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Have you tested the pins for continuity with each other? By that I mean pins that are shorted together that shouldn't be? Yep. I tried every pair of adjacent pins on the ROM, no shorts.

I hate to leave a hanging thread, so just to give this some closure... I made a trade with shadow460, who sent me an original bios mask ROM. A couple days ago I finally worked on this console again. I reverted the mod back to standard. That means I moved the OE wire back to the non-inverted input, and moved the jumper at W1/W2 back to W2. Plugged in the mask ROM, and it still doesn't work. I removed the ZIF and plugged the ROM directly into the base socket (aligned correctly). Behavior with this configuration (original mask ROM): 2600 games always boot to TIA bars 7800 games always boot to a black screen empty slot always boots to colorful untuned video noise. The appearance will change periodically. It actually looks similar to what I used to get when I tried to use the Asteroids bios on an EPROM. Supply voltage is at 5.01v on maria, and tested same on some other chips. I repeatedly checked continuity on everything I altered, plus many other things, and I just can't find anything wrong. There are some errant scratches on the board from when I was cutting the pins on the original ROM, but I've tested continuity and they're all intact. I've checked countless connections against the 7800 board schematic and everything I've checked is correct. But it doesn't work. Somehow I screwed up something on this console, but I can't find it. I've put it in the junk parts drawer.

I've always liked Contra for testing gamepads. It needs quick and precise control or it's impossible to play. Unfortunately, my own PC gamepad fails that test. Donkey Kong is probably just as good a test though. I don't think it could play that very well either. In a few more versions, they'll emulate the original control panel. You'll use a mouse to point at the controls, click the buttons, and click and drag to move the stick. Dual mice are recommended. Joystick support will be removed. It's more accurate this way.

Back in the days of the 7800 programming mailing list, somebody posted a demo using arcade galaga sprites in high resolution. They looked great, but it flickered badly and was probably very slow. However, this was caused by a flaw in how the display lists were being generated (that was the question being discussed in the post). If it was coded differently it might work fine.

I switch between a Radica stick and a Genesis pad, using the radica most of the time. The Genesis pad only gives 1 working button for Atari, but I don't know many games that need good diagonals and also 2 buttons. I prefer the radica unless diagonals are a major issue. To be more specific, to me it seems the radica registers diagonals fine, but it gets physically stiff when you leave the 4-way axes. That makes it hard to do diagonals quickly. It's been a while since I used it though, I haven't had my 7800 hooked up recently.

The Radica joystick is great for 2/4-way games. I have a hard time using diagonals with it though. The buttons are acceptable, though not as good as the joystick. It's my favorite controller for Pac Man, Dig Dug, Galaga, etc. I don't like it for Choplifter, Food Fight, or anything where I need to move diagonally.

Have you tried putting it back up to 9v? It's possible it could turn on but not have adequate power to run properly. The regulator might not be able to achieve a steady 5v output if the input isn't high enough.

Besides the above, I'll add Rygar. Very fun and simple early NES action adventure game. Goonies II is possibly my favorite of the genre, but that might be partly because it was the first adventure game I ever played.. after Adventure anyway.

Moisture might have fried something when you turned it on the first time. 1) Even so, I'd take the board out and wash it with alcohol. Scrub some alcohol on the chips with a toothbrush to remove anything that might be wedged between the pins and causing a short. Something that simple has resurrected a Genesis for me in the past. I also had to clean the cart connector to get it going. 2) Also, ditto the above about checking the solder joints. My early model Genesis had a very bad solder joint from the factory on one of the video RAM chips. 3) Try a different power supply if you haven't already. That might be what's actually dead, not the console itself. Even if it turns on the power could still be bad enough to keep it from running properly. 4) Do you have A/V cables for that system? It might just be a bad RF module. It sounds like you've narrowed the problem down to video, so maybe a video mod would fix it, if the A/V cables don't. The HDG marking just means it's an older console. The older boards tend to have better video/sound then some newer models. If it doesn't say HDG, I think it still has a chance to contain a good board but it's also likely to be a "bad" one. See the first post here: http://www.sega-16.com/forum/showthread.php?t=7796 Apparently the good ones still have a spot on the back for the EXT port, though it's not installed. The bad ones don't leave a space for it.

From looking at the screenshots, I apparently have been using the Atari version. But I like the idea of being able to fill the screen with a selected color. Actually, that thread that was linked above makes it look like the Atari version can do something similar - I never knew that. I guess I never tried playing with the controls.

Personally I don't trust the really cheap, new erasers. Especially considering they probably come from some anonymous manufacturer in china who has no reason to worry about safety or upholding any sort of reputation. I bought a used, brand name eraser (Logical Devices) for about $30-$40 shipped, and it also has a timer. This was much more appealing to me - I prefer stuff that's cheap because it's old, not cheap because it was built that way.

If you're really interested, I suggest trying out QBASIC on your PC, if you can find it. If you enjoy that, then maybe try to get your parents to buy you an Atari 800 computer. It's very similar to the Atari 5200, but it's a real computer so it's easier to work with. And you'd be programming the same hardware as a 5200. I've never owned one, but I had an Apple IIc as a kid and I learned a lot from it. Those old computers have BASIC readily at hand, so it's easy to play around with writing code on them. The Apple has BASIC built-in, but I think Atari put it on a cartridge. Either way, it's easy to get into it and start learning. You can do BASIC on a modern PC, but I'm not sure where to find it anymore. I know they used to include QBASIC with MS-DOS, so maybe it's hidden in the Windows discs somewhere. If you master BASIC, then eventually you'd have to progress to assembly. At that point I'd switch to an Atari 800 if you aren't already on one.

