Nutron II LED "off-time" *FIXED!*

[jighead81]

This thing sounds great, but the LED is staying off for more time than the "on-time". Is this normal? I've tweaked the trims with no luck, swapped out all the IC's with known working chips, used different charge pumps, and checked all traces.  Could it be the 2n4401?  It just seems like I have phasing, then it's off for more time then it's on. 

[jighead81]

Switched out 2n4401, no luck.  But, when I hooked up the LED for the blinking indicator, both LED's just stay on, no more blinking, just on.  Weird

[GrindCustoms]

IIRC, TR1 sets the maximum depth and TR2 the maximum brightness, they should'nt have an influence on the Lit up/Lit down of the LED.

Couple time ago i figured out that the LFO in this circuit was too «complicated» for what it really needed to be... so i now stick a daughter board with a simplier LFO with no trimpots and it works flawlessly everytime.

Sorry, this does'nt help a lot...

[GrindCustoms]

I see that you used a LT1054, is your pin1 lifted?

[jighead81]

No it's not lifted, I tried the 7660, max10"", and same problem. 
I couldn't get TR1 to do anything, but it sounds like that's not my problem anyway. Gonna start reflowing some more joints, just to make sure, thanks Rej

[midwayfair]

No it's not lifted, I tried the 7660, max10"", and same problem. 
I couldn't get TR1 to do anything, but it sounds like that's not my problem anyway. Gonna start reflowing some more joints, just to make sure, thanks Rej

You *must* lift pin 1 of the LT1054. Separate issue, obviously.

[jighead81]

I just had the LT1054 in there for a sec while I was troubleshooting, but took it back out.  Tried reflowing everything and still have the pause. 

[alanp]

My guess would be a wrong resistor value somewhere.

[Haberdasher]

My guess would be a wrong resistor value somewhere.

this.

iirc, i could adjust mine to stay off very briefly or longer.  sounds like a wrong value somewhere.

[jighead81]

Thanks guys, that's my next little journey for this.  Hab, how were you able to adjust that?

[Bret608]

Hey man, I'm trying to check your resistor values out for you. I'm working on one of these too so happen to have the build doc handy. I can't see every value (R34, R35, and R36 in particular), but things mainly seem to check out. I would just say double check those as well as what you have for R38 (which I can't make out clearly). Also, on R30, make sure you don't have 100k in there instead of 10k. That fourth bank looks like it could be orange but I can't tell for sure.

[Haberdasher]

Thanks guys, that's my next little journey for this.  Hab, how were you able to adjust that?

well it's been a long time, so i don't remember exactly.  i just followed the advice from this post by bangerang101
http://www.madbeanpedals.com/forum/index.php?topic=6749.msg60231#msg60231

[jighead81]

Bret, I couldn't find a bad resistor anywhere. 

Bad cap maybe? When I try to hook up the  rate indicator LED it stops blinking and stays lit, the yellow one does the same then. I think I'll swap out the diodes next just to make sure about those, and socket them.

[Bret608]

Something else I wondered...would using tantalum caps have any impact?

I wish I had more to offer you here...hang in there!

[jighead81]

I think I saw where Brian used electros, and Rej used tants?....so I thought I'd try the ones I had.  My next plan is a reflow party, and the whole board is invited.