Altair 8800b Final PT 9

okay I found it the processor board that was giving me trouble it worked one time and it and the day after it stopped working along with a lot of other things on the adat board for number two number twos original one the 74 LF it’s a 74 367 right off of the processor board right next to it way I found that set that good board next to this one is a common ground which I used off of here then you just compare pins but I compared this side I didn’t bother comparing the other side so flip it over and it was at Penn a green I’ve got tinted green this one here is the one that was acting up so I started pulling chips out one at a time and seeing when that would change and get measurement it was door near a dead short so pulling them out one by one soon as the value change you can start there and I pulled that one out while I had this out I head out processor out as far as I God then I yanked that one and that’s when it changed so i dug up another 367 put it in their bag fine so that’s all we did it that’s how I do it so that one’s back in business this is to be continued it’s 916 it’s a monday morning first off these two these 80 ones there’s machine number three I spoke the switch off it somehow when I hit it in the corners which is gone I’ve got this temporary one down here the problem seems to be I am missing my plus 18 volts I’m getting three holds up in like that all the way across I got my eight volts on the two top ones here I got my mind is 18 i also had pictures you this minus 18 circuit must have had a problem with it because they’ve got the jumper in between here here here yeah and the upper between this morning this and as you can see its front lights all lit up to and i also have got my turtle bored in here but even it’s it’s not reading its light as so the boards that’s the grand one day and the following day no all the lights came on and the things stopped working and that’s when you started testing out number two yeah this is to really if I there this one started clapping out 24 hours later also the same one that popped the capacitor and the other machine you yeah those number three here number two on right now I’m doing the same thing I did to this one I’m switching boards out trying to find out where the problem is so far I have done to that so that’s an update for that one I guess I’m gonna get a switch for today put the thing back together the clients no big deal so let’s the update

this is my s100 had a piece this together to a scanner gave up just sitting on the hill don’t even use it HP last time i use it work fine put it up in the shelf 23 years later i want to use it again doesn’t work doesn’t come on and bold it back to the circuits so up the door it goes I had another free HP more high-tech scanner plugged it in sat on sat there waiting did it’s a little test and everything it just would not be talking the scan a copy wouldn’t do it disappearing set on ready waiting we just sit them so that’s the update well here’s number three I got it running it fixed the the others processor board so this one has its own back in it again problem is now was I give up on it the 232 k board 0 to 30 to 32 to 64 it’s 32 to 64 k board the longer it sits the more the memory disappears whatever is in there it just starts disappearing and it goes back to 0 the 0 2 32 k board works fine nice and clean in there no errors that i can say i think the one bit may have been bad maybe at this board here 32 to 64 I’ve been through it it’s a ravine seaboard this is a revision eboard here there are some slight differences I got this off a line or online since these are expanding ram boards but this only goes up to revision b which is close enough to the sea where i could do some checking but i’m just not sure where an act to go foot from here with this thing so i give up on it i’ve been a disabled via these switches here this is yeah this memory protect here’s the address which is the for the 88 rolls 468 so now I’ve got it addressed out so we can sit in there but it won’t do no good Manco digital analog board I’m not really going to get into that I don’t know what the homebrew board was for I’ve got its disk drive boards back in it I’ve got it’s a prom board back in it and here’s a riddle process abort so yeah it uh it will run if these other boards are removed I’m guessing it a load of disks no root no real reason to load a disk in it so but it will run get a good processor board good memory board one at least turn keyboards good I also had to take my console my terminal board and put it in here to run terminal and had to remove all of them as they weren’t needed but yeah for the most part it runs all it needs now is software to turn the other stuff on and figure out where their terminal I think this was their terminal I think can’t be sure so I’m going to put her back on their health leave some notes behind that’s number three I’m going to get that out of the way and by her chance while repairing that one I did manage to find the original prams that went in

this one 1702 so what my next attempt is going to be put this one back the way it was I had to dig up some 2102 memories chips for it but I found the original prams that came with this thing I think their mitts problems that’s the latest update and it is 923 of 2013 and here’s number two to put the lid on it got the original prams back in there and they still work the two on the left is in our disk copy prams and they work but you have to access them using the optimal address the one on the right far right is a bootloader distant loner it’s at FF 377 octal and the two on the left started us f e C D F D started FD 0 0 0 37 for anyway s original ones the I took there’s the 2708 board the memory stops at 56 k which is where this board picks up I had did what I did where’s it happening of those what I did this here is the diagnostic program this is for programming the things this one here I believe that’s a four yeah this is the one here’s the one I moved it from here from the f c 00 or the other problem or is so i can’t have nothing in this slot so i moved it from here over to here just keep it handy yes this is an original an original and original for some reason they’re all empty we’re just filled with zeros I don’t think they got erased I don’t know if they may have gotten zapped somewhere along the line but I have a copy you know I don’t have a copy of those I was curious what was in them so I just stuck them in there anyway just in case for some reference I don’t know I don’t know what happened to him so that’s Vaseline works on these slides pretty good so I got that there and silicone on the connectors turn it on is Lisa Lisa also has its original processor board in there I got it fixed I mention that or not so access the little disk program in those problems 74 or 75 G 37 5000 there now someone made those copies from this 12 disc 01 @ address 0 when ready what you do hit the reset button which is loaded at something zero that’s all it did move itself to zero and you go well we can do this way HD 20 see it’s that it’s really not quite that much it just

loads itself on 202 00 d is the same thing that voltages so that’s the update it’s 925 it’s after midnight again Selassie look what I happen to find s100 bus Motum 100 by hayes i don’t know if that’s a 100 bod if that’s a 300 baud had that thing laying around for some reason I don’t know if I even tried it don’t have no software for it so a little box that goes with it that I just think come on your camera well what I did this is 926 156 what I did took out my capacitor like a filter it took it out took out my resistor just using the knob there’s just too many variances between the two disk drives for some reason I still think it’s all in that board and I did the mod on the disk drive board one was chipped d3 10-7 you cut that and jump it to chip be 5 10 9 apparently when running more than one disk drive with those boards there was a problem reading to supper disks hist 5 so I took a chance jumpered it did there a modification it don’t care I think still has a problem with these two discs it’s like variants of voltage on the strobe that’s what that was supposed to fix I don’t know what to do about it I’m not gonna worry about it i’m going to close the lid on this thing and they’re all going back on the shelf because they all work trying to get words down here but the road star yes x Oh beers that comes up with all this so will exit they run for now until someday when someone turns it on and then smoke will emerge out of one thing or another I know that that’s another day you