Cassu

I did ground the audio inputs, no change on the hum level. I have tested three PSU's, no change on the hum level. Its pretty loud ... http://cassu.net/mb/mb_hum.mp3 [783K] Edit: - Recorded from the first pair of 6581 SIDs. - Hum volume is even in all four pairs.

Now its confirmed; that LCD-module i bought from Mouser is broken, everything else works. Testplay via midi is done. Receives midi as it should, SID's squeak out notes as should. Its just a bit hard to use that thing without a display ;) Well, takes week or two until i get the new LCD-module. Background hum (generated by the C= PSU, i think) is quite nasty. Its irritating and something i really need to get rid of or i cant use this thing to music production as much as i was planning to :-[

"solderable jumper"s are all open, i did not touch / solder those (i've been reading the construction manuals very very carefully). There is no voltage in the D2, its cold as i have measured it now few times again - so forget that. One of the LCD-modules chips is getting hot as hell. It seems that my LCD-module is faulty. I'll buy a new one... Backlight wont keep on and it shows some bizarre lines, effects and characters. I measured all once again, inserted the chips, plugged it to MIDI and ran MIOS studio. Seems to work fine there, upload works like a dream. Now i'll wait until i get a new LCD-module. Takes a week or two. Now im going for a vacation for few days... Maybe it works like it should afterall, i just might be panicin for nonsense :)

I've Checked those bridges many times. I first tried my best to solve the problem by myself. J15_CORE1 (where the LCD-cable goes), PIN 11 I removed the J1_SID1, J2_SID1, J1_SID2, J2_SID2, etc jumpers. Hum is gone! :) So i'll check out voltage outputs ... Voltages i have measured from those regs seems to be ok, i'll measure yet again. I have tried two C64 PSU's, result is the same - and both PSU's works fine with my C64's. (No, not the C64C-model, i dont like it. I mean the good old breadboxes). ...but i'll do some more checking...

R80 is installed. Problem as i noticed something is wrong: - All suggested measurements were ok, so i was ready to power it up. - I turned the power on (Fully constructed with the control surface - except the SID's were not installed yet). - All audio outs sound like a ship's horn. - LCD backlight lid up, stayed on about three seconds and then shut off. Some strange characters flashed few times on the display. - Display got very hot in an instant. I quickly measured the lcd wires and found out that base board's PIN 11 (D2) gave 2,9volts (ground from VSS)!? - I turned power off and uninstalled all the chips. Then PIN 11 (D2) gave out 4,11volts (ground from VSS) and all audio outs still sound like a ship's horn. Im puzzled. I have checked for shorts multiple times, no shorts. I have checked the power trails multiple times - should be ok, since measurements are good to go - except that LCD's D2 pinouts voltage what i think is wrong. I have checked that all the components are as should be multiple times... Im really starting to feel beaten with this thing...

I have a strange problem with my MB-6582 base board (board & kit bought from SmashTV). I bet there is a simple cause for this, but i just cant find it. I have checked everything out several times for the last three days and i just cant find the error. Here is link to a flash-video what shows you the problem i have. (Contains audio). http://sites.google.com/site/cassu77/Home/mb_problem.swf?attredirects=0 Any ideas what could be causing this? Built with PSU option B, and im supposed to use eight 6581 sids.