Timothy Kline Posted May 31, 2016 Share Posted May 31, 2016 (edited) Got taken by an eBay seller (long story) who shipped me a rather dead, beat-up 800XL, quite unlike the one they pictured as selling in their listing. Considering the price I got it for, it would've cost me more to ship it back with a signature requirement (to protect my complaint) than to just leave them with a terse negative feedback. So, I finally took it apart to see why there's no display whatsoever and my first check was to determine whether any of the RAMs get hot. Was fine until U15, and I'm pretty sure I lost a layer of skin off my index finger. In fact, I can still smell burnt flesh. But the RAM is throwing me off. I expected Hitachi RAM, but here's what's on the RAM chips: W.Germany 4C3U HM4864P-2 When I went searching for the HM4864P-2, it comes up as Hitachi memory, but none of the images matched this "W.Germany 4C3U" so I just want to be certain before I actually order replacement RAM. The upside is that the mainboard is completely socketed, so swapping out the RAM will go fairly smoothly, I suspect. The only other chip that felt a little warm was the CO61598B-01 at U5, which, oddly enough, has stamped on the mainboard, next to that socket, "CA061854" and I didn't leave the system on long enough to see if this chip would get any hotter, considering how blasted hot that RAM got within seconds. Hoping someone can provide some direction. Thank you, in advance! Tim [Edit: Ignore the part of my post about the CA061584, as that just means it is a socketed NTSC 800XL mainboard.] Edited May 31, 2016 by Timothy Kline Quote Link to comment Share on other sites More sharing options...
Simba7 Posted May 31, 2016 Share Posted May 31, 2016 First thing.. Check your power supply. Is it putting out 5v or much higher than that? Quote Link to comment Share on other sites More sharing options...
+MrFish Posted May 31, 2016 Share Posted May 31, 2016 Got taken by an eBay seller (long story) who shipped me a rather dead, beat-up 800XL, quite unlike the one they pictured as selling in their listing. Considering the price I got it for, it would've cost me more to ship it back with a signature requirement (to protect my complaint) than to just leave them with a terse negative feedback. It shouldn't cost you anything to ship it back; it should be entirely on the seller, if not as described. Quote Link to comment Share on other sites More sharing options...
Timothy Kline Posted May 31, 2016 Author Share Posted May 31, 2016 First thing.. Check your power supply. Is it putting out 5v or much higher than that? Nope, power supply is fine. Tested it AND connected it to a fully working 800XL. This seems a RAM issue. The U15, specifically. I just want to be sure I'll be fine replacing it with any available Hitachi RAM matching the HM4864P-2, since the "W.Germany" atop the chips is something I don't recall ever seeing before in other systems. Quote Link to comment Share on other sites More sharing options...
Timothy Kline Posted May 31, 2016 Author Share Posted May 31, 2016 It shouldn't cost you anything to ship it back; it should be entirely on the seller, if not as described. You're probably right (I've never been snubbed up until this point by a seller, in all my years on Ebay, so I'm not very familiar with the whole Ebay guarantee process or how long it all takes), but considering the price I paid, I guess I'm just "meh" at this point, and looking to see if I can this up and running with a reasonable amount of investment (if it's just a matter of RAM replacement, that's a worthwhile investment on top of my initial cost, for example). It was priced far below what I've seen 800XLs on eBay. It was sorely misrepresented as to physical condition and "works." Neither being true in this case. So, do I go through the trouble of applying for eBay's guarantee (since the item was sold as-is), or drop an additional $10-30 in parts to get a fully working machine? Replacing the missing key and a bad RAM, and giving it a good cleaning would satisfy me at this point, since I left the seller a blunt, negative review over their misrepresentation anyhow. (Maybe I should've stuck with 1200XLs, lol!!) --Tim Quote Link to comment Share on other sites More sharing options...
Simba7 Posted May 31, 2016 Share Posted May 31, 2016 800XL's are great machines. Mine lasted for >10 years (new.. as in 1985 new). Unfortunately, all my Atari equipment disappeared when I went active duty in 1997. Ya.. I was not to pleased. Lost a pair of 1050's, a XEGS (full system), my Atari 800XL (what I started on when I was 7), and a good chunk of software.. along with all the power supplies and SIO cables. Quote Link to comment Share on other sites More sharing options...
Rybags Posted May 31, 2016 Share Posted May 31, 2016 Occasionally there will be mixed brands of Ram in a machine. The main thing is that you don't have MT branded Ram, it's by far the most prone to failure. Replacement Ram chips can be had from various sources, arcade/pinball part suppliers are a good source. The requirement for 8-bit Atari is 250ns access speed or better. Generally any replacement Ram you get for XL or later will meet that requirement. 2 Quote Link to comment Share on other sites More sharing options...
