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Low voltage on Mangler build

Started by donj, April 27, 2016, 08:17:21 AM

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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

Quote from: Martan on April 30, 2016, 11:55:36 AM
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... :D

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... :o 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

Quote from: donj on May 03, 2016, 05:22:31 PM
Hi,

actually there is continuity in Q1 socket, between sockets 1 and 3... :o 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...