Harbinger One -- Light On but no flashing...

[zombiesonore]

Hello everybody,
again, it's time for a complex build (for me, anyway!)
Everything seems in place, there's sound but no sweep. The bulb light is working and seems bright enough but there's no flashing, like if the LFO was not working...
I've tried different transistor in Q13: MPSA18/14, BC108C, nothing change.
Is it normal that there's almost 0V on each pin of VOL and INT ?
Does anyone have any idea?
Thanks in advance!
Etienne

Some Voltages:
LT1054:
1# 1.06  5# 0.2
2# 4.99  6# 2.6
3# 0.01  7# 1.48
4# 0.01  8# 9.07

78L15
I# 17.08
G# 0
O# 16.24

Q1: C# 2.13  B#0.9    E#1.01
Q2: C# 4.17  B# 2.13 E# 1.52
Q3: C# 13.17 B# 4.19 E# 3.74
Q4: C# 17.0  B# 4.8  E# 4.95
Q5: C# 12.6  B# 4.95  E# 4.36
Q6: C# 17.15 B# 4.85  E# 4.99
Q7: C# 12.7  B# 4.99 E# 4.40
Q8: C# 17.14  B# 4.84  E# 4.97
Q9: C# 12.7  B# 4.96 E# 4.37
Q10: C# 17.13  B# 6.15  E# 6.33
Q11: C# 16.29  B# 4.50  E# 8.60
Q12: C# 16.26  B# 8.95  E# 8.41
Q13: C# 3.82  B# 1.18  E#0.49 (2n5088)
Q14: G# 0 S# 0.6 D# 17.04

[midwayfair]

Did you connect the rate LED?

[zombiesonore]

Hello midwayfair,
yes, I've connected the rate LED. It's ON but no flash...

[luks999]

Hi

i cant tell by the voltages but check different tings:

-) is the wiring of the speed pot correct? (that was the reason why it once didnt worked for me)
-) which resistor did you use for R46? maybe it works with 4k7 instead of 47k
-) i used MPSA13 as LED driver. you can try 2n3904, 2n5088 also
-) check soldering pads (i once had a bad soldering issue, why some transistor from the LFO wasnt connected with a trace)

hope that helps a little

[zombiesonore]

Hi!
I really think that my speed pot his properly wired.
I've tried to substitute 2n5088 to 2n3904 => nothing
I've changed R46 from 47K to 4K7 => nothing
I'm going for a (third!) full solder check...
Thanks for helping!
Etienne

[luks999]

hmm...are you sure your LED is working?
i think there is no use for this LED as its very dim (i used if differently, used a LED driver transistor for more brightness)

you can try to shorten your LED, and see if the light flushes.
i guess your trim pots are all set? if they are set too high, then lamp does not flush either.

ok, i would recommend measuring the speed pot to be sure
i really had exact your case, when the speed pot was incorrectly wired
maybe you can make some photos of the wiring?

and i guess the voltages are there because your LAMP is on

[luks999]

i would recommend the simpler pot wiring:


less cables and simpler

[midwayfair]

Ignore Q13 for now. In fact, if you used a socket, simply remove it for simplicity. The actual oscillation occurs in Q11 and Q12, and you can ignore everything to the right of C26 in the oscillator section. Measure each component if you have to, reflow the solder on every component from R38-R45, and focus on getting the LED to flash and the voltage to vary on the emitter of Q12. The bulb is the simple part -- it will flash as long as the voltage on the base of Q13 is oscillating pretty much regardless of how the trimpots are set.

Also, post a picture of the board. Both sides. It helps to have more eyes.

[zombiesonore]

Yeah! Thanks for all this help!
I'll do what you've said.
There's 3 pictures in attachments. In those, I've jumper the LED, I will solder it for the next tests.

[zombiesonore]

Last pic...

[luks999]

spd pot wiring looks right. eventhough i would go for sure if theres no contact between lug3 (both sides) and for example lug1 (maybe theres a shortening)

15v regulator in TO92 ? never seen that, but seems to work (17V at the 7815)

hmm yes Q13 should be no problem as long as the pinout applies

i cant see anything suspicious :/

as jon said, just trace the whole LFO section (you can also use a multimeter to see if some parts are connected as they should, thats what i do if im unsure)
the mistake must be there
u you the trannies from the BOM ?
ok, i had this problem that the solderings of Q11 and Q12 were bad. maybe you can solder these pads again just to make sure

[midwayfair]

For starters, your regulator is in backwards.

[zombiesonore]

Ok,
Now, I've solder the regulator in the good way. I've a nice +15V on it's output.
Just for the precision, I've used a LM7815 in the first place, when I've took the voltages but then I've fried it...
I've check every components and re-solder everything. I'm loosing my mind and thinking to put this build away for some times.
This is the first time that I spend this much "efforts" on a pedal. Maybe I have not the good approach...
There's one thing I didn't tried: removing the Filter PCB. But I don't see why this would be a problem.
Also the bulb and the photocells I'm using are not the ones on the B.O.M. Everything else is... (I've also used 10µF Tantalum on C26 and C27 'cause I was out of electrolytic...)
Anyway, thank you (both of you) for your time!
Etienne

[luks999]

have you fried it on the board? (Lm7815)
the filter pcb does not matter (it has no connection to the rest of the pcb), i left it there for my build too for mounting reasons

photocells are not really part of the LFO, and the lamp is on so it must work (i found out that the lamp itself is not so critical)

dont know how critical c26 and c27 is, but in my optionion as long as it has the right value the LFO should still work. (still i would use electrolytic if you have some)

all i can say is that your problem sounds like a connection issue to me i would go through every wire with a multimeter and check if the connection is there.
can also be, that there is a bad soldering. the arrangement of your parts seems correct to me

i had this feeling sometimes, but dont give up on it maybe try it the next day, then you see things different
good luck man!

[midwayfair]

photocells are not really part of the LFO, and the lamp is on so it must work (i found out that the lamp itself is not so critical)

The lamp is not part of the LFO. The lamp's blinking is controlled by applying 15V on one side and a varying voltage on the other side. The varying voltage is applied by the current applied at the base of the transistor whose collector is connected to the lamp. The only thing the lamp being on tells you is that (a) current is flowing through the bulb (meaning, the +15V and math to ground through Q14 are working) and (b) the voltage is sufficient to light the bulb (probably 12V minimum). You can remove the lamp entirely and the oscillator will still work just fine as long as it's working.

zombiesonore, I suggest building the oscillator on a breadboard up to Q13, it will allow you to make sure nothing is wrong with those components and compare them with what's on the PCB.