Hello world! Its been YEARS! (STRETCH!)
I've unfortunately sold most of my repair equipment. Still have a couple of Fluke meters though!
Soundstream Ref 700s. I got it with all outputs and one of the output driver boards blown (A1479) driver. Most of the gate/bias resistors on the outputs also blown open. The little Bias? transistors under the board between the outputs also blown.
I removed both driver boards, and ALL TIP102/107 output transistors from both channels, clipped off anything blown shorted, blown open, that I could find. With the little knowledge I remember; I got the amp to the point where most points measure similarly between channel 1 & 2, and nothing else seems to be shorted on the audio side of the pcb.
None of the 6x power fets are blown open/closed. Gate resisters are all good. Nothing seems shorted.
So next I check power. Again, no REAL equipment. 7.5a fuse inline with a small 12vDC lead battery. Also some 30ga clip leads. I get this amp to power up as careful as I can without the proper equipment.
Upon power-up, the High Power light lights up and stays ON the whole time. Within seconds, the amp draws power down from 12.5vDC down to about 7vDC at the amp power terminals. My clip leads start to get slightly warm, but the 7.5A fuse doesn't blow. I think my clips leads may be pretty bad. They are cheap from Amazon; but still this amp seems to be drawing way more than it should even through these cheap test leads. I do not want to put larger power wires on it at this point - it might pull down amperage and blow more parts.
I get rail voltage. First it starts off at 32vAC across the -&+ rectifiers but it drops to about 20vAC within about ~5 seconds of runtime/draw.
Nanny voltage regs start at about 10vDC and get dragged down to 8vDC.
I pulled the 4x Rectifiers and amp does the same thing. The rectifiers off the board measure good.
I have not let the amp sit powered like this for more than about 10 second. I smell something slightly like a circuit that might want to let the smoke out or maybe trying to get warm (Or the amp just hasn't powered up in forever), but nothing gets really warm at all.
Thanks for your time. Hope to fix this one for my personal use!
I've unfortunately sold most of my repair equipment. Still have a couple of Fluke meters though!
Soundstream Ref 700s. I got it with all outputs and one of the output driver boards blown (A1479) driver. Most of the gate/bias resistors on the outputs also blown open. The little Bias? transistors under the board between the outputs also blown.
I removed both driver boards, and ALL TIP102/107 output transistors from both channels, clipped off anything blown shorted, blown open, that I could find. With the little knowledge I remember; I got the amp to the point where most points measure similarly between channel 1 & 2, and nothing else seems to be shorted on the audio side of the pcb.
None of the 6x power fets are blown open/closed. Gate resisters are all good. Nothing seems shorted.
So next I check power. Again, no REAL equipment. 7.5a fuse inline with a small 12vDC lead battery. Also some 30ga clip leads. I get this amp to power up as careful as I can without the proper equipment.
Upon power-up, the High Power light lights up and stays ON the whole time. Within seconds, the amp draws power down from 12.5vDC down to about 7vDC at the amp power terminals. My clip leads start to get slightly warm, but the 7.5A fuse doesn't blow. I think my clips leads may be pretty bad. They are cheap from Amazon; but still this amp seems to be drawing way more than it should even through these cheap test leads. I do not want to put larger power wires on it at this point - it might pull down amperage and blow more parts.
I get rail voltage. First it starts off at 32vAC across the -&+ rectifiers but it drops to about 20vAC within about ~5 seconds of runtime/draw.
Nanny voltage regs start at about 10vDC and get dragged down to 8vDC.
I pulled the 4x Rectifiers and amp does the same thing. The rectifiers off the board measure good.
I have not let the amp sit powered like this for more than about 10 second. I smell something slightly like a circuit that might want to let the smoke out or maybe trying to get warm (Or the amp just hasn't powered up in forever), but nothing gets really warm at all.
Thanks for your time. Hope to fix this one for my personal use!