{"id":171,"date":"2015-09-14T05:12:25","date_gmt":"2015-09-14T01:12:25","guid":{"rendered":"http:\/\/www.jrtwine.com\/blog\/?p=171"},"modified":"2015-09-14T05:18:24","modified_gmt":"2015-09-14T01:18:24","slug":"bringing-joust-back-to-life","status":"publish","type":"post","link":"https:\/\/jrtwine.com\/blog\/bringing-joust-back-to-life\/","title":{"rendered":"Bringing Joust Back to Life"},"content":{"rendered":"

So it came to pass that I ended up with three cabinets for $100 each. \u00a0A Great Golf in a Midway cabaret, some Toaplan run-n-gun in a Taito Qix cabinet, and… A Joust(!) in its original cabinet.<\/p>\n

I agreed to purchase all three sight-unseen<\/em>. \u00a0When I get them all home, the golf game worked except for a rolling screen, the run-n-gun has an board issue where some sprites are being displayed at the wrong horizontal locations, and the Joust?<\/p>\n

Well, the Joust was dead<\/strong><\/em><\/span>. \u00a0Simple static video (monitor needs a cap kit, too), watchdog barking, no response to \u00a0inputs, nothing on the LED on the ROM board.<\/p>\n

\"Image-She's
She’s dead, Jim!<\/figcaption><\/figure>\n

Power cycling sometimes gives me a different color screen.<\/p>\n

\"Image
She’s still dead, Jim!<\/figcaption><\/figure>\n

Power voltages were where there should be but ripple was high. \u00a0Recapped power board. \u00a0Both voltages and ripple are good now, but board still dead, same screen as above.<\/p>\n

Replaced CPU – nothing. \u00a0CPU’s address and data lines look like they are trying to do something, so I go through the SOP of reseating everything. \u00a0Noticed some RAMs were getting hotter than others (some were really fricken hot<\/strong><\/em>) and some had floating pins that sometimes saw activity when pressed on. \u00a0Pulled a few RAMs and noticed some nasty stuff on some pins and on sockets. \u00a0Decide to replace all 27(!) sockets on the CPU board which turned out to be a major PITFA!<\/p>\n

The PITFA part was not the clipping and desoldering of each individual pin(!), it was that it appears that Williams boards are allergic to me! \u00a0I must have pulled more traces and pads on this board than all other boards I have touched in my life! All in all, I had to repair no fewer than 6\u00a0pads and 4\u00a0traces on this one board alone. \u00a0While I was there, I also did the lithium battery mod for the CMOS memory.<\/p>\n\n\n\n
\"0818151529a\"<\/td>\n\"0818151530\"<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

(After removing all sockets I took the time to wash the board with a little soap and a nylon brush, followed by a distilled water rinse and a little time in a warm oven, because of this brownish crud that was on it and under some sockets.)<\/p>\n

Anyway, after that 3+ evenings of work I still had a dead board, but this time I has a little more activity on the screen:<\/p>\n