Can the IBM PS/2 P70 be overclocked with a Cyrix Cx486DLC?

[@THEtechknight]

Tony359 did discover those HDDs have a plastic thing inside that deteoriates and gets all over the platter, damaging the drive. so FYI.

[@Epictronics1]

We'll have a look inside! Thanks

[@Atarian1993]

I imagine this has been a frustrating repair, but it's excellent to see more progress!

[@Epictronics1]

I'm at least partially in it for the challenge :)

[@Darxide23]

"Dry" solder wick is something of a misconception. What's really happening is the copper is oxidizing and that prevents it from taking up solder as easily. Keeping wick in an airtight container would help the problem and make wick last longer, although the most common number I'm seeing by Googling is that wick should last about two years stored in the open before it oxidizes too much to be effective. I wonder if a soak in something like Deoxit would work to rejuvenate old wick. That would be an interesting experiment.

[@Epictronics1]

I keep it in the fridge in an air-tight zip-lock bag. I have probably had this wick for more than two years :)

[@g4z-kb7ct]

@@Epictronics1 I just add some flux onto the wick and then it sucks like Jenna Jameson.

[@Epictronics1]

@@g4z-kb7ct 😆

[@AnnaVannieuwenhuyse]

Deoxit wouldn't do much of anything except for poison you when you breathe in the fumes given off when you burn it.

[@tigheklory]

​@@Epictronics1This is true I use the fluid no clean flux by MG Chemicals and just saturate the end of the wick with it and it's great!

[@xephorce]

I smell Fish the words no electronics repair person wants to say. lol. I hate it when a RIFA cap leaks or pops. cant wait to see window 3.1 on that Amber beauty. thank you for the video. don't forget to like the video everyone.

[@Epictronics1]

Thanks :) Should be interesting to see how some DOS games look on that display

[@danielktdoranie]

LOVING this series

[@Epictronics1]

Thanks :)

[@faberfox]

I'm really enjoying your videos on this lovely PS/2, such a beautifully over engineered beast!

[@Epictronics1]

Thanks :)

[@DavidPagett]

This is a great series, I'll almost be disappointed when it's all fixed! 🙂

[@Epictronics1]

Thanks :)

[@GeckonCZ]

The "missing ADF" issue might be related to the work you've done on the PCB. If the hard drive was recognized correctly before, it's possible that one of the bus connections is faulty. You can check the POS ID that the system detects using QBMCA/IDMCA or a similar utility. Then, just compare the detected ID with the correct one to figure out which bit could be causing the problem. And yes, these drives do attach directly to the MCA bus. The pinout for the DBA connector is available on The Tool - it's a subset of the 16-bit MCA interface.

[@Epictronics1]

Hmm... Has anyone ever tried to hack these drives to work in any MCA machine? :) Thanks!

[@GeckonCZ]

@@Epictronics1 You could totally do that. Some effort was put into doing the opposite - adapting regular drives/solid-state storage to the DBA-ESDI interface. There are some annoying limitations though - like the 16-bit address bus (compared to the regular 24-bit one).

[@AnthonyRBlacker]

This video probably has the best title I've seen in years! : )

[@jasmijndekkers]

Hi Epictronics, Nice repair again and i look forward for part 2 from this beauty. Greetings from Steven from the Netherlands

[@Epictronics1]

Thanks :)

[@DimasFajar-ns4vb]

wow and peace be upon you sir from me

[@JenniferinIllinois]

Overclocked with a Cyrix. A phrase I thought I would never hear! 🤣🤣🤣 Had a Cyrix back in the day and all I can say is it was cheap. Oh and I guess it did work. But it was CHEAP, which is why I got it.

[@Epictronics1]

On other boards, this Cyrix is crazy fast!

[@g4z-kb7ct]

14:50 Easy to fix, just file the top flat. I keep a flogged-out tip handy for when I need to remove something that is too big for the standard tip, such as an RCA jack or whatever then the tip with larger hole can be used. Also, put almost no pressure on the PCB when desoldering pins and if you do it correctly the mask paint won't be scratched. This reduces the chance (when resoldering parts) of making a solder bridge from an exposed trace running along side the chip to a chip pin.

