Duo showing the solid color screen instead of the Super CD screen

[D-Lite]

Know how your system shows the blue/orange/whatever solid color screen when the HuCard is in and not reading correctly?  Yeah, I'm seeing that with no HuCard on a Duo, instead of the normal Super CD Rom "Press Run" screen.  But the system boots HuCards fine.  So is it not seeing the System 3 on chip?  I just finished a cap overhaul on it and the sound is fine.  I haven't tried putting a system card in the Hu slot, probably try that later tonight.  Any idea?  What IC is responsible for the system so I can track down any pulled/crossed traces?

[nat]

I wonder if something in the HuCard port is f--ed up and it thinks there is a HuCard in there when there really isn't, thus it's not even trying to boot from the on-board BIOS. I'd check that first...

[D-Lite]

I wonder if something in the HuCard port is f--ed up and it thinks there is a HuCard in there when there really isn't, thus it's not even trying to boot from the on-board BIOS. I'd check that first...

Good idea.  What's the "detect" pin on the slot?  Is there one that just checks for feedback or is it merely a completed circuit that signals presence?

[Charlie]

To the best of my memory:
Pin 1, tied to ground (pin 18) on card = card present; therefore, should be high w/o card.

Might also want to check the Reset, pin 36; low for reset, high for run

Charlie

[D-Lite]

To the best of my memory:
Pin 1, tied to ground (pin 18) on card = card present; therefore, should be high w/o card.

Might also want to check the Reset, pin 36; low for reset, high for run

Charlie

Fantastic, I'll check that first, thanks.

[blueraven]

I had something similar happen a few months back on a PC Engine Duo (Black);

I was getting an alternating beige and magenta screen with no hucard, and a black screen with a hissing noise with the hucard in. One of the 90 degree angle pins that connects from the card port to the board had a rust deposit that ran down to the motherboard from something (condensation? errant electrolytic fluid? i have no idea). I carefully removed the deposit and cleaned the pin as thoroughly as possible, and re-flowed the solder to the pin, which ultimately fixed the problem. 

Connection to the hu-cards resumed on boot, the CD-ROM screen is accessible but the drive/HOP-M3 has been and is still dead at the moment.   

[nat]

Yeah, it's much more likely a HuCard port problem than a problem with the System 3 BIOS chip. Of course, anything's possible, but I've never seen a bad BIOS chip before.

[D-Lite]

Had a chance to do a quick test and so far it doesn't seem to be pin 1 grounding.  Need to keep plowing through.

[esteban]

Had a chance to do a quick test and so far it doesn't seem to be pin 1 grounding.  Need to keep plowing through.

Clearly, this is a case of phantome hucarde.

I suggest an exorcism.