SOLVED !! minerva only loads minerva logo

[techy]

Help !!

I got a ql which only loads the minerva logo and does not continue any futher ( so the rectangle on the left with ram and time is not present ).

- tried several roms .
- left rom position
- 27c512 adapter board


Any ideas ?

[tofro]

If it comes that far, most of CPU, ROM and RAM must be functioning.

About at this point QDOS changes from linearly executing initialization code to becoming an interrupt-driven system. I'd check if the interrupt lines /IPL0-2 and /IPL1 on the CPU for pulses. The ZX8302 should generate a 50Hz signal on these lines, and If that's missing, the symptoms would look like what you're seeing.

[martyn_hill]

Good morning techy!

Getting that far through the DRAM test to display the Minnie logo is typically (though not 100% of the time) indicative of an issue accessing the 8302 ULA whilst attempting to read its RTC.

Do you have a spare, known good ZX8302 to drop in and test?

[techy]

at work right now ,

so quick test revealed ;

8302 -> no change
8301 -> no change
02 and 01 -> no change
processor -> no change
original rom's -> no change

it is an iss 7 board

[Derek_Stewart]

Hi

In my experience, the Red Minerva Logo on the screen only, was a faulty 8049, so maybe worth trying that.

[techy]

Thanks to all for trying to help me !!

@ derek ,


That was the problem .

Apparently the 8049 died .