MX7000, no sound

Reply

MXBjorn Posted: Tue, Sep 2 2014 5:42 AM

rated by 0 users

mx7k_psu.PNG

Hi,

B&O MX7000
It kept going into standby and then died. 

BUT12+TR11 were shorted and dry joints at C12, C102.

After some soldering and a new fuse the picture is back...but there is no sound.
There should be +- 20V at board (46) according to the service manual.
I measured +25 to 32V and -1V on the negative. Not good.  

Q: Could a bad lyt C46 cause these problems alone?

I don't have a capacitance or ESR meter so checking caps is not that easy.

C56/100nF: no short
D33 (RGP30?): seems OK

Any hints?

Reply

tournedos replied on Tue, Sep 2 2014 8:11 AM

rated by 0 users

MXBjorn:

Q: Could a bad lyt C46 cause these problems alone?

It's possible. Don't spend too much time wondering around cheap failure prone components, just replace it. It would be a good idea to replace all the small electrolytics in the power supply area as well while you have the set open. Most of them will be tired already.

Good job so far!