davebot Posted January 6, 2006 Report Share Posted January 6, 2006 Hi there,Well, I've just about finished the project when I've hit a wall. This morning the midisid was responding to midi notes and CC ... very nice.But I noticed there was a problem with the long bridge on the bottom of the sid board. When I pushed it down, the sid would stop making noise. So I replaced the wire with a shorter piece and now I've lost all sound! So I've begun looking for the problem, with no success.My voltage on IC 2 & 3 on pins 16 is 4.8V The voltage on IC 1 pin 25 is 4.8VBut the voltage on IC 1 pin 28 is only 9.7V even though when I check the voltage across the C10 cap is 11.0 V.I'm using an old C64 psu.Is that a problem? It's strange that it was working... Any help is very much appreciated!!!!!! Quote Link to comment Share on other sites More sharing options...
davebot Posted January 6, 2006 Author Report Share Posted January 6, 2006 Oh, by the way, I'm using the 7812 regulator with the 6581 sid.thanks! Quote Link to comment Share on other sites More sharing options...
TK. Posted January 6, 2006 Report Share Posted January 6, 2006 Hi Dave,yes, the voltage at pin 28 is the problem, once it's below ca. 10V, you won't hear the sound anymore. Also the voltage at C10 is too low, it should be >= 14VMaybe the C64 PSU you are using doesn't deliver enough voltage for the simple PSU circuit, you should consider the use of the optimized PSU - all parts can be canibalized from a C64Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
davebot Posted January 7, 2006 Author Report Share Posted January 7, 2006 Thanks very much! That gives me some direction. I'll post back when I have any news. Quote Link to comment Share on other sites More sharing options...
davebot Posted January 10, 2006 Author Report Share Posted January 10, 2006 hello again!I have finished the optimized power circuit, and I am now getting the correct voltages.However, no sound. I ran the interconnection test, and all pins checked out.Although, I did have 10mV on the #CS pin, instead of absolute zero. I'm guessing that doesn't matter.Here's a question: if the interconnection test works, does that say anything about whether the sid is OK or not?Just wondering if I fried my sid chip while trouble shooting.Anyway, making progress!Thanks,dave Quote Link to comment Share on other sites More sharing options...
raphael Posted January 10, 2006 Report Share Posted January 10, 2006 Here's a question: if the interconnection test works, does that say anything about whether the sid is OK or not?No, this test says nothing about the SID.Just wondering if I fried my sid chip while trouble shooting.Only way to test the SID is to put the chip back into a C64 and play a game... Quote Link to comment Share on other sites More sharing options...
TK. Posted January 10, 2006 Report Share Posted January 10, 2006 Hi Dave,the 10mV at the CS# pin are ok. If all signals can be toggled from the core, then it's either a very general problem (e.g. notes played on the wrong MIDI channel), or there is a problem with the clock (oscillator - one guy just had this some days ago, he mounted this part in the wrong direction) or the audio stage of the SID module (around transistor T1)In order to exclude those "general problems", I've written a testtone applications which is available at the MIOS download page. Once you've loaded this app into the core, the SID should output a 1kHz tone. I hope that this helps you with debugging.Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
davebot Posted January 13, 2006 Author Report Share Posted January 13, 2006 Hello,At one point, using my volt meter (I had all chips in the sockets, the unit was plugged in) I had a small electrical arc between my volt meter and one of the legs of the voltage regulator. Is it possible that I could have fried the sid? I'm going to try another sid and see if that fixes it.Thanks for all your help! Quote Link to comment Share on other sites More sharing options...
TK. Posted January 14, 2006 Report Share Posted January 14, 2006 At one point, using my volt meter (I had all chips in the sockets, the unit was plugged in) I had a small electrical arc between my volt meter and one of the legs of the voltage regulator. It could be, that this was caused by a temporal short circuit caused by the probes. The propability that this fried your chips is low, but it cannot be excluded.I just had an idea for a simple check of the transistor amp circuit: instead of using the SID, you could attach another audio signal (e.g. from a radio or a walkman) to pin 27 of the empty SID socket. You also need to connect the ground to pin 14 - now you should hear some sound at the audio outBest Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
davebot Posted January 14, 2006 Author Report Share Posted January 14, 2006 GREAT IDEA! I'll let you know how it goes. -dave Quote Link to comment Share on other sites More sharing options...
davebot Posted January 15, 2006 Author Report Share Posted January 15, 2006 OK. The problem is in the audio out. When audio was applied, there was some output, but it was very quiet, "poppy" , low frequency and heavily distorted. Kind of "farty". When I run midi into it. I can hear the sid reacting and making little audible pops. Could this be the transistor?Thanks good ideas!-dave. Quote Link to comment Share on other sites More sharing options...
pwx Posted January 15, 2006 Report Share Posted January 15, 2006 OK.  The problem is in the audio out. When audio was applied, there was some output, but it was very quiet, "poppy" , low frequency and heavily distorted. Kind of "farty". When I run midi into it. I can hear the sid reacting and making little audible pops.  Could this be the transistor?did you check your Ground-Connection @ audio-output? Sometimes, this is a real common problem with crappy and noizy sound?Be shure to check this again and again....greets, pwxpwx Quote Link to comment Share on other sites More sharing options...
davebot Posted January 15, 2006 Author Report Share Posted January 15, 2006 Yes I actually thought of that, and gave it a dedicated ground wire from the power supply. Quote Link to comment Share on other sites More sharing options...
TK. Posted January 15, 2006 Report Share Posted January 15, 2006 The error could also be located in the circuitry around the transistor, thats hard to say without seeing your PCBDo you have a digicam? Maybe you could make a snapshot of the bottom side and post it here?Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
davebot Posted January 17, 2006 Author Report Share Posted January 17, 2006 I'll try to get that tonight. It's a Smash TV board. Quote Link to comment Share on other sites More sharing options...
davebot Posted January 18, 2006 Author Report Share Posted January 18, 2006 OK here's a couple pix... one of the bottom of the sid board, and one of my power circuit, just for fun. What a mess!http://www.davebot.com/images/sidboard.JPGhttp://www.davebot.com/images/power.JPGI hope that helps!thanks,dave Quote Link to comment Share on other sites More sharing options...
davebot Posted January 19, 2006 Author Report Share Posted January 19, 2006 Good News!!I just finished clocking the Sid from the core. Very easy. Then just reheated a few of the connections, and viola!A working, singing Sid!!!!Thank you all so much for help. I will post the finished result when done with my control surface. I already have the panel layout done. I have to recommend ableton live ... with the CC envelope modulations on a loop, whoa dude, as we say on the west coast.thanks again.dave Quote Link to comment Share on other sites More sharing options...
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