keenerb wrote:

I pulled apart this Tandy 1000SL late last night and took a look at the feasibility of repurposing the case for my xi8088. […]
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I pulled apart this Tandy 1000SL late last night and took a look at the feasibility of repurposing the case for my xi8088.

It's a pretty big/roomy case, so it's no surprise that the motherboard actually fits well internally, none of the 8 slots will be blocked completed, and only a few are blocks length-wise by the built-in speaker. Right now the only thing holding it in place are the two expansion cards.

The mounting holes for the Tandy motherboard are (unsurprisingly) completely wrong for the micro-atx backplane. The three along the back of the case are not in any danger of causing a short circuit but the three staggered along the middle of the case are of great concern to me.

The two smallish cards above and to the left of the motherboard are the audio interface card and the joystick/keyboard interface card. I've left them in there mostly to avoid losing them in my giant stack of parts. However, when I looked more closely at the audio interface card, it occured to me that possibly I could use that as an interface to a Soundblaster card.

The audio interface card has mic/line in, audio out, volume control, and a reset button. There are eight pins connecting the daughterboard to the main 1000SL motherboard, so that has me wondering if there's simply four sets of two pins, one set per front-panel connectors. If that's the case, I should be able to leverage that potentially utilize the internal Tandy speaker along with the built-in amplifier chip and volume potentiometer for audio, and the input, speaker jack, and reset button. At the very LEAST I think I can use the front speaker (sans volume control) and reset switch.

*edit*

I'm going to make this into a seperate post, this is far beyond any xi8088 specific discussion.

For the ones in the middle of the case, you can place felt between them and the board should make sure it makes contact

for mine, my ancient backplane screw holes didnt line up with the modern case, so i folded up antistatic bags and taped them over the posts, the tape is only on the floor of the case, i had heaps of AS bags laying around so they folded up and did double duty.

yeah but I'm worried about the leads poking through. I'm terrible at soldering, the back of my board is like a thousand razor blades...

I picked up some tiny plastic push clips (like for automotive trim) and I think they'll provide a nice nylon cap over the screw holes.

Make a backing for the board out of cardboard. Corrugated cardboard if you have the clearance.

been testing my new bios, seems like my little tweaks have been good but need more time testing it, seems to have fixed the vga startup tho.

tested my 3c503 network card, it has jumpers for io, but it assumes DMA + IRQ it seems, and of course its DMA 1, same as my soundblaster card ugh. going to have to mess around and see what can be changed or not. I _think_ you can change the dma/irq in software...

BloodyCactus wrote:

been testing my new bios, seems like my little tweaks have been good but need more time testing it, seems to have fixed the vga startup tho.

tested my 3c503 network card, it has jumpers for io, but it assumes DMA + IRQ it seems, and of course its DMA 1, same as my soundblaster card ugh. going to have to mess around and see what can be changed or not. I _think_ you can change the dma/irq in software...

Yes there is a setup program that you can use to set parameters. It's been many years since I used a 3c503 but I remember distinctly using suck setup to set parameters manually on one.

(edit) Uh no I was wrong. I must have been thinking of another card. It turns out that the jumper sets not only the IO address, but also the IRQ. http://docs.oracle.com/cd/E19504-01/805-3980/ … dbph/index.html

(edit2) I found the technical reference manual for 3c503, and it says that the IRQ and DMA are selectable by software. Ugh. https://ia801604.us.archive.org/35/items/bits … rence_Jan89.pdf

(edit3) this says that the IRQ is passed as option to the packet driver http://www.vcfed.org/forum/showthread.php?645 … -with-the-PC-XT

Indeed if you use the crynwr packet driver from http://www.crynwr.com/drivers/many-other-drivers.zip you have to pass the IRQ and I/O as parameters; doesn't use DMA (see install.doc and 3c503.asm in http://www.crynwr.com/drivers/pktd11a.zip)

My Tandy EGA card won't work in this system any more. It worked once or twice (and displayed a very very unstable image, like heat waves running up/down the screen), and now won't work at all.

It's 100% fine in two Tandy systems though.

Very odd.

stamasd wrote:

Yes there is a setup program that you can use to set parameters. It's been many years since I used a 3c503 but I remember distinctly using suck setup to set parameters manually on one.

thanks, I have the 3c503 driver disks and the software and the only packet driver i could find is the crynwyr one. When I tried to change the settings the screen ran garbage and the box reset... ill try it again tomorrow.

Yep firmly back in "weird things are happening" territory. Occasional POST hangs at 06, 54, and 60 during extended testing with an otherwise perfectly functional CGA card now.

I think I'm going to throw in the towel on this for now, I must have cooked something good when I shorted that speaker connector. I'm ordering a new board and will work on populating it with basics and then transfer over my logic and see what happens.

BloodyCactus wrote:

stamasd wrote:

Yes there is a setup program that you can use to set parameters. It's been many years since I used a 3c503 but I remember distinctly using suck setup to set parameters manually on one.

thanks, I have the 3c503 driver disks and the software and the only packet driver i could find is the crynwyr one. When I tried to change the settings the screen ran garbage and the box reset... ill try it again tomorrow.

