Good morning guys I was given a 100 dsm not working, I premise that it was repaired but they ruined it, I restored it, now the amplifier turns on, only I have a problem on one channel, Basically in output I have 32 volts between negative and positive output, on the output of one channel, the 'other works fine, I made the.test of inverting the 2 vertical driver boards, and as I suspected , the problem moved to the other channel, so I assume problems with the driver .
See if these will help. The marked components correspond to the designations in the 200ix diagram.
Confirm that the low-value resistors on the driver board are within tolerance.
The 10uF@16 SMD electrolytics need to be replaced, if they haven't already.
Confirm that the low-value resistors on the driver board are within tolerance.
The 10uF@16 SMD electrolytics need to be replaced, if they haven't already.
Attachments
If you briefly touch a dummy load across the speaker terminals, does the voltage drain off or does it cause the amp to draw excessive current?
DCV on R159 and R167 on the terminals that are NOT connected to D110 and Q111.
DCV on R159 and R167 on the terminals that are NOT connected to D110 and Q111.
Thanks Perry for the tips.
Then pinout irf 540 channel failed amp on.
14v bench power supply set at 1.3 amps (so as not to damage in case of excessive shorting amp parts).
VDC value readings mos q103/104
G: 41.1v
D:32.6v
S: 32.6v
Q107-108
G:-31,5
D:32.6
S:-32.3v
Output between positive and negative 32.6v fixed, I connected a load (resistor 50 watts, 3.3 ohms ) it shorts out and draws more than 1.3 amps ( maximum I set on the power supply to do no damage).
Then pinout irf 540 channel failed amp on.
14v bench power supply set at 1.3 amps (so as not to damage in case of excessive shorting amp parts).
VDC value readings mos q103/104
G: 41.1v
D:32.6v
S: 32.6v
Q107-108
G:-31,5
D:32.6
S:-32.3v
Output between positive and negative 32.6v fixed, I connected a load (resistor 50 watts, 3.3 ohms ) it shorts out and draws more than 1.3 amps ( maximum I set on the power supply to do no damage).
good morning guys, so having had some time, I tried to fix the amplifier.
I tested the vertical driver cards and found faulty SMD components, transistors, on one channel. I replaced them. Now the amplifier turns on. The channel that initially couldn't be heard and sent the amplifier into protection now works, but I have a further problem:
on the channel exit I have approx
-1.3volt with the bias closed, by correctly polarizing the channel with the bias trimmer, this voltage rises, and the no-load absorptions rise dramatically.
I have a high offset value, with negative voltage.
I tested the vertical driver cards and found faulty SMD components, transistors, on one channel. I replaced them. Now the amplifier turns on. The channel that initially couldn't be heard and sent the amplifier into protection now works, but I have a further problem:
on the channel exit I have approx
-1.3volt with the bias closed, by correctly polarizing the channel with the bias trimmer, this voltage rises, and the no-load absorptions rise dramatically.
I have a high offset value, with negative voltage.
I solved the initial problem that I had a fixed 32.5v dc at the speaker output, now the channel works but I have a high offset value that grows according to the bias potentiometer, even reaching negative -1.6v at the output, and absorptions at empty canal exaggerated