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identifying this XT clone motherboard~

sparky4

sparky4

Experienced Member
Joined
Sep 26, 2013
Messages
76
Location
Ruston, Louisiana, United States
I lost the original bios chip and i cannot find it and i looked and looked but i found no manual or bios rom on the Internet or anything

The mother board is apparently a Gold star Technologies turbo plus 2 board

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I am trying to overclock the turbo mode from 8Mhz to 16 MHz ^^;
 
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I noticed the thick white lines printed around sections of the board. They are the same lines found on the following motherboards:
* X'GOLDEN BOARD
* X'GOLDEN TURBO-BOARD (an 8 MHz board)

Now that I have seen your motherboard, made by Golden Star Technology Inc., I think that there is a good chance that the X'GOLDEN motherboards have the same maker as yours.

In case you would like to try them, the BIOS' for the X'GOLDEN boards are at [here].
 
Some of the sources I have seen suggest that the 10 MHz 8088 chips were capable of being clocked much higher. I just wonder if the OP has verified that all the support chips and cards also be pushed that hard.
 
krebizfan said:
Some of the sources I have seen suggest that the 10 MHz 8088 chips were capable of being clocked much higher. I just wonder if the OP has verified that all the support chips and cards also be pushed that hard.
Click to expand...
And adjustment of timing loops and delays in the BIOS may be required, and possible circuit modification (beyond faster rated chips). Maybe the OP is aware of all of this, and is up for the challenge.
 
Well, back in the day, a few boards used the 9.5MHz variation (2x4.77) as turbo. That should be close enough to 12 for hardware this old, don't you think?
 
I think the problem is with the 8288...must be a 82C88-10 and is not able to give the good timing at 16mhz...
Same problem with the 8284 ; the 82C84 need a different circuit for the Xtal (no 300 ohms resistor and 20pf capacitor to ground instead),and the external clock is limited to 25mhz,good enough for 8mhz turbo,extrem limit 30Mhz for turbo 10Mhz.
the µPD71084C and µPD71088C-10 are not better.
Another problem is that my XT clones run in turbo mode after reset , before checking the turbo switch and selecting the clock source of the 8284..
If they don't crash,the card is running correctly in 4,77 only after switching the clock,but most of the time they crash before and you need try minimum 10 time reset even you select no turbo.
sorry for my poor english
 
It's looking very the same as my empty XT mainboard, same layout. But mine has no "Turbo XT" name and manufacturer. I think they are a kind of standard layout, many manufacturer did (except some unimportant details) the same boards.
 
DUPONT said:
I think the problem is with the 8288...must be a 82C88-10 and is not able to give the good timing at 16mhz...
Same problem with the 8284 ; the 82C84 need a different circuit for the Xtal (no 300 ohms resistor and 20pf capacitor to ground instead),and the external clock is limited to 25mhz,good enough for 8mhz turbo,extrem limit 30Mhz for turbo 10Mhz.
the µPD71084C and µPD71088C-10 are not better.
Another problem is that my XT clones run in turbo mode after reset , before checking the turbo switch and selecting the clock source of the 8284..
If they don't crash,the card is running correctly in 4,77 only after switching the clock,but most of the time they crash before and you need try minimum 10 time reset even you select no turbo.
sorry for my poor english
Click to expand...

ok i willl look at the chips you mentioned ww
 
I have two "very" fast XTs. One is Commodore PC10-III which is capable to run at 2x4.77MHz. Even faster is Juko XT motherboard, which can run at 10MHz with 8088-1 and at 12MHz with μPD70108 (a NEC 8088 clone).
 
Good job...
but like i said before,these 8284 and 8288 generate the very critical clock timing for all the other chips..
and there are no higher speed replacement.
the best are M5L8288S or µPD71088C-10 for the system bus controler and µPD71084C-8 for the clock generator
Even you use a 16Mhz processor like a tke NEC V20 µPD10108HCZ-16,it will not work properly without a good timing "earth"
 
Given that most XT-class machines operated at 4.77MHz, one has to ask "what's the point?". One thing that can plague you is that software timing loops are common in XT-class software where the clock speed was taken for granted as 4.77MHz. That's one of the reasons that many 286 "turbo" systems have a non-turbo mode. This can create real problems with some peripherals.

I wonder if some systems that used a delay line for RAS/CAS separation on DRAM access will work by simply cranking up the clock.

If you want to fool around with overclocking a slow machine, the 5170 made for a far better platform for that.

Just IMOHO.
 
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