On the occasions when I've bought something heavy or otherwise fragile, I try to look for a seller who specializes in those type of items. I don't trust somebody who normally sells random stuff, and doesn't have a track record shipping the item I'm concerned about. The heaviest items I've ever bought on ebay were a very heavy workstation PC, and a used laserjet. Both came from sellers who dealt with those items routinely, so not surprisingly they each showed up in great packaging.

Nobody is working on this (unless you are)

That would be my attitude about any game really. I hate modifying other people's code. I much more enjoy starting from scratch and doing things my own way. Finding old 7800 source code is fine from a historical standpoint, but it really doesn't interest me as anything to build projects from.

You can get up to 144K (128K + 16K) onto a C300565. And yes, the XBoard would be ideal for this, since it would eliminate the need to put POKEY in the cartridge. The problem with 128KB EPROMs is the 32 pins. Not a big deal to hack that into a devcart but I'd be uncomfortable with it for distribution. In terms of the work involved though, it might not be any more of a pain than installing 2 separate 28 pin chips.

Tengen didn't have a legal license for home console Tetris. They thought they did, but it turned out later that their license wasn't legitimate and thus the games they had produced were copyright infringing.

Unfortunately I think POKEY would be a problem, since the Ballblazer boards only support 32KB. The Commando boards are too uncommon/expensive. A custom board would work, but I don't think an appropriate board has yet been designed. Somebody could do it but it would inflate the cost for sure. I think you could get up to 80KB (64KB+16KB chips) on old bankswitched carts without needing heavy modding. So a board like that with xboard support would be pretty economical. Not many people have xboards though.

You can add the tracking information manually. Just go into the Paypal payment details, click "add tracking info" and enter the delivery confirmation number. This also makes it possible for the buyer to look it up on their end.

Feedback is very broken. I don't really blame ebay though. I think the real problem is that buyers aren't discriminating enough. It's not just ebay that has this problem, I see it on everything. Youtube videos? All 4.5-5 stars. Morrowind mods? All 9.0-10.0. Game ratings? Usually 7-10 - not as bad but still inflated. Newegg product reviews? All 4-5 eggs. It's like people are afraid to critique anything. ebay feedback is so inflated that sellers actually have to obsess about the difference between 99.5% and 100%. Below 98% is considered a disaster. This is unfair to low volume sellers, who get slaughtered by a single neg. Meanwhile the high volume sellers are guaranteed sky-high feedback unless they're scammers. Star ratings are just as bad. Supposedly it's a 5 star system, but everybody is between 4.5-5.0. eBay has caught on to this and uses a 4.3 average (I think) as the threshold for flagging a bad seller. Because of this, sellers try to make buyers feel guilty for leaving even a 4. Don't buy into that - if ebay sees the typical star ratings going down, they'll recalibrate the threshold. In the meantime, remember it's an *average* - your individual rating isn't going to get them banned. Don't feel guilty about leaving 1s and 2s either, if the seller deserves it. Scores this low are added up separately and can get the seller into trouble, but if they earned it, then they earned it. It's not the buyer's problem to worry about the seller->ebay relationship. eBay will always recalibrate their rules/thresholds over time. If you don't want to leave a neg, then fine, but leave a fake positive and give honest star ratings. Don't just leave nothing. The star ratings are anonymous, unless the seller happens to notice the change in their rating immediately after you left feedback. Unlikely to happen, and even if they notice, who cares? That said, be fair, but I wish people didn't toss out perfect ratings constantly. Then we might actually be able to tell the difference between an average seller and an unusually good one.

This is something I like. There's a review site somewhere (don't remember) that has articles of this type. The article I remember was a comparison of many 80's ports of Choplifter. It's interesting to see all the differences between versions of a game, and which are the best to look for. Articles like that, with the possible addition of newer remakes, would be fun to read. Doing these comparisons pretty much requires you to have a big collection of systems though.

Oh, it's a palette change for character mode graphics, I see. Thanks for the explanation.

I'm confused about this part - the maria never releases the bus in the middle of drawing a scanline, does it? Maybe you mean the cloud color is being changed between white and light blue.. but I don't get that either because there's lines where both white and blue appear next to each other. I'm sure you know what you're doing, so I must be misunderstanding something.

Are the tracking numbers recorded with the "add tracking info" link on each payment? This might allow the tracking to be recognized automatically, rather than requiring human intelligence to be involved.

I think he's just trying to maintain S-video quality, since that's what he has coming out of the console. I'm assuming these are modded, older consoles since he has svideo output but not component. He doesn't have an svideo input, so he's forced to mix svideo->composite. By instead converting svideo -> component, the luma and chroma would stay separated. But somehow the chroma needs to be filtered properly into Cb and Cr, otherwise it'll probably look terrible. The chroma -> Cb+Cr filtering probably wouldn't be any better than what the TV can do internally, but the point is to keep chroma and luma separated so it maintains S-video quality. So unless I've misunderstood, the key question is if there's a reasonable way to achieve chroma -> Cb+Cr. (I don't know the answer myself). Several years ago I had a Viewsonic box made for watching TV on a monitor, but it also had Svideo input on it. I used it on my PS2 for a while. It worked fine, but it died after about 12-18months. I don't recall any noticeable lag. FWIW, only 60Hz output mode is useful. Mine advertised a 72Hz mode but that just makes everything jerky because it doesn't match with the NTSC input. There might be some ugliness with converting resolutions. The box already has to convert once, then your TV might have to convert it again to the native screen size.