Aion Refractor (Klon clone)Issues

[Big mike 1100]

I'll take better pix with a scanner tomorrow Aph.  Hopefully that will help.  And I'll also check the polarity of C16, Slowpoke.  Appreciate the assistance!

[Big mike 1100]

Hey Slowpoke- I think you're onto something here! I do believe that C16 is reversed!  That could be part (or all of the issue)  I'll try to reverse or find another if I can't get it out cleanly.

[Slowpoke101]

Yes, it is reversed. It probably isn't the primary cause of your troubles but everything helps.

It is not recommended to re-use a reversed capacitor. If you have a new one, use it and throw the old one out.

[Big mike 1100]

I wasn't able to take good pics of the board with a scanner but will try later with a better camera.  In the meantime, it's possible that the PCB might have either residue or scratch marks that could be bridging.  Is there a way to remove the "in-between" stuff as that might also cause the problems?  Alcohol? etc?

[Aph]

Alcohol will remove flux but not solder. You would have to reheat the solder to remove. Flux usually does not cause a problem in audio frequency devices.

[Big mike 1100]

Thanks APH- It's possible that when I scraped the PCB that I exposed a bit of the copper underneath.  Maybe that could be one of the bridges?  Can I use something (like a Sharpie concept or something non conductive) to cover up the copper, thereby eliminating the possible bridge?

[Aph]

That's highly unlikely. If you scraped hard, you may have produced a sliver of copper that's touching something, but once again, pretty unlikely. Use a stiff toothbrush and brush the bottom of the board. Take a magnifying glass and inspect every connection on the bottom. If something is shorting, it's almost always a solder bridge. Having bare copper exposed on a PCB is not a problem. Years ago, a lot of PCB's were not coated at all.
The fact that you had to run a wire from pin 3 of IC3 to ground means that either that solder connection was bad or a copper trace to that pin broke on the board (kind of hard to do)... Perhaps other connections are bad or other traces have lifted off.

[Big mike 1100]

Is there an easier way of desoldering the small bypass board on the 3pdt switch?  I think there might be a solder bridge issue as there don't seem to be any on the main PCs board.  And using the continuity meter, a few of the lugs test as if they are grounded.

[DIY Bass]

Although it doesn't directly show it on the bypass PCB documentation, it looks as if it could be reasonable to see three of the switch lugs connected to ground.  If you look, the three lugs that don't show any connection to anything else on the PCB I think could all be safely connected to ground (and I think at least one of them needs to be in order for the LED to function).  One thing to check is to make sure that the switch is rotated the correct way.  I have a vague memory that somewhere you said that the LED was working correctly though.  It wouldn't if the switch was the wrong way around.

[Slowpoke101]

I think that DIY Bass is correct regarding the bypass switch. Ground should be found on some of the switch lugs.
I do not recommend attempting to de-solder the 3PDT switch. You would most likely destroy the switch and the board. Without professional tools you are limited to using de-solder braid or a solder sucker (both are good tools to have anyway). The amount of heat that would be applied and the length of time involved would almost certainly damage the switch and the board.

On to a different problem, I've been looking at the latest voltages that you posted. The one that stands out the most is IC2 pin 7. You may have a short between pin 7 and 8. With no power applied do a continuity test between those pins. If you have a short try to resolder and test again. If it still shows a short remove IC2 and test those pins again. If the short has disappeared IC2 is most likely toast and needs replacement.

If there was a short or IC2 was faulty re-measure the voltages and post them here. You will get the problems sorted out, it will just take time and effort.

[bluebunny]

Is there an easier way of desoldering the small bypass board on the 3pdt switch?

If I recall correctly, Paul (PRR) has suggested a brief kiss from a blow-torch and a sharp tap on your bench-top.  But that came with a pile of caveats and warnings involving fire and death and other non-optimum results...    TBH, I'd sling it out and wire a new switch yourself without the mini-board.

[EBK]

...without the mini-board.

+1

[Big mike 1100]

So I swapped IC chips 1 and 2 for TL072s and replaced the gain and tone pots in addition to touching up the solder joints.  I think the voltages are more in line, yes?

