That I don;t know... No. The PROM went with the printhead and that's it... I nthe 12/7 the PROM (known as the PinFire Compensator) is one one of the lgoic boards inside. There's a label stuch on it with a serial number that matches the serial number of the printhead. If I remewmebr the service manaual correctly, you got a new PROM with a new printhead and replaced the one in the machine with it. In the 700, the PinFire Compensator PROM is on a little PCB on the back of the printhead itself. The printhead assembly is easy to change, IIRC it plugs into an adge connector in the carriage and is reetained by a clip mechanism. I assume you bought the complete assembly as a spare part, including the PROM. Strangely, at least in my 700, this PROM is socketed (as are all the other PROMs, etc in both the 12/7 and 700) so it would be easy to replace separately. Made it easy to take a backup of it too. FWIW I don't think it's as crticial as they made out... When I got my 700, the brazing betweenm one fo the printhead armatures and its pin had failed. I got a tecnician where I was workign to braze it for me (he had access to a breazing hearth, etc). Until I had it done, I 'borrowed' a pin asembly from my 12/7 [1]. I could detect no degrading of the output, even though I obviosuly didn't try to reprogram the PinFire Compensator. [1] In many ways the 12/7 is the better machine, so I did want to keep that eotking. However, the 700 bas both RS232 and Centronics interfaces as standard (the 12/7 has oen or the otehr, mine has RS232), and I had a better collection of forts for the 700. And anyway I wanted to try it out. -tony