Hello, tryin to reach out to anybody that knows the Soundcraftemen amplifiers. .purchased a pm860 shoe box amplifier that was working great, but not leaving well enough alone I decided to open it up to check the bias. The amplifier was dead on but in the process of checking I accidently touched one of the LM 342 pm15 voltage regulators and it sparked ....now the fan is stuck on high and the 2 red clipping indicators are flashing. ....as for the sound it just sounds intermittent like a stuck CD player.. any body know what controls the fan speed?
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I don't have any formal electronics training but I have been lucky solving problem with these forums and some YouTube. I was able to fix the fan speed and get the amp out of protect mode a couple of bad transistor on the pwr supply board. I am reading 6 and 10 mv of dc offset ... the amp sounds better than the class A diy amp I built. The only thing I am left to solve is a hum that seems to be coming from the power transformer. Any help would be aprectiated.
Good, small job, some of those are big headaches to fix.
The offset seems small, but I have no experience with Hitachi Mosfet amps, so I cannot say good or bad.
Other members, please comment.
There are threads about transformer hum here, the preferred method is dipping in varnish.
Look them up.
The offset seems small, but I have no experience with Hitachi Mosfet amps, so I cannot say good or bad.
Other members, please comment.
There are threads about transformer hum here, the preferred method is dipping in varnish.
Look them up.
Thanks for your reply.the hum is actually heard through the speakers with no signal just the amplifier
Hello, it seems I have had bit of good luck, one of the grounding tabs for the rca connectors was loose and causing a ground problem. ... the amplifier is dead Quiet and the dc offset 6mv left and 10mv right
Hello, good day everybody. I have another soundcraftsmen pm860 this one is working really well it sounds good but i have 1 of the clip led lights that wont shut off. The schematic looks pretty complex for new bee like me.e can anybody here give me a starting point?
I changed c12....35volt 4.7uf it looks like it is close to the red clip led....if i were to accidently short the 2 legs of the capacitor would it cause the light tp stay on? the leads are really close to each other
i have another pm860 that works fine. would it be a good or bad idea to pull it and try it in this amp?