Repair : C64 No signal, black screen fix - part 2

Who's the suspect?

So at this point I was stuck.  I scoured and read every bit of Ray Carlsons C64C chip notes.
http://personalpages.tds.net/~rcarlsen/cbm.html

I'd looked at every single picture of the C64 pictorial fault guide.
https://derbian.webs.com/c64diag/

The only cart I had that sort of worked was my dead test cart.

But then I had a flash of inspiration.

Ultimate II 1541

Now I mentioned Gideon's Ultimate 64 in part 1 of this article.  However I also had an Ultimate II 1541.  Initially I wanted to use it to make sure the disk test I had done with the 1571 was okay.

When I plugged the cart in and turned it on . . . nothing.  The disk light flashed but the screen was black, but then something great happened.  When I brought the menu up with the middle button on the cart I got this!

Looking at it I could make out where the menu text was meant to be.  There was a lot of junk on the screen but I could definitely see the menu.

 

The Kernel is a bit iffy

Looking back at the Ray's site and the Fault guide, everything started pointing to a Kernel Fault.  This also made sense as the Kernel and Basic ROM are on the same chip.  So when I returned back to Basic I'd get a black screen, but then when I went back to the Cart menu, it didn't use basic.

So it's definitely the Kernel Basic Rom and probably the Character Rom too.

I didn't have anything that could replace the Kernel Rom, OR DID I!!!  One of the great things you can do with the Ultimate II is to use a replacement Kernel Rom and VOILA!!  When I return back to basic I get nothing, but that's to be expected as the Cart can not replace the Basic or the Character Roms.

Slow boat from China . . .

At this point I'm waiting for some EPROMs and a Burner to come from AliExpress and for some replacement parts from Ebay . . . so stay tuned.