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About 2 weeks ago i finished a BM 1900, (big restore), when testing I connected my BG 4002 to it, had it playing for 4-6 hours, the BG maybe 2 hours, when finished I left BG and BM connected, the BM in standby.
A couple of hours later I heard a big loud sound from the CX100 connected, I went to investigate, the light on the power strip with surge protector was out, but the standby light on the BM still on. I disconnected both of them and next morning opened the BM and found the fuses blown, I changed the fuses, powered up with my variac and checked the V supplies, everything was as I had it before. In the BG the fuses was also blown, (300 mA, should be 250 mA) changed those and ´powered up with the variac, no problems.
Connected it all again through a voltage regulator and surge protector, played about 10 LPs and left it on for about 3 hours, BM phono on, BG connected, turned it off. and next time i turned it on to play a record the BG 4002 was dead, again the fuses blown, changed the fuses and tried again, fuses blew emidiately, I could observe that the sledge motor made a very small movement at the same time as the fuses blew, disconnected the P5 and checked the motor resistance 15 ohms so no problem there.
I went through rectifier diodes D1-4 and all other diodes on the board PC1, checked transistors and changed the Tip 120 and 125, checked electrolytic and tantalum caps (ESR) and have found no problems.
The BG has been playing for 2 years nearly every day since restore before this
Question; If I power up only the PC1 (everything else disconnected, PC1 connected to transformer ) with my variac, what will i have to look for and where.
OR should I just go ahead and change all small transistors and tantalums
If anyone has a suggestion on what to look for and how please help.
Collecting Vintage B&O is not a hobby, its a lifestyle.
Just keeping this one alive
Solved thanks to Sonavor
Hi Soren,
Just read today your post and will be curious to know what was the issue and the solution you get to solve this.
The US model has 2 x 250 mA slow blow fuses, as I didnt have slow blow, I put in 300 mA fast blow, after various play and stop the fuses blew again, but as there had been an lightning overload I went through all components on the PCBs, found various Tantalums way off specs (may have been like that before) changed all of them with Wimas changed also some of the smaller TRs and the 3 Darlingtons TIP. Adjusted speeds and voltages again and have now been playing at least 30 LPs without problems. I have now 400 mA fast blow fuses attached until the slow blow fuses arrive.