Aristocrat troubles...

[non-reverse]

I recently populated a single sided V4 aristocrat board and I can't get it working correctly.  I've built a gillion pedals and I've exhausted all my troubleshooting talent trying to get it running. 

I got the thing wired up and in an enclosure and when I fired it up (weather battery or DC) I get strange results.  Firstly, I can hear the distorted signal but it's at a vastly lower volume than unity even with the volumes turned up.  Secondly, the volume only fluctuates over a very small portion of the pot's travel.  Thirdly, if I turn the volume up all the way, the sound completely shuts off. 

I populated a second board and measured the value of every component before soldering it in so I could compare it to the first build and everything seems identical (I haven't wired the second board up yet).  I'm using the 4580 chips but the same thing happened with 4550s. 

I replaced the pots, tried rewiring the power/ground scheme and searched the forum but man, this has got me stumped. 

I will post voltages next time I have the board in front of me but has anyone heard of such a thing?  Any ideas where to go from here?

Thanks in advance.

[gtr2]

voltages would help

[madbean]

Volume all the way up = kills sound -- I'd say 9v and ground are somehow not consistent in your wiring, but that's all I got so far. Unless the pot is wired backwards 

[non-reverse]

I will definitely get voltages next time I get to my bench, probably won't be till Monday though.

Anyone know what kind of voltages I should be seeing on the ICs?

Thanks again.

[madbean]

It should be 9v on pin8, 0v on pin4, 4.5v on pins 1, 2, 5, 6, 7 and probably a little less than that on pin3.

BTW--are you Joe?

[non-reverse]

Yep, it's me, Joe. 

On my way to the lab to take another stab at the Aristocrat.  Will post voltages and pictures when I get back this evening.

Thanks!

[non-reverse]

I went to the lab and messed with the Aristocrat for a while again yesterday, took some voltages and such but left the sheet with my notes on it elsewhere.  I'll get those posted as soon as I can.  That said here are a couple pictures along with a description of what's going on.




I think part of my problem, originally was that I was testing with a weak battery.  I replaced it with one reading 9.12V and I could hear a noticeable difference in how loud the circuit was.  Weird thing is, it only seemed to help one channel and after just a few minutes of testing, the voltage on the battery was about 8.55v.  Makes me think something is wrong.

Also, touching any of the lugs of the channel two tone pot made things louder.  I use pot condoms so I held the pot in one had (not touching the pot case) and touched one of the lugs and it got louder.  So, only one channel is mostly working.  Everything on channel 2 save for the volume pot dieing at full rotation is okay.  I don't remember all the voltages but I do remember that with a fresh battery pin 8 was only getting about 8v.  There was 5.6 milivolts on pin 4 and the rest were about 4 or so volts if memory serves. 

I tested the unit by connecting the 9v in to the + side of a battery, the G1 pad to the negative side of the battery and then connecting the lugs of a jack to the appropriate place on the board, i.e. sleeve to the ground point on the lower left of the board and the input to the input of ch 2.  I hope that's consistent with the functioning with the pedal. 

Thanks again, I think my next step is to get it back into an enclosure and go from there. 

Do lugs 4 and 7 of the 3PDT have to be permanently jumpered like 7 and 8 are?, I'd never seen that done that way before so I figured I'd ask.