IC1
1 4.69
2 4.69
3 3.55
4 0
5 4.7
6 4.7
7 4.7
8 9.36

IC2
1 4.81
2 4.7
3 4.6
4 -6.9
5 4.7
6 4.6
7 4.6
8 14.85 (seems a little low??)

IC3
1 9.36
2 4.8
3 0
4 -3.35
5 -6.84
6 4.3
7 5.8
8 9.35

Still no gain or tone control

[Big mike 1100]

If the voltages are right would an audio probe be the next step?

[Slowpoke101]

The voltages are fairly close. I would recommend taking out IC2 and then seeing if the +18V and -9V lines get closer to those actual voltages. If they do come up to those voltages, try a different chip for IC2.

An audio probe is the next step to try.

But before that have another look at C16. Usually a tantalum capacitor will have its positive leg marked on the capacitor's label area. Also the positive leg is longer than the negative (this is only valid when the capacitor is new and hasn't been installed and trimmed). On the Aion board the polarised capacitor positions have a square solder pad which identifies with the positive leg of the polarised capacitor. So with C16 its positive leg will be positioned next to R17 and its negative leg will be next to R6.

[Big mike 1100]

I believe C16 is correct- negative leg is closer to R6 and IC1.  The writing was on one side of the cap, so the picture/PCB is orientated so it can be read.  If I'm incorrect, please tell me.

Also, you are correct, Slowpoke.  When I remove the TC072 from IC2, the pins read -9 and -18v.  I tried 3 other TC072s, but all had lower readings.  Are there a few "hotter" IC chips that I should try? 
***
Edit- i tried JRC4558,LF353,NE5532,RC4558- all with same or worse results- nothing hit 18v.   Would also swapping IC1 to make some other combination possibly increase the volts?

[Slowpoke101]

As shown in your pictures C16 is installed correctly. Sorry to be so annoying about it but incorrect installation is a very common error with this particular effect.

It is interesting that the other chips that you have tried have similar to worse results with the +18V and -9V rails. I don't see these chips being able to pull enough current to pull those rails down unless they are faulty - which is not likely. IC3 may be a low spec' chip - works but isn't working well. If you have another one try it and see. I have had problems before with these chips working but falling over when slightly loaded or just plain failing. But your voltages should be high enough to see if the effect will work.

An audio probe is next. Start off IC1 pin 3 and then pin 1. If there is audio there move on to pin 5 and then 7. Then IC2 pin2 and then pin 1. Next is pin 6 then 7. Audio should be present at all stages. Remember that the gain and tone controls will have some effect on the levels and tone. Where the audio stops go over that area carefully and the one before it.

The board connection SW2-1, make sure that it is not permanently grounded by the footswitch. It should be grounded only in bypass mode. If you do have audio passing in bypass mode IC1a (pins1, 2 & 3) is fine.

[Big mike 1100]

I'll try testing the pedal tomorrow, but swapping out IC3 for another chip definitely helped.
I now have a JRD558 in IC1 and a TC072 in IC2
The new IC3 readings
1 9.36
2 4.82
3 0
4 -4.36
5 -9
6 4.3
7 5.8
8 9.36

New IC 2
All 4.7s except Pin 4= -9 and Pin 8= 17v

[Big mike 1100]

Thanks, Slowpoke.  Really appreciate your help.  Here are the results so far.

IC1-
Pins 1&3 are fine
Pins 5 and 7 are quieter than 1&3 but clear

IC2
Pin 1 is fine
Pin 2 - NO sound
Pin 6 NO sound
Pin 7- good sound and good volume

I tested SW 2-1 and it's only grounded in bypass mode.  You also wrote "If you do have audio passing in bypass mode IC1a (pins1, 2 & 3) is fine."  Was I supposed to do something with that? 

[Slowpoke101]

My comment regarding passing audio in bypass mode was referring to IC1a. If audio does pass then that section of the circuit should be OK. But from your tests it is OK anyway.

I would expect IC1 pin 7 to have a very high volume level on it. Check your gain pot and make sure that it is working. Double check all components around IC1b and IC2a. I do have a question regarding C8 (390pF) and C13 (820pF), are you sure that they are the correct values? They seem to be overly large for those small values.

Any progress on a better camera? Clearer pictures would really help.