channelmaniac

Sorry for the delay. Been out for vacation the first 2 weeks of August and then catching up at work this past week. Here's a pic of the boards... A is on the bottom B is in the middle C is on the top I put 2 next to each other so you can see the top & bottom of the boards.

Hi everyone, I've picked up a slew of NOS empty cart boards and wanted to post 'em up here in case there was an interest in them. Board A: An Atari 2600 cart (2716 pinout) without the inverter... Atari # C010789 Rev O Board B: An Atari 400/800 cart board. Takes 2 2364 8k x 8 bit 24 pin ROMs. Atari # C012963 Board C: An Atari 400/800 cart board. Takes 2 2364 8k x 8 bit 24 pin ROMs. 3rd Party board 75 cents each. Whatever doesn't get sold here in the next couple of weeks will be put up on my website at .99 each. Thanks! RJ

You sure the AC adapter didn't die? Check the voltages on the CV system with the power on to see if it's at the correct levels.

More likely a bad RAM chip than a bad VDP.

Nice! I have a box full of blank cart boards I picked up surplus if anyone needs some...

Self taught after reading a few books back in the early 80s. Fast forward to '93 and I took a class from PACE Industries on surface mount soldering with their gear. That was an amazing class for learning and perfecting techniques. I still use their gear today.

The keyboard problems on the SX-64 won't be CIA related, instead it will be dirty keys which is a common thing on those. Disassemble the keyboard and clean the gold/copper contacts on the PC board itself with a pink pencil eraser (NOTHING more abrasive than that!!!) then clean with alcohol. Reassemble and they keyboard will work well once again. Just beware that the keyboard is a real PITA to take apart to clean. Have you looked down inside the cartridge slot to see if there's junk shorting out the contacts? That's a common issue. Also, before you declare bad RAM chips, try swapping out the 3 ROMs for the ones in the old C64 you have. You could have a bad Kernal ROM, etc... Do carts play in the system OK? If so, look at the BASIC ROM.

Some of the old Atari custom chips had silver plated steel legs. You will need to clean the tarnish off of those pins and try the test again.

Mac 128 had black and white video with stippling for shades... poor choice for gaming as it had a lot of business apps.

Bad STIC (AY-3-8900) or Color IC (AY-3-8915)

That 7404 on perfboard is some kind of mod... the empty socket on the drive is for a terminator resistor pack. That should be installed on the drive that is farthest from the controller and NOT on the drive in between. Think of it like a SCSI bus terminator.

Before you go too hog wild, check the cables to make sure pin 1 on them line up with pin 1 on the drive and controller. If the cable is backwards you'll have exactly the issue you describe.

You should check the upper most address lines on the cartridge slot for continuity to the CPU: CPU Pin: Signal: Cart slot pin --------------------------- 2: A12: 24 3: A13: 19 4: A14: 20 And the enable lines from U5 to the Cartridge slot for continuity U5 pin: Signal: cart slot pin ------------------------- 11: EN_80: 18 10: EN_A0: 22 9: EN_C0: 2 7: EN_E0: 27 If those lines are corroded through then the larger carts will not work.

There are 3 different VIC-II revisions and they each offer different video quality on output... there's an R56 - a.k.a. R5 - the oldest. Then R8 and finally, R9 - the newest

TI-99/4 - $30 + tax It's nice to find a rare computer for a good price! I have 3 expansion boxes, some spare disk drives, and other parts to put together one hell of a TI-99/4 system.

Yes. Install +5v only memory. Poof. No more relying on the +12v switching cleanly to keep the memory from glitching. It's not a 100% fix, but it sure is a 90% fix.

Hello, Instructions for installing a Dual BIOS mod and for doing the +5v only memory are on the downloads section of my website. Feel free to download them and use them if you have your own parts to install. The dual BIOS is easy to create if you have an EPROM programmer. Simply program the bottom half of a 27128 with the standard BIOS and the upper half with the no-title-delay BIOS then follow the instructions to install it.

Hey Preppie... If you haven't seen mine, the link is in my signature. RJ

Pick up the audio at C88 (at the back of the board near the RF Modulator) and you'll get the audio from the CV and the Expansion modules. Don't tap on the sound chip itself or you'll miss the audio from the expansion module. RJ

There are 8 video RAM chips in the CV. You can always remove all 8 and modify the system to use +5v only DRAM. This will make it run cooler and more reliably. The current DRAM in the system is 4116. These require +5, +12, and -5v. The +12 and +5v is switched by the CV's power switch and the -5v is always on. The modification removes the +12v and -5v connections from the chips and replaces the chips with sockets and either 4516 or 4164 DRAM chips. These 5v only DRAMs don't suffer from the dirty power switch issues that the 4116s have. I have complete kits on my site. They come with the chips, sockets, and a short piece of kynar wire to install a required jumper. Instructions are on the downloads section if you have the chips and want to do it yourself. http://www.arcadecomponents.com/modkits.html RJ

I am glad to hear the Expansion module #1 ATARI 2600 adapter works fine with your composite video modification. In the past that was a issue with the ADAM computer and other peoples modifications of the Colecovision. If you tap on C88 for the audio output it's right in the middle between the audio output of the CV and the audio from the Expansion Module which makes it the perfect place to nab the audio.

I used a hammer. Just repeatedly whack it on the short side of the seam all the way around the power supply until you crack the seam. The one I fixed was FULL of bad solder joints. I just shotgunned the whole thing and re-assembled it. There were 3 component legs that had broken loose from their poor solder connections. The case can be superglued or epoxied back together when you finish. Use tape to hold it together until the glue/epoxy sets. Hell, while in there you could shotgun the caps.

The power supplies can be fixed if they fail.

You'd be shocked if you saw the tip I used for surface mount work. It's pretty big...

I have a few in a bin from some that I parted out if you can't find any new ones.