bugbiter Posted December 3, 2015 Share Posted December 3, 2015 Hi all, Ive purchased a "reimagined rambo256k board" by lenore underwood which I want to install into one of my beloved 800 xls. That product refers to the original rambo installation manual. The original had the ribbon cable already connected to the board and the manual only says to connect the ribbon cable end to those five pins of the PIA chip with the black line to the right one, like. However, my board didnt come with the ribbon cable attached. I have to do it myself and I dont know which of the five board pads goes to which of the five PIA pins. I havent got an answer from lenore yet, maybe you guys can help me faster? Quote Link to comment Share on other sites More sharing options...
Guest Posted December 3, 2015 Share Posted December 3, 2015 (edited) here's mine: there's two different jobs here - the first was how mine was initially done - but ribbon cable wasn't ideal. the second is the fix that Jon [flashjazzcat] did for me - much improved hope these helps Edited December 3, 2015 by Guest Quote Link to comment Share on other sites More sharing options...
flashjazzcat Posted December 3, 2015 Share Posted December 3, 2015 Key wire on rightmost PIA pin to front PIN on RAMBO (see feint black marking in photo). Ignore other jumpers in photo, BTW: this board was repaired. Quote Link to comment Share on other sites More sharing options...
bugbiter Posted December 3, 2015 Author Share Posted December 3, 2015 Great! That'll do! Quote Link to comment Share on other sites More sharing options...
ClausB Posted December 3, 2015 Share Posted December 3, 2015 RAMbo is based on this homebrew upgrade: http://atariage.com/forums/topic/122470-ram-upgrade-applications/page-2?do=findComment&comment=1481893 1 Quote Link to comment Share on other sites More sharing options...
bugbiter Posted December 6, 2015 Author Share Posted December 6, 2015 (edited) Meh! I've soldered the 5 connections between rambo and PIA; the line from pad D for the moment I just tucked around the right end of R32.. and - it doesn't work :-( I then checked the position of the jumpers on the board - they were all in the position as marked on the board. The Rambo guide says to put them into position "0" which means NOT like the marking. After changing them It still doesn't work. Then I noticed in your pictures that IC1 socket is not empty like mine but you placed that little IC U27 in it that gets replaced with rambo board.. Putting that IC there also didn't do the trick... What about it? neither Lenore nor the original manual says what to do with that chip that was in U27... At the moment I'm clueless what to do.. After switching on, the Atari first shows that random brown or yellow screen, then it goes black and you hear that familiar pop, but it stays black and no blue GR0 screen comes up.. The machine itself is good - removing rambo, putting U27 back in and another PIA with all the pins (leaving the new 256bit RAMs in) it works perfect. Help! Dammit! Found it! I took the wrong PIA 5 pins! I have to desolder and shift all the lines 1 pin to the left :-) Silly me! I keep you posted.. Edited December 6, 2015 by bugbiter Quote Link to comment Share on other sites More sharing options...
bugbiter Posted December 6, 2015 Author Share Posted December 6, 2015 well, I resoldered the wires to the pins, the machine boots up and goes directly into the Memory test. The first 16 dots come out green, then the display turns blank and the dark green background turns brown. I assume this means accessing memory above $4000 has some unwanted effects... Can anyone give me a clue? Quote Link to comment Share on other sites More sharing options...
flashjazzcat Posted December 6, 2015 Share Posted December 6, 2015 (edited) Have you hooked the other jumper wires up yet? I can't see any in the photo. There are four additional connections between the motherboard and RAMBO. Scratch that... Not on the 800XL there aren't. Edited December 6, 2015 by flashjazzcat Quote Link to comment Share on other sites More sharing options...
ClausB Posted December 7, 2015 Share Posted December 7, 2015 Yes, you must put the 74LS158 chip from U27 into the IC1 socket. There should be no empty socket on the RAMbo board. It seems you have a PAL ANTIC. I don't know whether it has 7 or 8 refresh bits. To be safe, assume 7 and follow the instructions for the old ANTIC. So you must wire jumper C. Quote Link to comment Share on other sites More sharing options...
Dropcheck Posted December 7, 2015 Share Posted December 7, 2015 Look at Brenski's first picture in his post. I believe your left jumper setting is wrong. Quote Link to comment Share on other sites More sharing options...
bugbiter Posted December 7, 2015 Author Share Posted December 7, 2015 I already fiddled around with the jumpers. Strange that the good setting is NOT as marked on the board. I will try the C cable when I get home, maybe that helps... Quote Link to comment Share on other sites More sharing options...
+Larry Posted December 7, 2015 Share Posted December 7, 2015 @brenski- 32-in-1 OS with the Rambo makes a very nice machine, doesn't it. Do you use a PBI hard drive and if so does it have any stability problems (from the 32-in-1 and/or Rambo)? I've got a couple similar setup XL's, and on at least one I had to do the Bob Puff "Stable XL" fixes. -Larry Quote Link to comment Share on other sites More sharing options...
