is there any reference of the voltages or schematics? I just screwed up and measured with my scope and shorted the high voltage output and tripped my residual-current circuit breaker, now I can't start it up like before. *sigh* typical me! Got some power out from it atleast, but would be nice to know what to be looking for.
So a reference chart on where to measure the voltages would be much appreciated! I'm a noob when it comes to audio electrical circuits, I have mostly dabbled with low voltage stuff and IC's. more of a software guy :(
The service manual is available for download from our main website (minimum silver membership level required) butservicing B&O is not like any other stereo, getting your Beomaster back on track may not be the easiestjob and - don't get me wrong - I have a feeling that maybe this is not a job for you.
Remember; Service manuals won't tell you how to repair faults. It will tell you how the thing is built.Diagnosing and fault finding requires technical and electronic skills.
No, you are right, this is a bit over my head, changing caps and lights was no problem, but now I'm in deep water. Do you know someone i Stockholm that could do this for me? I rather get it fixed by someone else then letting it collect dust while I gather the information and knowledge to fix it.