This may help. http://files.mpoli.fi/hardware/NET/3COM/3C503.ZIP

It has the following in a text file

1Configuring the EtherLink II Adapter
2
3.lt
4Adapter Name: Etherlink II       Data Path: 8-bit
5   Product #: 3C503                    Bus: ISA
6  Assembly #: 2227                     RAM: 8 KB
7         aka: IE-6                     CPU: none    
8
9           |         |             |             |         |
10E'Link II  |standard |  available  |   driver    | adapter |
11           | setting |  settings   |   params    | jumpers |
12============================================================
13DMA ch     |    1    |     1-3     | /D:dmach    |   ---   |
14------------------------------------------------------------
15int level  |    3    |     2-5     | /I:intlvl   |   ---   |
16------------------------------------------------------------
17I/O        |   300h  | 250h, 280h, | /A:iobase   |    1    |
18base       |         | 2A0h, 2E0h, |             |         | 
19address    |         | 300h, 310h, |             |         |
20           |         | 330h, 350h  |             |         | 
21============================================================
22DMA type   |   {1}   |   1-4 {2}   | /M:dmatype  |   ---   |
23------------------------------------------------------------
24xcvr sel   |   BNC   | BNC,DIX {3} | /T:xcvrtype |   ---   |
25------------------------------------------------------------
26memory     |disabled |dis, C8000h, |    ----     |    1    |
27base       |         |     CC000h, |             |         |
28address    |         |     D8000h, |             |         |
29{4}        |         |     DC000h  |             |         |
30------------------------------------------------------------
31.el
32
33Format of the device driver specification in CONFIG.SYS may 
34either be keyed parameter format 
35
36.lt
37	device=eth503.sys [/A:iobase] [/D:dmach] [/I:intlvl]
38                          [/M:dmatype] [/T:xcvrtype]
39.el
40
41or positional parameter format, with "x" indicating the default 
42value for the corresponding parameter
43
44.lt
45	device=eth503.sys [intlvl [iobase [dmach [dmatype 
46                                            [xcvrtype]]]]] 
47.el
48
49Examples of the device driver specification for using interrupt 
50level 3, I/O base address 310h, DMA channel 3, DMA block mode 
51transfer in an 8086 machine, and an external transceiver:
52
53.lt
54	device=eth503.sys /d:310 /i:3 /t:2
55	device=eth503.sys x 310 3 x 2
56
57{1}   Default for 8088 and 8086 class machines: 3
58      Default for 80186/286/386 class machines: 4  
59
60{2}   1 - DMA byte mode transfer

61      2 - Programmed I/O loop (or no DMA ch on computer)
62      3 - DMA block mode transfer
63      4 - Programmed I/O using REP instruction (valid only
64          on 80186, 80286, and 80386 class machines)
65
66{3}   1 - BNC
67      2 - DIX
68.el
69
70{4}   If the optional EtherStart II PROM is installed, enable it   
71by setting this jumper to select one of the four 16K blocks 
72of memory.  8 KB are reserved for the Start PROM, and 
738 KB are reserved for Shared Memory.  The adapter 
74driver will attempt to operate in Share Memory mode rather 
75than in DMA mode.
76
77If the optional EtherStart II PROM is not installed, set 
78this this jumper to "disable"; the adapter/host CPU 
79interface will use the DMA mode specified in CONFIG.SYS. 
80

The rest of the replacement logic will be here tomorrow. At this poitn I've ordered enough components to assemble a complete second xi8088, and I don't feel really happy about that, although I did go ahead and order a second main board!

If the logic replacement fixes my existing board I'll just package the rest up and see if I can sell it on Ebay as a "kit".

WELL it looks like it was a problem with possibly the 00 or 32-series logic, even though it all tested fine in my minipro.

The problem changed significantly when I replaced the 00 logic, and completely vanished after changing the 32 series chips. The U45 chip that was mentioned as potentially being in direct line with the PC speaker was one of the 00-series chips I replaced, so that is pretty suspicious. I did swap the 00's around to see if anything changed before replacing it and it didn't...

SO FAR, anyway, I've thought I had this problem licked before and been wrong...

This does mean I have enough parts left over to build another complete, working xi8088 system, which is a lot of $$$ I would rather have not spent, but I'm still pretty pleased regardless.

I'll just package everything up and sell it on Ebay as a complete build-it-yourself project kit and see if I can get my money back...

Wait! You can never have too many XT-class computers! 😀

(if you thought this hobby is cheap, you're mistaken. Well perhaps cheaper than having a mistress or something...)

My ega card will not work at 10mhz, and my cha card eventually experiences graphical corruption at 10mhz. I have backed down to 8mhz and things seem much more stable.

Got everything tucked away in my Tandy 1000SL case without making any modifications to it.

The power/reset switch that's hanging out of the front is pretty 🙁 but I'll figure out something there...

I'm glad you got it all working! my change tot he video stuff on bootup does not appear to be working so I need to revert my bios patch. been away at a pinball tournament for the last week, so now I need to get my network card working and try and round up a floppy controller card to tie up to my gotek with hxcsd firmware.

Apparantly my fully functioning xi8088 angered whatever celestial beings are in charge of retro computing.

A massive thunderstorm yesterday evening apparently zapped my machine. I had a scrambled, rolling image on the screen for a few reboots and then nothing. the on-board POST diagnostic reports code "60".

errno.inc reports that's a fatal error in the keyboard controller. I haven't pulled it apart to replace that chip yet, I ended up with 10 of them so it's not like I have no spares...

Oy gevalt.

UPS time.

That was precisely my first though, should have had a UPS.

On the topic of power, though, I looked up the specs on that picopsu I'm using (90w); it provided 5 amps on the +5v rail, which is more than enough for this machine. My latest Kill-A-Watt measurement says 14 watts total power draw with EGA card, xi8088, SB 2.0, sergey's floppy controller, hxc floppy emulator, and compactflash ide card and adapter with the picopsu, under typical load (looping Champions of Krynn demo).

thats crazy. my chassis has a like 300wat at psu. good thing these are just on/off psu and not needing a load like atx ones!