Altos ACS 8000-7 (8200) mainboard wanted / Shugart 4008 motor pulley

Long story, but.... I recently acquired an Altos ACS 8000-2 with an 8100-01 mainboard (which currently is not functioning). Acquired it on eBay where it was represented as an ACS-8000-7, along with an Altos 8000-7A 29MB hard disk (a Shugart 4008). The hard disk was fine, but the computer wasn't the one shown in the photo. (I arranged for a partial refund. At least the disk was the one in the photo. ;) ). I was wondering if anyone had an 8200 mainboard (the one with the logic for the hard disk on it) that they would be willing to sell at an affordable price? Also, I have a second Shugart 4008 hard disk, but it was configured for 50Hz - so the motor pulley is the wrong size. Anyone out there have a dead 4008 that they would be willing to have part with its motor pulley and belt (and get the 50Hz set in return)? (For example, I saw a posting on youtube with a wobbly platter set that probably is a good candidate... ;) ). Any tips on troubleshooting the mainboard on a double density Altos 8000 computer (mainboard 8100) would also be appreciated. I have already reseated the chips, polished the tarnish off some chips the apparently had silver-plated pins, etc., to no avail. Have dumped the ROM (2708). Next plan is to disassemble that, and slap a logic analyzer on "J2" which has all of the bus signals on it. Thanks in advance... JRJ