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commodorejohn
February 18th, 2014, 02:04 PM
It isn't exactly a vintage computer, but I've got a Proteus MPS keyboard I'm trying to get working. The short story is that, while I was removing the soldered-in backup battery for the patch/settings memory, the little ring of contact metal on the hole for the battery's positive terminal came out with the post. Luckily, the board uses a standard DS1210 for powering the RAM, so it should be a simple matter to solder the new battery's positive lead directly to the VBAT1 line on the chip instead of into the hole. However, it's an SO-16 version of the chip rather than a DIP-8, and I've never worked even indirectly with surface-mount soldering before. SO-size leads are still pretty manageable as compared to newer SMT form factors, but I'm just trying to plan my approach here before I break out the soldering iron. The datasheet shows that the leads on either side of VBAT1 (pin 4) are not connected - am I correct in assuming that they're simply not connected to the die at all? If that's the case, then I don't need to sweat it if a little solder bridges the gap or something...can anyone give me some advice on this?

Chuck(G)
February 18th, 2014, 03:00 PM
In old databooks, you'd sometimes see "IC" or "Do not use" on the pinout chart. "NC" usually means exactly that--no connection to anything. If you want to do an "almost perfect" repair job, there are circuit board eyelet kits, but they're pretty pricey ($200+).

commodorejohn
February 18th, 2014, 03:04 PM
Okay, good to know. I'm not going to bother with a $200 repair, I got the keyboard itself for half that! I'll try soldering to the VBAT1 lead; guess I'll just go carefully and break out the X-Acto knife if the solder gets over to one of the other leads...

Chuck(G)
February 18th, 2014, 03:22 PM
Got a "permanent" fine-tip "magic marker"? Use that to paint the leads that you don't want to solder to. Clean up with alcohol.

commodorejohn
February 18th, 2014, 04:22 PM
Well, that's simple. Thanks for the tip!