Yamaha EMX88s Mixer Problems

[Bob W.]

I have a the above mixer and it won't turn on all the time. There is power to the unit but the time delay to the power amp section won't kick in sometimes. Once in awhile it comes on after 10 secs or so, other times an hour or so, sometimes never. All voltages are fine, preamp side works fine even when amp section won' t kick in. If I unplug the preamp from the amp the amp kicks in in the 10 sec time frame every time, no long delays. Just kind of wondering if anyone else has run into this problem and what the answer was. Thanks

[g1]

service manual here: YAMAHA EMX68S EMX88S SM Service Manual free download, schematics, eeprom, repair info for electronics (click where it says Get Manual)

[Bob W.]

Yamaha EMX88s Problems

Thanks for the manual site. I have access to Yamaha for their service info. I have even discussed the problem with a Yamaha tech. He had no idea what it could be either. I guess I was more interested in whether anyone else had seen and corrected the problem. There are some TP's on the schematic but no one, not even Yamaha U.S., has what values they are supposed to be. Thanks again for the URL. Bob

[g1]

Sorry, I have never seen this problem.
It's very odd, if disconnecting the preamp clears the problem, then I would normally expect the preamp to be the source of the fault.
However, even in fault mode, the preamp is functioning normally? All preamp functions?
Could a slight weakness in the LV power supply cause such an issue?

[popoahi]

aloha,

noticed you doing work on your yamaha so;
I'm trying to do a cosmetic overhaul on my yamaha mixer a old 300 model..
do you know of a place where I can find new slide controls???
I need 4 new sliders since mine hve broken off almost at the panel level leaving very little sticking up above the face panel level....
I'm about to call the local music store to see if I can order those slide levers and buy a schematics manual?
otherwise I'll need to braze some metal on the old slide levers and fit them to some kind if tubing to form the "T" on top for sliding..

aloha, popoahi

[Enzo]

popo, may I suggest starting a new thread for your amp. Yours is a different model from the one the thread is about, and we don;t like trying to fix two units within the same thread, it confuses everyone. And always provide your model number. EM300? EMX300? Some other 300?

[popoahi]

sorry Enzo,, will do..
I'll try to find the right forum and hopefully do it right?

aloha, popoahi