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Cmherndon79

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Everything posted by Cmherndon79

  1. Hi, Just wanted to say that I ran across this post after running into issues with the Gary Cromwell document. I actually did the work 3 times, the first two learning because of the way it outlines the steps results in a messy looking mod. I checked and verified all my connections on all three attempts and could never get it to boot. I was able to get the @ClausB mod working on the first attempt. Not sure if there are revision differences or something else that cause issues with the Cromwell implementation, but it just didn't work for me. Thanks for posting the alternative @ClausB!
  2. 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.
  3. 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."
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. Looks like a pretty reasonable solution, assuming the height dimensions work out. Probably will, just eyeballing it.
  10. 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.
  11. 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.
  12. 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?
  13. Just happened to be doing one of those UAV mods tonight. Looks like this once done. RF is left and can still be used.
  14. 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.
  15. 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.
  16. 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.
  17. Huh. Interesting. I've done a lot of AV mods, but never pulled audio from the TIA chip directly. For the 6 switchers I always remove Q202 and pull audio from the empty hole connected to C210, appears to be the same on the PAL version as the NTSC board.
  18. Yeah, there are 2 820 pF polystyrene at C206 and C207 that handle the audio and these tend to fail in the way you're describing. When I work on these I always proactively replace them with new MLCC caps. Info: https://console5.com/wiki/Atari_2600#Styrene_Capacitors
  19. Yeah, it's a little finicky getting it in there just right if you've not done it before or a lot. Usually I'll put the board back into the aluminum sarcophagus and gently wiggle it a bit side to side while putting it in, with a gentle non-forceful pressure. Before screwing everything back together, hold the board in place (make sure you're grounded first) and try putting in a cartridge and see if it's aligned. After confirming it's aligned, then put in the 2 screws to secure the board onto the shielding, then put the aluminum backing back on, check to see if there is a gap on the top end, between the 2 pieces and if there is you're going to have to readjust it again. If you see that gap, if you were to secure the two pieces into place, it ends up bending the board slightly and causes the cartridge connector to become misaligned.
  20. @CaptainCanadian I third Console5.com, they have amazing selection and customer service. I know that if I order from Console5, I'm getting quality and legitimate parts. I've probably done 50 orders with them. Console5 also has a great tech wiki and primer section for beginners on repair (as well as a link to a pinball related one that applies to a lot of classic consoles as well) For standard components like electrolytic capacitors and such, for systems that I do a lot of work on I buy a lot from Mouser Electronics. However, if you're just wanting to do a system here and there, you may as well use Console5, as their prices are good enough and you don't need to order qty's of 100 to get the price you're looking for. If I need more obscure parts like old DRAM I use Unicorn electronics. Hope that helps and happy repairing!
  21. @vitoco No, unfortunately it won't fix the problem you're having with the color accuracy. This fix improves color saturation. Per <Start> Atari Tech Tip #4 11/17/1982. Subject: Blanking Resistor. Description: Some 2600A PCBs have an 820 ohm 1/4 W 5% resistor installed on the solder side (bottom). The resistor is located between pins 6 and 9 of A201 (TIA) and improves the color reproduction of the unit. The addition will result in improved color saturation. Rev. 16 PCBs and above will have the resistor incorporated into their design. <End> (Removed bits about Atari PNs for the resistor and expenses of the part, no longer relevant) I've also seen many RIOT chips cause a no output situation, though every single time I have seen that the behavior is over any title I try. I've seen others boot up with garbled graphics or strange behavior. With only 128 bytes of RAM in the RIOT, pretty much every title uses all the memory, all of the time I'd estimate. I'd say it is possible you've got a TIA problem and if you've got a friend that you can swap TIAs between, it's worth experimenting as at least the Rev. 13s all have socketed chips (Some Rev 16s and all 17s I've seen they're soldered down, as well as the Jr.). When swapping TIAs it isn't uncommon for the colors to come up differently from one to another and adjusting the trimmer/pot is necessary and I usually use Pitfall! as my reference. If you're going to swap TIAs make sure you're swapping them that are made for the same region, I think you said yours was NTSC, so you'll need an NTSC TIA - Atari PN C010444. RIOTs and CPUs are not region specific however.
  22. And, here are the screws shown on a metric ruler. I'm not sure what size they are as I've never have to buy any. Unfortunately, I get enough consoles that were poorly packed with damaged cases We use a mismash of systems in the states and local hardware stores will usually have both, especially since building materials are always measured in imperial. They have metric as well, because, well everything we buy new, even most manufactured in the US use metric fasteners now. IMO, very worst case you can get screws that are similar in length and if can't get a spot on match the diameter, get ones that are slighter more thick in diameter. Use a drill bit for the new size screw and use a piece of painters, electrical tape etc to mark the maximum depth on the bit and drill pilot holes for the new screws. There is enough material in the shaft to accommodate a screw that is fractionally larger than the original and in fact I have done that with larger screws in the past when I receive a case that the screw threads are stripped out on.
  23. @vitoco Took a picture. Sorry, these are Imperial measurements in the picture, but that's the ruler I have on hand in my shop. Then again, at the time these were built everything was measured in inches, so period accurate haha. The longer screws go into the holes near the front, the ones that go in straight. The shorter screws go into the holes in the rear that go in at an angle.
  24. Np ?. This is the guide I used when I got started: https://vintagegamingandmore.com/installation-guide-4switch/ It doesn't mention removing R222, R209 and C209 which I also do. Here is a picture of a board I finished last night
  25. Hey @vitoco. Yeah, if you do a composite AV mod you won't get video interference when the RF shielding is removed. As far as removing the RF modulator, there are two options when AV modding. If you do the simple AV mod consisting of a pair of resistors and a transistor, yes the RF modulator needs to be removed or disabled (back when I started I'd just cut the pins and leave the modulator in place, now I remove them entirely and sell them to people looking for them for not much more than shipping cost.). I have probably 80+ RF modulators compatible with light sixers and 4 switch boards if anyone wants one. If you do the UAV mod you can leave the RF modulator in place and continue to use either. Probably using both at the same time won't work well, just one at a time. Also if using the UAV mod, you do not want to install or make sure that there is no 820 ohm resistor installed between pins 6 and 9 on the TIA as this, while recommend originally by Atari messes with the UAV mod.
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