All right. well. I tried to modify the john hollis easy vibe to have a 3pdt footswitch and both mattery snap and power input jack. I seem to be having some real trouble. so here goes the whole shebang.
Problem: NO clean sound. No fx. Weird pulsing noise when hooked to Amp. Also LED 6 lights up automatically....
Original project: http://www.geofex.com/PCB_layouts/Layouts/easyvibe.pdf
Wiring diagram for modification I came up with... (hope it's correct):
(http://i68.tinypic.com/29aplaq.jpg)
And my opamp ic chips read as follows:
U1: (1) .03
(2) 1.5
(3) 1.07
(4) 0
(5) 1.38
(6) 1.38
(7) STARTS AT 5.0 AND GOES UP INFINITELY
(8) 8.9
U2: (1) 4.6 AND GOES UP
(2) 4.6 AND GOES UP
(3) 4.9 AND UP
(4) .03
(5) 4.8
(6) 4.7
(7) 4.7
(8) 8.9
U3: (1) O
(2) 4.7
(3) 4.7
(4) .11
(5) 1.08
(6) 4.26
(7) 4.4
(8) 8.9
U4: (1) 4.5
(2) 3.0
(3) 4.5
(4) .02
(5) 4.7
(6) 4.7
(7) 4.7
(8) 8.9
If I had to guess i would think the readings for the first chip are not good... but I'm still trying to learn the troubleshooting process. Please help!
(http://i.cdn.turner.com/asfix/repository//8a25c3920e1ded1c010e1edb838d0052/12oz_ep001_06.jpg)
(Sorry, not helpful, but your artwork reminded me of this)
Quote from: thermionix on July 22, 2017, 09:17:38 PM
(http://i.cdn.turner.com/asfix/repository//8a25c3920e1ded1c010e1edb838d0052/12oz_ep001_06.jpg)
(Sorry, not helpful, but your artwork reminded me of this)
haha. oh god. mine is definitely not artwork hahahaha
This is the schematic, maybe it will help someone spot something with the voltage readings you posted
http://www.hollis.co.uk/john/easyvibe.jpg
Yes I'm in real dyre straights here. I'm kinda surprised no one has been able to help me yet. Usually these threads go fast!
Unfortunately the schematic is not numbered
So I'm guessing which is which
In the input buffer and subsequent phase stages pins 1 2 3 5 6 7 (if it's a dual package)
Should be around Half of V+ (4v5)
Pins four at gnd
Pin Eight at V+
That is unless it's the lfo.
And my opamp ic chips read as follows:
U1: (1) .03 it's looks like the whole thing is off. Biasing should be 4v5
(2) 1.5 ?
(3) 1.07 ?
(4) 0
(5) 1.38 ?
(6) 1.38. ?
(7) STARTS AT 5.0 AND GOES UP INFINITELY how far? Just kidding. Not good.....
(8) 8.9
U2: (1) 4.6 AND GOES UP. This might be the lfo
(2) 4.6 AND GOES UP
(3) 4.9 AND UP
(4) .03
(5) 4.8
(6) 4.7
(7) 4.7
(8) 8.9
U3: (1) O very suspect
(2) 4.7
(3) 4.7
(4) .11
(5) 1.08 suspect ? Might be meter loading.
(6) 4.26
(7) 4.4
(8) 8.9
U4: (1) 4.5
(2) 3.0
(3) 4.5
(4) .02
(5) 4.7
(6) 4.7
(7) 4.7
(8) 8.9
If I had to guess i would think the readings for the first chip are not good... but I'm still trying to learn the troubleshooting process. Please help!
[/quote]
Quote from: Kipper4 on July 24, 2017, 05:18:20 PM
That is unless it's the lfo.
And my opamp ic chips read as follows:
U1: (1) .03 it's looks like the whole thing is off. Biasing should be 4v5
(2) 1.5 ?
(3) 1.07 ?
(4) 0
(5) 1.38 ?
(6) 1.38. ?
