Low voltage on Mangler build

[donj]

I really need help with this...

Built the Mangler, all Pieces in place, Before mounting the transistors i wanted to check the voltage in the circuit, when i check the voltage at the tc1044 it reads - 0.4v. i checked for cold solder joints and such but couldnt find anything.
all the other components seem ok.

Please Help...

[selfdestroyer]

Pictures and voltages of all pin will help us troubleshoot this.

[donj]

Hi thanks for the reply, i couldn't get around to this until now.

checked again and the voltages are good, nonetheless the effect doesn't work right,  lowest voltage on the trimmer reads  7.2V, when connected i get a signal but lots of squilling and no fuzz...

Voltages:

I.C.:

1.8.78   5.-8.76
2.4.41   6.4.53
3.0        7.4.07
4.-4.35  8.8.78

Q1:
e.0
b.-0.07
c.-0.16

Q2:
e.-0.11
b.-0.16
c.-7.39

Thanks for any Help....

[donj]

Of course the voltages are NOT good, just thought that the I.C. voltages are good... dont know what is the problem. maybe it is cause i am such a noob... 

[Martan]

Hi,

I would check R2 joints and the resistor value. Check out the schematic in the build doc. The -9V leaves IC pin 5 and heads toward you transistors. It splits and makes it to Q2 but not Q1 based on your readings. Measure the voltage on the IC-side lead of R2 and see if you have voltage there.

[Orbis_Ignis]

Hi,

I would check R2 joints and the resistor value. Check out the schematic in the build doc. The -9V leaves IC pin 5 and heads toward you transistors. It splits and makes it to Q2 but not Q1 based on your readings. Measure the voltage on the IC-side lead of R2 and see if you have voltage there.

Came in to say this^^^

[donj]

ok,

i re-soldered R2, when i check one side (the IC side) it gives me -8.8v (like on pin5). when i check the other side i get 0.7v.

Does this mean that R2 is fried? should i change it?

and much thanks for the replies...

[Martan]

I would check for a solder bridge at Q1 socket or C4, or see if C4 is bad. Check continuity on the Q1 socket to see if there is a connection where there shouldn't be.

[donj]

Hi,

actually there is continuity in Q1 socket, between sockets 1 and 3... how could this be? i don't see any solder bridges, funny thing.. when i check for continuity between the solder joints of the socket i get nothing but when i check between the sockets themselves i get a beep.

How do i check if c4 is bad? the solder joints are good and i get the same voltage reading in both leads... but i guess that is not the way... 

[Bret608]

What are you using for transistors? Your Q1 voltages actually don't look off for a Fuzz Face. Q2 on a Tonebender would do the same thing. Continuity between your Q1 emitter and collector is troubling since the emitter is grounded.

[Martan]

Hi,

actually there is continuity in Q1 socket, between sockets 1 and 3... how could this be? i don't see any solder bridges, funny thing.. when i check for continuity between the solder joints of the socket i get nothing but when i check between the sockets themselves i get a beep.

How do i check if c4 is bad? the solder joints are good and i get the same voltage reading in both leads... but i guess that is not the way...

did you measure continuity with or without Q1? Try both

[donj]

Hi,

The trannies are ac128, when i check continuity with the transistor in the socket i get the same result in Q1.

also there is continuity between emitter  and base in both of them...