JoSch Posted May 31, 2016 Share Posted May 31, 2016 800XL's are great machines. Mine lasted for >10 years (new.. as in 1985 new). Unfortunately, all my Atari equipment disappeared when I went active duty in 1997. Ya.. I was not to pleased. Lost a pair of 1050's, a XEGS (full system), my Atari 800XL (what I started on when I was 7), and a good chunk of software.. along with all the power supplies and SIO cables. Man, that hurts. :-/ Quote Link to comment Share on other sites More sharing options...
+tf_hh Posted May 31, 2016 Share Posted May 31, 2016 But the RAM is throwing me off. I expected Hitachi RAM, but here's what's on the RAM chips: W.Germany 4C3U HM4864P-2 When I went searching for the HM4864P-2, it comes up as Hitachi memory, but none of the images matched this "W.Germany 4C3U" so I just want to be certain before I actually order replacement RAM. The only other chip that felt a little warm was the CO61598B-01 at U5, which, oddly enough, has stamped on the mainboard, next to that socket, "CA061854" and I didn't leave the system on long enough to see if this chip would get any hotter, considering how blasted hot that RAM got within seconds. Hoping someone can provide some direction. Hi Tim, I´ve seen many 800 XL with these DRAMs. They are from Hitachi and yes, far times ago Hitachi has let produced these DRAMs in a fab near Cologne, which later were acquired by Infineon, a Siemens spin-off. The Hitachi HM4864 are equivalent to any 4164 DRAM. And yes, these kind of DRAM could be get very hot if something inside is damaged - like the Micron MT4164, too. The CO61598B is the operating system ROM. It get´s a little bit warmer than usual, when the computer can´t start normally, because CPU is doing endless loops in the ROM sometimes. But as long you can put and holt your finger on it´s surface, all is fine BR Jurgen 1 Quote Link to comment Share on other sites More sharing options...
Rybags Posted May 31, 2016 Share Posted May 31, 2016 Usually when you turn on an XL the screen will be entirely reddish brown for about 1/4 second before turning black. This is good diagnosis evidence. If the screen remains brown it means the OS is unable to start up, which could mean bad OS Rom, CPU, or MMU (or <other>) 2 Quote Link to comment Share on other sites More sharing options...
Timothy Kline Posted May 31, 2016 Author Share Posted May 31, 2016 Hi Tim, I´ve seen many 800 XL with these DRAMs. They are from Hitachi and yes, far times ago Hitachi has let produced these DRAMs in a fab near Cologne, which later were acquired by Infineon, a Siemens spin-off. The Hitachi HM4864 are equivalent to any 4164 DRAM. And yes, these kind of DRAM could be get very hot if something inside is damaged - like the Micron MT4164, too. The CO61598B is the operating system ROM. It get´s a little bit warmer than usual, when the computer can´t start normally, because CPU is doing endless loops in the ROM sometimes. But as long you can put and holt your finger on it´s surface, all is fine BR Jurgen Thank you for the info. I ordered replacement RAM earlier this morning. Hopefully, that's all which is needed--but I doubt it. --Tim Quote Link to comment Share on other sites More sharing options...
Timothy Kline Posted May 31, 2016 Author Share Posted May 31, 2016 Usually when you turn on an XL the screen will be entirely reddish brown for about 1/4 second before turning black. This is good diagnosis evidence. If the screen remains brown it means the OS is unable to start up, which could mean bad OS Rom, CPU, or MMU (or <other>) Thank you, Rybags! This system doesn't even get that far. Absolutely no response, unless you count the very loud "OUCH!" that went off when I found the bad RAM. Replacement RAM is on the way, and then I'll see where things stand with this one. ^_^ I appreciate everyone's weighing in as I muddle my way through this refurbishing / restoration. --Tim 1 Quote Link to comment Share on other sites More sharing options...
russg Posted May 31, 2016 Share Posted May 31, 2016 Thank you, Rybags! This system doesn't even get that far. Absolutely no response, unless you count the very loud "OUCH!" that went off when I found the bad RAM. Replacement RAM is on the way, and then I'll see where things stand with this one. ^_^ I appreciate everyone's weighing in as I muddle my way through this refurbishing / restoration. --Tim You said you have a working 800XL and pwr supply. Instead of guessing it is RAM, if your working one is socketed, you can trade chips until it works. Quote Link to comment Share on other sites More sharing options...
