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WTB: Pentium III MMC-2 CPU Any speed

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kfzhu1229
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WTB: Pentium III MMC-2 CPU Any speed

#1 Post by kfzhu1229 » Fri Feb 14, 2020 9:35 pm

Hi,
I am looking for any Pentium III MMC-2 CPU to test my Dell Latitude CPx (found locally for free) which does not turn on and I suspect a CPU failure from it (insufficient heat transfer for a 20W PIII-750 chip).
I would want to pay as less as it can be because I have no idea whether I am just wasting my money. Any speed is fine (but preferably not a Celeron variant) as long as I know it is gonna work in that Dell if it were a CPU failure. If anyone who has a spare is in Toronto, Canada it would be even more appreciated for me to save postages.
Thanks a lot!
Dell Lat CP MMX-233 64mb 40gb W2k
600 PII-266 416mb 40gb WXP
T23 PIII 1.13ghz 1gb W7
Precision M4300 X9000 8gb 160gb WUXGA Ultrasharp fp W10
T530i 15.6" i7 16gb fp W10
UXGA:
A30p PIII 1.2 1gb W7 (IDTech)
T43p 2.26 2gb fp W10 (Sharp)
Lat C840 P4-2.5 2gb 60gb W7 (Ultrasharp)

RealBlackStuff
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Re: WTB: Pentium III MMC-2 CPU Any speed

#2 Post by RealBlackStuff » Sat Feb 15, 2020 2:19 am

Found this:
the web wrote:The Thinkpad 600X series came factory with the 650 on models -5FU and -9FU. Those boards also natively support the 850 module. All others came with a 450 or 500 chip and will see both the 650 and 850 at 150Mhz below their original clock since they don't support speedstep. The 770X and 770Z came with MMC slots and could be upgraded to a PIII but I don't remember the limitations. I believe the 770X works better than the 770Z for the upgrade,
Also check with forum user hwattys, he's got loads of oldies.
Still NOT a great day for a Guinness! (the Real Black Stuff).
Ireland is on FULL lockdown until at least 31 January 2021!
Covid-19: Stay safe, so Mask it or Casket!

kfzhu1229
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Location: Toronto, Canada

Re: WTB: Pentium III MMC-2 CPU Any speed

#3 Post by kfzhu1229 » Sun Feb 16, 2020 5:53 pm

Okay I have bought an entire Dell Inspiron computer instead to diagnose part by part and waiting to see whether I still need such a CPU. Offers are still welcomed though.
Dell Lat CP MMX-233 64mb 40gb W2k
600 PII-266 416mb 40gb WXP
T23 PIII 1.13ghz 1gb W7
Precision M4300 X9000 8gb 160gb WUXGA Ultrasharp fp W10
T530i 15.6" i7 16gb fp W10
UXGA:
A30p PIII 1.2 1gb W7 (IDTech)
T43p 2.26 2gb fp W10 (Sharp)
Lat C840 P4-2.5 2gb 60gb W7 (Ultrasharp)

kfzhu1229
ThinkPadder
ThinkPadder
Posts: 1843
Joined: Tue Sep 22, 2015 10:59 pm
Location: Toronto, Canada

Re: WTB: Pentium III MMC-2 CPU Any speed

#4 Post by kfzhu1229 » Sat Feb 22, 2020 3:54 pm

Update: Well turns out the Latitude CPx that I got is CPx J so it supports speedstep. The inspiron I got doesn't. But with the help of the Inspiron, I found out that that 750Mhz PIII CPU is indeed dead, and that the motherboard was dead too. However, when the Inspiron developed the same issue as the Latitude, I found out it was a RAM error (and that these models are known to be flaky with RAM and RAM slots). But with not a single of my PC100 modules working inside the Latitude in either of the slots, with nothing to lose I decided to bake it with 385F of temperature for 8 minutes, and it worked!
So long story short, I indeed need any Pentium III MMC-2 CPU (SpeedStep is also good) so that I don't have to share a single 450Mhz CPU between two computers.
Dell Lat CP MMX-233 64mb 40gb W2k
600 PII-266 416mb 40gb WXP
T23 PIII 1.13ghz 1gb W7
Precision M4300 X9000 8gb 160gb WUXGA Ultrasharp fp W10
T530i 15.6" i7 16gb fp W10
UXGA:
A30p PIII 1.2 1gb W7 (IDTech)
T43p 2.26 2gb fp W10 (Sharp)
Lat C840 P4-2.5 2gb 60gb W7 (Ultrasharp)

kfzhu1229
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ThinkPadder
Posts: 1843
Joined: Tue Sep 22, 2015 10:59 pm
Location: Toronto, Canada