[@Epictronics1]

That's a good idea, I'll file it flat and keep it for removing soldered heatsinks with huge pins

[@SockyNoob]

"Some of these pads were really stubborn, but I'm stubborn too." xD

[@Epictronics1]

:)

[@MonochromeWench]

MCA Bus hard drives, IBM really wanted to get rid of every last remnant of the AT bus so no industry standard IDE drives instead they created their own MCA variant of IDE. They could have at least used SCSI drives but no they needed to keep it entirely proprietary for the P70 as if the people who spent money to buy one of these would then go and get a third party HD upgrade.

[@nickwallette6201]

I think I tried three of those things in my PS/2 386, all with a "controller failure" error, before I gave up, bought an MCA SCSI card and SCSI HDD, and made a custom 3D-printed bracket and PCB to pull power from the MCA edge connector. I really like to run all-original hardware whenever I can, but those drives are rare as hens' teeth, and all seem to be borked.

[@BigBadBench]

That's a shame about the crystal. At least the CPU is working! Holding out hope for my model 80!

[@Epictronics1]

I was hoping we would battle the P70 against the 80 :)

[@SudosFTW]

yep, I said it in the comments of the first video, the plasma caps need done.

[@Epictronics1]

and you were right :)

[@GeckonCZ]

Many PS/2 systems are quite sensitive to overclocking - it could be the hardware, the POST routines, or a combination of both. Can you use a parallel port POST reader to check if there's any activity when using the 50 MHz oscillator? If there is, it would also be helpful to see at which checkpoint it halts...

[@Epictronics1]

I most certainly do! I'll check. Thanks

[@fra4455]

Great video

[@Epictronics1]

Thanks :)

[@fra4455]

@@Epictronics1 thanks

[@vhfgamer]

That moment you yeet an electronics project into the dumpster that you've been struggling with for weeks if not months, and it's fought you the whole way. It's finally crossed the line, and you're sick of it. Before you turn away, you say one last thing to that wretched hive of wires and circuitry. "So long and thanks for the fish."

[@Epictronics1]

😅

[@neozeed8139]

My PS/2 Model 60 with a Kingston/IBM 486SLC2-50 and an 80387sx, and I get a 6.1 on the Superscape benchmark FYI.

[@Epictronics1]

We'll try it out in the Model 50 when it's time for its next video. They have very similar motherboards.

[@AsmodeusDeviluke]

There are sockets just for these crystals. Look for Full Can or Half Can oscillator sockets.

[@Epictronics1]

Excellent. I presume they are made for the oscillator's thin legs. I'll order one and we'll try it out. Thanks

[@phreapersoonlijk]

28:55 nice river !

[@Vermilicious]

You left your fish dinner inside?!

[@CandyGramForMongo_]

This model is a fantastic example of an IBM PC failing to meet the then-current standard for IBM Compatibility. 😂

[@bikkiikun]

Considering the nasty corrosion that went through that nozzle...

[@Epictronics1]

haha, that nozzle sure has seen some VARTA juice :)

[@lindoran]

Unpopular hot take: in my opinion double wipe sockets are better for restoration than turned pin sockets.

[@GGigabiteM]

Depends on where they're used. If you have old ICs, double wipe sockets. If you have board to board connections with pin headers, machined sockets are better because of a better mechanical connection. If you have new ICs, machined sockets are generally fine to use.

[@g4z-kb7ct]

18:20 Ummm yeah don't use machine pin sockets for crystals, use a regular dual-wipe socket. Machine pin sockets are made to mate with machine pins....

[@Epictronics1]

Learned it the hard way

[@laurdy]

I wonder of the crystal also controls the MCA bus frequency and is causing it to be overclocked, an alternative may be a DLC2 clock doubled CPU

[@Epictronics1]

Yeah, unfortunately, they are crazy expensive :(

[@Renville80]

Anyone know what that fourth pin is for on these oscillators? On one board I have, three pins of course go to +5, ground, and output - the fourth pin goes to an unpopulated capacitor location (and from there, to ground).