Bikerbob Posted May 31, 2016 Share Posted May 31, 2016 Occasionally there will be mixed brands of Ram in a machine. The main thing is that you don't have MT branded Ram, it's by far the most prone to failure. Replacement Ram chips can be had from various sources, arcade/pinball part suppliers are a good source. The requirement for 8-bit Atari is 250ns access speed or better. Generally any replacement Ram you get for XL or later will meet that requirement. I have MT Ram in a machine I am trying to get working.. Is there a good thread on testing ram? aka determine what chips are bad? and What ram can I buy that will mix with it so that I can get the machine up and running? Suggestion? Quote Link to comment Share on other sites More sharing options...
BillC Posted May 31, 2016 Share Posted May 31, 2016 I have MT Ram in a machine I am trying to get working.. Is there a good thread on testing ram? aka determine what chips are bad? and What ram can I buy that will mix with it so that I can get the machine up and running? Suggestion? If you have MT RAM chips I recommend replacing all of them, they are well known to be failure prone and for the small bit you would save I don't recommend keeping any that may not have failed yet. If you have any difficulty finding 4164 DRAM you can use 41256 instead, you just won't be able to use the extra capacity without some additional circuitry. If your PCB isn't socketed just cut all the legs off the RAM chips and desolder each leg individually, then use a socket when adding the new RAM. Desoldering each leg individually reduces the risk of damaging the PCB. 2 Quote Link to comment Share on other sites More sharing options...
Bikerbob Posted June 1, 2016 Share Posted June 1, 2016 If you have MT RAM chips I recommend replacing all of them, they are well known to be failure prone and for the small bit you would save I don't recommend keeping any that may not have failed yet. If you have any difficulty finding 4164 DRAM you can use 41256 instead, you just won't be able to use the extra capacity without some additional circuitry. If your PCB isn't socketed just cut all the legs off the RAM chips and desolder each leg individually, then use a socket when adding the new RAM. Desoldering each leg individually reduces the risk of damaging the PCB. Got ya.. well 4164 is what I am looking for eh? because it is MT4264 ram.. the sockets I have in the board are not a great job.. wish it was easy to reflow the solder and just put pressure on them to flatten them out.. but I guess the best way to clean it up is to desolder and resolder the sockets. Anyone have a good suggestion of where to buy? or just do ebay? James Quote Link to comment Share on other sites More sharing options...
bugs Posted June 2, 2016 Share Posted June 2, 2016 I got them on ebay from a guy in poland, Took a week to get to Canada so pretty good. http://www.ebay.ca/itm/251666089005?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT Quote Link to comment Share on other sites More sharing options...
Madi Posted June 2, 2016 Share Posted June 2, 2016 I got them on ebay from a guy in poland, Took a week to get to Canada so pretty good. http://www.ebay.ca/itm/251666089005?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT I would prefer to buy brand new dynamic ram 256K 1Bit. They are much cheaper and are found everywhere. They could be handy if you decide to upgrade to 256K later-on madi 1 Quote Link to comment Share on other sites More sharing options...
BillC Posted June 2, 2016 Share Posted June 2, 2016 (edited) Got ya.. well 4164 is what I am looking for eh? because it is MT4264 ram.. the sockets I have in the board are not a great job.. wish it was easy to reflow the solder and just put pressure on them to flatten them out.. but I guess the best way to clean it up is to desolder and resolder the sockets. Anyone have a good suggestion of where to buy? or just do ebay? James MT4264 is the Micron part#, other manufacturers have different part #s. 4164 is the common name/# for 64K x 1bit DRAM. They are available from many sources, here is a link to ABRA Electronics which has a location in Montreal. https://abra-electronics.com/ics-semiconductors/dynamic-video-rams/4164-150-16-pins-64k-x-1-150ns-dram-4164-150.html?currency=CAN They also have 41256(compatible 256K x 1bit DRAM) for a lower price https://abra-electronics.com/ics-semiconductors/dynamic-video-rams/41256-150-16-pin-256k-x-1-150ns-dram-41256-150.html If you are going to desolder the sockets why not replace them with better quality machine pin sockets. https://abra-electronics.com/sockets/machine-tooled-low-profile-sockets/16mlp-low-profile-machine-socket-16-pins-16mlp.html PS: I checked and found ABRA has a $50 minimum order before shipping. Edited June 2, 2016 by BillC Quote Link to comment Share on other sites More sharing options...
