wb8foz@mthvax.cs.miami.edu (David Lesher) (12/03/90)
>While adding chips to my PC100B Memory Expansion board recently I bent >the tan 10 pin resister pac near the middle of the board. >I want to replace the resister pac that I believe is faulty but I am >unable to find a value for it. I can't picture this, as it's been a few years since I've seen one. But most dip resistor packs come in one of 2 forms: 1 lead common, 15 resistors 8 pairs of resistors across the package, so to speak. (It sounds as if this may be a SIP pack, however.) If you have access to another board, you could use a DVM in low-ohms mode to trace out the pack. Or, you could measure the bad pack, guessing that only SOME of the 'r's are damaged. Extrapolate from there. Another approach would be to call Allen Bradley or another resistor pack mfgr. (Not a dealer, the factory!) Maybe they can identify it. -- A host is a host from coast to coast.....wb8foz@mthvax.cs.miami.edu & no one will talk to a host that's close............(305) 255-RTFM Unless the host (that isn't close)......................pob 570-335 is busy, hung or dead....................................33257-0335
fzsitvay@techbook.com (Frank Zsitvay) (12/04/90)
In a previous article, the author's name unknown at this moment, someone said: >>While adding chips to my PC100B Memory Expansion board recently I bent >>the tan 10 pin resister pac near the middle of the board. > >>I want to replace the resister pac that I believe is faulty but I am >>unable to find a value for it. if this is a 9 pin SIP resistor, remove the remnents of the old one from the board, and make sure you end up with 9 clean holes. you'll want to install a 9 pin SIP socket (radio shack carries a sip socket, just trim off the unneeded positions with diagonal cutters or a razor saw. a butcher's cleaver can be used as a last resort.) then, find a 22k resistor pack (usually, pin one is common, and there are eight resistors connected between it and the individual pins.) and insert it into the socket. the reason why you should use a socket is because, although 22k ohms is common for this application (pull-up or pull-down resistors with LS TTL glue) it may not be the correct value, and it would be easier to pull out the resistor pack and insert another one than to solder one in, and have to rip it out if it doesn't work. it is best to err on the high side of resistance. i don't think you could do any damage with a low resistance, but you may not want to take that chance. you'll know when it works, as you'll get no errors during the memory test. digi-key carriers the stuff you need if you can't find it anywhere else... -- fzsitvay@techbook.COM - but don't quote me on that.... American Oil Company motto - Bend over, We'll pump!!!