With 5v on pin 4, the TLx94 should have no drive on pins 8 and 11 (or on pins 9 and 10) in 'normal' amplifiers. Confirm that the drive that you saw on the gates was coming from the TLx94.
This amp is an outlier/oddball but some things will translate for other class D amplifiers.
When learning new material, it's common to simply familiarize yourself with the basics then to go back and get ever-increasing fine details every time you read through material.
This amp is an outlier/oddball but some things will translate for other class D amplifiers.
When learning new material, it's common to simply familiarize yourself with the basics then to go back and get ever-increasing fine details every time you read through material.
Pin 8 and 11 both output drive signal only when the remote wire is hooked up. Without remote wire hooked up pin 5 has 5vdc. When I hook remote wire up pin 5 has .5vdc. What you are explaining is exactly my results.
I know this may be a bit monotonous but confirm that you have gate drive signal again and confirm that the TLx94 has no output (pin 4 at 5v).
Same results. Amp off = 5vdc at pin 4 and no drive signal at any test points . Amp on = pin 4 .5vdc and have drive signal at fets and on pin 8 and 11. The drive signal at the TLx94 does look like its riding on dc voltage as it is not in center of scope display. There is 12vdc on pin 8 and 11 along with drive signal when remote wire is in. On the fet mounting holes the drive signal looks like it should.
I can't see how it was drawing current blowing fuses without remote applied. This was happening, correct?
No it was just sqeeling so I was hesitant to keep the power to it. When I did finally keep the power to it it was fine until I hooked remote up. Then it squeeled or sizzles for a few seconds and popped the fuse. This may be of interest. The drive at the fets has .1vdc on the one bank with amp off and when on it has .18vdc. The other bank is .000vdc on the drive all the time. It is the bank that holds fet 436 that has a small dcv all the time.
No signal of any sort? Straight DC?
The reading of 38.3 ohms for both banks of FETs makes it difficult to understand DC voltage.
Are the FETs still out of the board?
The reading of 38.3 ohms for both banks of FETs makes it difficult to understand DC voltage.
Are the FETs still out of the board?
The drive signal is there when the amp in on. The fets are still out of the board. The reason I found that voltage is because I went to ohm out the 38.3 ohm resistors I have installed just to make sure they didnt drift or overheat. I ohmed hem shortly after shutdown and the ine was not wanting to read right. That's when I found the small voltage. It might be nothing but figured I'd point it out because the other bank doesn't have it. Yes when the amp is off there is no signal just straight dc
So, the DC is only there when the remote is applied?
Straight DC is 0v DC, correct?
If those are correct, the DC could be due to slight differences in the shape of the drive signal, which won't be identical because it's being produced by a transformer.
Straight DC is 0v DC, correct?
If those are correct, the DC could be due to slight differences in the shape of the drive signal, which won't be identical because it's being produced by a transformer.
Ther is .1vdc on the one bank with amp off and when the amp is on it has .18vdc. The other bank is .000vdc on the drive all the time. It is the bank that holds fet 436 that has a small dcv all the time.
Is 100% of the flux and other contaminants cleaned from the solder pads?
I don't think this is an issue but this amp is having very unusual problems and I want to eliminate all possible issues.
I don't think this is an issue but this amp is having very unusual problems and I want to eliminate all possible issues.
Well you nailed that one. The top of the board wasnt bad but I cleaned off the little that was there. I powered it back up and had allmost a full volt for a second as it quickly dropped. So I pulled the board and the bottom of the socket was filthy. I cleaned it up good and now it is about gone. I've been pulling the ps fets from the top so I didnt see the bottom. I have it clean and now there is about 20 to 30 mv between amp being on and off. I wasn't sure if that was relevant but there was close to 1 volt on start up.
Lift one terminal of each of the rectifiers (or remove them if you prefer) and try powering up again to see if anything changes.
Sorry. Yes, disconnect/pull the rectifiers, install the FETs and try to power up.
Are the insulators in good condition and clean (no slivers of metal that could cut through them when the FETs are clamped)?
Are the insulators in good condition and clean (no slivers of metal that could cut through them when the FETs are clamped)?
The sil pads are getting beat up. But before powering up after reclamping anything I check continuity between fet tabs and case to make sure they are not compromised.
I replaced a couple of them. It fired up and the fuse didnt blow. It had a slight screech on start up wich turned into a whine. Not reall loud but again I'm not used to amps making noise.