PC Engine HuCard not reading: cleaning and tensioning the card slot

What the behaviour tells you

A console that works after reseating the card has dirty contacts. A console that works only when the card is held to one side has lost contact tension. A console that never works, on any card, may have a cracked solder joint where the slot meets the board, and that is a different repair.

Test with more than one card before deciding. A single dirty HuCard produces exactly the same symptom as a dirty slot, and cleaning the card is a two-minute job that does not require opening the console.

Isolating slot from card

Clean the card first, then test. The HuCard edge connector is on the underside of the card and it is easy to clean with a pencil eraser followed by isopropyl alcohol.

If more than one known-good card fails in the same slot, look at the slot's contacts under a loupe. The tell for a bent contact is a single pin that sits lower or further back than its neighbours, and it is usually the pin nearest the end that gets damaged when a card is inserted at an angle.

1. Clean one HuCard edge with a white pencil eraser, then wipe with isopropyl alcohol and let it dry.
2. Test the console with that card and with a second known-good card.
3. Look into the slot with a loupe and check each of the 38 contacts for height and alignment.
4. Check for a cracked joint where the slot's pins meet the board by flexing the board gently while the console is running.
5. Check for corrosion or green residue in the slot, which points at storage in a damp place.

Cleaning and restoring tension

Clean the slot with a thin card wrapped in a lint-free cloth soaked in isopropyl alcohol. The standard trick is to cut a strip of stiff card to the width of a HuCard, wrap it in cloth, insert and withdraw it several times, then repeat with a clean strip. Never use anything abrasive inside the slot; the contacts are thin and plated.

For lost tension, use a fine needle to bend a contact very slightly back toward its original position. Work with the board out and under a loupe; the movement needed is a fraction of a millimetre, and contacts break if pushed further than that.

1. Cut a strip of stiff card to HuCard width, wrap it in lint-free cloth and soak it in isopropyl alcohol.
2. Insert and withdraw the strip eight to ten times, then repeat with a fresh clean strip.
3. Allow the slot to dry completely before inserting a card, since alcohol left inside will attract dust.
4. For a low contact, bend it back a fraction of a millimetre with a fine needle under a loupe.
5. Re-solder any cracked joints between the slot pins and the board.
6. Test with three different cards before closing the shell.