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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022

 

Beomaster 5000

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georganic
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georganic Posted: Sun, Sep 20 2015 1:04 AM

I have a BeoSystem 5000 that has operated flawlessly for 4 years of ownership.  Until yesterday.  I fired it up and waited for the record to start paying and...nothing.  Tried the tape deck, radio couldn't here a sound.  Turned the volume up (default is 3:2) and around 5:0 I started to hear faint sounds.  At 6:0 I could hear the music, but it sounded like it was playing at approximately 2:0.  This was across the board, Beogram, Beocord and radio. 

I searched the forums.  First I tried the headphones.  Same faint sound.  I tried the old in and out, no change. Then I thought I'd check the line in/out jumpers, since they were mentioned a couple of times for similar problems.  My unit had standard RCA cable's, so I switched them with a Beomaster 5000 that a friend had given me that had other problems (turns itself off after a few seconds).  It had the proper U shaped jumpers. Changed them, they seem to go in quite a bit deeper than the RCA's, and Voila...problem solved.  Listened to it all night, everything worked perfectly.

Tonight, I put a record on and...back to the same faint sounds.  Switched back to the RCA's, same problem.  Took the cover off of the spare unit to check the RCA board and it looks a little too advanced for me.

Any suggestions would be appreciated.

Peter
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Peter replied on Sun, Sep 20 2015 9:50 AM

If it was fixed by changing the jumpers, it sounds like a connection problem. If the jumpers are never used (graphic equaliser etc) it would be very tempting to solder in a permanent connection. I wonder if you have a crack in the connection board though.

Peter

hemenex
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hemenex replied on Sun, Sep 20 2015 10:39 AM

Had exactly the same problem on a BM5000 that had not been used for 5 years this friday.

Playing for 2 minutes then no sound on whatever input selected.

Replaced C1 on board 3 - was a "golden" ROE 100µ/25V (and replaced the other 4 found on all the boards as well).

C1 had a shortcut, the other ones at most 40% of the original value. So it's not always the famous red ROE's that fail.

Long shot but probably helpful.

Best,

   hx

Lee
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Lee replied on Sun, Sep 20 2015 12:56 PM
Could be an issue with the muting relay. Try the speakers in socket 2.
georganic
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georganic replied on Sun, Sep 20 2015 5:35 PM

Does sound tempting...but scary.  Maybe I'll try replacing the board with the spare.  That will let me practice disassembling.

georganic
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georganic replied on Thu, Sep 24 2015 3:54 AM

hemenex:

Had exactly the same problem on a BM5000 that had not been used for 5 years this friday.

Playing for 2 minutes then no sound on whatever input selected.

Replaced C1 on board 3 - was a "golden" ROE 100µ/25V (and replaced the other 4 found on all the boards as well).

C1 had a shortcut, the other ones at most 40% of the original value. So it's not always the famous red ROE's that fail.

Long shot but probably helpful.

Best,

   hx

Thanks hx. 

Swapped out board 3 with a spare from a BM5000 that has other issues.  Worked great, sounded great, everything was great...until I turned it off and back on again., Exactly   Back to square one, no sound unless I crank it all the way up. 

The 'other issues' with the spare BM5000 is that it shuts off on its own after a few minutes, but it sounds fine and volume doesn't need to be cranked up to hear it.

This suggests board 3 is not the problem, does it not?

Appreciate the help

 

 

Dave
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Dave replied on Thu, Sep 24 2015 2:56 PM

There is a quick fix somewhere on the amp board inside the unit, that is a temporary solve for your spare one that shuts down, it involves turning two of the little pots on the board all the way anti clockwise I think. I did this some months ago now and my BM 5000 has worked fine since. They are on the board that is under the fan at the top end by the heat sinks.  I just cant recall what they are called, but I am sure someone on the forum will know?

Dave
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Dave replied on Thu, Sep 24 2015 2:56 PM

There is a quick fix somewhere on the amp board inside the unit, that is a temporary solve for your spare one that shuts down, it involves turning two of the little pots on the board all the way anti clockwise I think. I did this some months ago now and my BM 5000 has worked fine since. They are on the board that is under the fan at the top end by the heat sinks.  I just cant recall what they are called, but I am sure someone on the forum will know?

georganic
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georganic replied on Sat, Sep 26 2015 1:29 AM

Thanks Dave,

Oddly enough, your quick fix worked.  Now the spare is working great, a little rough looking and the drop down door is temperamental, but sounds right.  Why?

Even oddlier enough, the original one is working as well.  I turned the power strip it was plugged into off so it wouldn't turn on with the remote when I tested the spare.  I needed to turn the strip back on, and on a whim tested the original.  It fired right up and was its old sweet sounding self.

More good news is that while I was wallowing in my sorrow of not having my BeoMaster, I cherried up my BeoSystem 7000...and it is nice.  Speakers all around, extra remotes, my hoarding is starting to pay off.  I might even tear into the troubled 5500.

Thanks again and if anyone out there knows about intermittent problems with the BM5000 (volume control, weak sounds, etc..) it would be greatly appreciated.  I have a feeling I haven't heard the last of that.

Dillen
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Dillen replied on Sun, Sep 27 2015 7:08 AM

I'm absolutely speechless!
The above mentioned "fix" is DEFINITELY NOT the way to repair things!

The trimmers are there for a reason - they set the output stage idle current.
Disabling the idle current will take your excellent Class B amplifier to a Class C.
Not even B&Os cheapest portable radios have amplifiers this bad. Also for a reason.

Even for a temporary fix, this is bad business;
It will introduce an ocean of crossover distortion, it will sound terrible and it
will be very likely to kill the tweeters in your speakers even at volumes below normal
livingroom listening level due to the extreme amount of harmonic distortion.

Replace the trimmers (yours are bad) and set the idle current (this can be a very delicate adjustment so work carefully
and monitor the idle constantly) according to the servicemanual.
This involves a millivoltmeter etc..

Martin

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