(7) STARTS AT 5.0 AND GOES UP INFINITELY how far? Just kidding. Not good.....
(8) 8.9
U2: (1) 4.6 AND GOES UP. This might be the lfo
(2) 4.6 AND GOES UP
(3) 4.9 AND UP
(4) .03
(5) 4.8
(6) 4.7
(7) 4.7
(8) 8.9
U3: (1) O very suspect
(2) 4.7
(3) 4.7
(4) .11
(5) 1.08 suspect ? Might be meter loading.
(6) 4.26
(7) 4.4
(8) 8.9
Thanks for checking those for me. So I'm looking at bad op-amps or a short before the ist opamp?
What would cause my op amps voltage readings to be so wrong?
The offboard wiring seems correct in the drawing you posted, so probably something not right on the board. Can you post pictures front and back of your PCB?
Quote from: thermionix on July 24, 2017, 10:06:33 PM
The offboard wiring seems correct in the drawing you posted, so probably something not right on the board. Can you post pictures front and back of your PCB?
Sure.
Back of the board:
(http://i67.tinypic.com/2ib1839.jpg)
Front of the board:
(http://i67.tinypic.com/2wgygk3.jpg)
Excellent, clear photos. Right off the bat I see that most, if not all, of your electrolytic caps are installed backwards. The + lead goes in the square pad.
There may be more...
Yeah I think even C7 needs to be reversed, but I'm not 100% sure on that one.
There's no indication on the Geofex layout of the orientation of LED1-4. My first thought is that it probably doesn't matter because they are being fed a sine wave. But you'd want them all the same way, right? Sorry, I don't know the circuit, so I'm a bit confused there.
Quote from: thermionix on July 24, 2017, 10:26:32 PM
Excellent, clear photos. Right off the bat I see that most, if not all, of your electrolytic caps are installed backwards. The + lead goes in the square pad.
There may be more...
Did I seriously do that? WTF. What a stupid rookie mistake. haha
Quote from: thermionix on July 24, 2017, 10:36:01 PM
...
There's no indication on the Geofex layout of the orientation of LED1-4. My first thought is that it probably doesn't matter because they are being fed a sine wave. But you'd want them all the same way, right? Sorry, I don't know the circuit, so I'm a bit confused there....
Yeah I assumed if there was no markings then it didnt matter. But if anyone knows which direction they go that would be great.
I rotated them so that they are all positive on the left side and negative on the right.
Still nothing. stay tuned.
Quote from: bifbangpow on July 24, 2017, 10:57:41 PM
Quote from: thermionix on July 24, 2017, 10:26:32 PM
Excellent, clear photos. Right off the bat I see that most, if not all, of your electrolytic caps are installed backwards. The + lead goes in the square pad.
There may be more...
Did I seriously do that? WTF. What a stupid rookie mistake. haha
Ah, nobody is born with it, we learn as we go. Some of the electrolytics may be fine swapped around. Some may have been damaged by reverse voltage. Only way I know to be sure is to replace them all.
When Duck gets here (6:30AM Pacific time) he will probably spot some things I missed.
I'd like it if someone more knowlegable than me can comment on those 4 LEDS. Should they all be the same way in the circuit? Two one way, two the other?
Quote from: thermionix on July 25, 2017, 12:30:14 AM
I'd like it if someone more knowlegable than me can comment on those 4 LEDS. Should they all be the same way in the circuit? Two one way, two the other?
Oh duh, I see the schematic that Ben posted. Has them all going the same direction. Don't know why there isn't a square pad on the Geofex PCB layout. Still maybe they can be reversed as long as they all are...?
Also seems John Hollis specified heat shrink over the LED/LDR combos. Maybe not such a big deal in a sealed up enclosure, but probably better to do it.
Quote from: thermionix on July 25, 2017, 01:06:56 AM
heat shrink over the LED/LDR combos. Maybe not such a big deal in a sealed up enclosure, but probably better to do it.
