Bill WB6FEH's Hints for Cleaning HT220 Battery Contacts

Corrosion of the contacts inside the radio can be a real problem, especially if the battery has been overcharged inside the radio. The corrosion is mainly caused by out-gassed electrolyte from the ni-cd pack.

This procedure is best done with the front cover removed from the radio. Carefully remove it, following the steps from the manual. Be sure to make note of the locations on the PC board where the B+ (red), common (black), mic (white), and spkr (blue) wires connect, so these wires can be re-connected to the right terminals.

Supplies Needed:

Old, soft toothbrush
Small, stainless steel parts brush (available at hardware and welding supply stores)
OR, Dremel moto-tool with miniature wire brush tip
1/4" straight-blade screwdriver, with a DULL edge
Isopropyl alcohol and water mix (rubbing alcohol)
Swabs, cotton
Typewriter eraser (pencil type)
Masking tape
Safety glasses

First, use the toothbrush to remove any loose, white deposits. Mask off the plastic areas around the metal contacts. Lay the front cover face-down on an old terry towel. If there are heavy, solid deposits, CAREFULLY scrape with the dull screwdriver to remove them. The object is to remove the bulk of the corrosion, not remove the plating from the spring-brass contact!

Next, use the Dremel with fine-point wire brush tip (OR, the SS parts brush if you don't have a Dremel tool) to polish all contact surfaces. Use light pressure, and keep the tool moving. Once again, you want to remove corrosion, not the plating. Be sure the edges of the curved spring areas are cleaned, too. When this step is done, the metal should have a fairly bright, silvery appearance.

For the final polish, use the typewriter eraser (you can sharpen it with a pencil sharpener to the desired point) to polish all the metal areas with a circular motion. The fine abrasive in the typewriter eraser does the trick. The contacts should be shiny now, with all the silvery plating intact.

Finally, remove the masking tape and clean up the white powdery residue with cotton swabs and rubbing alcohol. The old toothbrush may be needed to get into crevices. CAUTION: use of straight IPA (isopropyl alcohol) may cause the plastic to "bloom", leaving a whitish appearance! Not pretty! Re-assemble the radio.

I have been able to restore a number of "lost-cause" front covers in this manner to near-new appearance. (HINT: I always charge batteries out of the radio and never store radios with batteries installed. This goes a long way toward preventing corrosion in the first place.) If you have any questions, feel free to contact me at

73 de WB6FEH

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