problems with ram head muff

[whomeno]

built from here  http://tagboardeffects.blogspot.com/2012/06/ehx-73-rams-head-big-muff.html
all my reading look good on d1 d2 d3 but d4 is way out.been working on it for 3 hours. replaced 100k-12k -both 33k -390k 3.3k. both 100n.
still getting 8.57 at collector.
d1
c  4.16
b  .64
e  .0
d2
c  4.17
b  .64
e  .03
d3
c  4.13
b  .64
e  .03
d4      the problem
c  8.57
b  1.77
e  1.3
checked traces by pictures.don't see any thing wrong rechecked  all values of parts going to D4.

[willienillie]

Are you sure that's a 3.3K?  There's a glare in the pic, so it's hard to tell, but that 4th band doesn't look brown at all.

Also hard to tell, but the 12K looke more like 1.2K, the 390K looks maybe like 39K.

Could all be tricks of lighting.

[whomeno]

yes they are the right values. I even tested each one before putting them in

[duck_arse]

but you can still reach the resistors, now they are fitted, with your meter probes to give us resistance readings for each [each; all] of the 12k resistors fitted, can't you? same for that 3k3. the reason being - if the 12k resistor is instead 1k2, your voltage measures fit the resistors. if instead your 3k3 is 33k, and the 12k is 12k, your voltage measures are correct. so on the evidence of your voltage measures, we point to some resistors that look iffy, then you measure them and tell us one way or the other.

according to your voltage measures, the base rsistor values seem correct.

are those BCxxx transistors you've fitted?

[whomeno]

yes they are BC550. had to rotate 180
12k resistors
Q1  11.70k
Q2   11.73k
Q3  11.40k
Q4   11.95k

3k3
Q4 4.1k

33k
center of board    29.76k
Q4   starts low then stops at 29.83

390k
Q4    131.6k



100k
Q4  83.4k

[whomeno]

What I don't get is I built the black russian, which is the same board just different part values and it works fine.

[duck_arse]

you do need to include the multiplier in each and every reading noted. 11.70 could be Amps, Megohms, milliVolts .....

so assuming all those 11 point something numbers are 11k ohms-ish, the 12k's look ok. but the "4.1" I have to assume is a 4k1 reading, which can't be. 3k3 resistor in circuit shouldn't read high. pull that transistor from socket and remeasure the resistance of the 3k3. if it isn't within 1% of 3,300 ohms ...... well, we'll wait to see the reading.

a copy of the circuit diagram pertaining to your build, posted in thread, would make it easier for those playing along at home.

[antonis]

Numbers without units say nothing..

[whomeno]

sorry it took so long all readings are k ohms
the 3.3k is now right at 3.29k
the 390k  is 393.5k with it out when put in board it starts at 8ok and only goes up to 167.9k

[whomeno]

ok here are my new voltages

Q1  C  3.97v    B  0.62v   E   0.03v

Q2  C  4.16v      B  0.64v   E  0.03v

Q3  C  4.09v     B   0.64v    E  0.03v

Q4  C  4.83v     B   1.68v     E  1.09v

Got it working. Thanks so much. it had to be that 3.3k resistor Thanks for all the help.

[whomeno]

here is what happened.
switched to all metal film. put in a large order to do it.
some how some 3.3 R got mixed with the 3.3 K. fixed that problem

[duck_arse]

excellent, and well done. everybody is happy now. and you can probably now see why we nag so.

[whomeno]

I do not mind you guys nagging. That is how I learn.
Thanks again