ohmstudiste Posted March 27, 2005 Report Share Posted March 27, 2005 I just started mounting the core and my SID and it all went very smooth:soldering core,SID, LCD, uploading MIOS and Midibox and I heard it scream for the first time yesterday.However today I had some short circuit(probably when I moved the different modules some cables must have interferred with some other) and since nothign appears on the LCD(it lights but I got this first range of 'full square' caracter). And when I plug in the Midi cables there is no incoming message either.I used the C64 PSU and when the problem occured, it blew the PSU fuse. I designed the PSU using the mbhp_sid_c64_psu.pdf.I checked the voltage on the core, and I get 5V where I should get them (I didn't tested all the connections, just the main ones, IC1 and IC2)and 12V on the SID.I noticed when I turn the unit on again, the PIC and the 7805 voltage regulator are getting very hot. I don't remember if it was the case prior to the incident. And if I keep the unit on for some time, it goes off by itself...Can anyone help me trace the problem ? Is there anyway to tell if a PIC is fried ? if the voltages are OK, does it mean the other component are safe ? I would really appreciate some help on that one... Quote Link to comment Share on other sites More sharing options...
Skunk Posted March 27, 2005 Report Share Posted March 27, 2005 Hi,it sounds like you have blown your PIC by a shortcut in your wiring to +5V. The fact that your PSU fuse was also blown leads to the same direction. The PIC normally doesn't get that hot. It might have died, and now it pulls a big current out of the 7805 regulator -- which works, by the way when you see clean 5V on the corresponding pins without the PIC.My proposal: change the PIC, but before you insert it in the socket, measure all PIC socket pins against GND and +5V -- just to be sure there is no shortcut anymore. AND: measure the 5V current from the PSU to the CORE board. Should be in the range of a few mA without the PIC.Your display might have been not affected by this "accident". The first row with black characters is nothing unusual. I think if the display is damaged, you don't see anything changing.Optocoupler died? Don't know, this is hard to say just according to one post. The only reccon: action in the same way as for the PIC: first measurement of all pins with 5V switched on, then insert the coupler if all pins show a regular voltage. If it does not work, try a new coupler.Cheers & good luck,Skunk Quote Link to comment Share on other sites More sharing options...
ohmstudiste Posted March 28, 2005 Author Report Share Posted March 28, 2005 Thanx for the answer...I'm gonna check the voltage and current everywhere to be sure.I ordered a new PIC (I intended to buy second core and SID modules to build a dual SID anyway , so it just hurried the process... and added some bucks to the budget for the PIC replacement :( )Gonna be more carefull next time. Still don't know what happened. 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.