VOGONS


First post, by Half-Saint

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Anyone here has one? Has anyone thought of reverse-engineering one? I mean, cloning it shouldn't be that hard as long as it's a two-layer PCB.

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Reply 1 of 5, by MrSmiley381

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I've actually got a Tiny Turbo Xtra. I think it uses some PAL and GAL chips, so some of the cloning might be hard to do. The real trick is cloning those fancy 286-to-386 or 286-to-486 upgrade cards. I just got outbid on one of those last night, and it even had the LCC adapter that the Tiny Turbo Xtra would require. Fiddlesticks.

Wouldn't mind sharing detailed pics of the Xtra though.

Last edited by MrSmiley381 on 2019-05-17, 16:00. Edited 1 time in total.

I spend my days fighting with clunky software so I can afford to spend my evenings fighting with clunky hardware.

Reply 2 of 5, by Anonymous Coward

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IF somebody is going to clone one of these, I highly recommend adding some memory or a SIMM slot.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 3 of 5, by dkarguth

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MrSmiley381 wrote:

I've actually got a Tiny Turbo Xtra. I think it uses some PAL and GAL chips, so some of the cloning might be hard to do. The real trick is cloning those fancy 286-to-386 or 286-to-486 upgrade cards. I just got outbid on one of those last night, and it even had the LCC adapter that the Tiny Turbo Xtra would require. Fiddlesticks.

Wouldn't mind sharing detailed pics of the Xtra though.

PALs and GALs are easy, you can read them with a PAL/GAL reader, which I just happen to have. GALs are re-programmable, and you can still get them today, so if you could find a pin-compatible GAL, you can program it to duplicate the original. PALs are harder to find, but if I'm not mistaken, a pin compatible GAL should work just fine.

"And remember, this fix is only temporary, unless it works." -Red Green

Reply 4 of 5, by Ozzuneoj

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I do have one of these, and it works quite well.

Upgrading 286 CPU on ISA upgrade card?

It is currently installed in my IBM 5150 and is used regularly. 😀

Now for some blitting from the back buffer.

Reply 5 of 5, by MrSmiley381

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All right, since I'm having some technical difficulties with the card at the moment, I figured I'd take it out, snap some pics, and drop as much info as I can. First up is a primary shot of the board:

MainBoard.jpg
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MainBoard.jpg
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Main board shot.
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Fair use/fair dealing exception

First row of IC's on the left are as follows:
SN74LS373N - FFAY9006 (octal transparent latch)
Sony 7K08 - CXK5461P-45L (X 4) (cache RAM?)
Edsun Labs EL286-88-10-B - M73V001 - 7Z03 (8088 to 286 signal converter)

The vertical IC between the first and second columns is marked SP8942 - DM74ALS373N (Differently branded octal transparent latch)

That second vertical column of IC's includes two more SN74LS373N - FFAY9006 chips and one SN74LS547NS - 824184. Looks like another latch.

The two IC's near the ISA connector include yet another SN74LS547NS and a &4LS374N - FGK5758 - 9001VF. The crystal in that area is labeled PLE - SRMP18 - 24.000 - 8938.

In the last column I see two socketed chips, four soldered IC's, and one more socketed chip at the top of the board. The four soldered IC's include MC74F521N - XXEE9009, MC74F244N - XXGJ9003, and two Sony 8G01 - CXK5416P-35L.

Those last three socketed chips are probably of the most interest to us. It's three PAL chips. PAL20R4BCNS - 005FCD3 - TW-30, PAL20L8ACNS - 001D9UZ - TW-20, and PAL20L8ACNS - 001D9UZ - TW-10.

There's also the obvious 80286, the 8088, and 80287 sockets. The 8088 installed was pulled from my 5160, the total bitch of an LCC socket holds an AMD 80286-16S, and the 80287 socket has a 287XL purchased off eBay.

The board has jumpers for 6 MHz, 8 Mhz, and 10 Mhz 80287 operation. I've stuck a 287XL in there, which I've read handles multipliers differently than a regular 80287, such that it should undo a 2/3 multiplier that most motherboards implemented on the 80287/8087 socket. Haven't been able to test due to some oddities with the board, but we'll get to that.

So, when I bought the board, I could flip the switches off to go straight to 8088 mode at boot. If I flipped the switch for 286 operation, it would hang with no screen output. Turns out the EL286-88-10-B was not properly seated, so gentle application of the thumb fixed that. TopBench showed that in 286 mode with the cache disabled, we were hitting speeds of a NEC V20 at 4.77 Mhz. When I flipped the cache switch on (and rebooted) we hit the speed of an 8088 at 10 MHz. The 286 will not hit full speed until about two minutes after boot, at which point TopBench shows a jump from a score of 4 to the highscore of 10. This was enough to run Number Munchers comfortably. Same goes for the Ultima remake from 1986. However, Ultima II with the upgrade patch failed to start and said something along the lines of the executable being damaged. The Ultima III upgrade patch ran way too slowly, whereas the unpatched executable ran just fine. I guess all that newfangled hacking needs just a little more power to keep things smooth.

That LCC socket holding the 80286, like I said, is a total bitch. As you can see in the image of my thumb below, I managed to get the heatsink off, despite all of the pins and components so close to the socket that Orchid decided to shave parts of the plastic socket away. I took a look at the CPU, then went for a very hamfisted reassembly. Obviously, I goofed a bit and now the heatsink doesn't quite latch right, which is probably why I can't boot into 80286 mode at the moment. I'll try and redo all that when I feel like shredding my hands again. This is a double bummer, because now a 486 upgrade or even a 286 upgrade requires an adapter, unless maybe a regular 286 socket can be soldered in. I'm not planning to attempt that any time soon.

MyIncompetence.jpg
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Good job, you got the heatsink off. Then you fudged putting it back. Dingus.
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All right, I think that's enough of my adventures and basic analysis of this board. Should we move on to cloning, improving, and wish listing?

First, I know those three PAL chips need to be read and reproduced. Hardware in general isn't quite my forte, and reverse-engineering stuff even less so. If anyone thinks these can be read, let me know how we should approach it.

Next up would be new board redesign. Obviously we'd need some better shops of the top side of the board, with all of its horrendously squashed component placement. For now, here's an OK shot of the rear of the board.

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Quit staring at my rear, silly boys~
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There's also the connector for the 8088 socket on the motherboard. My biggest complaints are that the cable is super stiff and not directly in line with the 8088 socket, so it's a bit awkward to manage.

General wish list items with the goal of retaining base unit functionality while adding stupid unnecessary bells and whistles:
Better 286 socket
Onboard 1MB base/Any MB EMS/Any MB XMS RAM
Bigger cache
Integrated improved PC-Sprint board for hardware turbo functionality (still might need some wires that connect to the main board for this to work)
Integrated reverse-engineered 386/486 upgrade
8088/V20 switch
Implementation of these features on clone/SBC machines

Imagine being able to run 8088 MPH and the latest and greatest CGA games all on the same machine. Or, at the very least, Wizardry with the correct CGA palette while also running it at super speeds.

I spend my days fighting with clunky software so I can afford to spend my evenings fighting with clunky hardware.