GaryR

Thanks for the reply Nathan. Actually before I did the chip swapping I did some basic trouble shooting. First I scoped the power supply for any issues and found a problem with the connection between the power supply board and motherboard. The non-working unit had a flexible printed type circuit connecting the boards and it had a problem with one of the 5 volts supply. Fixed it. Second, I documented the voltages on all the chips pins with a working cartridge installed. Compared the voltages with the non-working unit and not a lot matched on the non-working unit So I went to checking wave forms good vs bad units and found some good waves but most gone on the bad unit. This is where I started swapping chips and studying chip functions. This is where I also felt that the project was taking to much time and I had other projects to finish so I quit to allow me to think this through and maybe get some new ideas from the experts. The chips are socketed in both units except the CD4050. I still think there is something strange about the TIA chip. It looks like a programmable chips we used in the 80s but it might not be. So I guess swapping all three good chips to the the bad unit is an option that makes some sense at this time. Maybe that's my next step. Thanks again.

Reading posts and other articles it appears that chip swapping is a valid method to test the condition of the RIOT, TIA and Processor chip in the 2600. Here is my experience and I’m wondering about the chip swapping process. I have a non-working early 2600 purchased in 1977. Chips are MOS Technology for RIOT and the TIA is an AMI brand. Motherboard CO10433 Rev 7 Riot(6532) CO10750 1977 (MOS Technology) TIA (Custom) 7733PX CO10444-01 C274DX Korea (AMI) Computer (6507) CO10745 2177 I have a working 2600 with a build date of 1982 and ALL the chips have a Silergy brand symbol. I have also seen similar the same Silergy brand chips in a 2600A. Motherboard CO10433 Rev B All Chips Manufactured by Silergy Riot 8052 CO10750-03 TIA 8037E CO10444D-03 Computer 8101 CO10745-03 Ok, swapped chips from non-working to working unit one by one. Working unit would not work with any swap of a single chip. Does that mean that ALL the non-working unit chips are bad or that swapping chips is more selective than reported by others? I did not swap chips from the working to the non-working unit. Might be interesting to move all three(3) chips and see what happens. Guess I’m a little scared of that move right now. One last comment, the non-working unit was a demo unit in a large store and was in demo Atari display case. I bought it after the Christmas rush the first year the 2600 was introduced. Could it be some type of prototype? I don’t really think so. I do know one thing, every kid in Sheboygan Wisconsin played the unit when it was in the store and it worked many years after. Would love to hear comments on your experiences repairing units with chip swapping.

I didn't see all these replies till today (1/9) A little background, I was a member of the forum years ago, at least 10, I was the person that submitted the copy of the magicard manual and the original schematics for the 2600 and 5200 (Boman). I repaired a few in the late 70s and early 80s. In fact I have to fix my original console now, it got some issues. I was an assembler programmer for the IBM main frame stuff so I thought that the 'mini' computer might be interesting to program. Wrote a few 'Block' moving stuff but lost interest. The storage/retrieval of the completed programs was a real hassle. Ran across my Magicard and accessories and thought it was time to possibly part with it. Have been told many times how rare it was when I purchased it in 78 or 79. Actually demoed the package at a couple computer stores when they were popular and every town had at least a couple. The Product Description sheet has a note on the back from Joseph R Biel whom I believe was a developer. He was the person I communicated with because I did pay a wopping $49.88 plus tax for the unit. Been asked to supply pics so here they are:

Looking to determine a selling price for my Computer Magic, Inc MagiCard. Years ago I was told this card and its accessories were very valuable to certain Atair 2600 collectors. I have written programs, a long time ago, using the MagiCard. I have: Blue label Cartridge (Computer Magic Inc) Purchased by me in the early 80s (Fox Valley Center-Aurora, Il) Original Manual MagiCard Template Right and Left Controller ?? Product Description single page with a note from Joesph R Biel (Fox Valley Center-Aurora, Il) Cassette tape interface ( Built by me) 6502 Software design Book by Leo J. Scanlon (Howard J Sams) Yes I know it’s worth what someone will pay for it but a general idea of what the MagiCard have been sold for would be a great help.