George, you're splitting hairs here. The chip that he's talking about is obviously the EPROM, I realize that some "chip" has to contain the volatile memory. Should we mention that it's a CMOS OTP PROM as well? 
My point was, and still is, that there is no damage to the module, and it can be reset to work with the original chip. Most people think of the "chip" as the PROM chip that contains the sound programming for the PS/1 module. Yes, I realize it takes a special chip to fix the deselect issue, again that is an option available to an MTH tech, as you well know.
Not really I am just being specific, we use chip pretty loosely on this board. You had corrected Sinc yet you really don't know what "chip" he was referring too.
Actually you don't have an MTH "chip" to correct a deselect. MTH has you order a new prom that over looks that memory location on the EEPROM. It is actually still set to deselect and if you reinstalled the old chip the engine would still be deselected.
I am the person who read through the old QSI documents and then extracted some hard to get information out of Art Boynton Deceased QSI tech). I found the memory locations that contain the ID information and then through trial and error found I could use a QSI chip to access those memory sections and reset them. At that point the old chip will still work.
MTH had specifically not wanted their version to have IDs, while QSI went forward with IDs.
Just some early engines that had PROMs with software that would look at the ID memory and read it, but would not let you select it. If the memory got the wrong data loaded during a shutdown on weak battery you wound up with a deselected engine with a chip that looks at that memory state and took action on it, but with no way to change it. Later MTH PROM had software that would not even read the memory segment. That is why the new chip works. So that is the full story on this specific PS-1 issue. 
G