Definitely do it because as soon as one LED lights up inside that enclosure,
all the LDR's are going to think it's the 4th of July.
Also, it's a good idea to tilt all those LDR's so they are facing dead on to the top of each LED because that is where the LED shines the brightest.
Further on the homebrew vactrols; these will work better if the LED is pointing directly at the LDR, not obliquely. You could sand a flat on the end of the LED and superglue it to the LDR, then cover with heat shrink. For added light protection you could seal the lead ends also (I do that with non-corrosive black RTV; Permatex Item #81158).
R.G. is the sort of smart cookie that would layout a board with all the leds oriented one way. looking at your leds, I can see the anvils of some, indicating the kathodes. second from left is obscured, but second from right is backwards to the outer two, which appear correct. [tayda users beware!]
(https://upload.wikimedia.org/wikipedia/commons/thumb/f/f9/LED%2C_5mm%2C_green_%28en%29.svg/450px-LED%2C_5mm%2C_green_%28en%29.svg.png)
I'd face the ldr's flat to the led-ends, but wouldn't be so worried about light leak once boxed. the leds will be swamping the ldr's cause they are so close, and they all go off together. but yeah, tube them.
how did you manage the trimpot connection, did you extenderise the wiper lead?
Quote from: duck_arse on July 25, 2017, 11:37:45 AM
I'd face the ldr's flat to the led-ends, but wouldn't be so worried about light leak once boxed. the leds will be swamping the ldr's cause they are so close, and they all go off together. but yeah, tube them.
how did you manage the trimpot connection, did you extenderise the wiper lead?
You're all very helpful. Yes last night I remembered the leadframe method of identifying negative lead and switched all the reversed leds. But I think I need to replace all the electrolytic caps now.
As for heatshrinking the leds and vactrols... I'm going to assume the entire vactrol and led head should be sealed inside the shrink?
p.s. extenderise? I'm not familiar. I simply soldered the wires into the lugs on the pots.
Quote from: bifbangpow on July 25, 2017, 01:01:20 PM
extenderise?
That's just Duck Speak for "extend"...he's kinda funny like that (and 2 hours late I might add!)
He's wondering how you connected the blue trimmer on the board, because it's a different package than what the board was laid out for.
exactamundo. extenderiser. late? me?
electros are cheap, can't hurt to replace them. and - can you do another run of voltage readings on the IC socket pins, with the IC's removed, please?
here is a "way" to knock-up some vactrols real quick, might give you some insights:
http://www.diystompboxes.com/smfforum/index.php?topic=114247.msg1060069#msg1060069
Quote from: thermionix on July 25, 2017, 01:39:38 PM
Quote from: bifbangpow on July 25, 2017, 01:01:20 PM
extenderise?
That's just Duck Speak for "extend"...he's kinda funny like that (and 2 hours late I might add!)
He's wondering how you connected the blue trimmer on the board, because it's a different package than what the board was laid out for.
ah well that is probably key. I connected the blue trimmer's three prongs into the three holes right most on top... then the top center in middle, then the left most on bottom. Not sure which is a , b, or c, . So in short... I probably did that wrong hah. Would love to correct it though!
Quote from: duck_arse on July 26, 2017, 10:33:01 AM
exactamundo. extenderiser. late? me?
electros are cheap, can't hurt to replace them. and - can you do another run of voltage readings on the IC socket pins, with the IC's removed, please?
here is a "way" to knock-up some vactrols real quick, might give you some insights:
http://www.diystompboxes.com/smfforum/index.php?topic=114247.msg1060069#msg1060069
1. ILl say what I just said to the Thermio... I probably put the trimmer in wrong if there is any difference visable in the photo. The ik trimmer i bought had it's pins formed in a triangular shape.
I used the right most pin (not sure if thats a b or c) and put it in on top, put the center pin in center (center pin being the top point of the triangle of pins) and then the left pin on bottom. Please advise.
