Dynacomp Debug

[bsmcc2010]

So i posted a week or so ago about frying a dynacomp circuit when i accidentally touched it directly onto the 9v power jack whilst my 1spot was plugged it.

Before i did this it was working perfectly so i know that the layout is right and is verified. It's a dynacomp with clean blend that i found in the gallery but i changed a couple of values and added an attack control (yes mark i know it's not really an attack control :')

Here's a link to the layout i used: http://imageshack.us/photo/my-images/857/orangesquashnotextpic.png/

That is a layout i drew myself with my changed values and added attack pot. It is exactly what i worked from.

I don't think that the chips are what's not working because i tried new ones in it and it still didn't work-they may however be a dodgy chip in one of the sockets at the moment because i mixed them up-but i have spare chips. Anyway, here are my results from my multi metre.

Unconnected Battery- 8.16

IC1
1-4.04     2-4.03    3-3.94    4-0.00    5-3.94    6-4.61    7-4.03    8-8.06

IC2
1-0.00    2-2.98    3-2.98    4-0.00    5-0.66    6-2.64    7-8.05    8-0.00

Q1
C-8.04    B-1.46    E-7.36

Q2
C-5.51    B-2.64    E-2.47

Q3
C-7.45    B-0.00    E-0.00

Q4
C-0.00    B-0.12    E-7.45

Q5
C-8.03    B-1.23    E-1.69


Hopefully someone can tell me what's up or tell me to measure something else-thanks in advance

[R.G.]

Here's a link to the layout i used:
That is a layout i drew myself with my changed values and added attack pot. It is exactly what i worked from.

Is there a schematic that goes with that, or did you work directly from the layout? It makes it difficult to follow if I need to reverse-trace it out.

IC1
1-4.04     2-4.03    3-3.94    4-0.00    5-3.94    6-4.61    7-4.03    8-8.06

Nothing noticeably wrong.

IC2
1-0.00    2-2.98    3-2.98    4-0.00    5-0.66    6-2.64    7-8.05    8-0.00

Nothing noticeably wrong.

Q1
C-8.04    B-1.46    E-7.36

Something wrong here. Emitter should not be higher than base.

Q3
C-7.45    B-0.00    E-0.00
Q4
C-0.00    B-0.12    E-7.45

I ... think ... that Q4 is inserted backwards in the layout. Both C3 and  C4 emitters should be at ground/0.00V.

Q5
C-8.03    B-1.23    E-1.69

Base lower than emitter indicates something wrong here.

The "something wrongs" could be the transistors or the components around them. A schematic would make this a lot easier.

[bsmcc2010]

Hi R.G. thanks for the reply.

You comments on the transistors are interesting because everything was working perfectly before I fried it which indicates that they are correct? Also i put new ones in afterwards to see if that made a difference.

From what you've said i reckon i've broken loads of the caps

[petemoore]

  Knowing what fried it'd help, even knowing we don't know what fried it would [ie the resistors would probably still thier original R values = good, traces are still traces etc., but something isn't yet all good].
   If it could have been AC or inverted supply voltage, consider the polarized components have been DC reverse polarized or "AC Zapped" and should be checked for [diodes, whatever else can be checked] or changed [capacitors are tricky to check, new one is POElimination tester for questionable caps].
  Working before means it probably 'just' needs everything on the board to follow the schematic again.
   It's in there....whatever it is !

[bsmcc2010]

Hi pete, sorry i forgot to mention that :')

I tested it outside the enclosure and it worked fine, but i tried to squeeze it into a too small enclosure and ended up touching part of the circuit (i don't know what) directly onto the DC power jack whilst plugged in.