Greetings
So I have this Roland spa-240 I would like to use. I build and design recording equipment bit repair amps too. I can't figure out why this trips whenever it turns on.
I have the schematic but can't figure out where to look. It seems they designed later on a protection circuit that they implemented in later versions. I've read of people modifying them but at this time I ust want it to work. Apparently the schematic is too big to attach here. Has anyone worked on these and or had the same issue?
Below is a link to the schematic:
http://bee.mif.pg.gda.pl/ciasteczkowypotwor/SM_scena/Roland/Roland%20SPA-240%20Power%20Amp%20Service%20Manual.pdf
Thanks in advance
So I have this Roland spa-240 I would like to use. I build and design recording equipment bit repair amps too. I can't figure out why this trips whenever it turns on.
I have the schematic but can't figure out where to look. It seems they designed later on a protection circuit that they implemented in later versions. I've read of people modifying them but at this time I ust want it to work. Apparently the schematic is too big to attach here. Has anyone worked on these and or had the same issue?
Below is a link to the schematic:
http://bee.mif.pg.gda.pl/ciasteczkowypotwor/SM_scena/Roland/Roland%20SPA-240%20Power%20Amp%20Service%20Manual.pdf
Thanks in advance
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Turn amp ON, without a speaker load, and measure for DC voltage across each channel speaker out terminals.
Any significant DC there , say >2V or so, will trigger speaker protection and relay will switch speaker OFF
Even better, since if DC present those terminals will be switched OFF , measure DC from the large 0.3 ohm 5W emitter resistors to ground.
Designation varies according to version, but in the first schematic they are R29/30/31/32 , the track joining them is the amplifier channel speaker out.
Any significant DC there , say >2V or so, will trigger speaker protection and relay will switch speaker OFF
Even better, since if DC present those terminals will be switched OFF , measure DC from the large 0.3 ohm 5W emitter resistors to ground.
Designation varies according to version, but in the first schematic they are R29/30/31/32 , the track joining them is the amplifier channel speaker out.
I found the problem while testing R30 the .3 5watt. I feel ridiculous that I didn't see this before.
So I have some bewildering to do.
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So I have some bewildering to do.