boardjunkie

Actually, the silicone grease is for sealing out moisture. The combination of dirt/contaminants and moisture can form a conductive arc path from the connector in the wire right down the plug where it arcs to gnd. I've seen this happen too many times to count. Ever have a car that is hard to start or misses badly on rainy days? This is why.

If you mod the board for single supply ram, you *have* to remove the -5v from it. I've had problems with the controller inputs when the -5 is still at the board (but removed from the ram sockets)....it acted like bad input buffers but was in fact caused by the -5. I have no idea why they used the neg-5 there....its OK to let it float. The trackball and driving controller are essentially the same thing (they both use slotted optos) so they should only need 5v.

I just gave up on it and snagged a *huge* torrent of updated roms for the newer MAMEui. 90% I don't care about (I like golden age games for the most part....late 70s up until about 84)so I hated to dedicate 24gb to it, but hey...the machine won't be used for anything else anyway. Just for the record, I screwed around with it long enough to have it do some good. Alot of them got fixed, but these are from my "ancient" version of MAME32 which gets used casually on the main machine. It was the last version to offer H or V scanlines game-by-game, so it looks best on a hi res monitor. Plus....I spent years tracking down obscure titles I never knew existed.....

I'm in the process of setting up a spare machine for use in a MAME cab that I'll be putting together soon. I have an old version that I have used for many years that the majority of the roms I want are working. That version doesn't play nice with "soft15khz" as far as keeping consistant resolutions, so I installed the latest version, which works quite well. But of course just moving the existing romsets from the old version to the new one renders about half the romsets invalid for this version. I installd Clrmamepro and am not familiar with it. Now....does clrmame need updated romsets to compare the existing roms to? I got as far as running the scanner, but I'm in the dark after that. How does the rebuilder work? I found a clrmame "tutorial", but its a little geeky even for me and I'm not understanding the hows and whys. Eh?

I think its the other way around. If alkaline batteries leak potassium hydroxide, that is a base. You would neutralize that with an acid. We always used watered down vinegar for arcade boards that had battery damage.

What is the downside of NOT having this capacitor, apart from the pop when connecting audio when the CV is turned on? Was this probably omitted by Coleco as a cost saving measure? This applies to the seperate video/audio output mods only. The audio to the RF box is cap coupled. But the popular internet modders don't know to cap couple the audio for the line level output, they're just running cable straight to the output connector, which is the wrong way to go about it. It states right in the datasheet for the sound generator chip that the output *needs* to be cap coupled. If you don't do this, you have 5vdc on the audio out all the time and your TV/stereo does not want that, it just wants the audio signal. So depending on the input design of whatever you route the audio to, you may risk damage leaving it direct coupled. A higher end stereo amplifier may be direct coupled from front to back, and DC voltage on an input will cause it to go into protect mode thinking there is a problem with the output section. If it is not protected, you'll have a DC voltage on your speakers which *will* damage them. I'm really surprised no one has caught this before. Its pretty important.....

Nothing you can see. Ram either works or it doesn't. The upgrade is mainly to increase reliability and make the console run cooler. The 4116 triple supply ram (stock ram) is fussy about "seeing" all 3 voltages at the same time at power up. If everyting isn't just so, it won't play ball and you'll have to either reset or turn it off and back on. Upgraded ram only uses a single supply voltage (5v) so there's no issues with the timing of several supply voltages reaching the chip(s) at the same time. Arcade game collectors have been doing this type of ram upgrade on their Williams hardware (Defender, Joust, Robotron, etc.) for years because of the problem with fussy ram. It *really* helps those boardsets boot correctly at power up. False "bad ram" error codes were common even though the ram was actually ok.

