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Cmherndon79

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About Cmherndon79

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  1. Solved: Everything is still running great after swapping out the oscillator crystal. I played about a dozen games and everything was consistent, with no color drift. I didn't see any issues before playing nor after.
  2. So... I had an Atari 400 computer come across my bench a few weeks back. I had a similar issue, where the screen would flip between black and white and color. Cleaned out the variable resistor and it persisted. I found a post on here from a few years ago, someone having the same issue and they swapped the crystal oscillator C010177 to correct the issue. I pulled that part off a VCS board I had for parts and installed it in the 400 and it solved my issue of the color cycling in and out. It occurred to me that I had not tried this on that 7800, so I looked at the crystal on the 7800 and it has a different Atari PN of C024912 and I found it for sale at Best Electronics for $5. The frequency though was also printed on the crystal of 14.31818, so I instead ordered 10 new from Mouser Electronics for less than $5. I swapped that out at 15:00 and it is now 19:11 and I haven't observed any color shifts. Perhaps this was the problem. I also found this, though I don't know how authoritative it is: http://7800.8bitdev.org/index.php/Atari_7800_Color_Documentation "Consistency Issues There are a number of factors that result in inconsistency between the palettes of 7800 consoles: Each 7800 console has a tunable resistor inside, which is used to modify the color signal frequency period. On any given console this resistor may be adjusted a number of different ways, with at least 2 published historic standards in play - one with hues ~25.7 degrees apart, and another with hues ~26.7 degrees apart. As a 7800 console warms up, so do the components that produce the color signal frequency period, while the colorburst frequency remains constant, so the distance between the various hues in the palette stretch out. When cold, the console's hue values have ~24.7 degrees of separation, and as the console warms up, up to ~27.7 degrees of separation can be seen between the hues. The separation is cumulative, and so is more pronounced with higher hue values; the $Ex hue can shift from being green through yellow/brown, and $Fx can shift from an initial greenish-yellow/brown through to a reddish yellow/brown. The majority of this shifting will happen in the first 20 minutes of console operation, though some additional shifting can be seen hours later. The NTSC and PAL standards don't consistently display the same colors from TV to TV, and almost all TVs allow the viewer to tune colors to their liking. The largest factor in these consistency issues is typically the warm-up issue. Since the latter hues shift more than the earlier ones, a 7800 game designer should generally avoid the last 2 $Ex and $Fx hues for critical items that need faithful color. e.g. one may wish to avoid using $Ex for green grass, or $Fx for for gold coins. The warm-up effect can be seen in commercial 7800 title Choplifter, where the ground utilizes a $E8 color value, and consequently shifts from green to yellow-brown."
  3. More updates: Cut one end of the diode and resistors and measured/tested those and they're in spec. Soldered those back down. Hit the SMS cart slot portion with WD40 contact cleaner, and then used a credit card wrapped in an old sheet to scrub the contacts. Followed up with 99% isopropyl and the same CC and sheet. Then installed a cartridge and removed 5 times. No change. Pulled out a few more cartridges to test. I found that Outrun, Alien 3 and Space Harrier will boot at least 1/4 of time, some nearly every time. Found the Alien Syndrome will never boot, just like Shinobi. Went back and did more extensive power testing on Spy vs. Spy on the Sega Card and I found that it also won't boot up perhaps one out of every 10 attempts.
  4. Figured while I had the thing disassembled already, I'd go ahead and swap out the 2 47uF and 1uF electrolytic caps. No change however.
  5. Recently got a console lot in, with everything advertised as "not working". One of the items in that lot was a Sega Genesis Power Base Converter. Thought it odd this wouldn't work at all, as the Genesis has the hardware built in for SMS support. Inspected the cart connectors and cleaned them, no issues there. Installed the converter and tried Shinobi and I indeed got a black screen. I know the cart works, as that lot also came with an SMS that i fixed by replacing the 7805 voltage regulator and used that cart to burn in the system after. Tried reseating the cart multiple times, but no change in behavior. Screen is always black when powered on. Next, I removed the Shinobi cart and I tried a Sega Card, Spy vs. Spy, which I'd also just used on that SMS I repaired and it worked fine in the Power Base Converter. Removed the Sega Card and tried the cartridge a few more times, but always black screen. So, it seems to be fine with a Sega Card, but not with a cartridge. Opened it up and not a lot going on inside. No visible damage. Not much going on inside either, got a few electrolytic caps, that I haven't tried replacing yet and a Sega chip, 315-5342 that i can't find much information about. Anyone ever run across something like this? Thanks! Edit: Other information: This is a Model 1 non-TMSS Genesis the Power Base Converter was tested on.
