Troubleshooting a red screening Jaguar

[Diederikgr]

So I got my hands on 2 Jaguars at the moment. One's absolutely fine, but the other one only red screens. First attempt was cleaning the cartridge connector, no luck. Second attempt was adjusting all pins and replacing all capacitors, red screen! Third attempt was replacing the cartridge connector and guess what, still a red screen!

 

So now I've let the system sit on the red screen for 10 minutes and see which chips get hot. The big ones all seem to heat up just fine, except for U35, the big chip closest to the DC connector. This chip remains stone cold. Console5 mentions this is a ROM chip, so it doesn't seem too odd that this is the culprit. Anybody ever traced the issue to one of these chips or has more knowledge on where to go from here?

[omf]

u35 is the system bios, it will never get hot. i suppose you could replace it just to be sure

 

i would change your attention to the small chips in front of the cartridge connector. i have had to replace one or two of these in the past in relation to red screen

 

look at the tops very closely and see if any of them are damaged

[Diederikgr]

u35 is the system bios, it will never get hot. i suppose you could replace it just to be sure

 

i would change your attention to the small chips in front of the cartridge connector. i have had to replace one or two of these in the past in relation to red screen

 

look at the tops very closely and see if any of them are damaged

Thanks for pointing me to those chips, because I now notice something a little odd there. U14 is a TI chip in my case. Console5 mentions that U12 and U14 are the same chip, though U12 in both our cases seems the AC variant (not HC).

I also don't notice any damage to any of the chips, all chips still have smooth surfaces.

 

Edited May 19, 2019 by Diederikgr

[Gummy Bear]

What are those little ones near the cart connector?

Is that RAM?

[Diederikgr]

What are those little ones near the cart connector?

Is that RAM?

Buffers from my understanding. These are used to minimize the load of data lines. In this case every signal going in and out of the cartridge. It's possible that even those chips got a load too big to handle.