... Several years ago one of the members of this forum provided me with an 8 inch diskette copy of Burcom CP/M 2.2 which worked great on my Altair 8800 with...
2948
stuartawyatt
Jan 11, 2013 1:11 am
It's been 40+ years since I stepped through that code, but I think it was a tight loop for the sector hole, then read two bytes at a time inline and then...
2949
Dave Sroelov
dsroelov
Jan 11, 2013 6:01 pm
i'll take a look for it as well. it's buried in a box here somewhere. it was a very tight loop. from what i remember, the controller spits out a byte every...
2950
B Degnan
billdeg
Jan 11, 2013 6:10 pm
There's a 680 on Ebay. Looks good, round paddles. Bill...
2951
steve
alltare
Jan 12, 2013 12:52 am
I guess he's referring to this one, with bat-handle switches: http://www.ebay.com/itm/321053564606 Too bad there are no internal photos. I worked with several...
2952
deramp5113
Jan 13, 2013 6:55 pm
Nobody in my circle of friends or family cares about this, so I'll post here! I purchased a non-working 8800b off eBay recently. The computer and boards are in...
2953
corey986
Jan 13, 2013 8:16 pm
I'm very happy for you. I remember that auction. You got a great price. I was going to bid on that system just for the sio-2 card and the MITS ram cards. I...
2954
steve
alltare
Jan 14, 2013 6:49 am
Congrats, Deramp. The original 8800 *may* be more collectable, but the 8800b is, in my opinion, a machine that not only looks better, but is also more...
2955
W Tom
wtsnet
Jan 14, 2013 8:08 am
My congratulations too. I'm an 8800b owner and fan, however there are problems. In my opinion the Altair 8800b was one of the best looking computers made. The...
2956
corey986
Jan 14, 2013 10:46 am
Better power supply is an understatement.... Just watch the power drop on a stock 8080 with a full set of cards... LOL Cheers, Corey...
2957
mfeberhard
Jan 14, 2013 7:11 pm
An easy way to blow that -18V power supply transistor (and the positive transistor) is to bump the -18V line against the +18V line with your meter probe. The...
2958
deramp5113
Jan 14, 2013 8:06 pm
When I found the -18v supply at -27v, I suspected I'd find the +18v supply at +27v for the very reason you mentioned. It was fine though. To be sure, however,...
2959
steve
alltare
Jan 14, 2013 10:57 pm
Tom- I'm certainly not going to say that the 8800b is perfect, but I think you have picked a couple of poor examples of "problems";. I have seen yellowed 8800b...
2960
Stuart Wyatt
stuartawyatt
Jan 14, 2013 11:50 pm
To B or not to B is a quandary I've had for years. I have an 8800 that was upgraded to an 8800B. The upgrade was virtually everything but the case, so we...
2961
mr_john_smith@...
mr_john_smit...
Jan 15, 2013 8:03 am
I was just curious if the Altair's were produced with a 220-240 volt power supply for the UK, Europe and Australia market? - MrSmith...
2962
steve
alltare
Jan 15, 2013 6:25 pm
All versions of the Altair had transformers with split primaries, which could be wired for 110/220. MITS/Pertec 8" floppy drives of the FD500 series (with AC...
2963
steve
alltare
Jan 15, 2013 6:35 pm
Stuart- Gates signed the cassette, but did he sign the computer? Do you have any kind of evidence that Gates played with your computer, or even looked at it?...
2964
steve
alltare
Jan 15, 2013 7:03 pm
I just took a look at my 8800 manual. I was mistaken about ALL versions being capable of 110 or 220V operation. The 8800 and 8800a require different...
2965
W Tom
wtsnet
Jan 15, 2013 7:30 pm
I have a 3202 chassis with a factory label that says 245V 50Hz. The chassis is now setup for US voltage. This chassis faceplate is brown/tan. I don't know if...
2966
MrSmith
mr_john_smit...
Jan 15, 2013 8:02 pm
Thanks for the replies Steve and Tom - John ... From: W Tom <yahoo@...> Subject: [Altair Computer Club] Re: Altairs with 240v power supplies? To:...
2967
Stuart Wyatt
stuartawyatt
Jan 15, 2013 9:07 pm
Steve, Gates didn't sign the computer. I guess at the time I thought the cassette made sense with the connection to Gates/Micro-Soft, but not as much for the...
2968
steve
alltare
Jan 16, 2013 3:01 am
Stuart- As antique collectors are fond of saying, a photo or signature would add "provenance" to your 8800b, just as it will to the cassette. The value is...
2969
W Tom
wtsnet
Jan 17, 2013 1:29 am
Steve- My poor examples come from the mainframes I am repairing. I have four 8800b regulator boards to repair. I don't know if heat or shorts caused the...
2970
David Chester
davidchester2
Jan 17, 2013 9:00 am
Hi guys, I've finally put my remaining S-100 boards on eBay for anyone interested: MITS 16MCD 16K Dynamic memory card with Intel chips MITS boot PROM board...
2971
W Tom
wtsnet
Jan 18, 2013 8:10 pm
Here is the MBASIC4 Program used to capture the CBIOS. 1 'GETBIOS - CP/M MBASIC4 10 CLEAR 10000: WIDTH 80 20 SA# = &HE600 'BIOS Start Address for 60K MITS CP/M...
2972
deramp5113
Jan 19, 2013 6:28 pm
Thanks to W Tom for memory dumps of the BIOS of Burcom CPM 2.2! As suspected (since the Burcom CPM works with a real drive), the disk write logic in the Burcom...
2973
steve
alltare
Jan 20, 2013 4:05 am
Deramp's "machine gun" sound reminds me of a program going around at MITS that would load and unload the head of an 8" drive, at a speed that increased from a...
2974
deramp5113
Jan 26, 2013 1:40 am
I'm about to write routines to transfer an image of a floppy disk in an original Altair drive (77 tracks, 32 sectors per track, 137 bytes per sector) to a file...
2975
D. Hugh Redelmeier
hughred
Jan 26, 2013 3:25 am
... Naive questions (from someone who has no disk on his Altair): Are you running some OS? Like, say, CP/M? If so, xmodem, zmodem, and kermit protocols...
2976
billdeg
Jan 26, 2013 3:33 am
I would love a routine that uses the 2SIO like you can download BASIC into the Altair! Hope you can pull this off. It would in theory work like a massive BIN...
