Bildger Tremolo build question...

[Barcode80]

So, i'm out of .68 uF caps. i had one, this build calls for 3. would .47 work in the other two spots?

ps - hey mark, that's quite a tight fit given the size of those caps man!!!;)

[markm]

.47's should work but, the LFO will probably be quite fast.
As far as fit.....I used the .68uF from smallbear with no fit problems.
Maybe yours are larger? Xicon Greens?

[Barcode80]

nope, pinkies from SB. mainly they don't fit because my .47's nearby on the board are futurlec red chiclets, absolutely gargantuan!

[markm]

nope, pinkies from SB. mainly they don't fit because my .47's nearby on the board are futurlec red chiclets, absolutely gargantuan!

Ahhhhh.
I see.
Yeah, that would be a problem. The .47's and .68's from smallbear fit fine in there together. 

[Barcode80]

Okay dang it, this is infuriating!!! I've built 2 EA tremolos and this bildger which i know is EA based, and in ALL THREE builds the LED just stays lit and doesn't blink. what the crap is going on?!?!?!

[Barcode80]

bump.

[Paul Perry (Frostwave)]

Likeliest is wrong pinout for the transistor in the LFO part.

[R.G.]

I apologize in advance if I'm repetitive but can you provide the information from "What to do when it doesn't work?".

That stuff is not just for newbies. It's a version of what I do every single time I have something that doesn't work. The urge to check the power connections, look for all parts in the right place, correct pinout, clear and ready schematic, parts list and layout and pin voltages ought to be what every single person who tries to debug circuits does by reflex. It's an incredibly effective way to nail down bugs.

[markm]

Likeliest is wrong pinout for the transistor in the LFO part.

Very much agreed.
I have built many versions of this circuit and have not had one that wouldn't fire.
THREE is just strange. 

[Barcode80]

it's odd, i've tried it with both mpf102's and j201's, which as i understood had a standard and common pinout. all are fairchilds. wierd. yes, three faulty builds with the EXACT same problem i agree is odd.

[R.G.]

I apologize in advance if I'm repetitive but can you provide the information from "What to do when it doesn't work?".

That stuff is not just for newbies. It's a version of what I do every single time I have something that doesn't work. The urge to check the power connections, look for all parts in the right place, correct pinout, clear and ready schematic, parts list and layout and pin voltages ought to be what every single person who tries to debug circuits does by reflex. It's an incredibly effective way to nail down bugs.

[markm]

Patrick,
Get some voltages from the circuit as R.G. said and that'll give an idea as to what's wrong.
Take it from me, in working some minor bugs out of the Vibrato with R.G., he is VERY sharp and when he knows what the voltages are, he can nail the problem almost instantly. I was completely amazed to say the least and the problem, all though minor, was solved quickly!
I wish I could do that. 
Chances are your issue with these builds is minor as well.

[Barcode80]

i'm sure its some minute detail. i'll get those voltages when i get home.

[markm]

I know this sounds bad but, I've had this happen to me before.
Check and make sure the resistor values are correct......sometimes black can look like violet and brown looks like red etc.

[Barcode80]

good thought mark, no offense taken. but i measuer for rough tolerance just before sorting into drawers. but then, i could have droped some in the wrong drawer.

[markm]

good thought mark, no offense taken. but i measuer for rough tolerance just before sorting into drawers. but then, i could have droped some in the wrong drawer.

Been THERE before too......

[Barcode80]

okay, transistor voltages, left to right, top to bottom according to markm's layout:

8.85
4.61
4.23

5.21
1.22
1.02

0
0
0 (obviously something is up here

1.75
.57
0

[R.G.]

Patrick, I'd have replied sooner, but it took me a while to find MarkM's layout, then go to GGG and find the schematic, then crossreference them and guess which parts match your numbers. I hope I didn't make a mistake in trotting down that path. This is the reason I put those requests for links to the schematics and layouts you used and to any changes you may have put in. By putting the onus on the debugger to look all that stuff up, it just makes it easy for errors to creep in.

5.21
1.22
1.02

This one might be wrong. IF that's Q2 on MarkM's and Q1 on GGG. And IF it's a 2N5088, then the base is only 0.2V above the emitter. IF the measurement is accurate.

0
0
0

Actually that's correct. IF it's Q3/MarkM and Q2/GGG.

1.75
.57
0

But I think your real problem is here. IF that's Q4/MarkM and Q3/GGG and a 2N5088. The collector voltage is too low. Simulating that section of the circuit shows the collector sitting at about 5V when it's held stopped. I can make it have 1.7V on the collector by changing the 2.2M to 270K. The LFO oscillates with anything between 1M and 3.3M in that position, but 2.2M gives the best balanced waveform.

My best guess is that it's one of:
- Collector resistor is not really 15K, or is shorted, etc.
- collector-to-base resistor is not really 2.2M, or is shorted, bad solder, etc.
- incorrect wiring or values of speed control or limiting resistors.

[Barcode80]

  yeah, woops. forgot to link the schems and layouts and such. thanks for taking the extra time for me.

you are correct in which transistors those are in markm's layout. i'll check those resistor values and get back with you.