Pasty Face / OC75 orientation

[studiodunn]

Pasty Face - Sola Sound
1n34A subbed for 1n270
No output


Just got the OC 75's from SB, dashed to the garage and built the board, but I got nothing!

Are my OC75's wrong? I have them in EBC - C being the dot lead. I get the feeling I need to swap lead 1(from the left) and the middle lead, but can't seem to find a finite image or explination.


thanks.

[Mike B.]

When leads are in the 'triangle' shape, the pinout would be like the 3rd example in this photo. So, looking down at the socket, it is the reverse.

[studiodunn]

When leads are in the 'triangle' shape, the pinout would be like the 3rd example in this photo. So, looking down at the socket, it is the reverse.

Thanks for that Mike!

The leads on mine are straight like #1, so compared to #3 they would be right wouldn't they?
Now if I'm comparing to #4  I can see how they are wrong, but what i think has obviously not worked all that well.

[JakeFuzz]

Based on that last picture I would say your emitter and collector are backwards. The red dot (collector on the oc75) should not line up with the tab (emitter on the can type package). Reverse the transistors and I would think that should work!

[Mike B.]

Sorry, I was trying to show the pinout of the socket, not the trannies - I think I just added confusion. JakeFuzz is correct, flip them and you should be good.

[studiodunn]

Well, flipping didn't cure the problem.  I even swapped out another circuit on the test rig to make sure everything was kosher there..working as it should.

I turned the sag all the way up / -9.1v
ran through the trim pot range
checked solder joints

I was sure it was the orientation.

[JakeFuzz]

Is there a reason you left off the output filter and divider network? Without at least R11 in the circuit there is no connection between the circuit and the output. I would look at R11, R12, and C7 and make sure they are there.

[studiodunn]

Is there a reason you left off the output filter and divider network? Without at least R11 in the circuit there is no connection between the circuit and the output. I would look at R11, R12, and C7 and make sure they are there.

I put the jumper in on 11. C7 and R12 are omit on the BOM.

I've got crazy Voltages though.
Q1
C- 9.31
B-9.36
E-.023

Q2
C-9.31
B-.023
E-.023

Q3
C-4.06
B-4.178
E-0

[JakeFuzz]

Hmm those voltages are weird. That Q1 base would make me think that R2 is open somehow. Looking at R2 and R3 from the pictures they may be the wrong values but I cant tell for sure. R2 should be 47K but it looks like 4.7K (Yel-Pur-Bla-Red). R3 should be 220K but it looks like 220R (Red-Red-Bla-Bla). Also it probably doesn't matter but that D2 doesn't look like a 1n34, to me it looks like a 1N400x.

[studiodunn]

Hmm those voltages are weird. That Q1 base would make me think that R2 is open somehow. Looking at R2 and R3 from the pictures they may be the wrong values but I cant tell for sure. R2 should be 47K but it looks like 4.7K (Yel-Pur-Bla-Red). R3 should be 220K but it looks like 220R (Red-Red-Bla-Bla). Also it probably doesn't matter but that D2 doesn't look like a 1n34, to me it looks like a 1N400x.

Thank you so much! R3 wasn't k, swapped and rocking!
Ill get back at it tomorrow, but at least Ill sleep tonight. 

[JakeFuzz]

Sweet! Yeah actually the 4.7K is the correct color code, I am stuck in the 3 band code  Let us know how it sounds when it is done.