I have further explored my 7081 including taking some pictures of the boards, archiving the EPROM's, and comparing them to the images posted by David Partridge. Of note, I found a second battery. One is B401, a VARTA, 3 wire, 3.6V, 110mAH, Ni-MH, 3/V110HT, mounted on the Earthy CPU Board that measures 4.008 VDC, and the second is B1, a Sonnenschein, 2 wire, 3.6 V, 1/2 AA, INORGANIC LITHIUM, SL-150, mounted on the Earthy Logic Board that measures 3.678 VDC and has what appears to be a date code of 03/89. I am not sure what purpose this battery has. I would appreciate any thoughts anyone has along with any recommendations about replacing it. The meter seems to be working just fine. Stan advertised it as having a 'new battery' and I suspect it was the VARTA that was replaced relatively recently. I archived all the EPROM's and compared them to the images posted by David Partridge. All agree with his images except IC803. All were Mitsubishi M5L2764K-2's. I have not explored what the differences are between the image of my IC803 and David's IC803. I would be happy to send the images to anyone that wants them. I also 'DUMP'ed the Cal Constants and retrieved the Zener current token value, once I solved my DB25 to DB9 adapter issue, using HyperTerminal. When connected, and you hit 'initialise' (British spelling?) on the front panel, the computer displays 'VDD BSW 8 De 86 8 50'. I do not know what this means but I suspect it reflects the date of the firmware. I would appreciate any thoughts. Joe