DavidMil

I'll give it a try. Thanks, David

I don't suppose you have any idea what happened to that program? I'd like to have a look at it. Just curious... DavidMil

Despite the common idea that Atari removed all the covers on the RAM cards for heat dissipation purposes, the real reason was to cut down on costs. That said, those cards could get REALLY hot in A800's that were used to run BBS's. It took a lot of heat but the 800's would eventually lockup after a time. Just ask anybody that ran a very active BBS (meaning lots of up and down loads). My friends that ran active BBS's always removed the covers from the RAM cards and also removed the large plastic piece that covered the RAM and cartridge slots. And some sysops positioned a fan to blow on the computer too! Atari also ended up removing the brown tabs that held the RAM/ cartridge cover on the machine and replaced them with screws to save a few more pennies towards the end of production. DavidMil

Yes I do know about the holes. But I wanted to keep the channel selector switch. This location only caused me to cut two traces and forced me to relocate a cap. David

There is a DIN connector on my 600XL. I know, I put it there. Pictures are better than words so have a look... This is the machine that was lost in the attic for many years. I had started to do another upgrade and it wouldn't work, so I got disgusted and sent it to the attic. I found it the other day and after playing with it a bit, I decided to do it a different way. It looks good but I'd like to add chrominance to pin 5 to see if that would make it any better. Right now it's a little bit 'grainy'. David

There is a DIN connector on my 600XL. I know, I put it there. Pictures are better than words so have a look... This is the machine that was lost in the attic for many years. I had started to do another upgrade and it wouldn't work, so I got disgusted and sent it to the attic. I found it the other day and after playing with it a bit, I decided to do it a different way. It looks good but I'd like to add chrominance to pin 5 to see if that would make it any better. Right now it's a little bit 'grainy'.

xrbrevin, This must be for a PAL machine. My American 600XL doesn't have Q7, Q8, Q9, nor any of the supporting components. There is no L12 or R124 on my board either, just empty locations there too. DavidMil

This is the one that I've been using for over a year now, and it works really great. Only problem is that after extended usage you have to clean the clear tube and change the filter in the tube also. If you don't the long barrel will plug up fairly quickly. Then you have to crank up the temperature to 900 F. degrees to melt the solder out of the barrel. But then you will have this same problem on any desoldering station if you don't clean it after each use. DavidMil PS. I'd rather shoot myself in the foot then use any type of digital social media arena. I don't feel the need to take pictures of my lunch and send it to everybody! DM

Does anyone have a modification to add Composite Chrominance to pin 5 of a 600XL? I'm not interested in any other types of video upgrades for the 600XL (boards, chips, etc.). Just a Composite Chrominance to pin 5 upgrade. Suggestions would be appreciated. Thank you all, DavidMil

We used to have a LaserJet II that worked beautifully with our Atari computers. Some people say you needed a special cartridge to use the LJII with Atari's but that was only if you wanted to take full advantage of the printers capabilities. David

Well so much for my Crystal solution... I don't remember what I was doing but I pressed down on the board just a bit to the right of R13 and the screen went black and the computer locked up. So I guess I'm going to reflow every thing around R13 and then I'll break out the wife's high powered magnifier to look at components. Also I'll have to connect the leads to end points of all traces around there and press on the board again to see if I get any open traces. It's a good thing I enjoy (well mostly enjoy) figuring out these kinds of problems. David

ClausB, What a waste of a LaserJet 4Si. I never met one that didn't have at least 1 million pages printed. Other than a full maintenance kit, about the only thing that ever went bad was the laser assembly. David

Pin 28 of the GTIA chip was where I first discovered the problem. The 1200XL field service manual is so poor I use the 800XL manual for trouble shooting. It says that no color or bad color (which I started having first) could be the clock circuitry. It was like the oscillator circuit was 'skipping a beat' every now and then. The scope would have these random very short 'flat lines' (where the voltage didn't move). And then it would start up again. And yes I was putting the test lead directly to the crystal. Thank you for the new knowledge! Ok, I'm open to suggestions here... David Other things: This was my first 1200XL and the boys played it for hours every day. I know for sure that it was dropped at least once. But there is now telling what kinds of torture a couple of boys could do to a computer over the course of several years. I've done the 'simple' trouble shooting (swapping all the chips including the delay chip) with known working chips in my other 1200XL. The problem stayed with the bad 1200XL. VRegs are solid and stable. Game cartridges work fine except there is no color (or just a flicker of color every once in awhile), at least until the machine locks up. DM

Please, don't beat your printer. Personally I've always preferred Epson printers for use with all my Atari computers (unless I was doing color graphics). David

I have a 1220XL that the color keeps going in and out and lately the PC is always locking up. I have traced it back to the clock circuitry. First I thought it was one of the transistors but changing them out didn't resolve the problem. When I put my scope on the crystal, it was not stable and moved all over the place. Sometimes up to 4MHz but mostly down around 2.xxxMHz. So my question arises from the fact that I don't have C061090 crystal, but I do have a C016010 crystal. Can I use the C016010 (from a 2600) in the 1200XL? They both seem to have the same frequency. Thanks, DavidMil

Have you tried booting into test mode (hold down the Option key while turning on the computer)? And also turn on the PC will holding down the Start key to see if you get a beep (tape drives is loading sound). David

I know that he has at least one other male person working there because sometimes someone other than Brad answers the phone and writes down my order. Once when I asked where Brad was, the voice on the other end said that once in a while Brad has to stop and go to the bathroom. That has always made me smile. Brad does stop for something other than sleep. David

I could easily be mistaken about the name. In the middle on the bottom of the screen it gave you a math problem. On one side of the bottom was the total number of problems and on the other side of the bottom was the number you had gotten right. The rest of the screen had numbers floating around and you used the joystick to click on the correct answer to the problem. If a number touched the bottom of the play area it meant the timer had run out and you got a raspberry sound. It also would list the problems you got wrong so you could see where you needed to do additional work. David

Here are the requested pictures. And yes, I believe that these would be good for attaching SIO sockets. But you will most likely have to go with a smaller nut and bolt as I believe the holes in the male SIO connector are smaller. Say a 3M x 8mm. David

When I was a kid, my Dad pounded the multiplication and division tables into my head with flash cards. When my boys were growing up I was sooo happy when I found Math Attack for the 2600. I didn't even have to watch them because I could tell by the sounds how well (or bad) they were doing. But unlike you, they both still hate that game! David

I just wanted to let anyone know that has a side piece that has come loose from the power supply board on their old 800 that a couple of M4 x 8mm nylon bolts and nylon nuts work very well to reattach it. I bought three dozen on Amazon for about $8.00. DavidMil

Thanks for your time Bob1200XL. David

Would you mind telling me how you knew what the name of this game is? Just curious... Thanks, David

I agree with you but I take it even further. Not only do I change out those 6 caps, but I change out all 8 electrolytic caps as well as all the diodes (except the LED's) and quite often the VRegs, power switch, the power connector and sometimes the channel 2/3 selector. My wife says I tend to over do things, and she is usually right. David

It is also the part number listed in the 400/800 Field Service Manual as the replacement part number for the 16K RAM chips. This number was put on a lot of different manufactures chips that could be used in the 400 & 800. David