Hello

I was wondering if anyone has a service manual for this speaker (Mackie SRM350 v3).
I have the same problem as in this thread: https://forum.allaboutcircuits.com/...kie-srm350-whistling-after-warming-up.175616/

Saltech posted a snippet/small image of the service manual there, but I need the rest of the circuit as well. I couldn't find anywhere to send a PM to him/her so I thought I'd start a new thread for it.

Thanks in advance
/Robert

 

Hello

I was wondering if anyone has a service manual for this speaker (Mackie SRM350 v3).
I have the same problem as in this thread: https://forum.allaboutcircuits.com/...kie-srm350-whistling-after-warming-up.175616/

Saltech posted a snippet/small image of the service manual there, but I need the rest of the circuit as well. I couldn't find anywhere to send a PM to him/her so I thought I'd start a new thread for it.

Thanks in advance
/Robert

Have you tried the mackie.com website?

https://mackie.com/en/support/schematics?folderID=10996

 

Yes, I have. Unfortunately they only have V1 and V2 on the website.

 

There is a very good chance that the different models are very similar.

 

I was hoping that, but the markings (U14, R232 etc) is completely different, which, at least for me, makes it hard to follow the signal without tracing it out.

 

The speaker is now fixed. It was the L7915 voltage regulator which was the culprit. In case someone else has the same problem.
The regulator is giving out -15 when measuring with a multimeter, but I would imagine that it's maybe not only DC or something else that's causing it.

 

Bobbano, I have the service manual in case you need in the future. I was wondering how you came to know it was the L7915. I have the same problem and I'm tempted to go back to try fix it.
Alex

 

Hi Alex

Thanks, I would like the service manual, please

I was a 100% sure it had something to do with heat as it came gradually. I was looking around the preamp board and I was using compressed air to try to cool things down and sometimes the sound went away when I pointed at certain op-amps. But then when I tried again it didn't work.

Then I got some "real" cooling spray and I was going to test it so I tried it on the heat sink on the amp board first just to see so that there wasn't any liquid coming out since it was a new can. And the whistling/squeeling sound went away immediately!

Then I looked at the heat sink and all the transistors and regulators are attached there, so I was easy to narrow it down.
I then changed the regulator and the problem went away and hasn't come back.

/Robert

 

I see. Unfortunately in my case the whine is there right from the beginning, I'll check out those parts anyway, I might be lucky.
If you can share an email address I'll send you the service manual which is for both 350/450v3

Alex

 

Hope it works out for you! Crossing my fingers
<snip>

Moderator edit: Private email removed to prevent spam.