My band recently obtained an old Yamaha EM-300 powered stereo mixer for use as a PA. It works fine except for the right channel, which does not output sound. I have yet to open it up, as I can't seem to find a schematic, but I'm lead to believe that the problem is in the right power amp. Does anyone here know what to look for, or have a schematic of this console?
hello.
looks like there was a "great short".
power off and
try to measure the output stage (transistors and resistors) of the working channel and the bad one (with a dmm,ohmmeter......) and compare that values.
perhaps you remove the fuses of the working channel too.
greetings.................
looks like there was a "great short".
power off and
try to measure the output stage (transistors and resistors) of the working channel and the bad one (with a dmm,ohmmeter......) and compare that values.
perhaps you remove the fuses of the working channel too.
greetings.................
He just suggested the MJ15022/23 pair. What is wrong with that suggestion? I would use them in a heartbeat. The Yamaha won;t much care, and they should work fine. AMps like this are remarkably flexible as to substitutions.
If ther is only one 747, then it doesn't have a partner to match to. If there are two on a side, then whatever sub you chose won;t be a 747 anyway, and it would be better to replace both for proper current sharing and thermal tracking. SO either way it looks like you are putting something else in there.
Allied sells the MJ15022/23 for $3.86 each. That seems reasonable against whatever an old Japanese number transistor would cost.
If ther is only one 747, then it doesn't have a partner to match to. If there are two on a side, then whatever sub you chose won;t be a 747 anyway, and it would be better to replace both for proper current sharing and thermal tracking. SO either way it looks like you are putting something else in there.
Allied sells the MJ15022/23 for $3.86 each. That seems reasonable against whatever an old Japanese number transistor would cost.
bigdeny
I picked up an em 300 mixer about a year ago to use in my small home recording stuio. I recorded a couple of tracks last night and it was working fine. I went to record this morning and it was as if the speakers had been unpluged. They had not of course and nothing had been changed since the night before. The meter shows input but there is not output. Since the system is in a small room the volumes are set very low, so it was not over driven. Could the output driver have still gone bad. If so, how do I check it to find out. And I was also wondering if anyone may have a schematic for this mixer.
Thanks
I picked up an em 300 mixer about a year ago to use in my small home recording stuio. I recorded a couple of tracks last night and it was working fine. I went to record this morning and it was as if the speakers had been unpluged. They had not of course and nothing had been changed since the night before. The meter shows input but there is not output. Since the system is in a small room the volumes are set very low, so it was not over driven. Could the output driver have still gone bad. If so, how do I check it to find out. And I was also wondering if anyone may have a schematic for this mixer.Thanks
Hi bigdeny,
I don't think anything is wrong with your unit. I think you might have just hit a button, like no forget that idea, I just checked the owner's manual (available on Search Results : Yamaha Manual Library website) and there are no buttons like mute or pfl. So, maybe your premap-out to power amp in cables got unplugged... It's the only thing I can think of... Unless the mixer overheated and shut down, or blew the fuse... Just check the fuse, it's simple to do. Open it up, take a look, maybe there's another fuse inside...
There's lots to do if you know a bit about electronics...
I don't think anything is wrong with your unit. I think you might have just hit a button, like no forget that idea, I just checked the owner's manual (available on Search Results : Yamaha Manual Library website) and there are no buttons like mute or pfl. So, maybe your premap-out to power amp in cables got unplugged... It's the only thing I can think of... Unless the mixer overheated and shut down, or blew the fuse... Just check the fuse, it's simple to do. Open it up, take a look, maybe there's another fuse inside...
There's lots to do if you know a bit about electronics...
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.