Beocenter 7700 Issues

[Imax5353]

Hello everyone, I just snagged a Beocenter 7700 that has issues, and just wanted to check here before I delve too far.

So, it power on and the main display shows, however everything else is dead, the P6 dial lights up, but not the tuning or stereo indicators. The phono doesnt move, but it recognizes that there is a record and even the phono light is off. The tape sensor and light work (couldn’t test mech as the belt is goo).

Any advice would be great. I was also wondering what the 15 v, 20 ma port next to the speaker connectors is, almost looks like a DC plug, is there supposed to be a fuse?

 

Thanks!

[Imax5353]

The processor check shows P O, so I’m assuming its good.  I’m out of town, so should be able to get a look at it soon.

[Imax5353]

After getting a good look, and waiting for parts, someone had been in there before and replace a few of the caps.  I replaced the powerboard caps and rectifier, hoping for the best, but no dice, and also discovered that the board has the wrong polarity on one of the main caps (POP!).

So still some digging to do.

[Imax5353]

Well after 2 years, I’m back at this.

I got the right caps in, but the same issues, system turns on, can select all the sources but no sound. All display segments are good, but cant tell about the level meter. I adjusted the right side no-load current to 10 mV, but the left wont budge out of 0.0-0.8 mV.  Ill replace the trimmers, but they tested ok in situ.  I’ll look at the transistors around as well, as those were bad on my Beomaster 6000.

I still have the tape, FM, boards to recap, but I didnt think those would affect sound output. If anyone has any advice I’d greatly appreciate it.

Thanks,

Max

[Gordon Mobbs]

Hi Max

Have you tried connecting the speakers direct to the board inside the unit or tried plugging headphones in ?

Gordon

[Dillen]

Missing blinding plug at the rear socket panel?

Martin

[Imax5353]

I havent updated in awhile, but have made progress.  I should have taken a holistic view from the top.  I realized that most of the issues were all on the 15V power, and after testing connections I found that a trace on board 4 had cracked.  Fixed that, same issues, and tested every trace, and sure enough there was another crack on the trace next to it, not visible to the naked eye, it was under the solder pad.  And now, it almost works! All lights on, controls, tuner P1-P5 and phono.

Biggest issue is the left channel is now out, and I am not getting any (0.5 mV) over 3TP100/101, that I am still working on. Weird thing was that I did have signal after replacing R124, but same low o.5 mV.  Then I took out and I tried testing TR110 and 111, as the similar position TRs on my Beomaster 6000 had caused a similar issue when the adjustment resistor for no-load went bad on that, but now there is no sound at all. I’m testing from the internal speaker connections.  The jumper is in and has continuity.  The cassette deck had expected melted belts, and the FF catch was totally gummed up, but now its not going into FF and play, so I have to fiddle with the mech, I hope its not the solenoid. Also the level meter is very slow response, and pegs if I touch the rec level. Finally tuner P6 wasnt working, it turns out the white gear connecting the tuning wheel to the tuner snapped, and I’m not sure if it will be possible to easily fix.  The gear is between a solid metal bracket, and I have to slide the tuner clutch into it (seems a poor design).
Oh, also the program door closes onto the Open bar, so I’m thinking it may have been dropped.  Not sure if I can adjust the brackets yet, cosmetics will be towards the end.

But I am making progress.  Biggest thing is getting the left channel up, as tuner P1-P5 all work for radio, its getting there.

-Max

• This reply was modified 10 minutes ago by Imax5353.

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