bushnrvn Posted July 4, 2017 Share Posted July 4, 2017 (edited) I picked up an 800 XL and a handful of games a couple weeks ago. I've been having some trouble getting video out of it. Right now the composite line on the 5 pin DIN is showing a slightly less than black screen with a faint vertically scrolling gray bar. No audio, and game carts have the same output.Troubleshooting done so far: Tried several monitors including a 1702 - the luminance and chroma channels are putting out garbage. Cleaned motherboard. Reseated all ICs touched up a couple bad solder joints Note: I don't have another 800 XL to test with. A little bit of research has led me to the very likely possibility that the power supply is the culprit. While I keep looking for my multimeter (still unpacking from a move) I thought I'd ask for your input. Does this sound familiar to anyone? Edited July 4, 2017 by bushnrvn Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted July 4, 2017 Share Posted July 4, 2017 Need more info to troubleshoot properly. 1. What region are you in (NTSC, PAL, SECAM)? 2. Did you buy or build a cable yourself? 3. Have you tried RF to be sure it's actually booting up properly? For a start. We might have more questions depending on your answers. Quote Link to comment Share on other sites More sharing options...
bushnrvn Posted July 4, 2017 Author Share Posted July 4, 2017 1. NTSC 2. Its a store bought cable I use with my Commodore. It is pretty old but I know it works. 3. I don't have a modulator that will work with the Atari 800 XL - unless any old modulator will work? I've got some NES\Sega modulators. Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted July 4, 2017 Share Posted July 4, 2017 Okay, NTSC 800XL's don't have Chroma connected to the DIN jack. So you won't get Chroma/Luma video from the Atari monitor jack without performing a fairly simple mod. You'll have to use Composite. Also, it looks like the Atari and Commodore pinouts are not 100% identical but if your C64 cable is a standard 5-pin DIN, then if you use Composite it should work. Not sure why it's not off-hand. For connecting to RF, all you need is a cable with a standard RCA male plug to connect to the 800XL RF Out and either an old manual switchbox (NOT an NES powered switchbox) or better, an RCA-to-F-type Coax adapter. Something like this: https://www.amazon.com/uxcell-Straight-Connector-Coaxial-Adapter/dp/B00LUS30QM/ref=pd_lpo_vtph_23_lp_tr_t_3?_encoding=UTF8&psc=1&refRID=5NZ3P8SKQHHDX8NFZ2KB 2 Quote Link to comment Share on other sites More sharing options...
bushnrvn Posted July 5, 2017 Author Share Posted July 5, 2017 (edited) Thanks. Photo of the output is attached. This is accompanied by a constant buzz. Edited July 5, 2017 by bushnrvn Quote Link to comment Share on other sites More sharing options...
bushnrvn Posted July 5, 2017 Author Share Posted July 5, 2017 Yeah - more research lie telling me the "ingot" epoxy PSU is notoriously bad. Buzzing on the RF line ...fingers crossed that my unit isn't toast. Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted July 5, 2017 Share Posted July 5, 2017 Thanks. Photo of the output is attached. This is accompanied by a constant buzz. Yeah - more research lie telling me the "ingot" epoxy PSU is notoriously bad. Buzzing on the RF line ...fingers crossed that my unit isn't toast. Ugh. Yeah. Dig up that mulitmeter and test the ingot before you use it again. Assuming it's NOT fried the machine, get a different PSU pronto! In the meantime, how is that XL connected to the TV? You mentioned having NES and Genesis RF switchboxes. I don't *think* those will work but it's been a long time since I've even seen a non-Atari/non-mechanical switchbox. Quote Link to comment Share on other sites More sharing options...
bushnrvn Posted July 5, 2017 Author Share Posted July 5, 2017 Connected with the cable and adapter I use for my 2600. No switch box. Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted July 5, 2017 Share Posted July 5, 2017 Dumb question but have you tried channel 2 and/or working the channel select switch back and forth several times? The switches can get cruddy with age - working them a few times, especially if you spray them with electrical contact cleaner, can help if that's the problem. Now having said that, I'd be really concerned about that power supply. Quote Link to comment Share on other sites More sharing options...
bushnrvn Posted July 5, 2017 Author Share Posted July 5, 2017 I've already got another PSU en route. It'll be about a week but I'll do some testing and report back. Quote Link to comment Share on other sites More sharing options...
Bryan Posted July 5, 2017 Share Posted July 5, 2017 1. NTSC 2. Its a store bought cable I use with my Commodore. It is pretty old but I know it works. 3. I don't have a modulator that will work with the Atari 800 XL - unless any old modulator will work? I've got some NES\Sega modulators. Also, the monitor pinout is different from the C64 so you'll have to swap the RCA plugs around. Quote Link to comment Share on other sites More sharing options...
bushnrvn Posted July 8, 2017 Author Share Posted July 8, 2017 New PSU arrived today. Looks like that issue is resolved. Sadly, whether it was the original PSU or something else, the 800XL is in need of more diagnosis\repair. On power up, the screen may flash a sort of off-white or dark red, always ending on black.Time to start testing ICs. I don't have any replacements or another 800XL on hand, so this may be it for awhile. Quote Link to comment Share on other sites More sharing options...
Kyle22 Posted July 9, 2017 Share Posted July 9, 2017 (edited) If the screen changes, it means the OS is at least able to run long enough to init GTIA before it crashes. Try RAM chips. Edit: fix iPhone autocorrect error. Edited July 9, 2017 by Kyle22 Quote Link to comment Share on other sites More sharing options...
bushnrvn Posted July 9, 2017 Author Share Posted July 9, 2017 So I have left this thing running for about ten minutes - none of the RAM chips are hot, but the CPU and GTIA are a little warmer than the rest of the chips. My assumption is this is normal. I do see, however, that U26 and U27 have blackened pins. These are RAM demux chips, correct? Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted July 9, 2017 Share Posted July 9, 2017 So I have left this thing running for about ten minutes - none of the RAM chips are hot, but the CPU and GTIA are a little warmer than the rest of the chips. My assumption is this is normal. I do see, however, that U26 and U27 have blackened pins. These are RAM demux chips, correct? CPU and GTIA normally run warm. U26 and U27 are the 74LS158 discrete logic chips. Are they socketed on your board (some 800XL's have these socketed, some not). "Blackened" doesn't sound good - sounds like perhaps the machine got zapped by a failing power supply. On the other hand, it could just be age-related surface corrosion. Pics would help. What would help even more would be a logic probe reading on the outputs to see if they're active. And for that matter, a logic probe would let you see if the rest of the chips are acting normally. Quote Link to comment Share on other sites More sharing options...
bushnrvn Posted July 26, 2017 Author Share Posted July 26, 2017 I've replaced U26, U27, and U28 as well as the RAM. The colors vary on startup, but are most often a light shade of blue. Quote Link to comment Share on other sites More sharing options...
toddtmw Posted July 27, 2017 Share Posted July 27, 2017 Is it at least a soothing shade of blue? Maybe use it to help with meditation while you curse it out? Sorry, at this point, I have nothing helpful to add, so I'm trying to help with a (admittedly weak) attempt at humor. -Todd 1 Quote Link to comment Share on other sites More sharing options...
bushnrvn Posted July 30, 2017 Author Share Posted July 30, 2017 Yeah. It will be a few more weekends before I revisit this. Your humor was well received. Quote Link to comment Share on other sites More sharing options...
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