My thanks to all who offered assistance on my issues with the 'tech special' Trak Systems 8820 GPS station clock. The unit was successfully repaired, and has been working for nearly a full week without any further signs of problems. For the curious: The problem turned out to be that one of the firmware EPROMs developed a broken internal bond wire on the output-enable lead. This caused the chip to appear completely blank to both the Unisite programmer and the Trak device. My contact at Trak was kind enough to send over image files to do a fresh set of EPROMs. The only other adjustment I found myself making was a fine-tune alignment on the 10MHz ovenized oscillator, to bring its center frequency back to a point where the reference circuitry could discipline it down to full accuracy. That was also accomplished without incident, and I now have a second Stratum-1 level clock and frequency standard for my lab. The moral of the story: EPROMs can fail too! Just not in the way we might expect. ;-) Keep the peace(es). -=-=-=-=-=-=-=-=-=-=-=- 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?"