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Do dual pentium 4 motherboards exist?

Posted on 2022-12-03, 10:04

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have an IBM server from 2003 sitting in the garage with a Xeon Prestonia in it. Looking for a next project, I decided to resurrect this old beast. The motherboard has two sockets, but only one is filled, so I hunted down a VRM and identical Xeon on ebay. For peanuts really, the CPU was just $9. …

Re: 486 MB frequency

Posted on 2022-11-17, 15:37

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The standard 486 and 486DX pin doesn't have a CLK2 pin (which is named that way, because it receives two times the clock speed). A CLK2 pin is present on 286, 386 and some special early low-power 486 chips. The ordinary 486 processor has a CLK pin instead and expects the actual processor clock at …

Re: 486 MB frequency

Posted on 2022-11-17, 07:57

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The frontside bus frequency of 33 MHz povided by the mainboard is doubled inside the CPU. So it effectively runs at 66 MHz. DX2 stands for "x2". After a lot of fiddling I found that it is a bit different. In your case the socket receives the 50MHz from the crystal, this goes to CLK2. In a normal ' …

Re: Should I get a Pentium 1 laptop?

Posted on 2022-11-14, 12:26

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've got a Thinkpad 760 with a TFT screen (single slider on screen!), P1-133, 48Mb ram. I love it! But of course my reasons are particular to my situation: -As I don't have a permanent spot for my retro stuff, its a lot less hassle to take out a laptop than to set up a desktop. -Dos,Windows 95 and …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-11-12, 19:36

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Not sure if you were aware I had a write-up on the cyrix.exe settings. https://www.vogons.org/viewtopic.php?t=45756 You generally want to start with disabling caching of the ROM region, 640k - 1024K, so -xA000,128 -xC000,256 which I think is the same as using -r Hey thanks, I didn't yet see that no …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-11-12, 12:05

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I mentioned earlier that I was having stability issues with my side-by-side interposer in an IBM P70. Vanilla doom ran fine, but basically everything else crashed. I tried fdoom yesterday, which surprisingly froze immediately after startup, not even displaying anything. After some trial and error I …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-10-26, 04:40

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Absolutely; U1 = M74VHC1GT14DTT1G -VCx U2 = M74VHC1GT32DTT1G-VNx I ordered both from AliExpress.

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-10-25, 18:48

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

v3.14159 CPUInterposer386-486 beta 3.14159.zip How does this look? There is a courtyard violation between cout and r2, but it is fine. we can ignore. :-) the 3d model shows 6 pins but there are only 5 holes don't worry. Sorry, took me a while to find the time to look into this with KiCad. Addition …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-10-17, 18:47

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Oh wow, very nice :p Hope you figure out why there are instabilities. Maybe a non related problem is rearing its head? Or maybe a timing issue? Are there faster components you can try? I think its not related to the interposer. I had an 486DLC in this sytem and it showed the same instability, …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-10-17, 12:09

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Nice bit of detective work for finding a MEMW alternative on MCA. That DOOM score of 3100 realtics is too good for an SXL2 at 40 MHz. Are you running it in full screen? By the way, the new PCB's are on their way from Hong Kong, as of last Friday. I'm running the low detail benchmark haha :) I guess …

Re: What era of computers do you draw the line at collecting and/or using?

Posted on 2022-10-17, 12:04

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Heh, cool topic. I guess the window is different for everyone. My dad was in IT and let me use his stuff, so I 'had' PCs from a pretty early age. First one was a 286. I mainly played games on them, and still do, so I classify systems by which games they play. For me the lower cutoff is Wolfenstein …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-10-17, 08:18

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've got a small update from my side-by-side interposer. As I didn't get the cache working, I wanted to hook up MEMW in order to be able to use cache flush. Normally, this is one of the pins of the ISA bus, however I have an IBM with only microchannel slots, and MCA doesn't have a MEMW pin. After …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-10-02, 16:23

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The only other thing I have to test this with is a second IBM P70, except this one is slower at 16MHz baseclock (33MHz xtal), instead of the 20MHz I tested the adapter with. Mobo is a little different, so who knows. I'll have a look tonight and let you know. Edit: The adapter unfortunately doesn't …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-10-01, 06:23

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It seems like it should be on vcc5. what does datasheet say? The data sheet says for pin J1: VCC5: TI486SXL-G40 and TI486SXL-G50 VCC3: everything else As you can see the manual does not specify anything for the TI486SXL-G66. Might not have been out at the time. The assumption so far has been it …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-09-30, 18:45

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I tested Blavius' board, but system would not turn on, even at 16 MHz. I need to test more motherboards. Not sure why it worked on his system. Sorry to hear that man. What processor are you using? For me it works with the SXL-40 at 20MHz base clock. Your soldering looks fine. Do you get a …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-09-15, 08:40

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Blavius, I'm not sure what these non-G variant 3.x volt SXL2 chips are. You may have a typo in your above statement. You've said that the processor I intend to use requires J1 set to VCC3. However, we are using the G variant in this upgrade, as shown in previous posts. I have a QFP144 SXL2-66 3.6V …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-09-15, 07:46

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Please clarify which j1 J1 of socket? J1 of fet? J1 of the socket.

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-09-15, 07:38

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Do you see an error on the pin designations/trace routing? On your last version I see JP1 is gone. Just wondering what you connected pin J1 to instead (VCC3 or VCC5)

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-09-15, 07:26

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What we definitely want to get rid of is JP1. VCC5 should always be 5 V, regardless of the version of SXL CPU used. I can see people confusing JP1 for bypassing the VRM, which it does not do. I agree the naming is confusing and we need to solve that. But the voltage on pin J1 of the processor is …

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2022-09-13, 18:16

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi guys! Amazing work going on in here! Had some crazy time at home and at work and couldn't reply, so I have some catching up to do: Yes the 286 and 368 halve the incoming clock signal. This does not mean that the buses between the CPU and motherboard (FSB) actually transfer at the same speed as …

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