Mtx 6500d

[mike49504]

gain was not at 0 the other op amps read

1=0.12
2=0.13
3=0.49
4=0.27
5=0.49
6=0.16
7=0.19
8=0.26

reading are on 1 op amp

another op amp reads

1= -0.6
2=0.46
3=-0.30
4=0.27
5=0.45
6=1.25
7=.05
8=0.27

[Perry Babin]

You don't have supply voltage on them (pins 4 and 8).

What's the voltage on the transistors next to D118, D119?

[mike49504]

4 of them total

the ones right by the d118 and d119 read

leg1= 18.24
middle leg 0
3rd leg= 17.68

leg1= -18.20
middle leg0
3rd= -17.63


the other 2 right abouve them read

leg1=0
leg2=0
leg3= -0.59

reads the same on the other

[Perry Babin]

You'll need to follow the traces from pins 4 and 8 to see where they go or use a multimeter to find the transistors they connect to. It's likely to be the third leg of transistors that look like the ones near D118 and D119.

[mike49504]

ok 1 reads shorted between legs 1 and 2 wondering whats the package on theese so i can order a couple

[mike49504]

sot-223?

[Perry Babin]

The transistors? PZTA06, PZTA56, PZTA42, PZTA92.

Which transistor reads 0 ohms between 1 and 2?

[mike49504]

sorry legs 1 and 3 but they are tied together on this amp a56

There are 4 a42 2 of them are reading 2.56 volts on the 3rd leg
the other 2 are reading 0 volts and i track it back and all the diodes and resistors next to them looks like they been messed with