[@Epictronics1]

Probably NC, but could be enable pin

[@Baoran]

Maybe you should try some other benchmark than the one you used. The benchmark you used could be easily limited by video chip speed while cpu could be more than 10% faster in reality.

[@Epictronics1]

Yeah, maybe also try a better graphics card to see if it helps. Thanks

[@awilliams1701]

I wonder if you're hitting a video card throughput limitation.

[@Epictronics1]

Could be. I'll try again with an XGA-2 card. Thanks

[@manganmegamangan]

bor du i sverige eller i usa/england? bara nyfiken

[@kompzec]

What are the values for the display axial caps?

[@Epictronics1]

I just placed an order on Mouser. Send me an email. I'll send you the list: [e-mail]

[@SockyNoob]

Yet again proving that machine sockets suck for the most part. Not sure why some people, *ahem* Adrian's Digital Basement, use them so much only to have issues with them lol.

[@1-eye-willy]

its not quite a lap top, but more like a luggable, a lap-luggable, aka "the electric vasectomy"

[@herauthon]

O.O

[@xero110]

The end of the video made me think of an old joke that I want to reinvent. "A blind man walks into a retro computer convention and says, Hello ladies."

[@NavJack27gaming]

i've only ever messed with IBM PS/2s in 86box and MAN are they temperamental machines even in "perfect" hardware situation of emulation like that. IBM was very opinionated with the design of how they should be ran. I'm loving watching this adventure unfold.

[@Epictronics1]

Thanks :)

[@briangoldberg4439]

i like your projects a lot, but i really don't like the soldering footage. no offense intended or anything

[@Epictronics1]

Thanks for the honest feedback. What's bad about it?

[@blakecasimir]

I see nothing bad about it. Care to elaborate?

[@briangoldberg4439]

​@@Epictronics1 I understand it's just my personal preference, but I see a lot of similar projects and I do plenty of such things myself at home, and I'm not really interested in seeing another cap replaced, etc. I'm more interested in the outline and the outcome of the work, and any meaningfully interesting steps along the way. One good example of how I think this is done really well is David Tipton (www.youtube.com/@DavidTipton101) When it's time to do a tedious thing like recapping stuff, he just does a jump cut and moves onto something only if it's unique or interesting. On your videos, I find myself skipping a lot of footage to get to something interesting and that makes the videos quite short.

[@blakecasimir]

@@briangoldberg4439 Personally I disagree and find Epic does a fine job finding an editing balance.

[@briangoldberg4439]

​@@blakecasimir i respect that

[@R.Daneel]

You know EBay sells these things called desoldering needl..... Nevermind.

[@2xtreem4u]

Mooo 🐄

[@TheSimTetuChannel]

You really need a Cx486DRx2 20/40GP to get CX486.EXE to do its magic on the P70. SuperScape 1.0c gives me: 64.4fps Then in your autoexec.bat you add: C:\CYRIX\CX486.EXE Q C:\CYRIX\FLUSH.CFG (assuming you saved the settings in the cfg file beforehand) For reference my FLUSH.CFG file reads: Setup Strings (all values in HEX) CR0=00000010 CC_0=13 CC_1=00 CC_2=13 CC_3=08 ARR_C4=00 ARR_C5=00 ARR_C6=00 ARR_C7=00 ARR_C8=00 ARR_C9=00 ARR_CA=00 ARR_CB=00 ARR_CC=00 ARR_CD=00 ARR_CE=00 ARR_CF=00 DIR0_FE=07 DIR1_FF=20

[@neozeed8139]

My Model 60 with the Kingston/IBM 486SLC2-50 upgrade gets me 37.6 fps. Kind of surprised it's that high tbh.

[@Epictronics1]

They are a bit pricy :o I'll start saving :)

[@TheSimTetuChannel]

Yes, 150$ was hard to swallow for the chip but I had the P70 for free so, who am I to complain!