Is this possible?

[Milkmansound]

This is almost related to the other SID posts of late:

my SID stopped playing as well, but I am fairly certain that it is not the 6581, since I put another one in and there was a similar problem (I can hear the oscillation still). The reg was getting too hot to touch, and I had already corrected the basing of the LCD transistor (bcc). So, I was thinking that maybe it was something on the SID board - like IC 2 or 3 (cause they get 5V) - when I switch them around (ie, change IC2 with 3) the reg stays cool. Is it possible that one of these went bad, and this is causing the SID not to recieve data from the core?

Also, where does the 2.5VDC come from? I notice that on the SC pin of J2 on the core, there is 2.5V instead of 5V - is this normal?

Thanks in advance - Tim

[TK.]

Hi Tim,

So, I was thinking that maybe it was something on the SID board - like IC 2 or 3 (cause they get 5V) - when I switch them around (ie, change IC2 with 3) the reg stays cool. Is it possible that one of these went bad, and this is causing the SID not to recieve data from the core?

possibly yes, but there must be a reason why one of the shift registers went bad. Maybe a short circuit at the bottom side?

Also, where does the 2.5VDC come from? I notice that on the SC pin of J2 on the core, there is 2.5V instead of 5V - is this normal?

the shift clock SC is a fast switching signal, therefore no DC. You cannot measure the voltage with a common multimeter.

However, the mbsid_interconnection_test_b.zip could help to determine if all 74HC595 output pins can be controlled from the core module. Just follow the instructions in the main.asm file of this package.

Another important hint: don't forget that with MIOS V1.7 and MIDIbox SID V1.6 the SC input of the SID module has to be connected to pin CORE:J11:MD of the core module. See also http://www.ucapps.de/mios_v1_7_hardware_mods.html

Best Regards, Thorsten.