Category Archives: Uncategorized

Fixing a Behringer MX8000 desk (3)

Some more advancement on  the mixing desk front…

Replaced the NJM4580 I thought was the culprit and no changes. gah

I also made a new cable that connects the main board and the input board but it’s not that either.

Next plan is to change the two 2SC2878 responsible for the muting of the Mix-B channel. I read on a HiFi forum that when they fail they put DC in the audio path. Sounds like my problem….

So I ordered some and waiting again for delivery.

Next things to fix / restore are:

– a dead channel on one of the voice boards.

– a deep clean up of all the sliders. They are filled with dust and gunk. yak

– Find a way to restore the color of the knobs. they all gone yellow and the grey ones are in the same state. Peroxide + UV treatment ahead…

– Get the whole thing back together. hm, hope i will remember what screw goes where… The damn thing has been sitting on my dining table for more than a month now…

And it will be done i think


Fixing a SCI Sixtracks

Yesterday I fixed a Sixtracks which had a silent Voice (#5). Swapping the CEM3394 from voice 6 to 5, revealed that the CEM chip was ok. The capacitors in the voice section looked a bit funky so i changed the one of voice #5 but that didn’t fix the issue. photo

A bit of scope probing later, i found that the 4051 was busted so i changed it too. After reassembly Voice #5 was working again but the pitch was super low. Checking in the service manual relieved me a bit as they state that after 30 sec after boot up the Microprocessor checks each voices and tune them. Indeed, after 30 secs the pitch of voice #5 was good again. Job’s done.

photo copie