Laslo Posted October 29, 2006 Report Share Posted October 29, 2006 alo again. Well i've got my pots all hooked up and it's a great feeling :)Though one little problem is on one bank of 8, the minimum value only goes down to either 29 or 30, even when the sysex created in vmidibox64 is made to be 0-127. Also the second pot in the bundle goes straight from 127 down to 60 with any movement then gradually down to 30 over the pot turn.I've triple checked the solder joints but of course i will check more, just curious to see if anyone has run into this problem or knows a solution?Thanks :) Quote Link to comment Share on other sites More sharing options...
HL-SDK Posted October 29, 2006 Report Share Posted October 29, 2006 Make sure you dont have any type A pots, and that they are all 10Ktype A is logarythmic, type B is linear... (At least the kind I ordered from futurlec, manufactured by alpha) Quote Link to comment Share on other sites More sharing options...
Laslo Posted October 29, 2006 Author Report Share Posted October 29, 2006 Thanks for your response HL, i'll have to unmount them to see whether they're A or B type, I know they're 'supposed' to all be B type but you never know if they've sent me a wrong one here and there. These are alpha pots too. It seems a bit strange that all the pots in the one bundle would be "A", but could one log pot be influencing the rest in the chain?Thanks again! Quote Link to comment Share on other sites More sharing options...
HL-SDK Posted October 30, 2006 Report Share Posted October 30, 2006 Well as it says, tie ALL unused inputs to ground, but I dobut that is a problem in your case.Make sure all pots are receiving +5V (+/- .2 is OK) and they are all the same value... it also depends on how many pots you have connected, but I dobut this is a noise issue as well... I hope someone else from the forum takes a look at this Quote Link to comment Share on other sites More sharing options...
pay_c Posted October 30, 2006 Report Share Posted October 30, 2006 Really sounds like a log pot, so this would be my guess, too. Really check that.Some other issue *can* also be the resistance to your pot. Check with a multimeter that the resistance of your pot wires (meaning those wires going from the PCB to your pot - !including! the connections (solder points)) is not to high - e.g. if your pot is 10k it should not be higher than 100 Ohm.Basic check is also the voltage on the high and the low side of your pots. Should be the same as the voltage on the core (+/- few 10s millivolts) meaning 0 Volt and 5 Volt.Anyhow some very weird stuff. Good luck! :) Quote Link to comment Share on other sites More sharing options...
Laslo Posted October 31, 2006 Author Report Share Posted October 31, 2006 I've checked all pots in that bundle and they're all the same as the others, linear "B" 10k. I'll check the resistance now pay_c, thanks :) Quote Link to comment Share on other sites More sharing options...
Laslo Posted November 1, 2006 Author Report Share Posted November 1, 2006 Still haven't isolated any issue yet. I might try replacing the one pot that goes straight from 127 to 60 and see if that makes any difference.any other suggestions would still be greatly appreciated Quote Link to comment Share on other sites More sharing options...
pay_c Posted November 2, 2006 Report Share Posted November 2, 2006 Don´t do that *yet*.First check if all pots got 0 Volts and 5 Volts on their outer pins ( = min and max values). If here something is wrong, *every* pot will give you the wrong value. Next check the middle pin of your pots whether there the min and max values (0 Volts and 5 Volts - but also 0,2 Volts and 4,8 Volts are ok) can be reached. If this is NOT the case, but the outer pins have 0 Volt and 5 Volt indeed, it´s definitely the pot itself which got some fault. Quote Link to comment Share on other sites More sharing options...
Laslo Posted November 3, 2006 Author Report Share Posted November 3, 2006 Hi Pay_cWhen measuring between the outer pins, all pots give 5.1vv, when measuring between the middle and outer pins, as i turn the pot, the voltage goes from 0v to 5.14v. All except the last pot in the bundle which connects to the AIN ground and 5v pins which measures from 0v to 2v. Though this seems to be the same across all pots and it is only this bundle that is affected. I replaced that one pot that went from 127 straight to 60 and that has solved that problem, but still, none in the bundle go lower than 30 Quote Link to comment Share on other sites More sharing options...
pay_c Posted November 3, 2006 Report Share Posted November 3, 2006 Ok, pls check the voltage between the GND of your pots against the AIN PCB and against the Core PCB (should both be below 10 mVolts). It also could be possible that the last pot in the row blowed off one of your multiplexers on the AIN (sounded like a short in the pot). Quote Link to comment Share on other sites More sharing options...
Laslo Posted November 9, 2006 Author Report Share Posted November 9, 2006 Sorry it has taken me so long to reply, i've been repainting my room so my internet was down. I measured the voltage as you mentioned and didnt find any irregularities. I may try swapping one of the multiplexers with that bundle to see if that isolates the problem.I shall report back :) Quote Link to comment Share on other sites More sharing options...
pay_c Posted November 9, 2006 Report Share Posted November 9, 2006 Yup, that´s some idea, cause the problem is definitely not @ the pots.If you still don´t get it working, try following: Put *all* pots to the lowest value (0 volts) and measure *the exit* of the multiplexer IC (goind to the core). It should normally be 0 Volt then, but I could bet it´s not in your case. This then can be either your multiplexer IC or - sorry to say that - your PIC IC. By deconnecting one of the exit ports of the multiplexer IC´s (not letting it go into the core) and measuring that again with the same technique the guilty should be found (it voltage is not 0 volts then it´s the multiplexer IC, if it IS 0 volts, it *should* be the PIC - although I really not think it´s the PIC as those PIC´s are pretty rough in taking hard stuff). Quote Link to comment Share on other sites More sharing options...
Laslo Posted November 10, 2006 Author Report Share Posted November 10, 2006 Arg! Well, while trying to fix that problem, the LCD stopped working for some unknown reason, no black bars, just the back light, so while trying to fix that (resoldering), now nothing works, not signals out of the core. :(So it'll be a while to fix this then i shall try yet again Quote Link to comment Share on other sites More sharing options...
Laslo Posted November 13, 2006 Author Report Share Posted November 13, 2006 Right, back in business. It was infact a dodgy 4051 that was the root of the problem, so i'll have to pick up another.Thanks for all the help Pay_C Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.