I tried to use 1.5k as CCS resistor. Then amp remain at 1.4amps but no drive signals at all. Then as soon I gave input it start to pull current and fets start to get hot.
I have RIGOL DS1052E.
I dont know much about differential settings. But I think I know we have to use math function.
It have good drive signals.
I have RIGOL DS1052E.
I dont know much about differential settings. But I think I know we have to use math function.
It have good drive signals.
It's difficult to tell but I think that's OK. Differential mode would make it easier to see the drive signal alone with DC (important).
I'm tired of fighting digital scopes that make things harder for no reason so you'll have to learn what you need to get your scope to work. With an analog scope, it's dead simple so if you have one, that's what I'd use. A battery powered/handheld scope is also an option. The explanation in a different thread:
https://www.diyaudio.com/forums/car-audio/352409-irs21844s-help-3.html#post6155766
https://www.diyaudio.com/forums/car-audio/352409-irs21844s-help-3.html#post6155766
Is there any where I can buy smaller transistor version driver board. I have two amps with bigger version transistors and both doing the same thing. Dont know what to modify in the board and what causing it.
Install the smaller transistors in place of the larger final drivers, legs twisted and insulated to match the pin configuration. Try one first. You may have to make a few other minor changes.
I will change all to smaller ones and try it as it is. Then u will help me do the necessary changes. Thank you.
Did you adjust the value of the CCS resistor?
Didn't you try a small transistor board and it solved the problem of excessive current draw?
Didn't you try a small transistor board and it solved the problem of excessive current draw?
Do you still have a small transistor board to compare the values of the rest of the components (mainly resistors)?
A little bit? Why did you stop increasing the value of the resistor?
A little bit? Why did you stop increasing the value of the resistor?
Yes I have the board. I compared the resistors and all matching good. Only thing I found is small board oscillating at 85khz frequency but this board is oscillating at only 65khz frequency.
But after changing big transistors to small transistors current draw reduced alot from 3.3amps to 2.5amps where as with small board it is only 2.1A.
But after changing big transistors to small transistors current draw reduced alot from 3.3amps to 2.5amps where as with small board it is only 2.1A.
Why do you believe that 2.5 amps is too high?
If you clamp all FETs and let the amp idle, does the heatsink heat up significantly?
If you clamp all FETs and let the amp idle, does the heatsink heat up significantly?
Are they getting hot when clamped down?
Dissipating 1/4W of power can make a TO-220 case device heat up to where you can't touch it. 1/4w is nothing for these outputs.
This may be left for you to work out if you want to get the idle current down to 2.1 amps.
The oscillating frequency varies during operation for self-oscillating amps like this.
The base operating frequency is often determined by the capacitors C144 and C145 on the small transistor board.
Dissipating 1/4W of power can make a TO-220 case device heat up to where you can't touch it. 1/4w is nothing for these outputs.
This may be left for you to work out if you want to get the idle current down to 2.1 amps.
The oscillating frequency varies during operation for self-oscillating amps like this.
The base operating frequency is often determined by the capacitors C144 and C145 on the small transistor board.