Old Thrashbarg wrote:

It's doubtful that the CPU is soldered in... more likely it's one of those so-called "low insertion force" sockets, which are rather counterintuitively named since there's nothing low-force about them. It can take quite a bit of prying to get the CPU out of one of those... there were even special 486 extraction tools made for the purpose.

That sounds scary! So do you know if it would take my AMD DX4-100? I also have a AMD 486 DX2-80.

Old Thrashbarg wrote:

It can take quite a bit of prying to get the CPU out of one of those... there were even special 486 extraction tools made for the purpose.

Useful tool to remove CPUs (Topic discusses a CPU extraction tool)

Success! The old CPU is removed. Not sure if I should try the DX4-100 in it though. Or I have the DX2-80.

Anybody know?

Try the DX4 100. Might as well shoot straight for the best chip you have.

GXL750 wrote:

Try the DX4 100. Might as well shoot straight for the best chip you have.

Well, it works, I think. When I go in to the BIOS it says the CPU is a 486SX at 100 MHz. But right under it, it says there is an integrated 387 compatible numeric coprocessor. Does this mean that it has detected the DX4-100 correctly?

Try the DX4 100. Might as well shoot straight for the best chip you have.

Except for the little issue of voltage... it hasn't been established yet whether or not the board will do 3.3V. It'll probably work OK regardless, but I wouldn't run it for any extended length of time.

Old Thrashbarg wrote:

Try the DX4 100. Might as well shoot straight for the best chip you have.

Except for the little issue of voltage... it hasn't been established yet whether or not the board will do 3.3V. I wouldn't try it.

Well, it is in and the system is running. See my last post.

rick12373 wrote:

GXL750 wrote:

Try the DX4 100. Might as well shoot straight for the best chip you have.

Well, it works, I think. When I go in to the BIOS it says the CPU is a 486SX at 100 MHz. But right under it, it says there is an integrated 387 compatible numeric coprocessor. Does this mean that it has detected the DX4-100 correctly?

So you're running the chip at 5v then?

Better read the manual for the jumper settings.
Btw, if you're worried about running a standard DX4-100 at 5v, then an Intel Overdrive 100Mhz could be your answer 😉
At least easier to find then one of those standalone voltage regulators...

Well, it is in and the system is running. See my last post.

That doesn't mean it's necessarily going to last long at 5V. Some DX4s will handle it fine, some won't.

Tetrium wrote:

So you're running the chip at 5v then? […]
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rick12373 wrote:

GXL750 wrote:

Try the DX4 100. Might as well shoot straight for the best chip you have.

Well, it works, I think. When I go in to the BIOS it says the CPU is a 486SX at 100 MHz. But right under it, it says there is an integrated 387 compatible numeric coprocessor. Does this mean that it has detected the DX4-100 correctly?

So you're running the chip at 5v then?

Better read the manual for the jumper settings.
Btw, if you're worried about running a standard DX4-100 at 5v, then an Intel Overdrive 100Mhz could be your answer 😉
At least easier to find then one of those standalone voltage regulators...

Don't know what voltage I'm running it at 🤣

I just stuck it in. I could check the jumper settings if needed. Is that why it says it is a 486SX 100Mhz with a coprocessor? I suppose that is describing the 486 DX4-100 though. It sounds right. If the jumpers/voltage were wrong would it not boot it just display the wrong speed of CPU?

* Edit * I don't have the and can't find the manual online by the way. I tried Googling some of the numbers on the MB as well as he model name and found nothing.

Just looked on a PDF that I found that has some info on the board. Using pin settings I can select processor speed of 25/50 MHz or 33/66 MHz. Another pin setting changes from 486 SX installed or other than SX installed. So obviously I need to change it to other than SX but as the processor speed max it goes up to is 66 MHz does that mean the DX4 100 will not work? It did detect it at 100 MHz though. It just said it was an SX not a DX. I don't how if there is a way to change the voltage. I don't know what voltage it is running at now really.

Well the AMD 486SX2-66 is a 5V CPU, so it probably still runs at 5V.
I somehow doubt, that this compaq mainboard even has 3.3 V support.
My board looks like this: http://mail.lipsia.de/~enigma/forum/innerei.jpg

elianda wrote:

Well the AMD 486SX2-66 is a 5V CPU, so it probably still runs at 5V.
I somehow doubt, that this compaq mainboard even has 3.3 V support.

So that might mean that as I am probably running this DX4 100 at 5 V that it might damage the CPU? Is there a way of finding out which DX4 100s can handle 5 V?

rick12373 wrote:

elianda wrote:

Well the AMD 486SX2-66 is a 5V CPU, so it probably still runs at 5V.
I somehow doubt, that this compaq mainboard even has 3.3 V support.

So that might mean that as I am probably running this DX4 100 at 5 V that it might damage the CPU? Is there a way of finding out which DX4 100s can handle 5 V?

Like I said, the Intel Overdrive, there are several versions. You'll want the DX4-100 Overdrive version

Note:The Intel Overdrive is a different animal from the Intel Pentium Overdrive 😉

Edit:I forgot, you could also try one of those upgrade chips like the Kingston Turbochip or that Evergreen. These have an AMD 5x86 mounted on a small pcb with a normal 486 pinout on the bottom and, even though the 5x86 is a 3.3v chip, are designed to work in motherboards that only support 5v chips.

Problem is, those upgrade chips may or may not work in your particular board.
The Intel Overdrive is designed as a drop in replacement and thus should have better compatibility.

@ elianda

My board looks different to that. I will try and get a picture. Might be tomorrow.

Sound like I need to get an overdrive though.

Is this what I need?

http://cgi.ebay.com/NEW-Intel-DX4-OverDrive-P … =item336706e3b0

rick12373 wrote:

Is this what I need?

http://cgi.ebay.com/NEW-Intel-DX4-OverDrive-P … =item336706e3b0

Looks like it. Price isn't too bad either for a NIB chip. Too bad it's in the US or I would've gotten one (if only for that extraction tool, 🤣)

Now if only I had the money right now. Anybody have one they want to swap for some other retro hardware that I might have 🤣

I had a CRT once with a similar problem to the screen issue mentioned in the original post and the solution was to change out a resistor that had gone bad. I never got around to it and ended up trashing the monitor because it was taking up too much space and poking around inside a CRT with metal tools can be dangerous.

rick12373 wrote:

Now if only I had the money right now. Anybody have one they want to swap for some other retro hardware that I might have 🤣

They are offered on cpu-world.com from time to time. It's where I get a bulk of my chips 😉