VOGONS


First post, by quicknick

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Hello,
Bought this board today, seemed to be in perfect shape for something built 26 years ago. But upon closer inspection I found one of the chips to be broken (split in two, as if hit with great force): it's the one labeled PAL 089-001. Removed the label, the chip is a PAL16L8BCN, which according to the datasheet is a "Programmable replacement for high-speed TTL logic". How screwed am I? Any chance of reviving this board? As it is now, with or without the broken chip, I get a series of three short beeps after power-on.

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Reply 2 of 42, by FesterBlatz

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I'd say your changes are pretty poor, unfortunately. The problem is whatever function that PLD was programmed to perform is unique to that board. In order to repair it, you'd need to find someone with the same motherboard who's willing to send the PLD to someone else with a device programmer. Assuming the device wasn't locked when it was programmed by the manufacturer, it could be interrogated to read the logic out of it and written to a new device.

Hoepfully you'll get lucky and someone else here has that same motherboard...I have a device programmer that could handle the rest.

Last edited by FesterBlatz on 2017-12-05, 00:12. Edited 1 time in total.

Reply 3 of 42, by bloodbath2you

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oouch, i have a similar mobo, an octek fox II, you could remove the sticker so we can read whats behind it.

my guess its a programable array logic chip, kinda difficult to replace because they need to be burnt like an eeprom.

Reply 4 of 42, by keropi

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it's a PAL like exactly like others mentions - says that on the label and for that age it's 99,99% to be one unfortunately....

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Reply 5 of 42, by Jo22

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FesterBlatz wrote:

Hoepfully you'll get lucky and someone else here has that same motherboard...I have a device programmer that could handle the rest.

As far as I know, the Schneider Euro AT had a Headland chipset, too. With two PALs, even.

Edit: Some universal programmers (G540, etc) claim to be able to measure the outputs of such chips.
Maybe there's a chance to make a duplicate ?

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Reply 6 of 42, by jesolo

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Will the TL866CS Pro be able to read such PAL chips?
Reason for me asking is that I recall having a 286 motherboard with a Headland chipset.
If it also has two PAL chips, then maybe I can give it a try?

Reply 7 of 42, by SSTV2

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Actually, there is a chance of restoring chips contents if the DIE crystal did not crack together with its plastic case. The most difficult part would be forming good connections with remnant microscopic bond wires.

Reply 8 of 42, by quicknick

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Thanks everyone for your answers and advices.
Unfortunately, finding someone willing to risk his board to send me (or to someone else) the chip for copying seems like an impossible task. (more likely to someone else, as I know nothing about the devices used to read and program these things).

Also, for those suggesting other boards with PAL chips, I believe that the chip should have the exact same label (PAL 089-001) for it to have a chance to work.

SSTV2 - this crossed my mind, actually. The die might be in one piece, as the chip is not cracked right in the middle - you can see the end of the metal substrate where the split is. However, at a hobby/amateur level I don't think I'm up to this task to even try it...

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Reply 11 of 42, by align_left

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It seems that they can't be read out with a normal Programmer (i have the TL886CS)...

http://www.vcfed.org/forum/showthread.php?126 … s-upgrade-chips

If there is a way, let me know and i can programm a GAL which seems to be working.

Reply 12 of 42, by quicknick

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Looks like i found the datahseet/application notes of the Headland chipset. At the end, a schematic of a demo 286 board along with the PAL equations!
I've traced most of the pins of the broken PAL and they coincide with the schematic. So i'm pretty sure that my board will happily boot again. I just need to figure out how to translate what's below into a JEDEC file to program it in a GAL16V8.

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Reply 13 of 42, by SSTV2

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Neat, how thoughtful of the chipset manufacturer. The equations are very simple, but the main question is... wether input pins of that broken PAL chip are assigned the same way as in the given schematic. I'd suggest you to use Atmel's freeware WinCUPL to create equation project and generate jedec file.

Reply 14 of 42, by quicknick

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SSTV2 wrote:

I'd suggest you to use Atmel's freeware WinCUPL to create equation project and generate jedec file.

Played a little with the program, it's way more complicated than i anticipated. Anyone that has experience with this stuff and is willing to compile the jedec file for me will be rewarded with my eternal gratitude. And a beer.

Reply 15 of 42, by Auzner

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Just playing around with it I got something to compile. It's a start?

Name     286fix ;
PartNo PAL16L8 ;
Date 2/6/2018 ;
Revision 4/12/1988 ;
Designer Headland Technologies ;
Company Vogons ;
Assembly None ;
Location retro basement ;
Device G16V8 ;


/* Device modes */
/* Registered=G16V8MS */
/* Complex=G16V8MA */
/* Simple=G16V8AS */
/* Auto=G16V8 */

/* Inputs */
PIN 1 = RAM1RAS ;
PIN 2 = RAM0CAS ;
PIN 3 = RAS6080 ;
PIN 4 = RAS40 ;
PIN 5 = MEMW ;
PIN 6 = RAM1CAS ;
PIN 7 = RAM0RAS ;
PIN 8 = EMEMR ;
PIN 9 = XA0 ;
PIN 11 = XBHE ;
PIN 16 = ERD ;

/* Outputs */
PIN 12 = !CAS1H ;
PIN 13 = !RAS1 ;
PIN 14 = !CAS1L ;
PIN 15 = !RAS0 ;
PIN 17 = !CAS0H ;
PIN 18 = !CAS0L ;
PIN 19 = !RAS ;


RAS = EMEMR & MEMW & ERD ;

RAS0 =
RAM0RAS & !EMEMR & !RAS40
# RAM0RAS & !MEMW & !RAS40
# RAM0RAS & !EMEMR & !RAS6080
# RAM0RAS & !MEMW & !RAS6080
# RAM0RAS & !ERD ;

RAS1 =
RAM1RAS & !EMEMR & !RAS40
# RAM1RAS & !MEMW & !RAS40
# RAM1RAS & !EMEMR & !RAS6080
# RAM1RAS & !MEMW & !RAS6080
# RAM1RAS & !ERD ;

CAS0L =
!XA0 & RAS40 & RAM0CAS & !EMEMR
# !XA0 & RAS40 & RAM0CAS & !MEMW ;

Show last 11 lines
CAS1L =
!XA0 & RAS40 & RAM1CAS & !EMEMR
# !XA0 & RAS40 & RAM1CAS & !MEMW ;

CAS0H =
!XBHE & RAS40 & RAM0CAS & !EMEMR
# !XBHE & RAS40 & RAM0CAS & !MEMW ;

CAS1H =
!XBHE & RAS40 & RAM1CAS & !EMEMR
# !XBHE & RAS40 & RAM1CAS & !MEMW ;

Reply 16 of 42, by quicknick

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Thanks for your effort!
I played around with the above code but couldn't get it to compile. WinCupl gives me 20 warnings (or three fatal errors if i try device dependent compile; btw, i don't know what should i choose). The program seems rather unfriendly towards noobs like me and doesn't specify what the warnings are about. However the simulation program outputs a few files with different extensions, and in the .so file i get exactly 20 lines like that, first two as shown and 18 more followed by the pin names: [0033sa] Please note: jedec vectors cannot be created with undefined pin numbers.

Reply 19 of 42, by Jed118

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Hah, I JUST got this board, paid $30 for it. Goddamn thing doesn't like anything else but 60ns - crashes continuously on anything higher. I have it doing a burn in overnight.

This board replaces my other 286/16 board that suffered from a latent trace failure.

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