Aion Aurora Compressor CA3080 Issue

[PRR]

0.2V in 2K is 0.1mA, much-less than the '3080's blow-up rating 2mA.

I'm mystified.

[cnspedalbuilder]

OK, I have linked photos of the PCB below:




-->You will notice that one of the sockets is empty, but that's not the problem. The transistor fell out when I moved it to take a picture. It's conceivable that there is a socket contact issue, but there is no room for an added resistor lead or anything else to stuff the gap.

@PRR yes, sadly I double checked and voltage goes from crazy to almost nothing after resistor is added.

[cnspedalbuilder]

Is there any other information I can provide that might help debug it? I don't think I've made a mistake with voltages, but I'm still on the new side, so if something here doesn't add up, please let me know. Thanks.

[PRR]

This is most strange:



I suppose you put the socket in, off-by-one, realized it, and offset the chip in the socket to make it work out right. (Interesting that pins 1 and 8 on '3080 are N/C-- it is a 6-pin device, but at the time 8-pin packs were a standard.)

I'd have to examine that very close to have any confidence. Hate to say it, but the best path may be to de-solder and do-over.

I'm also wondering if some solder joint "looks soldered" but is not really touching through tarnish.

[cnspedalbuilder]

I suppose you put the socket in, off-by-one, realized it, and offset the chip in the socket to make it work out right. (Interesting that pins 1 and 8 on '3080 are N/C-- it is a 6-pin device, but at the time 8-pin packs were a standard.)

Paul, you got me, I accidentally offset the IC socket by one (and I put it in the wrong orientation) when I soldered it in. Once I discovered, I tried to desolder it, but I discovered that it is nearly impossible to get an 8-pin socket out of a double-sided PCB. So, I added two pin sockets and oriented the chip the right way using the IC and pin sockets. Then I put the resistor into the last two holes of the IC socket. I think this should be fine, because I assume all the socket does is provide a contact from the IC to the PCB. So even if the socket is put in wrong, I'd think that the components should work if they are in the right place.

I'd have to examine that very close to have any confidence. Hate to say it, but the best path may be to de-solder and do-over.
I'm also wondering if some solder joint "looks soldered" but is not really touching through tarnish.

Yes, I've been thinking that too. The problem is that either I lack the skillz or the equipment to successfully desolder the multi-pin components (pots, transistor sockets, IC sockets). If I could at least get out the pots, that would be great. But every time I try the pump, there's always some leftover solder in the hole that does not want to let go! Can this be done w/o buying a desoldering iron?

[cnspedalbuilder]

OK, I've done more troubleshooting. I got new components and went ahead replaced any part that I had substituted with nearby values (e.g., pot and resistors that were close to spec). I also pulled out the attack pot, redid all the solder joints on the IC socket, along with some resistors, and the solder joints for the attack pot. Then, I figured that maybe the transistors were loose in socket, so I added solder joints to connect the transistor leads to the socket holes (so there should be at minumum a connection via the top metal part of the socket).

To be careful with 3080, I went ahead and checked voltages *without the 3080*. Result: all voltages were pretty much the same as last time I checked. So, yes the voltages don't seem to change much with or without the IC in place, and definitely this is the case for evil pin #5. 

I am stumped. I know I'm doing something wrong, but not sure what. This should be dead easy, and I am really mad at myself. I don't expect anyone to solve it for me, but if you can suggest any troubleshooting tests, that'd be helpful. At least can anyone confirm whether the problem lies along the part of the circuit that is linked to pin 5? Thanks as always.

[cnspedalbuilder]

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[DAF]

Hi
I was wondering if you managed to solve your issue?
I have a similar issue and would be keen to understand how you fixed it

Thanks
D

[cnspedalbuilder]

Hi DAF, no this is the only pedal that I've been unable to complete. I eventually got too busy and decided to focus on other projects. If I had to guess now, the only thing I can think of is that back then I did not check my capacitor values with a tester, so maybe I put a wrong capacitor value somewhere.

Do you have that weird voltage reading at Pin 5?

[PRR]

> weird voltage reading at Pin 5?

'3080 pin 5 not being nearly 0.6V means the '3080 is useless.

We see this a lot on '3080 bought from various sources. There are a LOT of fakes on the market, so many that the sellers may not know what they are selling. (Or don't care.)

Small Bear Electronics is known to have good-working '3080s. If you got it anywhere else, try his.

[cnspedalbuilder]

@PRR, haha, I think you said that earlier in the thread. I did get it from SmallBear, and he was nice enough to send me a free replacement. Still didn't work, so I'm thinking there's something wrong somewhere else.

I am a little more skilled than I was when I first started this thread. If you all think you can help me diagnose the fault, I'll try to fix it.