easyvibe problem

[mat]

Hi,

I'm still not getting the easyvibe ( http://www.geofex.com/PCB_layouts/Layouts/easyvibe.pdf ) to vibe.

I posted earlier about the problem:
http://www.diystompboxes.com/sboxforum/viewtopic.php?t=23166&highlight=

I ordered TL062ACP's and low current leds and installed them but nothing changed. The two leds at the bottom are on all the time, eaven when bypassing the effect with 3PDT. The four leds in row do not blink - they are off all the time.

the picture of hand drawed pcb can be found in here: http://tinypic.com/1j5fa

I cant seem to get this thing working..
mat

[R.G.]

Take your meter and hook the black lead to signal ground, then measure the voltage on all pins of all the ICs, and post them back here.

[Hal]

if you're not blinking, pay special attention to the LFO - make sure its getting power.  Also make sure the LEDS reach ground.  It probably a promlem in a trace, not a component, but you never know...

[mat]

Hi,

If the pin closest to the dark dot on top of the IC is pin 1, then the results with battery giving 9.23 V are:

1. IC

pin1 3.78
pin2 3.78
pin3 1.97
pin4 0 (all IC's pin4 are 0V)
pin5 9.23 (all IC's pin5 is 9.23V)
pin6,7,8 3.77 (all IC's pins6,7,8 are 3.77V)

2. IC

pin1 0.66
pin2 3.59
pin3 0.24

3. IC

pin1 8.7
pin2 0.22
pin3 3.77

4. IC

pin1 0.65
pin2 3.77
pin3 0.65

Thank You,
mat

Take your meter and hook the black lead to signal ground, then measure the voltage on all pins of all the ICs, and post them back here.

[petemoore]

Q&very D analysis...
 Bias issues.
 pins 8 of dual OA should all = V+, in this case 9.23v.
 Pins 4 should all be at 0v or ground
 The rest...inputs / outputs should be near 1/2v, in this case ~4,6v...give or take some, usually they jump to the 'correct' voltages when a miswire is found, and stubbornly sit 10% or 20% or more 'off' from near 1/2V where they shoudl be.
 Check check the resistor color codes, and wiring...

[R.G.]

If the pin closest to the dark dot on top of the IC is pin 1, then the results with battery giving 9.23 V are:

It is, but the pin numbering runs around the IC at the "bottom", so what you have as #5 is really #8. No biggie, but it will confuse you if you don't get on board with the industry standard.

pin4 0 (all IC's pin4 are 0V)
pin5 9.23 (all IC's pin5 is 9.23V)
pin6,7,8 3.77 (all IC's pins6,7,8 are 3.77V)

This is all correct. Power (9V) appears on the power pin, ground (0V) on the low voltage power supply pin, and the linear sides of the signal paths are at the same voltage. OK there.

1. IC

pin1 3.78
pin2 3.78
pin3 1.97

Hmmm.. are you sure you measured that right? the output on pin 1 is right, about 3.77V, so is the inverting input, but pin 3 should be at 3.77V too.

2. IC

pin1 0.66
pin2 3.59
pin3 0.24

There is a problem here. Pin 3 should be sitting at 3.77V, as should pin 2, and pin 1 should be ramping up and down. This is the source of the ramp/up down voltage for the LED modulation.

3. IC

pin1 8.7
pin2 0.22
pin3 3.77

Also a problem here. Pin 3 is at the reference voltage OK, but the opamp output is fully high and the inverting voltage is nearly ground. That can't be correct, as pin 1 and two are supposed to be shorted together. There is at least a missing trace between pins 1 and 2, if not other problems.

4. IC

pin1 0.65
pin2 3.77
pin3 0.65

This one might be OK. This amp is being used as a comparator, and since the opamp it's getting its signal from is "stuck", this one is stuck too. We'll have to check it out when you get the ramp up/down running.

[mat]

Hi,

First I have to make sure that i have not misunderstood the IC-numbering. I named them (1. IC, 2. IC..) when looking at the components side and wires on top of the pcb..

do we speak the same language ?

Thanks,
mat

If the pin closest to the dark dot on top of the IC is pin 1, then the results with battery giving 9.23 V are:

It is, but the pin numbering runs around the IC at the "bottom", so what you have as #5 is really #8. No biggie, but it will confuse you if you don't get on board with the industry standard.

pin4 0 (all IC's pin4 are 0V)
pin5 9.23 (all IC's pin5 is 9.23V)
pin6,7,8 3.77 (all IC's pins6,7,8 are 3.77V)

This is all correct. Power (9V) appears on the power pin, ground (0V) on the low voltage power supply pin, and the linear sides of the signal paths are at the same voltage. OK there.

1. IC

pin1 3.78
pin2 3.78
pin3 1.97

Hmmm.. are you sure you measured that right? the output on pin 1 is right, about 3.77V, so is the inverting input, but pin 3 should be at 3.77V too.

2. IC

pin1 0.66
pin2 3.59
pin3 0.24

There is a problem here. Pin 3 should be sitting at 3.77V, as should pin 2, and pin 1 should be ramping up and down. This is the source of the ramp/up down voltage for the LED modulation.

3. IC

pin1 8.7
pin2 0.22
pin3 3.77

Also a problem here. Pin 3 is at the reference voltage OK, but the opamp output is fully high and the inverting voltage is nearly ground. That can't be correct, as pin 1 and two are supposed to be shorted together. There is at least a missing trace between pins 1 and 2, if not other problems.

4. IC

pin1 0.65
pin2 3.77
pin3 0.65

This one might be OK. This amp is being used as a comparator, and since the opamp it's getting its signal from is "stuck", this one is stuck too. We'll have to check it out when you get the ramp up/down running.

[R.G.]

Since you mentioned my PCB layout from GEOFEX, I assumed that you were using my numbering scheme for the layout - that is, U1 on my layout was the same as IC1 in your reporting. Is that the case?

The layout is looking at the component side, with PCB traces as seen looking through the PCB.

[mat]

Hi,

Yes R.G. i was meaning the same order of the IC's, sorry for the mess..

Ok, now i know the pinout. The U1 (1. IC) pin 3 is actually 1.97V. I found out that i had wrong capasitor (C1), 0.01 instead of 0.001. I did put in 1.5n (gotta buy tomorrow the right value cap) but that did not change anything.

The U2 seems to be the problem now. The voltages are now as follows:

U1
pin1 3.77
pin2 3.77
pin3 1.97
pin4 0 (all)
pin5thru7 3.77 (all)
pin8 9.11 (all)

U2
pin1 0.7
pin2 0.62
pin3 0.19

U3
pin1 thru 3 3.74

U4
pin1 0.64
pin2 3.76
pin3 0.68

Yes, there were a missing trace between pins 1 and 2 and after fixing that the leds are all on now but not blinking.

The depht pot and the trimmer puts the intensity for the leds but the rate pot does nothing obviously because of the led modulation problem.

I try to look again for missing traces and so on, but am little blind for the job.

Thank You very much for the very informative comments.
mat

[mat]

Success!!               ........ :oops:

I had missing trace also between U2 leg3 and D1. After fixing that the leds start to blink. I putted my self made strat trough the blinking piece of pcb to my just modded Princeton Reverb sf.

Man! this thing sounds better than the 500+$ DejaVibe i just tried... maybe not so objective opinion because it has only been a few minutes i got the easyvibe working. But the sound seems to be very 'pure', just the kind vibe effect i was after.

So big thanks to everyone who helped me with their input. Thank You R.G. very much. This group Rocks! and Vibes!

Damn its 9pm here, gotta wait till morning to play with my new toy  :evil:

mat