  6. I think that is a slick way of doing it @Dopy25 ! Congrats on the completion! I've used a washer like that on a Genesis someone wanted me to installed a S-Video port where the RF modulator had been. I had to dig around the parts bin at an Ace hardware to find potential matches, before I found a black nylon one.
  7. Awesome @soon! I've got a half dozen TIAs that I've pulled from systems due to various audio issues. Haven't run across one that starts out working and then stops yet. Most have one channel missing and I know I've got one that introduces an audible him and another that has the 2 channels with their timing off, which makes for some entertaining audio.
  8. Looks like a pretty reasonable solution, assuming the height dimensions work out. Probably will, just eyeballing it.
  9. Fairly certain all that snow on the screen is a not optimal RF issue, either with the cabling the onboard RF modulator. Some of the Woody/Vader 4-switchers have under-rated caps that cause snow, but nothing in the severity of what you're seeing. I'm pretty sure if you convert it it will clear up the signal over composite. Also, another thing you might want to consider if you do decide to convert it to composite: The Jr. cases are very fragile in comparison to earlier models. You've got to be extra careful if you drill into a Jr case. When I do drill into them to install jacks, I move up from 1/8th to 1/4 one size at a time. I prefer to stick to dedicated RCA cables tied down and running from the rear from where the RCA RF port was prior.
  10. Well that's an encouraging sign there @Dopy25 . The suggested above is good advice if you want to keep playing with RF out. Personally, now that you've verified it works, I'd just convert it to RF output, as it seems like you've got the skills and tools. You can purchase a kit with a PCB, the needed transistor and resistors and RCA jacks for $10 shipped off eBay.
  11. Hi @kalgran You've got quite a lot going on there. When troubleshooting stuff, it is always best to change one thing at a time, at least when possible and check the result of your change. On your second post, it isn't very probable that you've got 2 6507 CPUs with the same exact problem. Since the Vader board was working prior to the composite mod, I think it would be best if you could put the original RIOT, CPU and TIA back in and take a picture of your board as it currently is and work from there. Possible just a small change could get it back up and running. Also, do you have a multimeter, so that you can check voltages, etc?
  12. Just happened to be doing one of those UAV mods tonight. Looks like this once done. RF is left and can still be used.
  13. If you've swapped out all of those components from the Console5 kit and from the photos, it appears you have and tried new RCA cables, tried different or checked the RCA to coax or coax/switchbox/rca connections and still have problems with RF, yeah, it's probably a bad RF modulator. I've got over 100 RF modulators I've pulled off boards when converting them to composite. If you want one I can send a pair (just in case) for the cost of shipping. DM me if you're interested. If you want to convert it to support composite (with S-Video available as well) you can install the UAV mod instead of the more inexpensive composite mod made up of a transistor and a pair of resistors that has you pull the RF modulator from the board. UAV mod just has you solder a socket on top of that 4050 hex buffer on the board draw in +5v and color off the board to the UAV, leaving the RF as is.
  14. Try channel 2 as well. The RF modulator on Atari 2600s uses 2 or 3 vs 3 or 4 like many other systems. You might have just knocked the switch into the channel 2 position when you were reworking the board.
  15. Hi @soon Always interesting to see different ways of doing things. I've bought some C64 stuff from The Future Was 8 Bit. Back when I started doing Atari refurbs and mods, I used this as a guide: https://vintagegamingandmore.com/installation-guide-6-switch/ . But yeah, looking at the schematics it is coming right off the TIA. The component locations are different on the NTSC version, but the location numbers are the same, so I ran a test on a Light Sixer I had here that I've been meaning to look at due to a hum in the audio (it was a TIA problem, swapped and it sounds normal now). I removed R209 and C206 and C207, put in Frogger about 20 minutes ago and the sound is working fine still. Being there isn't much there, you're getting audio for the first minute of use, thinking you might have a TIA issue.
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