VOGONS


First post, by aop

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I'm getting completely random freezes (computer becomes unresponsive, no BSOD, only reset helps) when using Windows 98SE on my retro PC. It usually happens without any load at all when browsing folders etc.

The specs:
AMD K6-III+
Gigabyte GA-5AX rev 4.1
256MB 100MHz SDRAM
Seagate 7200.7 80GB HDD

What I have tried this far:
- swapping the sound card (SB Live!, SB AWE64, Terratec EWS64) and running the system without a sound card at all
- reinstalling Windows 98SE
- running Memtest86+ to test the RAM, it seems to be fine
- check the HDD on other PC, SMART data OK, surface check OK
- recapping the motherboard (replaced all Choyo caps with Rubycon)
- tested two different power supplies (HEC 300W and Corsair CX400W)
- updated latest BIOS (F4) on the motherboard
- checked that I have correct CPU voltage settings on the motherboard
- swapped video cards (Velocity 100 ---> Voodoo 3 3500)

The thing is that I'm not getting these crashes with a K6-2 400MHz processor installed. The K6-III+ seems to be unlikely to crash under gaming loads, atleast it ran 3DMarks fine, I could play Interstate 76 without crashes and it seems to run SuperPI for hours without crashes but when I start to use the PC normally on desktop it'll hang sooner or later.

Is there anything I can do short of buying another K6-III+ CPU to test what could be wrong (mobo or CPU)?

Reply 1 of 12, by aop

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Damn, I managed to get it crash even with the K6-2 in 3DMark2000 loop. No BSOD or anything, the screen just freezes and nothing else but power button works.

I'm starting to suspect the motherboard is bad. If that's the case my Super Socket 7 build project is pretty much dead since getting a decent working SS7 mobo seems to be downright impossible and I'm not about to buy another 50€+ board from ebay to find out it's not working properly even after recapping.

Reply 3 of 12, by aop

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lazibayer wrote:

Have you tried PCI video cards?

Nope, just those two Voodoo 3 based cards.

I just wonder why does it crash almost instantly with the K6-III+ but now it has been running 3DMark2000 CPU tests for about an hour with the K6-2.

Reply 4 of 12, by fitzpatr

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Even though you've run Memtest, just to be safe I'd buy a different set of RAM and try it out.

What are your memory timings set to?

100MHz CL2 is actually more demanding than 133MHz CL3 RAM.

MT-32 Old, CM-32L, CM-500, SC-55mkII, SC-88Pro, SC-D70, FB-01, MU2000EX
K6-III+/450/GA-5AX/G400 Max/Voodoo2 SLI/CT1750/MPU-401AT/Audigy 2ZS
486 Build

Reply 5 of 12, by aop

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100 MHz CL2 Fast. The sticks are 100MHz CL2 specced. I could try to loosen them and see if the K6-III+ still causes quick crash.

I'm starting to suspect there is something wrong with the voltage regulation or current supply since once you get the board warm it's much more stable (after the first crash in 3DMark2000 CPU test I restarted the PC and put the CPU test to run looped and it didn't crash during the 2 hours I let it run) and the higher voltage K6-2 is much more stable on the board (K6-III+ crashes within minutes).

Reply 6 of 12, by CkRtech

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Most of the hard freezes I have encountered are usually power related or thermal related. I was actually going to ask about your VRM output levels.

A quick search of you board shows results that suggest ram timing detection can be a bit finicky.

Displaced Gamers (YouTube) - DOS Gaming Aspect Ratio - 320x200 || The History of 240p || Dithering on the Sega Genesis with Composite Video

Reply 7 of 12, by aop

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CkRtech wrote:

Most of the hard freezes I have encountered are usually power related or thermal related. I was actually going to ask about your VRM output levels.

A quick search of you board shows results that suggest ram timing detection can be a bit finicky.

I don't have an oscilloscope so I can't really measure how the VRM output is (ripple etc). Thermals seem to be fine, none of the components on the board heat up noticeably (even the VRM mosfets are cool), I have applied thermal paste between the heatsink and the CPU and the heatsink stays cool even under full CPU load.

RAM timings could be a good thing to check out but I was under impression that if Memtest86+ checks out fine it's very unlikely to be memory related issue. It could be related to CPU/mobo cache though as the K6-2 is significantly more stable than the K6-III+ and the L2 cache is the major difference between those two CPUs. I also thought memory problems would manifest as an BSOD instead of a hard lock with no feedback at all.

Reply 8 of 12, by CkRtech

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aop wrote:

I don't have an oscilloscope so I can't really measure how the VRM output is (ripple etc).

Hmm. Well I suppose you could monitor with a multimeter and see if you have a concerning level of voltage dip? Not quite the same, but I suppose it is something?

<Obligatory low ESR question for the chosen line of Rubys, your solder joints look OK, blah blah blah goes here 😁 >

Sorry you're dealing with this! You have put some time into it! This was the interesting page I saw earlier (timings/RAM slot): http://www.ianstedman.co.uk/Technical/GA-5AX_ … x_problems.html

Displaced Gamers (YouTube) - DOS Gaming Aspect Ratio - 320x200 || The History of 240p || Dithering on the Sega Genesis with Composite Video

Reply 9 of 12, by aop

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CkRtech wrote:

<Obligatory low ESR question for the chosen line of Rubys, your solder joints look OK, blah blah blah goes here 😁 >

I cheaped out a bit on the Rubycons, went with ZLH series but they should have lower ESR than the Choyos I replaced. The system was unstable before the recapping too. Solder joints looked fine (I used a Weller @ 350C and lead solder).

I also have a Soltek SL54U5 and PC Partner MVP3BS7 motherboards but both of them have turd quality caps on them and the Soltek has pretty high minimum CPU voltage of 2.0V and the PC Partner has 1.8V.

Reply 10 of 12, by aop

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It might have been the memory after all. I loosened the timings to slowest possible and now the rig has been running 3DMark2000 CPU test for hours with the K6-III+ CPU.

I'm not declaring victory yet though since the behavior of the PC has been extremely erratic, to say at least.

Are there any good sources for 133 MHz CL2 RAM (for future Slot-1 build too)? I checked through an entire pile of SDRAM (50-100 sticks) and had one 100 MHz CL2 stick there, all the rest were either 100 MHz or 133 MHz CL3.

Reply 11 of 12, by meljor

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pc133 cl3 should work fine at 100mhz cl2 for ss7 and slot1 boards.

I prefer to use 128mb sticks as 256mb was pretty big back then and although they might be supported they seem a bit flaky to me on some boards where 128mb is always rock solid.

asus tx97-e, 233mmx, voodoo1, s3 virge ,sb16
asus p5a, k6-3+ @ 550mhz, voodoo2 12mb sli, gf2 gts, awe32
asus p3b-f, p3-700, voodoo3 3500TV agp, awe64
asus tusl2-c, p3-S 1,4ghz, voodoo5 5500, live!
asus a7n8x DL, barton cpu, 6800ultra, Voodoo3 pci, audigy1

Reply 12 of 12, by chrismeyer6

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If your in the US newegg still sells pc-100 and pc-133. I bought 3 512 meg pc-133 sticks over the summer for them for a socket A build I did for my son.