The PSU isn't strained at all, stays at a constant 12v. Seems there is a lot of voltage drop across a 4.7ohm resistor that was burned up when the amp first died. 12v on one side, 4v on the other when remote is on.
Now I'm finding out the 4.7ohm resistor reads 1k ohm now, that's weird
Now I'm finding out the 4.7ohm resistor reads 1k ohm now, that's weird
all I can say is bruh, replaced the resistor, it no longer does the buzzing thing. Now I'm a bit afraid to let it try a full power up.
The lightbulb now lights up harder.
Do I just let it try a full power up? PSU is 5a capable so hopefully should shut off if something goes wrong.
The lightbulb now lights up harder.
Do I just let it try a full power up? PSU is 5a capable so hopefully should shut off if something goes wrong.
The lamp should limit the output stage. I wouldn't expect it to light very much.
As a side note... Didn't you say that the halogen lamp was 80 ohms?
As a side note... Didn't you say that the halogen lamp was 80 ohms?
it's an incandescent lamp, the resistance is 88 ohms. It did light up a bit when doing short tests. Gonna try a full power up now
95v across the lightbulb. Still goes into protect. What could I test now?
PSU Gate drive now is solid.
PSU Gate drive now is solid.
Are the output FETs clamped?
If not, are the ones from one IC heating more than the ones from the other IC?
If not, are the ones from one IC heating more than the ones from the other IC?
Currently it has the output FETs removed. I guess I will throw them back in because they aren't shorted, so they probably are fine
Where could the current be going?
Solder bridge?
Bad rail cap?
Rail cap installed with reversed polarity?
Rectifiers installed in the wrong locations?
Solder bridge?
Bad rail cap?
Rail cap installed with reversed polarity?
Rectifiers installed in the wrong locations?
Very good that I have taken pics. Thought the rectifiers havent been removed, that's why I pulled up the middle pin.
Turns out at some point the rectifiers have switched places sometime after may 2024... Usually I'm very good at keeping stuff in place, unsure how this happened.
I guess I should change around the rectifiers and see what happens.
Turns out at some point the rectifiers have switched places sometime after may 2024... Usually I'm very good at keeping stuff in place, unsure how this happened.
I guess I should change around the rectifiers and see what happens.
it powers on!
Tomorrow I'll try installing output FETs and check the output IC shutdown I disabled, maybe it pulls it high during power up, that's also possible.
EDIT: confirmed the output shutdown, the photocoupler only is high during power up, after that it goes to 0v
Tomorrow I'll try installing output FETs and check the output IC shutdown I disabled, maybe it pulls it high during power up, that's also possible.
EDIT: confirmed the output shutdown, the photocoupler only is high during power up, after that it goes to 0v
As far as I can see, it's working. Powers up, produces a sine wave on the output (haven't turned it up high, but 4.6v RMS shows that it does work)
the voltage regulators get slightly warm, I guess they really want to be clamped down, otherwise everything seems cool.
I guess tomorrow it will be safe to connect the rectifier.
Also is it safe to power a load with one missing PSU fet (and one replacement fet)? Won't be doing anywhere near the 3.5k rating of the amp, maybe 300w at most.
the voltage regulators get slightly warm, I guess they really want to be clamped down, otherwise everything seems cool.
I guess tomorrow it will be safe to connect the rectifier.
Also is it safe to power a load with one missing PSU fet (and one replacement fet)? Won't be doing anywhere near the 3.5k rating of the amp, maybe 300w at most.
Unless the oddball FETs are taking all of the load, it should be safe.
Voltage regulators can (And often do) run hot. Don't let them overheat and fail. They can do a lot of damage (don't ask how I know).
Voltage regulators can (And often do) run hot. Don't let them overheat and fail. They can do a lot of damage (don't ask how I know).
Yeah, they power basically everything, makes sense now they can do lots of damage. They were slightly warm to the touch, far from overheating.
Tomorrow gonna be a big day, gonna test it out. If it works well, next weekend I Will test it for multiple hours 300w load
Tomorrow gonna be a big day, gonna test it out. If it works well, next weekend I Will test it for multiple hours 300w load
Until you get all of the replacement parts in it, use a 30 amp fuse in the B+ line if you don't intend to run it hard.