Hi Christian, the red dot is present. the 19.8VDC were measured at P51-pin2 connecting the 7RL2 directly. At this point I should see at least 23.8VDC as per circuit diagram - should I not ?! just taken out PCB6 and replaced BD676 with a higher Hfe reading than the old one. have not checked the other points.  The BM has seen a complete recap !! the voltage at 6IC9 - collector is about 23,x VDC - have not yet checked 6IC10. will get back with more findings….. ALF  

Hi Alf So if you measure 23.x Volt at 6IC9 there should be the same Voltage at P51-2 and at Relay RL2. Measuring always with the same negative point. Tis 23.x volt should be steady present after you plug the mains in. The conection goes directly via P51-2 to the relay. The other line to the relay RL2 comes from TR 18 via P51-1 to the relay. Take a look for these connections and mesure at the Collector of TR 18 Check the voltage on P48-4 (ST BY) and P48-5 (RELAY ON) Both should be LOW when the amp is switched on. Regards Christian

Hi Christian, no !! i do not measure 23.xVDV at P51-pin2 but just under 20VDC, same as at the 7RL2 the voltage is only present when I try to start up the BM - it is not present by just connecting to the mains. same appears at 6TR18-C - at start up I see about 20.xVDV. interestingly enough I can not find +/-55VDC either ?? nor can I verify the voltages at P48 in ON status as the BM does not switch on ! ALF

Hi Alf Sorry maybe we missunderstood... and Sorry but I ran in a wrong way to say that the 23.x voltage should be present after connecting mains, not right The voltage is caused by 0 volt at P48-4. Comes from uPC PIN14 "ST BY" As you wrote: the voltage at 6IC9 – collector is about 23,x VDC – have not yet checked 6IC10. I thought that you measured 23.x Volt at collctor of 6IC9. Is the voltage on C33 and c34 ok? (about24V) also at Emitter of 6IC9 and 6IC10 but anyway there should be 5 volt at P48-4 and 5 volt at P48-5 in "St By" mode. If you connect to mains there is a short "klick" right?   55 Volt are comming up when RL 2 is engaged, a short "klick" would not be enough to charge the big Caps c3 and c4. The 55 Volt is used for the delayed relay circurit. is the amp responding to any pushbutton?

Hi Christian, just had a suspicion the BM may actually not getting the required VAC ? it is a US model, type 1903 (120VAC !) and its been operated using a step-down transformer (110VAC output). that BM had always had some trouble with the start-up and so far it worked just ok. i decided to measure the actual VAC it is getting, showing only about 97VAC. using my variac and cranked up the mains voltage to about just under 120VAC…..and surprise - no trouble with the start up ! It is a power-hungry beast. So I used my other AC to AC adapter which is delivering 120VAC output. right after reassembling I noticed the tuner “is gone”, meaning it wont pull any stations in ?? Of course I checked all connections, nothing suspicious to detect. could that pre-scaler chip have died in the process ?? The other inputs work. regards ALF

The rush-in current at power up is quite substantial. Not all voltage converters like that. A dead prescaler usually won't affect the function of the tuner. It would merely mess up the displayed frequency. Check the cables to the tuner boards, at least the screened one that goes to the CPU board is easily pulled off inadvertently. Check also the solder joints at the two tuner boards interconnecting plugs. Martin

alf: Are your startup issues resolved?  If not, I'll have one of my BM8000's on the bench within a few weeks for a full recap. I can capture some scope traces of the start-up procedure if you think that it would help you. Let me know. One thing that I noticed about the BM8000 is that the receiver is sensitive to startup conditions. Both of my BM8000's start normally when plugged directly into an outlet. Neither of them will start when I run them connected with a light bulb (current limiter) in series. Glitch

Hi Martin & Glitch, thank you for helping out - sadly my BM has turned into a salvage operation…… to explain: I had indeed solved the start-up by using a much more suitable AC-AC adapter providing 120VAC instead of the ordinary step down, delivering only 110VAC, with a defacto output of only about 100VAC. after reassembling I noticed no tuner signal - all the preset stations were still on display but no sound …… I  verified all plugs / connections are properly connected which was the case. one fatal mistake occured - I forgot to put back that insolating cardboard protector which sits over the small stand-by transformer. Putting all down, obviously something touched where it shouldn’t - all hell broke loose, smoke coming from the power transistor assembly…….the end ? so, whats left for me to do is to check what I can salvage - very sad, that BM had a full recap !!! once again, thank you all for stepping in and offer to help - very much appreciated. ALF  

Hi all, Working through getting a BM8000 working, now having issues with startup circuit. The issue lies somewhere with the right channel output board. When both L and R boards are connected, the second relay does not activate, causing the R1 and R2 resistors to glow red and smoke. R236 and R237 on the right channel board also starts smoking (I have cut power within a second every time this has happened). I have replaced R226 and R200 with no change. All boards including power have been re-capped, and I have re-flowed almost everything in an effort to fix. With the right board unplugged, the unit starts up perfectly fine and I am able to correctly set the no-load current of the left board to the desired 18mv. Any pointers?