Heh....dig the Atari XE game in yer avatar. I too was suckered by Atari one last time and bought onna those. What was I thinking.... Anyway....the video garbage was prolly not related to the input buffer(s) going south. I'd check the pwr switch first, then the output voltages of the pwr supply. I've seen several just over the last couple weeks that were putting out wrong voltages. One had a 5v output that was close to 9v. This is baaaad for your board.... Haha , Actually I think apart from its ugliness and brief history , IMO is the best Atari I have . It plays the old Atari 800 carts and all the games are better in every aspect compared to the 2600 . Its an 8 bit console and top of the range in Atari console in the 80's . Unfortunately it had an Identity crisis and was marketed bad and too late anyway as Nintendo started to dominated . The XE is very rare here in Australia and I think I bought the last 3 on ebay a year ago and havent seen any since lol . Thanks for the tip on power , I will check all the voltages and give the power button an overhaul . But last night it played beautifully and for some reason NO display issues The last home game I bought was the Turbografx 16 shortly after it was released. I thought it was a great system, but it never really caught on. I still play TG16 on the Magic Engine emulator sometimes. I think it holds up ok....

Aahh.....Zappa fan I see. Nice. The way I see it Barry, this should be a very dynamite show......

Oh, OK. I run a 12V lamp on a couple of my spares with a modded switch replacement. Would that still work with a board that had the RAM replaced and the new power supply? Well, I know that the ColecoVision wasn't the only machine to use that odd 4 prong adapter. The TI-99 4A also shared the same connector for it's power-supply. The replacement supplies for single supply ram modded units will have no problem with a lamp. The original supply was spec'd at 300ma for the 12v and the replacements I use are 2a on the 12v. IMO you'd be better off with an LED for a pwr on indicator since it will draw less off the opriginal supply's 12v line. You may be taxing the original one too much with the added current draw. I'd be careful doing that.....yer video ram might not be happy if the voltage sags..... Well other things may have used that connector, but that was 30 years ago. If anyone can identify it and who made it I'd like to know.

Just another "Jakks Pacific" plug and play type thing ainnit? I've seen those around......

Heh....dig the Atari XE game in yer avatar. I too was suckered by Atari one last time and bought onna those. What was I thinking.... Anyway....the video garbage was prolly not related to the input buffer(s) going south. I'd check the pwr switch first, then the output voltages of the pwr supply. I've seen several just over the last couple weeks that were putting out wrong voltages. One had a 5v output that was close to 9v. This is baaaad for your board....

It is possible, but I don't have a line on the required mini din connector right now. So I'm just doing composite at this time. Using a board mount mini din with no provisions of panel mounting is a bit too much of a kludge for me. The video processor IC in the console puts out chroma-luma type video, so thats the easy part. Its not like there is a huge difference in pix quality between composite and s-vid anyway. But composite is light years ahead of the old style RF "ch 3" in pix quality. The power supply upgrade interests me. The replacement pwr supply only works with consoles that are modded for single supply video ram....they won't work with a stock one because they only have 5 and 12v outputs (no -5v). But....I am going to be putting together replacement supplies for stock consoles sometime soon. They will be similar to a Commodore 64 type with 2 cords, so they won't be a giant wall wart like the stock ones. Over voltage and over current protected....unlike the originals. The kicker there is getting the 4 pin connector. Its not a standard type as far as I know and I don't have a source for them aside from hacking them off dead pwr bricks. Maybe a crash course in making molded connectors will speed it along.....

I was testing a CV I repaired tonite and noticed when I plugged the audio cable in with the console already on, I got a "pop" in the sound. It sounded to me like DC on the audio output, and sure enough my meter showed around 5vdc there. I looked up the datasheet for the sound generator chip and it *does* need to be cap coupled to remove the DC voltage. A 10u 16v part should be plenty good enough. You can go bigger, the value isn't critical. Negative side goes to the audio out connector (pos side to the chip). Just FYI.....

It is possible, but I don't have a line on the required mini din connector right now. So I'm just doing composite at this time. Using a board mount mini din with no provisions of panel mounting is a bit too much of a kludge for me. The video processor IC in the console puts out chroma-luma type video, so thats the easy part. Its not like there is a huge difference in pix quality between composite and s-vid anyway. But composite is light years ahead of the old style RF "ch 3" in pix quality.