When something's wrong

Symptom first. Find yours below.

Nothing on the screen at all

Work through these in order:

1. Is the power light on? No light means no 5 V. Check the supply is center-positive and actually delivering 5 V.
2. Is the monitor on the right input? VGA monitors are cheerfully silent about being on the wrong channel.
3. Try the serial port. If you have a USB-to-serial adapter, plug it in, open a terminal at 19200 8-N-1, and press reset. If the header appears there, the computer is fine and the problem is the video path — cable, monitor, or the video card. The next section is about the card.
4. Press reset and listen. A beep means the machine got as far as booting.

If there is genuinely nothing — no picture, no beep, no serial output — the machine may have stopped before the header because it couldn't find any console. Get a serial cable on it; that's the fastest way to find out what it thinks is going on.

The header comes out on serial, and VDP isn't in it

The third line of the header lists the cards the machine found, and a missing VDP means it didn't count the video card as a screen. So it did the next best thing and sent the whole console down the serial port.

The machine only takes a video card that identifies itself as a 6502-PICOVDP and carries its own character set, because the ROM has none: the letters on the screen come from the card. Three things fail that test:

• The card isn't seated, or its IO ENABLE switch is off.
• It's still running the Pico9918's original firmware, which behaves as a TMS9918A. That card is for BIOS 1.6 — see Setting up.
• Its 6502-PICOVDP firmware is older than the built-in character set. Update the firmware.

No sound

• Is the RCA lead going to something powered? The ACE puts out line level, not enough to drive a bare speaker.
• Have you set the volume? VOL 15 at the prompt, then SOUND 1, 440, 50. You should get a beep.
• If the startup beep is missing too, the sound chip isn't being seen — check it's seated properly in its socket, and the right way around.

No beep at startup, but everything else works

Same cause as above, and it's harmless: the machine skips the beep when it can't find a sound chip rather than complaining about it. Everything else works normally.

The memory card isn't found

DIR says ?NO DEVICE ERROR instead of listing files.

• Reseat the card. It should click in without force.
• Try a different card. Very large and very new CF cards sometimes don't support the 8-bit True IDE mode the ACE uses; anything from about 128 MB to 8 GB is a safe bet.
• Check the CF adapter board is fully seated on the Storage header.

If DIR lists nothing but doesn't error, the card is fine and just empty — FORMAT it and you're away. See Storage.

Keys repeating, or keys getting missed

Press reset first: the keyboard controller sets itself up at power-on and very occasionally gets it wrong, and a reset makes it start over. Your program survives, so this costs you nothing.

If one particular key is unreliable, it's the switch rather than the computer — mechanical switches can be cleaned or replaced.

If you're using a PS/2 keyboard in place of the built-in one, try a different keyboard: some USB keyboards with passive PS/2 adapters are only half-hearted about supporting it.

A program won't stop

Press Esc. If that doesn't do it — because the program is stuck in machine code rather than BASIC — press reset. Your BASIC program is still in memory afterwards.

?SYNTAX ERROR

BASIC didn't understand the line. Nine times out of ten it's a typo:

PRIMT "HI"

?SYNTAX ERROR
OK

The other time, it's a keyword that doesn't exist in this BASIC. LIST and look at the line carefully.

Asking the machine what it found

One command tells you what the ACE found when it looked itself over at startup. Type MEM:

MEM
 30718 BYTES FREE  HW=$FF
DISK 0

OK

HW=$FF is a full house — everything present and accounted for. Anything less means one of the pieces wasn't found, and the number tells you which:

Reading the HW number

It's a hexadecimal number, and each bit stands for one part of the machine. Add up the values for everything that's there:

Value	Part
$80	Video Card / VGA Card
$40	Sound Card
$20	GPIO Card / Input Board
$10	Serial Card
$08	Storage Card
$04	RTC Card
$02	RAM Card
$01	RAM Card

So HW=$7F is everything except video — which is what you'd see on a machine with no video card, driven over a serial cable. And HW=$FF is everything.

Still stuck

The hardware itself — schematics, board revisions, bill of materials — is all in the 6502-ACE repository. If you're chasing something at the board level, that's where to look.