The first challenge was to remove all the parts from the PC board.  At some point some form of motor oil had be spilled on to the board.  This allowed all the dust and dirt to become some form of yuck coasting on the parts and the board. So the best option to restoring the Elf to its former clean and running state required all the part to be removed.

Parts like resistors, capacitors, diodes, IC sockets and switches where still readily available from parts suppliers. These parts where carefully cut off the board and discarded for later replacement.

The no longer manufactured parts like the original CDP1802 processor, the two 2101 RAMs, the 82S123 PROM and the two TIL311 HEX displays where very carefully removed, carefully cleaned, placed on anti-static foam and stored in a anti static storage box.  Like a antique diamond ring, these parts where locked away for safety.

The unsoldering of parts and removing the excess solder from all the holes was done slowly, with much thought and care.  Had to be careful not to damage the foil traces, component pads or platting in the holes. In the end one oops did occurred. The center lead of the RUN toggle switch (S13) was already damaged and the foil on the board was cracked and loose.  When the switch was unsoldered and removed, the plating in the hole came free with the removed switch. In addition about half inch of foil trace on the component side of the board close to the removed the switch also pulled up.  You can see the damage on the bare board picture and the patch on the high resolution picture of the restored board.

I had lost my original schematic for the revision 2.1 board I build back in 1977.  I ended up having to reverse engineering the above version from the original Quest Electronics printed circuit board dated 9-12-1977. 

After I had completed the project, I ran in to another 1802 collector who also had an original Quest Elf. He generously provided me with a scanned copy of the original Quest schematic shown bellow.

But there is something interesting missing.  On the board there are part locations for another voltage regulator and supporting parts.  I had never installed these parts on my original unit.  I tried to "best guess" what was intended to go there in my schematic.  Once I received the original Quest schematic I was surprised to find that it to did not have any indications as to what parts go in to these extra holes.

I am not sure if my guess is correct at all.  Again I still have not added these parts to my unit. I am still working on finding what these extra parts are and one I know I will update this web page and add them to my unit.

The final documentation step was the creation of a parts list for the Elf. I used both versions of the schematics and a on-line parts list I located to generate the following parts list.