Neovibe Debug Help Please

[gtrplaya101]

So I finished my neo-vibe last month and have been having some trouble with the effect. Let me try to explain my problem to the best of my ability!
Overall the pedal works fine it just the sweep on the effects seems wrong. With the trimmer turned all the way down (bulb barely pulsing) the effect seems to bottom out the range. Meaning its not a fairly uniform wave sound but instead sounds like the sweep is not right! I really am stumped on this one! My voltages are all in range but here we are anyways:


I could prb take some video with my phone if that would help. Thanks Curt

[R.G.]

So I finished my neo-vibe last month and have been having some trouble with the effect. Let me try to explain my problem to the best of my ability!
Overall the pedal works fine it just the sweep on the effects seems wrong. With the trimmer turned all the way down (bulb barely pulsing) the effect seems to bottom out the range. Meaning its not a fairly uniform wave sound but instead sounds like the sweep is not right! I really am stumped on this one! My voltages are all in range but here we are anyways:

Those voltages are OK-ish, but you don't show the voltages on Q13, the bulb driver.

It may be that you have a high-current bulb and the driver can't give it enough.

[gtrplaya101]

Thanks!
I am using this bulb:
http://www.smallbearelec.com/Detail.bok?no=716
Specs: 12v 40ma
Seems alright to me, I can still take the voltage however if you would like it. Which would you need collector?

[gtrplaya101]

Ok question
Q13 C: ~20V   B:Flucs up to ~6v E E: Flucs up to ~6.4v

Heres my question. The bulb i have in there is rated for 12v however Im getting a reading of 22.54V on one leg of the bulb!!!!

Thanks so far!!

[R.G.]

Ok question
Q13 C: ~20V   B:Flucs up to ~6v E E: Flucs up to ~6.4v
Heres my question. The bulb i have in there is rated for 12v however Im getting a reading of 22.54V on one leg of the bulb!!!!

Your emitter is going way high. Turn it off, disconnect power, and measure the resistance between Q13 emitter and ground, then post it back here.

R.G.

[gtrplaya101]

with the black lead touching the enclosure and the read lead on Q13 emitter I get 288.4 ohms. Thanks

[R.G.]

From your earlier post, the emitter of Q13 swings up to 6V. Ohms law says that this can only happen if the current flowing from the emitter to ground through that 288.4 ohms is I = 6/288.4 = 0.0208A, or about 21ma. So on absolute peaks, your light bulb is only getting about half it's rated current.

You need to do something to reduce that emitter resistance by about half. What is supposed to be there is a 68 ohm resistor in series with a 200 ohm trimmer, to make a maximum of 268 ohms and a minimum of 68 ohms. Is your trimmer cranked all the way to one side? Try repeating the resistance test, but turning the trimmer all the way to one side, then the other. What resistance do you see?