Re: WTB: Pentium III MMC-2 CPU Any speed

#5 Post by kfzhu1229 » Tue Mar 03, 2020 12:15 am

Update 2: I got a Pentium III 650Mhz CPU from fellow Torontonian pkiff at no cost! Thanks so much!
After the CPU replacement the machine did indeed turn on just fine at last.
But before I call it a day, I decided to investigate where the CPU actually failed. Then I remembered that the two small transistors near top right portion of the CPU runs burning hot (I have highlighted them in one of the photos below), and the capacitor inbetween them have a short. So obviously my guess is the capacitor is dead, but removing it there is still a short and those transistors run just as hot.
Now with the 650Mhz CPU I measured the continuity of that same capacitor and there is no short! So following the traces towards the back of the CPU card, it went towards a SMD IC, and it turns out that IC is the ADP3420, the predecessor to the famous ADP3421 that plagued thousands of T2x devices into blink of death!
That capacitor trace went to the 3rd pin towards the bottom right of that chip, which by the datasheet of ADP3421, is a 2.5V trace connected to a PNP transistor, and that is shorted to ground! (I then checked the voltage of that same capacitor on the working 650Mhz CPU and it indeed is 2.5V and definitely not shorted to ground) No wonder why the transistor is burning hot! Sure enough after taking the chip out with a heat gun the short is gone (and when I put the CPU back to try turn it on, the transistors no longer get hot either)!
Now it begs the question, I cannot seem to find a supplier for ADP3420, can I replace the chip with ADP3421, or SC1406ACTS, which is the chip on the 650Mhz CPU that I have?
https://1drv.ms/u/s!At7-rt1KJ7WviPcsNhG ... w?e=DhbP7e
Dell Lat CP MMX-233 64mb 40gb W2k
600 PII-266 416mb 40gb WXP
T23 PIII 1.13ghz 1gb W7
Precision M4300 X9000 8gb 160gb WUXGA Ultrasharp fp W10
T530i 15.6" i7 16gb fp W10
UXGA:
A30p PIII 1.2 1gb W7 (IDTech)
T43p 2.26 2gb fp W10 (Sharp)
Lat C840 P4-2.5 2gb 60gb W7 (Ultrasharp)

RealBlackStuff
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Re: WTB: Pentium III MMC-2 CPU Any speed

#6 Post by RealBlackStuff » Tue Mar 03, 2020 1:57 am

Great sleuthing!
And you can buy ADP3420 here: https://www.pchub.com/analog-devices-co ... 0-j-p80876
Still NOT a great day for a Guinness! (the Real Black Stuff).
Ireland is on FULL lockdown until at least 31 January 2021!
Covid-19: Stay safe, so Mask it or Casket!

pkiff
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Re: WTB: Pentium III MMC-2 CPU Any speed

#7 Post by pkiff » Wed Mar 04, 2020 6:42 am

kfzhu1229 wrote:
Tue Mar 03, 2020 12:15 am
Update 2: I got a Pentium III 650Mhz CPU from fellow Torontonian pkiff at no cost! Thanks so much!
You are much more industrious and patient than I am with regards to these old and failing parts. I hadn't looked at that MMC-2 board since pulling it out of one of my 600X's to upgrade it, and anyone with as much determination as you deserves to have it!
X1 Carbon Tablet (3rd Gen) · P52 · W520 · Legacy: T60p, X61T, 600X, 770Z
Nostalgic for: 600X PIII 850MHz in a SelectaDock III with 64MB Voodoo 5 5500 and Sound Blaster Audigy 5.1.

kfzhu1229
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Location: Toronto, Canada

