PC Engine Duo - white screen

[ModInFrance]

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

[ModInFrance]

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.

[thesteve]

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

[ModInFrance]

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