Dropcheck Posted December 7, 2015 Share Posted December 7, 2015 (edited) I already fiddled around with the jumpers. Strange that the good setting is NOT as marked on the board. I will try the C cable when I get home, maybe that helps... Not the C cable, but the actual jumper pins along the left side. I believe you need to move the jumper from the last two pins to the first two pins. That is the difference between your pic and his first pic on the board. There is no 'good setting' for this board. It was meant to be as changeable as possible to accomodate the various versions of Atari computers. Sometimes combinations came out after it was original produced that created problems with it working. I don't think your machine is the problem. I just think that sometimes we need to experiment to find the 'right' setting for your machine. Understand that if you add other mods to the machine there is a chance you may have to experiment again. Edited December 7, 2015 by Dropcheck Quote Link to comment Share on other sites More sharing options...
bugbiter Posted December 7, 2015 Author Share Posted December 7, 2015 I have already changed the left jumper after I read in the manual it should be set to "0" meaning not as marked on the board. It came preassembled in "-" position though. Quote Link to comment Share on other sites More sharing options...
bugbiter Posted December 7, 2015 Author Share Posted December 7, 2015 In the pic it is still in "-" position Quote Link to comment Share on other sites More sharing options...
Dropcheck Posted December 7, 2015 Share Posted December 7, 2015 I have already changed the left jumper after I read in the manual it should be set to "0" meaning not as marked on the board. It came preassembled in "-" position though. Yes, because the '-' position is the default on my original board. So right now the jumper is closing the top and middle pins? Not the bottom and middle pins. Quote Link to comment Share on other sites More sharing options...
Dropcheck Posted December 7, 2015 Share Posted December 7, 2015 If it is still not working please take another pic of the mainboard so I can see what's connected and not. It seems you've made some changes since your last pic. Quote Link to comment Share on other sites More sharing options...
ricortes Posted December 7, 2015 Share Posted December 7, 2015 Try moving your ribbon cable one pin over? Quote Link to comment Share on other sites More sharing options...
Guest Posted December 7, 2015 Share Posted December 7, 2015 @brenski- 32-in-1 OS with the Rambo makes a very nice machine, doesn't it. Do you use a PBI hard drive and if so does it have any stability problems (from the 32-in-1 and/or Rambo)? I've got a couple similar setup XL's, and on at least one I had to do the Bob Puff "Stable XL" fixes. -Larry Larry, actually, err, no it doesn't. it's a shame - but it just didn't work. to put it correctly - it worked for ONE HOUR and occupied far too much of FJC's time trying to fix it for me. in the end i've given up leaving the rambo in place and the wiring for the 32-in-1 but the 32-in-1 removed. shame i know, but there it is Quote Link to comment Share on other sites More sharing options...
bugbiter Posted December 7, 2015 Author Share Posted December 7, 2015 (edited) Hi Guys! I got it! I now put all jumper bits into the "0" position. (I still had the left one on "-") Now it's up and running, even without the C cable attached. Thank you all for your great helpfulness! sorry if I got you confused with my erratic trying around and posting old pictures :-) My 128K APAC animation is playing fine on the 800XL! Edited December 7, 2015 by bugbiter 2 Quote Link to comment Share on other sites More sharing options...
ClausB Posted December 7, 2015 Share Posted December 7, 2015 Congratulations! If it works without the C wire, then the PAL ANTIC must have 8 bits refresh address. Can anyone confirm that's true? Quote Link to comment Share on other sites More sharing options...
Dropcheck Posted December 7, 2015 Share Posted December 7, 2015 Quote Link to comment Share on other sites More sharing options...
ClausB Posted December 8, 2015 Share Posted December 8, 2015 My question should not be ignored. The answer determines how reliable the upgrade will be. If the PAL ANTIC has only a 7 bit refresh address, and you don't wire jumper C, then the RAM will not get refreshed properly. Even worse, it can fool you, because some graphics modes will cover all the refresh addresses, so it all seems to work until you run certain programs with custom displays and then it crashes. So, please, those of you with 256K upgrades in PAL land, please reply with your experience. 3 Quote Link to comment Share on other sites More sharing options...
Dropcheck Posted December 9, 2015 Share Posted December 9, 2015 (edited) Hi ClausB, Found this. I believe this will answer your question. http://www.atariage.com/forums/topic/105124-chip-differences/ Also found this in a Nir Dary PAL/NTSC upgrade text at http://www.myatari.com/nirdary.html >>Special Note For Users With RAM Upgrades: if you have a RAM upgrade with wires attached to the ANTIC chip, carefully desolder those wires when you remove the old ANTIC. The new PAL ANTIC CO21698 is functionally equivalent to the newer NTSC ANTIC, CO21697. If your old ANTIC was CO12296, consult the documentation for your memory upgrade for the correct re-wiring. In general, the wiring is simpler for the newer ANTIC chips CO21697 or CO21698. Edited December 9, 2015 by Dropcheck 1 Quote Link to comment Share on other sites More sharing options...
ClausB Posted December 9, 2015 Share Posted December 9, 2015 Thank you for researching that. So the bad news for Bugbiter is that he needs to wire jumper C and change JP3. Quote Link to comment Share on other sites More sharing options...
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