lead bromide Posted July 25, 2009 Report Posted July 25, 2009 I've run across a problem with my MB 6582 where a core will produce the testtone when I connect pin 8 to pin 27, but produce no tone when I insert the SID chips. So I've uploaded the interconnection test app to the core, and checked the voltages, and this is what I got:A0: 3.79VA1: 3.79VA2: 3.79VA3: 3.79VA4: 3.79VRES: 3.79VD0: 3.79VD1: 3.79VD2: 3.79VD3: 3.79VD4: 3.79VD5: 3.79VD6: 3.79VD7: 3.79VCS: 9.05VThats on both SID sockets. The readme in the interconnection test file says that all the pins should be 5V and CS should be 0V. Am I doing something wrong? Or is there another problem? I don't have the sid chips in the socket, could that mess up my results? Quote
Wilba Posted July 25, 2009 Report Posted July 25, 2009 Those voltages suggest a sagging 5V supply or some kind of other problem perhaps...9.05V on the CS pin is bad, that suggests CS pin is being shorted with the 9V supply to the SID.Maybe you got the CS pin wrong and you were really measuring the Vdd pin (pin 28)... but in case you were really measuring 9V on the Vdd pin, you should check voltages everywhere.Do not insert the SID chips again until you fix this problem! You do not want to be putting anything over 5V into the data I/O pins!It is possible that you have made some wrong connections setting up the PSU Option A or B... please check these first and check the voltages of pins that should be 5V and 9V (assuming you're using 9V SIDs like 6582/8580)... specifically, the supply to the 74HC595 underneath the SID sockets and the PIC. Take out ALL the ICs in the entire board and check voltages everywhere!The interconnection test should be run without a SID in the socket. Quote
lead bromide Posted July 25, 2009 Author Report Posted July 25, 2009 Thanks Wilba, I'll check the voltages again and check for shorts. I do have three working SID pairs though, so I think it might be isolated to core 2. Quote
lead bromide Posted July 25, 2009 Author Report Posted July 25, 2009 Alright, so I've been able to get a testtone from each SID pair on each core. But I've run into another problem, PIC01 won't transmit or receive midi messages at all, and when I connect the LCD to the PIC, the LCD does not show any text when I turn the trim pot from all the way left to all the way right. Is this the sign of a dead PIC? Quote
fussylizard Posted July 27, 2009 Report Posted July 27, 2009 The LCD backlight is only powered for CORE0, and without a backlight it can be very difficult to see any text from the LCD. How much you can see probably depends on your backlight. At first I thought there was a problem with my CrystalFontz LCD on CORE1 but then I realized it was just the backlight wasn't powered and I could *barely* see the text with the contrast set just right.The easiest way to test for a dead/partially-dead PIC is to test CORE0 with a good PIC, then move the suspect PIC to CORE0. That way your backlight works and you know everything else is working so you can isolate any problems to the suspect PIC.One final thought-don't forget to set J11 to connect CORE1 to the MIDI Out port when testing MIDI to CORE1. Quote
lead bromide Posted July 27, 2009 Author Report Posted July 27, 2009 The LCD was working, then it stopped working. I got an error when uploading the MB-6582 hex file the PIC and it stopped showing any text at all. I'll definitely test out that PIC though, thanks for the suggestions. Quote
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