Replacing 80C188 and 68HC11

Fellow Techies, I have a device (a GPS-referenced clock) that uses an Intel N80C188-16 microprocessor, in a 68-lead PLCC package. Odd as it may sound, I suspect this chip of being defective, and I've been attempting to locate a match for it so I can prove or disprove that theory. The original part is, of course, no longer manufactured as far as I can tell. Hunting around on the 'net turned up a couple of modern equivalents, one of which is an Intel TN80C188EA20. As near as I can tell, the only difference with this chip is that it can be clocked a bit faster (20MHz instead of 16), and that it has an extended operating temperature range. There are two other possible candidates available, though not in stock at the moment. Both are made by Intel. One is the N80C188XL20, and the other is the other is the TN80C188XL20. I know just enough about these chips to be wary of differences in prefix and suffix letters. With that in mind, I have two questions for the group. (1) Of the above replacements I've mentioned, which one is most likely to be a direct plug-in replacement for the suspect chip? (2) Failing that -- Does anyone happen to have a known-good N80C188-16 that they could be convinced to part with? In this same instrument is a Motorola MC68HC11A0FNC11W in a PLCC-52 package. I need to find a viable replacement for it as well. I've had a harder time tracking down possible replacements for it. The only ones I've come across so far, that are available without an enormous minimum purchase, are the MC68HC11E0CFN2, the MC68HC11E1CFN2, and the MC68HC11E1CFN3. Once again, I'm very leery of mixing/matching suffix codes due to lack of knowledge. I do know this much: The Motorola part is operating with an external EPROM, so the chip itself is ROMless. Assistance with this mess would be much appreciated. Thanks in advance. -=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner & Head Hardware Heavy, Blue Feather Technologies -- http://www.bluefeathertech.com kyrrin (at) bluefeathertech do/t c=o=m "If Salvador Dali had owned a computer, would it have been equipped with surreal ports?"