guest@amos.ling.ucsd.edu (Stranger in Town) (06/29/89)
Thanks to all who mailed me with help on replacing a surface mount chip. The hard drive seems to be working fine now. Here's what I did: Using an X-acto knife and a magnifying glass, I carefully cut the leads to the old chip. Downward strokes weren't working too well, so I tried coming up from underneath. This worked much better on all but the last lead. Since almost the entire chip was loose by the time I tried to cut the last one, I managed to separate the pad from the board. Fortunately, the pad wasn't part of the second layer and it was connected to a nearby larger pad which I could use later. A couple people suggested "dead-bugging," that is, lying a regular IC on its top, feet in the air, and soldering wires down to the pads. Space was too tight (not enough headroom) to do this, so I used an uglier but just as functional solution. I cut fourteen 3" lengths of wirewrap wire and stripped a small (1/8") from each end. After cleaning up the pad a bit (removing the leftover legs and checking for excess solder), I quickly soldered each wire to a pad, either using the existing solder on the pad or placing a very small amount on the tip of the iron. The other ends I soldered to a DIP socket. I reassmbled the drive with the new socket sticking out the side. A regular chip was plugged in and the drive powered up. IT WORKED! I just saved myself about $280. The iron I used was Radio Shack's modular type (the kind where the handle, heat element, and tips must be bought separately) and is ungrounded. It was running 23 watts and I bought the special surface mount soldering tips. Now, if I can just get the OMTI 3527 SCSI card working.... Anybody know if a Tandon TM 364 is RLL compatible? Barry Brown 6600hgns@ucsbuxb.bitnet <== note the new address