+DrVenkman Posted June 13, 2015 Share Posted June 13, 2015 So I have a 4-Switch Woody I got for a song on eBay two weeks ago ($15 SHIPPED!) Externally and internally, it's clean as whistle - it's either been completely cleaned and restored, or it's been sitting in a closet for decades. Seriously, it's almost pristine other than a missing serial number sticker. The problem is that the difficulty switches are fubar'd. Player 1 is seemingly stuck in "A", player 2 is stuck in "B" (verified with a two-player game of Space Invaders). I sprayed into both switches with electrical contact cleaner and then cycled them several times, touched up both sets of contacts with the soldering iron, and visually inspected all the traces. No difference - moving the switches doesn't change anything. Everything else seems to work great - games play normally, the other switches all work smoothly and do what they're supposed to. Before I go track down a replacement 6532 RIOT chip, does anyone have any suggestions? Thanks! Quote Link to comment Share on other sites More sharing options...
Nutsy Doodleheimer Posted June 13, 2015 Share Posted June 13, 2015 Could be a slight crack at the solder joint. That would be my guess. 1 Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted June 13, 2015 Author Share Posted June 13, 2015 Well, as I said above, I've already touched up the contacts on both switches and inspected the traces - they all look fine. Is it possible to take those plastic switches apart to look inside them, or is the standard practice just to squirt alcohol or something inside and cycle them back and forth (as I've also done)? Quote Link to comment Share on other sites More sharing options...
tpugmire Posted June 13, 2015 Share Posted June 13, 2015 You can take them apart. It's not exactly easy, but it can be done. Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted June 13, 2015 Author Share Posted June 13, 2015 I made another go at things again today. I cleaned the switches again, and this time I even entirely desoldered and then reattached one of the difficulty switches just to see if there was a cold solder joint. I removed and reseated all three IC's and then tried again. No difference whatsoever. Player 1 is still stuck on A, Player 2 on B. Whatever is going on is common to them both. Time to find a new RIOT chip I guess. Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted June 20, 2015 Author Share Posted June 20, 2015 I decided not to wait on my literal slow boat from China to get here in a few weeks with my new 6532 chips and I swapped one in from a working 1050 drive. No change at all. This is a real head-scratcher. I cleaned the switches again (sprayed contact cleaner into them and worked them repeatedly), checked the solder joints and traces ... I can't find a damn thing wrong with them except they just don't seem to work. If they were physically failed or clogged with dirt, you'd think they'd both be giving me open circuits and not carrying current. But since they Player 1 gives me nothing but A and Player 2 gives me nothing but B no matter the position of the physical switch, I have no idea what's going on. Is there any other common point of failure besides the RIOT chip? Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted July 3, 2015 Author Share Posted July 3, 2015 Follow up! As I noted above a couple weeks ago, I swapped a 6532 out of a working Atari disk drive, but still had no change. That worried me, as the disk drive continued to function as did the VCS, but still no difficulty switch control. Damn. That would seem to rule out the RIOT chip as being the culprit right? Just for giggles I tried again today. First I opened up the switches to spray contact cleaner into the guts directly and worked them back and forth vigorously for several minutes, but AGAIN there was no change. With nothing to lose I decided to try my new-old-stock replacement chips. The first one I installed gave nothing but a screwy screen of squiggly lines with Space Invaders, and blank screens or vertical bars of color with several others. Looked like my chips were duds. Feeling a bit at a loss, I tried a second chip out of that batch. I powered up the VCS and whaddaya know? This one actually powered up correctly. Space Invaders began dutifully marching across the screen. So at least not ALL the chips are defective. Of course, I've already tried a known-working chip from the disk drive but that didn't correct the problem with the difficulty switches. So without much hope I flipped the Player 1 difficulty switch. Holy shit!!! The missile base at the bottom changed from wide to narrow and back with each change of the switch! I selected a two player game and then tried and the Player 2 switch works again too! So I've discovered something interesting, at least. Perhaps several somethings. First, RIOT chips can fail selectively; both those original chips seem to work just fine in that 1050 disk drive, as they do in the VCS, yet they both fail to register the difficulty switch settings when installed in the VCS. I have to wonder if those signal lines are simply not used in a 1050 drive? I ought to dig out some technical docs and see. The second thing I learned was it pays to be persistent when screwing around with old electronics! The third thing I learned is that Atari re-branded OEM chips (which I knew) but sometimes didn't do a good job removing the original markings. The chip I pulled out of the 1050 to try has the Atari COxxxxx part number on the top, along with an week 28, 1982 date code. Yet underneath the chip, the part number is stamped as well, but with a week 38, 1981 date code. So I guess that top date is when the manufacturer (Rockwell) pulled it out of storage and prepared it for shipment to Atari, or something like that. Anyway, this old 4-Switch Woody is now fully functional again and I'm feeling quite pleased about that! 1 Quote Link to comment Share on other sites More sharing options...
Nutsy Doodleheimer Posted July 3, 2015 Share Posted July 3, 2015 Glad to see you got your difficulty switch working again!! It sure gave you a difficult time pun intended. I'm glad everything worked out. I thought it could have been a soldering issue or needed to be reflowed so a chip all along. Quote Link to comment Share on other sites More sharing options...
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