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Cmherndon79

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About Cmherndon79

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  1. Thanks @DrVenkman. Ordered a few 74LS32s from Unicorn Electronics. Needed some 4164-150 DRAM as well, so they covered both needs. Will update once the part comes in. Thanks again.
  2. Thanks @DrVenkman. Sounds logical. Don't have any 74S32s on hand, mainly just logic chips for the C64, which the 64 doesn't use that model. I usually place an order with Mouser about every 10-14 days or so, but may need to really take some inventory, since I just got my last order in yesterday. I had tried Food Fight and Centipede (7800) earlier and the behavior is the same there. Thanks for checking the schematics, as I don't have the 7800's readily available as I do the 2600. I appreciate it!
  3. Put the previously socketed MARIA into the 7800 lacking color, other than yellow and the problem follows the board. Sure is an odd defect. If chroma were not being mixed at all it would make more sense, but I'm getting yellow, and it isn't the combination as far as I know of Luma/Chroma into composite, at the high level, or else TIA graphics would have the same/similar issues, I'd think at least. Might just have to set this one aside and think on it... Thanks @-^CrossBow^- for the suggestion, as it gave me the confirmation I needed to think I wasn't crazy and it might be the MARIA. Also, appreciate the video you did on the UAV for the 7800. Had someone request S-Video on a 7800 and used your video to help me along that project. It was fantastic and got everything wired up without any issues at all.
  4. K, so desoldered the MARIA from the board I'm working on. Removed the known working MARIA from the socket of the other working 7800 I've got here. Installed the desoldered MARIA and we're getting color which appears normal as I can tell. Thinking it must be something else. At least it isn't an Atari chip that isn't made any longer, so that's a relief.
  5. Thanks! I'll give the MARIA a shot. I did check the color pot and reflowed it as well just in case, so fairly certain that isn't the issue.
  6. Hi there, Got an NTSC 7800 in from someone that wanted it modded for composite video and audio output. Board is CO25233-002 Rev A. This is just the simple and cheap mod using the 2.2K, 3.3K resistors and the 2N3904 transistor, mounted on a PCB. Done many of these on 2600s (maybe 150+ by now) and probably 10 7800s before. When I got the unit in, I just booted up Frogger in 2600 mode over RF channel 3 and sound and video were working fine. Foolishly I didn't check to see that the MARIA chip in 7800 mode was working before I did anything further. I took the board out and replaced the 3 electrolytic capacitors from a kit from Console5 that I had on hand and replaced the audio polystyrene caps at C4 and C5 with so 820pF MLCC equivalents. I removed the RF modulator from the board and I installed the composite mod. I booted Frogger back up and the screen looked normal, colors were correct. TIA audio was playing fine on the startup sound in Frogger. Next, I put in Ballblazer since that had a POKEY chip in it, it is typically the first one I'll use. When it switched into using the MARIA for the 7800 I got almost all black and white in the Atari rainbow, except for yellow. When I watch Ballblazer in attract mode I see all black and white, but after the ball is hit, I see it turn yellow and after a second grey again. No problems with POKEY audio. Put in Food Fight and Centipede (7800) and same behavior. Started looking for problems on the board. Noticed the rear leg of C57 was sitting in the mounting hole for the power connector, seemed unlikely this was the problem, but I connected it to where it was supposed to go and no change. Checked all the component connections around MARIA and didn't find any problems, but did reflow a few things that looked like they could be marginal. Checked for bad solder joints everywhere else and same thing, nothing apparent but reflowed a few points anywhere I thought things could be marginal. Double checked the polarity of the electrolytics I installed and they were right. Reflowed the solder on the 220uF cap sitting next to the MARIA just in case. Did a search and found someone had B/W only here on a 7800, which was a bad solder connection at the slot, so I checked that, but didn't find anything wrong there. Can't see any cut traces and checked continuity if I wasn't sure. Just looking to see if anyone else has run into behavior that fits this description. I've got a known working MARIA in a socket on another 7800, but I really don't want to desolder the one from this board, unless I'm fairly confident that is the problem. Thanks!
  7. Console5 has them back in stock (10 available as of this post). I just ordered some the other day as I was starting to harvest from working boards lol $2.49 ea. https://console5.com/store/male-joystick-port-atari-2600-7800-colecovision-new-old-stock.html
  8. Jealous you have an actual 2800. I'd be keeping this one if it wasn't the Sears variety (I still think it's kinda cool, but I've got tons of 2600s). I'll just be posting it up for sale instead.
  9. Thanks for getting back with me @slaanesh. I appreciate it. Anyhow, I got it working and I figured I'd better document it so when the next poor guy googles and finds this thread (as I did) they'll find what they need Remove parts: Q2 - Transistor C10 - Capacitor R14 - Resistor R19 - Resistor Connect audio to capacitor to the left of C10 that was removed if the system is facing you from the front (Can't read the location as the component is blocking the silkscreen After that it's like any other VCS where you attach GND, +5 and Video to pins 1, 3, 4 in that order where the RF modulator was/is. Probably if an admin reads this, it should be moved to Hardware if possible?
  10. Hi @slaanesh, did you ever figure this out? Just recapped one of these and AV out was my next step. The Atari Field Service Manual Rev 02 I have has reference to the CX2800 in the Tech Tips section and it has the schematics for the 2600 and 2600A, but not the 2800. I know where to pull GND, +5 and Video from the RF modulator once removed. Not 100% clear on where to pull the audio, nor which resistors to remove. Fairly certain I need to remove the transistor next to the 2 audio caps that I replaced from the original 820pF polystyrene caps (I can't read the silkscreen for location, it isn't very clearly marked. Looks like "Q2") Think I can figure this out by comparing this board and the 2600A and some trial and error, but if anyone knows it'd save me the hassle
  11. Good guy. Our transaction went very smooth. Recommend!
  12. If there are any other particulars you're looking for let me know. I get way more VCSes in, but I try to pick up the 7800s whenever I can get them for a somewhat decent price.
  13. Oh. And congrats! Getting a model 1 Genesis recapped and working is tricky and if you've done it, it's an accomplishment! The VA3 and later revisions are especially tough. Sounds like you've made a lot of progress in the past month.
  14. I think it is okay to run without the RF shield, but they certainly do use that for extra heat dissipation. I always put them back on, and I like to put a bit of thermal compound between the voltage regulator heatsink and the RF shielding, both upper and lower pieces. Better heat dissipation is a good thing generally. After I recap one of these I like to have it run Gunstar Heroes for 24 hours, just in it's attract mode. It's a pretty late title that pushes the system pretty well.
  15. No sorry @vtadave. Mostly 2600 and a few 7800s. I've got a 400 and 800xl lying around (keeping the xl). I've never used a 5200 growing up and I've been scared of the controllers, though I'm sure I could rebuild them, the non-centering nature has pulled me towards 8 bit computers instead.
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