Re: WTB: Pentium III MMC-2 CPU Any speed

#8 Post by kfzhu1229 » Wed Mar 04, 2020 10:55 pm

RealBlackStuff wrote:
Tue Mar 03, 2020 1:57 am
Great sleuthing!
And you can buy ADP3420 here: https://www.pchub.com/analog-devices-co ... 0-j-p80876
Thanks! I have already ordered one and I will see whether I have placed my heat gun on the broken chip for too long that some CPU BGA pins get desoldered.
Alas the problem doesn't quite stop there. After replacing the CPU the machine did boot to BIOS perfectly fine. However, upon booting to Windows, I see vertical lines across the loading screen... This thing has a dead Vram chip! What a waste of time! It's not the GPU soldering because pushing or bending the board gives no change. Fortunately after loading the ATi Rage driver and put the colour into 32 bit mode in Windows 2000 it seems to work fine for the most part with only artefacts around the mouse cursor so I guess it does the job just running Windows.
And then there are the RAM slot problems. The Latitude CPx lineup have RAM slots as faulty as the T30! The solder they use on the RAM slots are more brittle and melts quicker than the low quality solder I bought off Taobao!
After putting the thing into oven twice, the RAM slots still don't work reliably.
I then manually use a soldering iron and some rosin and go through each pin, and then still no good.
And then I spray contact cleaner inside the RAM slots, still no good.
And then I spray even more but this time also give a deep brush with my retired toothbrush, and only then one of the DIMMs work reliably.
And then I have to replace one of the sticks and finally the ram works 100%!
If I were literally anyone else I know of, I would've lost patience long, long ago!
I mean I kind of see the RAM slot problems coming because when I got the computer, it came with a single 256MB of Samsung PC100 SODIMM, which is NOT a factory configuration for such a laptop! Most likely one slot have failed and the owner just left that slot empty.

Also in case you don't know, the CPx J that I have here is practically the direct competitor of ThinkPad 600X with Speedstep (CPx H has no Speedstep and CPx J has, they differ by a different sound chip and BIOS), but it has ATi Rage M1 with 8MB of VRAM and 32 bit colour mode. But when I open up the lid, the LCD is actually IBM branded. IBM made displays back then? I haven't seen one on any of the ThinkPads that I have!
Dell Lat CP MMX-233 64mb 40gb W2k
600 PII-266 416mb 40gb WXP
T23 PIII 1.13ghz 1gb W7
Precision M4300 X9000 8gb 160gb WUXGA Ultrasharp fp W10
T530i 15.6" i7 16gb fp W10
UXGA:
A30p PIII 1.2 1gb W7 (IDTech)
T43p 2.26 2gb fp W10 (Sharp)
Lat C840 P4-2.5 2gb 60gb W7 (Ultrasharp)

RealBlackStuff
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Joined: Mon Sep 18, 2006 5:17 am
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Re: WTB: Pentium III MMC-2 CPU Any speed

#9 Post by RealBlackStuff » Thu Mar 05, 2020 1:50 am

When I do my LED-mods, I always use a flux-pen to resolder the (30) pins of the LCD-connector.
https://www.ebay.ie/itm/113718782057
I used the same stuff -way back when- to fix some T30 RAM slots.
Still NOT a great day for a Guinness! (the Real Black Stuff).
Ireland is on FULL lockdown until at least 31 January 2021!
Covid-19: Stay safe, so Mask it or Casket!

kfzhu1229
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Posts: 1843
Joined: Tue Sep 22, 2015 10:59 pm
Location: Toronto, Canada

Re: WTB: Pentium III MMC-2 CPU Any speed

#10 Post by kfzhu1229 » Wed Apr 08, 2020 7:14 pm

Well that ADP3420 chip finally arrived today.
I first applied a crap ton of flux, and then I soldered a few pins on the chip to position it properly, and then I brought out a heat gun and solder most of the pins on that, and then I go over each pin again with a soldering iron, and after a few more attempts of going over the pins the CPU finally decides to work!
And then I spent like half an hour using mechanical removal by lightly scratching it with the tip of a push pin and brushing with alcohol to remove the flux (not sure if there is a better way to do that).
The result is that on the outside the CPU looks pretty normal. But if you look at the capacitors around the chip, those have some strands of solder sticking out like a unicorn because my soldering iron touched that when I was going through the pins. And while the chip soldering works, it seems like it isn't centred vertically that there are more exposed solder pad on one side than the other. Not bad for first time doing soldering on a surface mount IC.
The chip ended up costing me around US$7, which isn't all that great of a deal since I doubt this 750Mhz CPU is worth too much more than that, but to be honest I am buying experience doing micro soldering than anything.
So yeah if you have a dead MMC-2 CPU with the capacitor inbetween two transistors on the top right corner getting hot (and the capacitor itself isn't shorted), then it could be a dead ADP3420 chip, kinda like the blink of death on the T20-T22 devices.
I took some pictures of the result of my micro soldering here:
https://1drv.ms/u/s!At7-rt1KJ7WviPdrTIs ... w?e=oCalvG
Dell Lat CP MMX-233 64mb 40gb W2k
600 PII-266 416mb 40gb WXP
T23 PIII 1.13ghz 1gb W7
Precision M4300 X9000 8gb 160gb WUXGA Ultrasharp fp W10
T530i 15.6" i7 16gb fp W10
UXGA:
A30p PIII 1.2 1gb W7 (IDTech)
T43p 2.26 2gb fp W10 (Sharp)
Lat C840 P4-2.5 2gb 60gb W7 (Ultrasharp)

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