Re: [N8VEM: 18401] Machine Tool IC Sockets - What am I doing wrong?

[John Coffman]

Andrew, I have used the machine-tool sockets for major components on a couple of boards; e.g., CPU chips, UPD7220 (ceramic), &c.  Yes, chips in those sockets are more difficult to extract. Before using an extraction tool, or even without an extraction tool, a thin-bladed screwdriver is probably the best.  You should ease the components up higher without bending any pins.  It practically take 2 such screwdrivers, because after one end is raised, unless you prevent it from being see-sawed down when you pry up the other end, you need to support the chip at the raised end. Be gentle.  Go easy.  They are fine sockets. --John On 07/09/2014 10:42 AM, Andrew Bingham wrote: When I built my Zeta and ParPortProp boards, I used the "double wipe" IC sockets.  After reading up a bit more on the whole build process I saw a lot of reference to using "machine tool" sockets instead due to being more reliable.  So for the SBC-188 and my SBC6120 (non-N8VEM CMOS PDP-8 board) I used gold coated machine tool sockets.  I figure I will only ever build these boards once so I want the nicest product possible. (especially the SBC6120 which is no longer available at all) I made a little jig with some ESD-packaging to allow me to more easily bend the pins on the ICs to just the right angle to fit into the sockets exactly. However - it seems like it is *almost impossible* to remove a fully seated IC from a machine tool socket.  I literally bent an extraction tool trying to get a 40-pin 8255 out, and ended up having to insert some tools carefully under the IC from each end and "pry" it up from below to get it out. This is somewhat concerning as I go into some of my other builds - the intent of the sockets is that if I have a bum part, or I need to switch to a different logic series on a '74 chip for some reason, or say I want to take the HD6120 out of my SBC6120 board to go into a hypothetical ECB HD6120 board - the ICs will actually come out of the sockets without breaking something! Am I doing something wrong?  Or are machine tool sockets supposed to be that much of a PITA to get chips back out of?  (Which I would understand since they are used in MIL-STD hardware subject to vibration environments). Andrew B -- You received this message because you are subscribed to the Google Groups "N8VEM" group. To unsubscribe from this group and stop receiving emails from it, send an email to n8vem+unsubscr...@googlegroups.com. To post to this group, send email to n8vem@googlegroups.com. Visit this group at http://groups.google.com/group/n8vem. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "N8VEM" group. To unsubscribe from this group and stop receiving emails from it, send an email to n8vem+unsubscr...@googlegroups.com. To post to this group, send email to n8vem@googlegroups.com. Visit this group at http://groups.google.com/group/n8vem. For more options, visit https://groups.google.com/d/optout.