At 10:41 PM 9/4/2006, Vitaliy wrote: >Hi List, > >I'm working on a test fixture that uses a small PCB that would plug into a >28-pin DIP socket (for use by the QA people). The problem is, if I use >standard 0.1" header pins, they deform the solder tail pins and I'm afraid >that they won't make good contact with the real chip's pins. > >Any ideas where I can find pins with the correct form factor? Another socket? We use Amp Diplomate sockets for most of our socketed stuff - anywhere where a socket is required (or useful) and where the socket itself does not need to be machined pin. I've successfully used one Diplomate socket to plug into another for test purposes. I simply tinned the wire leads, stuck them into the top of the test socket, then soldered them in place. A piece of lacing cord (the flat, waxed cord that looks like overgrown dental floss) tied lengthwise around the socket holds the wires in place. This whole assembly just plugs into the target socket on the board. In your case, I'd just use standard 0.025" square pins coming out of the bottom of your test PCB, then plug a sacrificial socket onto those pins. The solder tails on the sacrificial socket are what plugs into your target socket. Use lacing cord to hold the sacrificial socket to the test PCB so that it doesn't get lost or forgotten. The advantage is that the socket solder tails are thinner than IC leads - that means they won't damage the target socket. Works very well when the target socket is brand new. May not work as well if an IC has already been in the socket. Otherwise, look to using ribbon cable header plugs. Weird pin offset needed on the test PCB (0.05") and you'll want to plug the header plug into a machined pin socket before soldering it to your test PCB - the plastic has a fairly low melting point and the pins move around while being soldered unless they are held in position. A machined-pin socket is best here because it locates / holds the pins more accurately. I've successfully used both techniques for years now. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 22 years of Engineering Innovation (1984 - 2006) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist