[Marto]

Hello guys, I have bought a set of Beolab Penta’s MKII with some defects. Of course mids were rotten (already fixed), one of the amps totally no sign of working when put in power plug. That one was with blown fuse 40mA and 1-2 capacitors also out. I’ve changed almost all the capacitors in it for any case and it started to working great. The other one was working on first sight, BUT it turns out that there were more trouble in this one. When I connect it to speaker, put the switch to OFF and plug it to power it goes red (normally), when switch to auto (light goes green – normally) it starts making some SSSHHHH noise and this was without any source connected to it, also never go to stand by. When connect source to line-in plug it starts playing, but the SSHHH noise stays on the background of music. Then I also changed the capacitors and calibrating the idle voltage in this one, but with no fix for the issue. Start reading all comments here for similar problems and I started to experiment. Checked and changed almost all transistors on PCB-2, resolder all big transistors, changed IC2 (4066) on PCB-22, changed the resistor R106 on PCB-1 and some voltage checks. I’ve try to connect to my Beosound 3000 with powerlink mk3 cables, to see what is going on from powerlink sources and unhappily realized that it won’t start playing at all (stays on red light), but when switch to auto it gets green light immediately with no other sound except SSHHH ofcourse. Please if somebody can guide me to something else that I can check will be great. Many thanks in advance!

Best Regards
Martin

[Die_Bogener]

Check the connectors of the flap, the solder breaks…

And all other connectors. I have one Penta here for repair, it’s power connector after the rectifier is broken on the mainboard… solder defect.

[Marto]

Hi and thanks for the suggestion, but today I’ve check all the connections and resolder them for any case and the main 2 problems stays:
1. The noise, even with no source cable inserted, which for me sounds like a buzzing.
2. Not goes to stand by mode.
Please, if You have any other things in mind to give an idea where to search.
Best regards,
Martin

[Marto]

P.S. I also found that when RCA was connect to Line-in socket and the amp is on OFF position, I still hear very very quiet music from the speaker. Is that normal?

[Author]

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