DavidMil

Vinegar didn't do much either so I've ordered so sodium carbonate (not bicarbonate) in the form of 'Arm & Hammer Super Washing Soda'. At $14.00 including tax and shipping, that's right down my alley. A 1.5 volt battery and some clean water in a plastic jar is all that is required to clean rust and black corrosion from metal. At least it worked in the U-Tube video. If this works I will certainly post before and after pictures. David

I looked at the Rambo XL image on ebay and I believe you are correct. The red side of the cable is connected to PB6. Thank you both for the feed back, DavidMil

I actually have the manual, and there are no pictures of the board or the wires just a note as to how to hook the wires up to the chip. There is an dotted outline of the board and chips but that is all that is shown. Thanks though, DaviMil

I was digging around in my storage boxes in the attic and I came across a RAMBO XL board. The five wire cable has been broken loose from the board, and I'm trying to decide which connection does the end with the faded red line connect to on the board. Is the red side of the cable near the connection by R1 (PB2) or is it by pin one of the 74LS74139 chip (PB6)? The three jumpers appear to be set for the Antic E version (all set to 0). Thanks, DavidMil

Thank you arcadeshopper. I'll call it this afternoon. DavidMil

I'm not talking about connecting over the internet (as I found after looking through about 10 pages of search results here) . I'm talking about picking up the phone and dialing a 10 digit number, hearing the modem respond, and putting the hand set into the coupler type BBS. If there are any, can someone post a couple of the phone numbers? I'm trying to show my great granddaughter what it was like in the 'dark ages'. When I tried to explain it to her she asked me why didn't I just use my smart phone... Thanks, DavidMil

So they weren't special versions of those chips? I know that Atari had a special version of the 6502 chip, I wasn't sure if there were custom versions of those custom chips too. I've already tried reseating all the socketed chips and I've tried swapping out the 8 RAM chips (and the 4050 chip) too. I was going to start swapping out the big chips next but wanted to make sure I didn't need to order something special from Best Elect first. The color does change by turning the veristor. DavidMil

I have an old 5200 that has been in my attic for about 32 years, and I decided to fire it up the other day, All I get is a deep blue screen. My question is about the three large chips (Antic, GTIA, and the Pokey chip), I noticed that the Field Repair Manual lists them all as custom versions of the normal chips. All use the normal part number but all have XX after them. Where they custom versions of the normal chips or is this typical mass confusion from Atari? Thanks, DavidMil

Someone asked me about the 835 power up self test the other day, and I thought I'd put my response here if others are wondering if their 835 modem is working. When you power up the modem, the power light should come on and stay on. Watch the online light and listen for the relay to click once, about the same time the online light will flash on for about a second then go off. This completes the boot up self test. If it does this, odds are good that the modem is working properly. If the online light flashes at a slow rate, the Controller Chip (M5) is most likely bad. If the online light flashes at a fast rate, the Modem Chip (M4) is most likely bad. If the online light stays on (or never comes on), or the relay 'chatters', it's time to do a visual inspection and start checking voltages. DavidMil

So the article I read is incorrect! And the correct resistor to bypass is R63 (right beside R53) and not R53 as the article states. Thanks for the correct info, DavidMil

I just read an old article written by, Tom Halfhill, about Atari 1200XL's that says Atari put a current limiting resistor (R53) in the SIO port to discourage anyone from designing devices that drew 5 Volt power from the computer itself. Has anyone ever had a problem with this.? He specifically points to to the XM301 modem as not working till this modification is made. The article goes on to explain how to get around this by replacing the resistor with a wire jumper. He also said that Atari recommends that you take computer to a distributer to have this done. Anyone have any more info about this? Thanks, DavidMil

Did Atari every put out a Repair Flow Chart for the 1200XL? All I've ever seen is a 'System Check List'. DavidMil

The boss (aka: Spouse) Has given' me some alternate fun and exciting things to do (fix stuff). So it's going to be a couple of days till I get a chance to look at them. But I want to thank you, because knowing you they will be just what I want. I'll let you know about Thursday or Friday. Thanks again, David

Any one have some cheats for 'Gateway To Apshai', to either give more time per level or more lives? Thanks, DavidMil

Were you planning on replacing all the chips you desoldered or were you going to try to reuse them? DavidMil

The seltzer water didn't do a thing. If anything it made it blacker. I like the idea of electroplating but I'm too cheap to spend that much money until I've tried every thing else (besides, I'm saving up for a 3D scanner), So next is the vinegar treatments... DavidMil

My brother suggested Q/M remove, that used to work very well on brass. I also have a can of spray-on lacquer I've been planning on using. Would polyurethane work on the metal as a protective barrier also? I'm not worried about interference, it's more of an Atari purest restoration thing. David Milsop

Thank you all for the tips. I like the idea of seltzer water and fine steal wool to give a good finish to a tarnished surface. I'll try that first, then go to harsher stuff if that doesn't work. Of course if all else fails I can order a new RF shield from Best for $9.00. I'll let you know how this turns out. DavidMil

Depends on what he's going to be doing with it. If he's going to be doing a lot of printing or looking for sharper text, then the FX980 is the way to go. But if he is only going to print a few pages a week, then I'd look for something that was cheaper and didn't take up half of a desktop. Believe it or not parts for both printers are still easy to find. DavidMil

Any ideas about restoring an RF shield that has a crust of black with some small rust spots on it? Funny, but the underside looks nice and shiny. I really don't want to use sand paper unless I have to. And yes, this is on that 1200XL I bought recently. DavidMil

I found this Tech Tip in the 1200XL service manual. I wonder if someone was trying to swap out the EPROM for a couple of ROMs? I can just move the three jumpers over to W7, W8, W9, (from 11,12,13) and put a piece of wire in W6. U13 already has a 28 pin socket and I'm going to add another 28 pin socket in U12. I believe that will make the board 'ROM' ready. David Milsop

They are the original white with a single black strip jumpers, and the rest of the vias are full of solder (no wires under the board) . After reading your response, I think someone may have been trying to modify this 1200XL because there is no socket for U12 (but you can see that the vias have been messed with). U13 is untouched. DavidMil

Just curious... Was the GTIA chip getting hot to the touch? DavidMil

When I opened up the 1200XL that I just bought I discovered that there were no ROM chips in the sockets. So, now besides a keyboard, I need to order a couple of ROM chips. My question is about the jumpers on the 1200XL motherboard. The following jumpers are installed: W1 W11 W12 W13 R44 I will be getting the latest ROM from Best. Do I need to move any of these jumpers for the new ROMs? Thanks, DavidMil

I'm looking for a 1200XL keyboard that looks relatively good with keys that don't get stuck. I don't care if there is a electrical problem or a connection problem with the keyboard. I am willing to pay for the keyboard. I bought a 1200XL without a keyboard thinking I could get one from Best or myatari, but both say they have been out for years. Help or suggestions would be greatly appreciated! DavidMil