PCEngine-FX.com

Hello to this beautiful community.

I have recapped my Duo a couple of years ago. It was working great but when I tried it again this week I got a white screen with or without a HuCard.

I've followed advices from @thesteve from a previous post. Removed Ic520. Tested the d lines with and without HuCard.
With HuCard, I'm noticing that D7 is stuck high. Not moving a bit. All other D lines are pulsing. I've followed D7 up to huc6280 and it's high all the way
Am I onto something? Is D7 always used or can it stay high?
Related question if I ever try to switch the 6280 and 6270, can I use chips for a white PCE on a Duo?

Thanks a lot,

Romi

Small update, it turns out D7 do pulse for a little time when turned on.
I have since swap Huc6280, Huc6270 and the Work Ram from a white PCE but no success.

I seem to be getting pulse from every pin on HuCard Side. At least for some time.

I'm not really sure what to look for anymore.

D7 is always used
All chipset versions are interchangeable
Don't recall saying to remove the chip
The bus is bidirectional, controlled by/we and /ce signals from the 6280
Most issues are bad address traces
Card to 6280 is direct

Thanks @thesteve

I feel so dumb. I missed one adress line : A9.

0 contact between the HuCard and the CPU.

It seems the trace broke somewhere below the HuCard reader. Impossible to see. I ran a wire and bam, it works again.

Thanks for pointing me in the right direction.

Romi