If it has an internal fuse, it could be blown. Use your other meter to read the resistance across the probes of the meter set up for amps.
Is it set the DC amps?
Is it set the DC amps?
I now have the meter back in series with the positive line. Red lead moved to the 10A Jack. Other meter ready for any voltage checks. 12V confirmed at input and remote jacks.
Ammeter reading from 0.00 to 0.15 Bouncing around
Ammeter reading from 0.00 to 0.15 Bouncing around
Measure from the driver emitters to the gate leg of the PS FETs (probe against body of the FET, not on the board). Do you read the value of the gate resistor?
I've been checking voltage on the emitters. Black lead on main ground terminal. Q2 and Q4 are 0.45V Q1 and Q5 0.00V. Is that expected?
Confirm that you have 0 ohms to ground on the collector of Q2.
Are you sure that you have good solder connections on all of the driver transistors?
Are you sure that you have good solder connections on all of the driver transistors?
No. In fact I was looking at that when I was measuring the emitters and thinking more solder wouldn't hurt.
I think you are on the money about the collector of Q2. I need to resolder it and see what happens. I'm back inside so it's not a problem. The Weller is still setup. I'll hit it real quick.
I think the collector pad has been damaged there. I can't get solder to stick. I changed to a brand new tip and, it still won't work.
Am I going to have to somehow put a wire through to the back side?
Am I going to have to somehow put a wire through to the back side?
Forgive my ignorance, I see C1 on the collector side of Q2.
Are you telling me to scrape down into the trace and try to solder across there?
Solder a small jumper from the collector to pin 16 of the 494.
I was looking at the 201s the first time. It was close but not exact. You can confirm that pin 16 is directly connected to ground before making the connection.
If you have a piece of computer ribbon cable, a strip of that makes a good jumper for low-current applications.
I was looking at the 201s the first time. It was close but not exact. You can confirm that pin 16 is directly connected to ground before making the connection.
If you have a piece of computer ribbon cable, a strip of that makes a good jumper for low-current applications.
I'm looking in there with a magnifying glass and light and, is it possible you can burn away the leg of the transistor itself? I see that looks like a little bit of the pad and it does have continuity to ground.
I'm wondering if that old Weller tip didn't just burn away what was left of that transistor. I've been trying to put a probe on the leg and it seems as if it's missing. If I have another sub I can use, it might be best to remove that driver.
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