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|by Bill Degnan - 09/27/2005 21:22|
Died on the table. I can sometimes get it to boot, but the hard drive is now dead. For about three hours I used this system, with Wyse terminal, M/PM OS. Then "click click click..." This unit was rebranded and sold as part of a business system by a company called Sentinel, and they called the system the "Dimension Five"
|by Bill Degnan - 09/28/2005 21:20|
COntinued with the Altos
1. Power on, clink sound some of the time. Maybe a character or two appears on the terminal. Often this character is a "P". No other activity. No disk drive movement, no hard drive activity. Fan comes on.
2. Opened system.
3. RE-seated top/motherboard chips/IC's. Enabled me to boot to self test:
ALTOS COMPUTER SYSTEMS
MONITOR VERSION 7.02
..."Self test running"...
..."Booting from hard disk"...
..."Hard disk read error status 07 (or 08 or 30)
|Altos 5-5AD Revisited|
|by Bill Degnan - 01/22/2008 08:15|
Still no progress, I can't get the computer to do anything. I have some new ST-506's on hand, I will try replacing the hard drive, but first I have to get past "nothing happening" other than the fan coming on. This bird needs help.
Here are some pics
|Altos 5-5AD board repair complete|
|by Bill Degnan - 02/03/2008 13:46|
With tutoring from B Grieb, I learned how to better troubleshoot the motherboard. I can again see the self test boot screen, referred to earlier in this thread.
Here is what we did:
Through careful observation we determined that something was wrong with the communications between the terminal and the RS232 port. With the terminal plugged in, powered on the computer appeared to stall early in the boot process. With the terminal unplugged the computer appeared to go farther (drive would spin, hard drive would light). No characters to the display. Hmmm...
1. clean all sockets and re-seat all chips
2. check chip connections (with power off) using Ohm setting in Fluke meter. By probing a pin connection under the board and at the pin itself one can verify that there are no bad solder joints. My fluke has a beeper to signify a connection, but it's so sensitive that you really need to let the ohm readout to make sure proper voltages were coming through. We also experimented with a sheet of tin foil pressed to the bottom of the board, and used it as a proxy for ohm probes, with limited success.
3. Locate the RS232 driver chips. These chips are near the RS232 ports, and will end in 1488 (send) 1489 (receive). To verify that they're getting the proper voltage, probe pin 7 and pin 1 = -12v and pins 7 and 14 should = +12v
4. Took a look at the cable that connects the terminal with the computer. It's a straight-through. The cable should plug into the "modem" port of the Wyse terminal (not Aux)
5. Using Oscilloscope to test RS232 output (1488)
-ground clip to computer
-probe to pin 3 of rs232
-oscilloscope = -5V (OK)
Check oscilloscope on pin 2 of the RS2232 receiver chip (1489) - found it to be bad, not receiving the signal. Replaced the chip.
6. For the TTL chips, you're looking for V=~5 (4.95/5.05 OK) *in general* there are exceptions and you should check your schematics. We did not have schematics so we had to guess. Probe the corner pins to check the voltage while the system is on.
7. Disk drive not responding: Found that the TTL chip in position D10 (74LS32) was bad by measuring pin 12. Going 14 ohms to ground. Replaced chip.
8. Discovered that the C2 jumper in slot 3, if pulled, will turn off autoboot to hard drive. By inserting a disk that does not boot (but is formatted for an Altos system) causes system to prompt choice of hard drive or disk boot.
|MP/M v2.14 Boot Disk|
|by Bill Degnan - 02/03/2008 13:46|
MP/M v2.14 Boot Disk
I was able to make an MP/M boot disk v 2.14. Thanks Dave Dunfield and his ImageDisk!
I was able to boot by floppy to both MP/M and CP/M, and through these regain access to the hard drive without replacing it (drive C) as I originally thought would be necessary. My guess is that when the system originally farted out, it chewed up a little of the file table making it loose it's ability to read track 0. I should be able to clean it up and boot without disk soon.
|Altos 5-AD Setup|
|by Bill Degnan - 02/09/2012 21:18|
So...here's a basic rundown of what you need to do to get your Altos 5-5AD running
1. Use image disk (imd) from Dave Dunfield's site to build two disks; ALTOS Diagnostics v 3.150 and the MP/M v. 2.14. Have fun, it takes a while to find the right combination of parameters to make usable disks. It appears that the images from dunfield's site were not built by the same person or with the same kind of set up, so you have to use different settings to build one disk vs. another. At least that's what I found using my Compaq Deskpro 386s and DOS 5.
2. Boot with the diagnostics disk and run HARDS5. Choose the hard drive format command. When asked "Do you want to continue?" rather than say "Y" enter "sotla" This is the secret response you need to bypass the format block...geez that took a lot of hacking time to find. If you do a hex dump of the disk search for SOLTA.
3. Use MP/M 2.14 INSTMPM command to move MP/M to the hard drive.
You will also have to go through additional hoops to get the system to boot from the hard drive. To do this you have to find a way to get MPMSETUP.COM onto the disagnostics disk.
Altos 5 MP/M Manual
|by Bill Degnan - 10/17/2012 15:33|
Some possible commands look like:
FILELIST <<<<< Maybe this is what you want?
And, of course, the ubiquitous