Black Russian Smallstone Debug

[sonicstylee]

Hey Forumites, first time poster here working on a 1999 black russian smallstone. I have been the only owner of this pedal, had it stored away for around 15 years and broke it out but it's a no-go. Here's the details:

1)What does it do/not do? does not pass signal when bypassed or when engaged unless amp volume is on 10 in which case it is hardly audible but I CAN hear the effect working in this scenario

2)Name of circuit? EHX Smallstone Phase Shifter (black russian 12/99 date)

3)source of schematic? can't find this particular version through all my searches, mainly keep coming up with the issue j board...

4) Mods? none

5) Part subs? nope

6) Positive to negative ground conversion? nope

7) Battery voltage- 9.37
     voltage at red lead- 9.36

Q1 (2n5088)- 8.58, 2.36, 2.95
Q2 (2n5087)- 5.53, 8.58, 9.19
Q3 (2n5087)- 7.30, 6.67, 7.33
Q4 (2n5087)- 6.71, 7.21, 7.38

C1 (CA3094E)- 4.52, 3.61, 3.59, 0, 9.18, 9.17, 3.61, .6
C2 (CA3094E) - 4.47, 3.61, 3.59, 0, 9.18, 9.17, 3.61, .6
C3 (CA3094E)- 4.44, 3.61, 3.59, 0, 9.18, 9.18, 3.61, .6
C4 (CA3094E)- 4.36, 3.61, 5.39, 0, 9.18, 9.17, 3.61, .6
C5 (CA3094E)- 1.70, 7.32, 7.98, 0, 7.98, 9.23, .21, 0

Notes: *C5 pin 1 starts at 1.70v and slowly drops to 0
          *270k resistor reads 0 on both ends
          *all other resistors and caps look ok
          *reading the transistors according to pinouts which from left to right go E,B,C

Have not run an audio probe yet, hoping something here narrows things down a bit as I am newly investigating pedals and my schematic reading skills are less than mediocre. Praying for some help as I'm going a little crazy here..

[sonicstylee]

Yikes... no help? maybe a link to the issue j schematics will spur some thought
http://www.montagar.com/~patj/smlstone.gif

[duck_arse]

how very rude of us all, sonicstylee, welcome to the forum.

the proper circuit diagram would help. but there is something screwy with your transistor voltages, the 2n5088 should have the base voltage higher than the emitter, and the 5087's should all have emitters higher than bases. as for the 270k, it appears to be DC isolated, so 0v is OK.

what voltage do you measure at the issue J point marked V ref? and can we see some photos of your board, please?

[sonicstylee]

Thanks for the reply! I am not seeing V ref on the schematic, what am i missing... the learning curve is steep lol

[antonis]

Thanks for the reply! I am not seeing V ref on the schematic, what am i missing...

You're missing absolutely nothing..!! 

Stephen is a very polite guy (he welcomes almost everybody on behalf of the rest forum members..) but he tends to think that all the people have established his own terminology.. 

To make long story short, Stephen's Vref & your sceme Vbias simply coincide..

[tonyharker]

Hi sonicstylee, If it doesnt pass signal when bypassed I would suspect either a bad soldered joint on the in/out jacks or faulty switch connections. 
I would resolder these first.

Kind regards  Tony.

[sonicstylee]

OK, it took me quite a while to trace to the bias... bias reads 3.61. Re-flowed solder on all jacks, switches, pots; no change. should I be getting any voltage readings on the "color" switch, the rate pot, or the footswitch?  I agree that the tranny readings are strange, what would cause them to be off? I read that the voltage should go low to high from emitter, base, collector- is that correct?

[willienillie]

had it stored away for around 15 years and broke it out but it's a no-go

I automatically suspect electrolytic capacitors.  They're pennies each, I'd replace them all.

[sonicstylee]

Thought I'd finish this thread out... After A LOT of time spent on this pedal, I finally found the issue. It had nothing to do wit the pcb, it was the footswitch the whole time! I audio probed and had signal into the footswitch but not coming out of it. I opened it up and yup, one of the little plastic teeth in there was broke in half. GLAD to be done with this and cranking the SM again. Thaks for everyone's help along the way!

[Mark Hammer]

I had one of those a while back, and if memory serves, the stompswitch was not exactly the most reliable.  Consider replacing it with a newer 3PDT.