ACML

Any chance the stickers got inadvertently on the wrong chips (i.e. swapped by accident)? If you have a way to read the EPROM, verify that the checksum matches.

It's actually U12, but yeah, pin 28 doesn't look like it's in the hole.

I meant the other side of the jumpers (i.e. cartridge side). Check the other side of the jumpers W9/13, W8/12 and W7/11 for a short between pads.

Look at this pin on the EPROM. Is it in the hole? Looks like it bent under the chip and didn't go into the hole.

Three observations: 1) The 2 pin extensions do not appear to be lined up with the existing 24 pin socket (they look bowed out). Looks like you had to bow out the legs 1,2 and 27,28. Maybe the photo, but pin 28 on U12 looks damaged from being bowed out. 2) Check your solder work on jumper locations W9-13 (especially the cartridge side). Make sure no solder is inadvertently shorting a neighboring pad (like W9/13, W8/12, W7/11). Accidently shorting to neighboring pads will cause a blank screen. 3) You have a loose 0 ohm jumper laying on the board between W9 and L2. Remove EPROM first: You can use a small pair of needle nose pliers to bend 2 pin socket back inline with the 24 pin socket so legs 1,2 and 27,28 aren't bowed out causing stress. Look over pin 28 on U12, is it damaged? Now that I look at it again, did pin 28 on U12 actual go into the hole? it might have bend the pin under the socket and didn't go in the hole.

Yes. You are just adding the two missing legs to each end so there are 2x14 (28) instead of 2x12 (24). Works great. You don't need to touch the existing 24 pin socket, you're just appending the last two missing legs. I've never understood why so many would desolder the existing socket and risk PCB damage when this is so much easier and safer. Just need to ensure they are inline so the EPROM goes in easily.

While you're ordering the 0 ohm jumpers, add this to your list. These Single Inline Package (SIP) are exactly what you need. https://www.digikey.com/en/products/detail/harwin-inc/D01-9973242/3727905 I just cut off section of two leads and stick them in the missing pins to make the 24 pin to 28 pin. Very easy, done it at least a dozen times on 1200XL for this very same purpose.

The -35 has me scratching head. Never seen one in the wild installed in a machine. Not sure Atari used SALLY's in 1980. It's possible, but if they are truly 1980 production, you'd think they would routinely show up in production units. Plus the overheating is uncharacteristic of Atari VLSI chips.

There are some good options on eBay if you're CONUS, but being located in Europe, these may not be a good option when considering shipping. I've had a few bad Rockwell (Mexico) 6502Cs, but I've had many more that are fine. It might have been just a bad lot or two that is getting all the bad press. Is the current one acting up?

And if he did, the display would likely be corrupted like the screen I posted. So, does the 80 column work on a RAMBO 256K mod, probably not.

That is still 40 columns.

Thank you for the photos, but that's 40 column output. What does it look like editing in 80 columns?

I just get a black screen during loading. Never comes up. Can you add photos of your output? Thanks!

Can you please upload the one you are using that works with a RAMBO 256K?

Atariwriter+ 80 Omniview.atr

You have the old ANTIC (CO12296). I think all 1200XLs have the older one. The new one is CO21697. Wow! I have the same RAMBO 256K and have not installed yet because I was told that the Atariwriter 80 column for Omniview would not work with RAMBO 256K. Using Altirra and setting the memory to 256K RAMBO, you can load it, but when you edit it, it's all corrupted. You are saying this is not the case using real hardware? If so, I will be installing this shortly. Can you include a photo of what your screen output looks like while editing? This is what I get using Altirra.

Yes it will load, but try editing a file or create a new one. Screen is corrupted with Rambo 256K.

I highly recommend the SIO2SD made by Lotharek. Works great on 800.

Well, if he's only getting $3,999 for it, I can't blame him for charging 3 times the reasonable shipping. Guys got to eat right?

For about two seconds, it actually looked like a 1450XLD. Then you realize its just a 1200XL with two 1050s stacked on top. Asking $1,500, but hey it's got free shipping! I'll give them credit for creativity, but as the old adage says, "Just cause you put your boots in the oven, it don't make'em biscuits" https://www.ebay.com/itm/394584656168?hash=item5bdf140928:g:WQ8AAOSwkGNkRTNs&amdata=enc%3AAQAIAAAA4PgBNyN%2BKA93hFo84H5hOpwsBfaa1digNJ2ZrRl29%2FvM1uC0SZPGzeSkFUiOjrgak3DSNuOAjKWNeBuoMjSY4y1S76HXblWwzAtwTWlbNTj3pUv8E3CyW5YtSRe5nqef3LCTMEzb9pFsqmJbfl9pY9F6DN04gOTAViHgsDHYVPwHBuovXlWFF%2Flby77nmEFXJtEaTqV4wPxTyLBGsDX2raF%2FnCurDDsPBmzfCJC01GYOm3rvDXoXy9FXhdcJCsieZbB%2B1fi7aZirEmICe8OEs%2FdzUMy723y%2BtbHMSsQsql8E|tkp%3ABk9SR8S91OX1YQ

I have been very fortunate to have two AA members sell me an Ultimate Cart they no longer wanted. I'd like to get one more for my brother's setup if possible. I does not even have to have a case, but the PCB needs to have the layout (any manufacturer) in the photo and the latest firmware (see photos). I know a lot of AA members have moved on to Side 3 and the AVG Cart, but the Ultimate Cart is better suited for my setup (1200XL). So, if you have one just lying around and don't seem to use it anymore and would like to sell it, please PM me. Thanks, as always!

Are you still looking for a genuine Atari Rev C ROM chip? I have a few I put in the original brown Atari BASIC cartridges that had two 4KB Rev A ROMs. The old brown BASIC cart is socketed for the two 4KB ROMs, but in Atari's infinite wisdom, an 8KB ROM in the right socket works so I pulled the two 4KB ROMs and replaced the right one with the 8KB 24 pin Rev C ROM. Works great. No modifications needed to the cart (i.e. no trace cuts or no added wires), just pop it in. It's in a socket, so you can just remove it an put it in a 800XL to replace the Rev B. PM me if you're interested, I could easily sell a few ($30 installed in a brown BASIC cartridge).

How did a glitched batch of 6502C meant for 5200 production (with required mods) end up in a 8bit computer? I believe the timing issue identified in the 5200 FSM is unique to the 5200, meaning those Rockwell (RC) marked CPUs should not have made it into the 8-bit computer supply chain. I guess the cannibalization of 5200 VLSI chips have introduced them into the available parts pool. I just bought one off eBay not knowing it's pedigree. Has that CPU been in your machine from the start? Have you had any issues with it operating (glitches, lock ups, dead screen)?

Bump.... I know the AVG Cart is now the fan favorite and many AA enthusiast like it better than the Ultimate Cart for good reasons. If you are one of those and have an Ultimate Cart you just don't use anymore, please think about selling to me. I have a 1200XL and the AVG does not fit like the Ultimate Cart. Honestly, I really like the Ultimate Cart. Thanks!

Don't know what RC stands for, but it's not China. Look on the bottom of the chip, it should say Mexico. I typically see the RC marked Rockwell in 5200s. Anyone know why some Mexico made Rockwell SALLYs have the RC stencil?