View Full Version : Rust and Circuit Boards


AUdubon5425
11-14-2010, 03:23 PM
I have a little '71 Motorola 12" portable I posted about cleaning the chassis earlier. Everything is mounted on a single board. It must have been rained in - all the metal shields and control bodies are rusty, and some pins actually show rust on the underside of the board. I'm not terribly committed to restoring this one - what's the consensus on rust and circuit boards? Can the traces be damaged by rusty leads?

Findm-Keepm
11-14-2010, 07:45 PM
That's CLEAN compared to a lot of the seaside hotel sets I've seen. Mix up a 90/10 mixture of Isopropyl and acetone and give it a good underside rinse. Then take a magnifying glass and inspect the heck out of the underside, cleaning up the solder connections with some solder.

Motorola used 63/37 solder almost exclusively (same solder in their military lines), giving a lower melting point. I've seen a Motorola Annual report and that was one of their "cost saving measures" in the 60's - aligning all of their manufacturing lines to a common 63/37 solder, a common wire vendor (Belden, IIRC) and a common hardware manufacturer (Richco).

Rain and water are easy contaminants. Mouse piss, CocaCola, and liquid fertilizers (watering the plants above the TV today, Mrs. Murphy?) are among the worse. Then there's the yellow glue used by Toshiba and others, a real PITA.

I remember those Motorolas had stiff turning tuners, or maybe undersized knobs. A friend's little sister had one, and she left it on one channel rather than having to nearly break her little fingers trying to change channels.

Cheers,

Findm-Keepm
11-18-2010, 11:37 AM
What's the model number? I just came across my old Motorola Lit looking for another manual.. I have '70-73 stuff. If I have it, it's yours for postage.

Cheers,

AUdubon5425
11-18-2010, 07:35 PM
Model BP309HHT, Chassis C12TS465D01

Thanks Brian