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486 Interposers

NeXT

NeXT

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Oct 22, 2008
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Location
Kamloops, BC, Canada
I'm getting some conflicting answers but I want to make sure I'm right before I blow up my last Kingston TurboChip.
So I have a system that uses an i486DX-50 but I want to install the Turbochip which is the Am5x86-133.
The rumor is that apparently if you try and drop the chip in a socket intended for the DX2 or newer the chip will simply blow up unless you have an interposer adapter. Others say a voltage regulator to go from 5v to 3.3v is already on the TurboChip (and yes there does seem to be some sort of a regulator onboard in the upper right) but is for eliminating the interposer? I'm not really willing to risk it with my last chip and if I do end up needing a socket adapter, where are they all hiding on ebay?
 
The determining factor would be whether or not your mobo can provide 3.45 volts for the Am5x86. I don't think the Kingston differs that much from any other 5x86 save for the cache. I have just about every 5x86 out there with the exception of the Kingston, so I can't attest to a regulator being attached. What type of mobo do have for this this setup?
 
This is verbatim from page 1 of the Kingston Technology TurboChip 133 User's Guide

"Introduction
Turbochip 133 features 16KB internal cache, onboard voltage regulator to interface 3.3V processor with 5.0V system automatically, a built-in math coprocessor, and Pentium-class processing power to run internally at 133MHz and externally at 33MHz."

From page 7
"Please Note: If your computer has a jumper setting for 3.3V or 5.0V, leave the jumper set to 5.0V. Also, if there is a jumper to set CPU clock speed, set it to 33MHz or DX (not DX2, DX3, or DX4)."

The bold lettering is in the manual so is probably important.
 
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What type of mobo do have for this this setup?
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It's a daughtercard for a PS/2 system.
From what I can tell the board is hardwired for 5V CPU's. The clock speed is also fixed at 50mhz which makes me wonder if the upgrade would work however over at MCA Mafia he says he has one installed with an interposer which conflicts with the other documentation that says "nah, you don't need one".
 
NeXT said:
It's a daughtercard for a PS/2 system.
From what I can tell the board is hardwired for 5V CPU's. The clock speed is also fixed at 50mhz which makes me wonder if the upgrade would work however over at MCA Mafia he says he has one installed with an interposer which conflicts with the other documentation that says "nah, you don't need one".
Click to expand...

Eh, its always easier to spend other peoples money but I'd try it anyway. I don't think you have anything to worry about. You're certainly not going to 'smoke' anything proving its socket 3 pin compatible.
 
The Kingston Turbochip works at 5V, I have used one before. However it's hardwired at 4X. It was common to overclock these to 160 Mhz (40 MHz x 4) but I doubt it will run at 200 MHz (50 Mhz x 4).
 
NeXT said:
It's a daughtercard for a PS/2 system.
From what I can tell the board is hardwired for 5V CPU's. The clock speed is also fixed at 50mhz which makes me wonder if the upgrade would work however over at MCA Mafia he says he has one installed with an interposer which conflicts with the other documentation that says "nah, you don't need one".
Click to expand...

The MCA Mafia is using an Am5x86-133ADZ , that is not a TurboChip package but just the CPU. Since the Am5x86-133ADZ CPU itself has no native voltage regulator (or fan either) , he needed to drop the voltage using the interposer.
 
I've got an i486DX-50 if you want it.
Click to expand...
I still got the original here but thanks for the offer.

Okay, so I'll try with the chip as-is and see if it works of course it's probably not going to enjoy the 4X multiplier. Thanks.
 
The AMD 5x86 chip can run at 150 MHz (3 x 50 MHz). It is best to use a chip rated ADY (built for 150 MHz) or ADZ (built for 160 MHz), but I've run an ADW chip at 150 MHz and it worked perfectly and was very stable.
 
I just dropped a Kingston Turbo chip I had lying about for half a year into a 5v 486 mobo today(replaces a 486DX33) and it is working fine. Even mistakenly fitted it incorrectly oriented initially, OOPS!!-not recommended, and nothing smoked/died.

System certainly boots a lot quicker.
 
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Caluser2000 said:
I just dropped a Kingston Turbo chip I had lying about for half a year into a 5v 486 mobo today(replaces a 486DX33) and it is working fine. Even mistakenly fitted it incorrectly oriented initially, OOPS!!-not recommended, and nothing smoked/died.

System certainly boots a lot quicker.
Click to expand...

Give that man a cigar! :D
 
Too lazy to put my close distance glasses on. Not going to do that again in a hurry.

The system reports the Turbo Chip as an Am486DXL4 running at 120Mhz.
 
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For a while there I thought I had an issue with the mobo. Just turned out it was a flacky Trident video card. Couldn't reset the setup using the keyboard without disabling the the L1 cache. Same issues with the DX33 cpu but without the screen corruption doing the same things(dir/w etc.) using the TurboChip. Replaced the card, now everything is fine and dandy. The Dx33 has now replaced an SX25 in another mobo. The SX in now in storage next to a DX4/100 which I don't have a home for right now.
 
Local auction site http://www.trademe.co.nz/computers/vintage Nobody else showed interest in it so I snapped it up. Thinking about it I got it well over a year ago. Got a HyperRace 586 cpu as well, but that seems DOA. The cpu extraction tool came in handy on the other mobo though. Got all my Acorn kit and a few 486s/isa cards on Trademe. Haven't used it much lately, but the TM computer community forum folk have been quite helpful. Got my XT Turbo from one who joined Tezza's forum. Scored quite a few 16megs 72 pin simms from some of the members at a reasonable price as well.

As with ebay there are some dreamers on TM who overprice things. Interest in things x86 seems to have increased somewhat lately with some quite interesting bidding wars
 
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Anonymous Coward said:
I would be careful with running the 5x86 at 200MHz. You might fry the L1 cache.
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I'll agree here. I really have no idea what going to happen when I push the CPU so far past its rated speed.
It has its own fan at least so at the minimum it has cooling beyond what the 95 will deliver.
 
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