As for IC Chip sockets with no IC in them here ya go:
U1: (1) 3.28 (2) 4.9 (3) 0 (4) 0 (5) 0.02 (6) 3.4 (7) 3.4 (8) 8.8
U2: (1) 7.3 (2) 7.3 (3) 7.3 (4) 0 (5) 8.3 (6) 3.3 (7) 3.4 (8) 8.8
U3: (1) 0 (2) 0 (3) 7.8 (4) 0 (5) 8.1 (6) 3.2 (7) 3.2 (8) 8.8
U4: (1) 8.4 (2) 8.4 (3) 8.4 (4) 0 (5) 7.4 (6) 3.3 (7) 3.3 (8) 8.8
also new updated photos. i heatshrinked three of my LED to vactrols.... does that look ok? I sure hope so.
(http://i63.tinypic.com/34gsz9f.jpg)
(https://preview.ibb.co/fOMT75/easyvibe_trouble1.jpg) (https://ibb.co/hwx1S5)
best photo hosting service (https://imgbb.com/)
What do you think?
p.s. Would this be a better solution?
http://www.taydaelectronics.com/1k-ohm-trimmer-potentiometer-cermet-25-turns-3296w.html
an appeal - does anyone - ANYONE - have a circuit dia with numbers on to match R.G.'s layout? please?
I don't know which is U4, but pins 1, 2, 3 should not be at/near supply. from what I can work out, all the non-supply pins of all the IC sockets should sit at or (resistor dividered) below the bias voltage, appearing at the resistor//led//led//diode string. possibly U2 is also having wrong voltages.
the trimmer you have should be OK, as the wiper is copper connected to one of the lugs on the pcb, so as long as you have the wiper to the middle pad, should be good. and yes on the tayda trimmer, it would fit [although 25 turns might be a little more resolution than you want there].
Quote from: duck_arse on July 31, 2017, 10:40:40 AM
an appeal - does anyone - ANYONE - have a circuit dia with numbers on to match R.G.'s layout? please?
I don't know which is U4, but pins 1, 2, 3 should not be at/near supply. from what I can work out, all the non-supply pins of all the IC sockets should sit at or (resistor dividered) below the bias voltage, appearing at the resistor//led//led//diode string. possibly U2 is also having wrong voltages.
the trimmer you have should be OK, as the wiper is copper connected to one of the lugs on the pcb, so as long as you have the wiper to the middle pad, should be good. and yes on the tayda trimmer, it would fit [although 25 turns might be a little more resolution than you want there].
what would cause this? I mean, what would you do from here?
is there a point where I just blame my shitty etching job and abandon this thing?
cause it - probably etch problems. but you can use your meter on ohms/continuity [power OFF to circuit] and probe around between the (+) supply line and the empty IC sockets. there should be low ohms at the pin 8's only. (without a circuit and pin numbers to refer to, debugging the pcb is doing my head in.)
Please don't throw this board out because you think it's a bad etch. I have had worse and got them working. I see a couple things. You ahve a couple pads not fully soldered. Probably not the cause but it bugs me. The other thing I notice is on the trace side, there is the printed dates and words on the bottom edge. After that is the triangular trace that jumps over a trace and pad in the middle bottom of the board. That last word printed appears to have copper above it bleeding into that trace just before it becomes the triangle. There might be something else but I am at work and that is what I see so far.
Oh right here?
(https://s2.postimg.org/ppsfdkyrd/34gsz9f.jpg)
Yeah that's a problem, definitely shorted. Scrape that away with your exacto.
Quote from: thermionix on August 01, 2017, 10:30:30 PM
Oh right here?
(https://s2.postimg.org/ppsfdkyrd/34gsz9f.jpg)
Yeah that's a problem, definitely shorted. Scrape that away with your exacto.
You guys are the best.
The pads that aren't full soldered are probably the ones to any pieces i had to take out and replace one or two times... i burnt my fingers in the midst of doing this and rushed the solder. I will correct asap. Time to scratch that connection away and try again.
HOw does this one look?
(http://i63.tinypic.com/o70ktd.jpg)