+kheller2 Posted June 2, 2016 Share Posted June 2, 2016 This brings up a good topic: is there a list of component providers by country that perhaps we should sticky that people on here have used and had good experience with? Quote Link to comment Share on other sites More sharing options...
Timothy Kline Posted June 2, 2016 Author Share Posted June 2, 2016 Hello, everyone! The new RAM arrived and I swapped it out. All of the RAM now remains cool enough to touch, but the system still isn't ready to boot to a BASIC prompt or Self-Test just yet. From what I can tell, the display via the monitor port is a green, and the RF shows the same when connected that way. None of the other chips are heating (beyond the OS, which does its usual barely-noticeable heat from just being the CPU that it is, I presume). I was searching the forum for any threads that touched on a similar situation and came across the topic of an 800XL Red Screen. In the first post, a picture of his 800XL mainboard is included, and I noticed that it is VERY different from my own 800XL that is presently the subject of my interest. Was this system modded at some point, and someone stripped parts out? I'm hoping someone has some experience and insight to provide some light on an otherwise displayless situation... If you look at the 800XL mainboard the poster has in that other thread, and then the image I'm including with this post, you'll notice that on my mainboard, for example, you'll see resistors between each memory socket, and the yellow wires on the right side of the board. His doesn't have a LOT of the things I'm seeing on this "dead" 800XL. Thank you, in advance! Tim Quote Link to comment Share on other sites More sharing options...
48kRAM Posted June 3, 2016 Share Posted June 3, 2016 Oooh... rework. :-) You clearly have an earlier version of the 800xl than the other picture you reference. Those yellow wires are mistakes made on the board design that were corrected by hand afterward - not uncommon on early rev units if I'm not mistaken. I'm not familiar enough with the XL/XE units to spot any problems visually though. Just browsing the threads. I don't think your board had been stripped. One thing I will say about socketted chips is they do tend to oxidize over time - especially if stored without care as I'm guessing this poor unit was. You would do well to just remove and reseat all the chips a time or two just to break any oxide on them. Be very careful - use a chip puller if you have one or can get one. 1 Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted June 3, 2016 Share Posted June 3, 2016 Remove and reseat all the chips one at a time, starting with the CPU. If that doesn't help, start looking at all the smaller discrete components with a magnifier, looking for failed or bulging caps, burned resistors, etc. Who knows what you might find. One other thing to look at, just a hunch, but maybe check the 4050 hex buffer chip (midway down the board below the RF modulator). One of my 800XL's died a year ago when that chip failed. I got nothing but a blackish/maybe dark red screen when it failed. I swapped it out with one from a spare 600XL and voila. 1 Quote Link to comment Share on other sites More sharing options...
Madi Posted June 3, 2016 Share Posted June 3, 2016 Nope, power supply is fine. Tested it AND connected it to a fully working 800XL. This seems a RAM issue. The U15, specifically. I just want to be sure I'll be fine replacing it with any available Hitachi RAM matching the HM4864P-2, since the "W.Germany" atop the chips is something I don't recall ever seeing before in other systems. Since you had an access to another 800XL machine, it would had been wise if you swabbed the RAM chips before ordering new ones. Now, you have he new ram chips. Just install them on the other XL computer (if it is socketed), just to ensure that they all working before jumping to other options. After swapping the RAM chips, start swapping the other chips one at a time Do not speculate. madi 1 Quote Link to comment Share on other sites More sharing options...
Timothy Kline Posted June 3, 2016 Author Share Posted June 3, 2016 Since you had an access to another 800XL machine, it would had been wise if you swabbed the RAM chips before ordering new ones. Now, you have he new ram chips. Just install them on the other XL computer (if it is socketed), just to ensure that they all working before jumping to other options. After swapping the RAM chips, start swapping the other chips one at a time Do not speculate. madi Nah, ordering the RAM was the right decision, if only to have replacement RAM on-hand for future restorations/repairs. And my other available XL isn't socketed, making the idea of swapping out the chips drastically reduce the inclination to go to the trouble at this point. This may become more of a downtime project in between the more productive Atari projects I've got going on. I do have still another, fully-socketed 800XL that I could use to swap out chips for testing, but that's my pride-and-joy, tweaked system and I'm not going to disturb it just to figure out what's wrong with this particular system. I'll go through, as has been suggested, and try a simple pull-and-reseat with all of the socketed chips, as well as look for any blistered or swollen components, this weekend. After that, it'll go on the shelf and be a downtime casual project. Even if I manage to get this 800XL up and running, I have my work cutout for me with the external issues it has. O.o --Tim Quote Link to comment Share on other sites More sharing options...
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