I got a DBX 118 off ebay and it showed up DOA so I bought another one that was tested and working. I've been determined to fix the broken one myself but I'm to the point where I better ask a few questions. I've been basing my troubleshooting conclusions off of my working unit.
Basically I've determined that the 12v dc power is not there. I replaced the PSU capacitors (C1 and C2) and that didn't solve the problem. Then I replaced CR1, CR2, R2, R4, R19, C3, and C4 all without any luck. I then replaced the UA723HC with a LM723HC. I did all this kinda thinking the problem would eventually surface. But it has not.
I think that the 12v dc power I'm searching for is coming off the PSU Capacitor C2 actually as -12v dc? So what does it mean when this voltage isn't there? Bad PSU?
Now I figured I could take the PSU off my working unit and it would work. Not the case. For some reason the PSU only puts out 3v dc as opposed to the 17.8v dc I was getting. I hooked the old power supply back up and get the same thing. BTW this voltage on my working unit is 10.6v dc.
Can anyone offer any help? I'd be greatful if anyone had any ideas or general help in how to trouble shoot a problem such as this.
Here's the schematic otherwise all this might read as jibberish.
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Basically I've determined that the 12v dc power is not there. I replaced the PSU capacitors (C1 and C2) and that didn't solve the problem. Then I replaced CR1, CR2, R2, R4, R19, C3, and C4 all without any luck. I then replaced the UA723HC with a LM723HC. I did all this kinda thinking the problem would eventually surface. But it has not.
I think that the 12v dc power I'm searching for is coming off the PSU Capacitor C2 actually as -12v dc? So what does it mean when this voltage isn't there? Bad PSU?
Now I figured I could take the PSU off my working unit and it would work. Not the case. For some reason the PSU only puts out 3v dc as opposed to the 17.8v dc I was getting. I hooked the old power supply back up and get the same thing. BTW this voltage on my working unit is 10.6v dc.
Can anyone offer any help? I'd be greatful if anyone had any ideas or general help in how to trouble shoot a problem such as this.
Here's the schematic otherwise all this might read as jibberish.
