Behringer ACX1000 schem?

[drewl]

Anyone have a copy of this schem they can send me?
You can't open the images here anymore for some reason.

The -15volt supply is being loaded down somewhere in the front panel pc board.

Thanks.

[Enzo]

After it has been on a few minutes feel each IC on that board for heat.

[drewl]

yeah, did that, but it's loading the -15 volt supply down.
Remove connector to front panel board -15v supply comes up.
I used a power supply to supply +/-15v to the board, one 45** opamp popped, removed it but there is still only 130ohms to ground on the -15v supply. The +15v is around 2kohms, and it's still loading down the -15v supply.

So, I need to see if the -15v power supply is or isn't damaged and can provide enough current.
And I'd like to get an idea of what all is connected to the -15v supply on the front panel board.

There have been schematics of this unit and others posted here, but for some reason these things don't show up anymore.
Do we know why that is?

[Enzo]

You haven't been following the forum lately apparently. The system took a dive recently and all the posted schematics went blank and are lost. we have been slowly reposting them as people ask for them.

You want to check the 15v supplies? Is this the power amp and power supply thing in the middle of the amp kinda cube shaped? A 10 pin ribbon to the preamp panel? Got a 7815 and 7915 on it to make those voltages? So unplug the preamp, and find the output pins of the two regulators. Got volts? Can they provide current? It is 15v, so 15 ohms across it should draw 1 amp. That is probably too much, so 150 ohms draws 100ma or 100 ohms draws 150ma. Got a 100 or 150 ohm 5w resistor? COnnect it from +15 to ground or -15 to ground. Watch the voltage. Stays up? 30 ohms should draw half an amp. I would not expect more than half an amp here. If the voltage collapses under those loads, then replace the regulator.


You powered it up from the bench and blew off the bad IC. Now it is removed. SO power it back up that way again. Let it sit a minute or two, and as it sits there, feel the other ICs. Any getting hot? There are also little (probably blue) tiny bypass caps by many of the ICs. Feel them for heat. Things that load down a power supply have to dissipate the heat that causes.

[drewl]

Well I put everything back together and it seems to be working properly.
Both 15v regulators are running hot. There are screw holes behind them to mount them to the big ass heatsink, but it come that way. Factory screw up?
Think it would be better to attach them?
Properly insulated of course.

[Enzo]

factory? MAybe. Or perhaps someone has been in it before you and removed than and never put them back. Especially if they were involved in the problems at hand.

Yes, of course they should be tight to the heat sink.

[drewl]

So the regulators come from the factory mounted to the heatsink?

Thanks, they were never replaced before, there were also a couple large loose nuts inside stuck to the chassis with the goop they use on the pc board screws.
So it may have been built by a new trainee or something.

[Jaminy]

I know this post is years old but I'm writing this here for track keeping of what I found:

The output socket of the toroïdal PS has 3 wide cables (lets call them 1, 2, 3) and 2 thin ones (4 &5). I measured (alternate current) 28v on 1 & 2, 28v on 2 & 3 and 10,3v on 4 & 5.

I though for years the PS was broken. Could find a replacement as I didn't had the voltage (and technical knowledge) to do the swap. I kept it nevertheless to dismantle it later for spare parts. Today I wanted begin that job, but decided to test the on/off switch before going on. This was the guilty. The switch is a 2 way switch. Only one is used, so I just soldered the wire on the second way and houraaaa

Back to work after a 5 years+ sleep!

Best regards
Eric

[Jazz P Bass]

It pays to be patient.