Fun! Back in the 90s when I was assembling PCs, we found by accident that AMD's DX2 (whch was the same as their DX3 and did support frequency tripling) worked perfectly fine under 5V, albeit very hot! We were running so-called DX2-66 at 150 MHz as 3x50 with a heatsink! When they released the next one (5k86 I seem to remember) which supported frequency quadrupling, some of their DX2 did support doubling or quadrupling and the trick still worked; so we could buy DX2/66 and operate them at 4x40 = 160 MHz. We had a few boot at 200 but they didn't go very far. Our customers loved this by then, as many of them were discovering PC games and you couldn't count on VLB vdeo cards to offload the CPU! We saw a few DX3/150 return and require to be lowered to 120 or 133 MHz after a few months, but that was marginal.

@scrap_computing

Жыл бұрын

Nice! 486s are pretty tough, they seem to tolerate quite a bit of abuse!

The fine grain control over voltage is very interesting - I wonder if this could help get the overclocked AMD X5 chips even higher than the current records.

@scrap_computing

Жыл бұрын

Yeah, you could even power it externally using a bench power supply!

I appreciate the Duke3D music.

@scrap_computing

Жыл бұрын

Yeah! This is the Space Quest Historian's remix, it is a very fine piece of work!

Thanks! Once again, awesome video. I guess it’s time for me to check out that repository too. It’ll probably take a while before I get to making the prototypes, but this is going to be very helpful for my projects too. Thanks again!

@scrap_computing

Жыл бұрын

Yeah, give them a try, they are not too tricky to put together. Thanks!

Digging everything about this video, blast on Master Blaster.

I was hoping that someone would make this project for years. I'll order some PCBs and try it out. Thanks

@scrap_computing

Жыл бұрын

Awesome! Go for it! And feel free to share your feedback :)

@Epictronics1

Жыл бұрын

@@scrap_computing I did! Awesome boards. Here's the vid :) kzread.info/dash/bejne/qHmko9GPdZexmrg.html

Supercool project. Staggering the pins diagonally is an interesting approach by the way. I was playing with the idea of building a voltage adapter but i was tinkering with using two prototyping breadboards on top of each other. Gave up after a while.... :D

@scrap_computing

Жыл бұрын

Yeah, I was considering using a breadboard myself, but I am pretty sure I would mess up the wiring and spend a ton of time debugging it :D

Wow what a nice idea. Now.. i did sell my 486 about 10000 days ago but it would be fun to have one again.. maybe with a little modern enhancments :)

@scrap_computing

Жыл бұрын

+1 It is easy to get them running these days. You can use an SDCard to IDE adapter for storage, a floppy emulator, and a modern ATX power supply with an adapter.

sheer guts if not madness ;-)

That was great work.

@scrap_computing

Жыл бұрын

Thanks! Glad you liked it!

Great little widget and very thought through. I suggest using tantalum SMD caps to minimize the ripple. 200mV is huge, I'm surprised you don't experience more problems. Perhaps consider using 100uH inductors????

@scrap_computing

Жыл бұрын

Yeah, I will give it a try. Perhaps, as others also suggested, it is worth implementing a good regulator circuit on the board itself, and not have to rely on these cheap regulators.

@varno

Жыл бұрын

I would look at Aluminium Polymer capacitors, also probably look at implementing a linear post-regulator with good high-frequency rejection. Maybe also a 4-layer PCB with the power on the inner planes.

@varno

Жыл бұрын

Maybe even a 6-layer PCB would be useful here, at these high frequencies, running power in traces is not recommended.

@MartenElectric

Жыл бұрын

@@varno definitely agree on 4 later design, what frequency runs through the board? 30 MHz to the bus? Also have a look at trace length matching, that might help with timing. Although all the amendments on PCBs are great I reckon the biggest performance increase will be from Linear regulator or some with lower noise, I'm afraid you will have to have a look at some more reputable sellers for these :)

@varno

Жыл бұрын

@@MartenElectric actually just looked at the regulator and it is a 4mhz version. I actually think this is probing issues and high trace inductance. I have seen this before. You probably should use the little spring to measure the voltage, not the alogator clips.

I like that stalker.mid version.

Watched all your videos already, this is an excellent project, time to dig my 486 boards out, looking forward to more uploads, I like that you show your mistakes/hiccups along the way, looks like we have another good retro community channel to watch, thanks and keep it up 👍(btw, I think your voice/accent is great, where are you from if you don't mind me asking ?)

@scrap_computing

Жыл бұрын

Glad you enjoyed the videos! Yeah 486s are the best :D :D

Love the video. I got a question. When you have your final version would you consider selling them as well. I have squat for soldering skills so for me I need them already made. Have a good one.

@scrap_computing

Жыл бұрын

I am not planning to sell them, but the design is open source, so anyone can build it and sell it.

This is a really cool project. Can it be used (or be modified to use) a 486 CPU in a 487 socket?

Through-hole caps are not really good at smoothing out high frequency ripple so the best would probably be a mix of bulk crapacitor and a couple of small ceramic ones. :)

Some really cool work. Necroware and you should get together on a project.

@scrap_computing

Жыл бұрын

Yeah! That would be awesome!

@sonicunleashedfan124

Жыл бұрын

@@scrap_computing maybe you could help him with his MMX-VRM he’s working on?

Nice update. I would like to just point out that your voltage isn't high enough. For Intel CPUs it should be 3.3 with 0.3 tolerance. I could see on your scope that the CPU was getting 3 which is just barely within tolerance. For St they want 3.45 with 3.3 minimum and AMD is about the same. Which means a tolerance of 0.15v so I'd say if you used and St/ibm/amd chip, you could have more stability issues than you've had with the Intel one. Personally I've used a 1084-3.3 regulator with an AMD CPU and have had no issues with it. There is a bit of noise surrounding this topic, some say to use 3.45, some say their boards are set to 3.6 out of the box. On regulators you could look at murata ones they make a selector of regulators, some small, some large. I've used a large murata for a socket 7 and it's been perfect. Though with building the regulator into the board, you could use parts available with smt services and have the board makers do that part of the soldering for you.

@scrap_computing

Жыл бұрын

Yes, 2.9V is not ideal. Thanks! I will check them out.

@RodBeauvex

Жыл бұрын

@@scrap_computing The crashing is interesting. Are the caps on your test motherboard fresh? I had a couple motherboards that were fine for light tasks but would crash under the quake Demo until they were recapped.

Need to make one of these for socket 7

@scrap_computing

3 ай бұрын

Socket 7 would be quite tricky because the pins are twice as dense and sockets/pins are not widely available.

Does the SB work on Socket 2 Motherboards?

@scrap_computing

3 ай бұрын

I don't have a Socket 2 board to test it on, but I think they are backwards compatible with the original PGA-168 socket of the 486. So I am fairly confident it should work on the Socket 2 too.

So if I were to get an AMD 5x86 133MHz and install it into my 486 machine's Overdrive socket with the Socket Blaster, it should work? FSB in this thing is 25MHz and it currently has a 50MHz DX2 Overdrive installed.

@scrap_computing

Жыл бұрын

Yeah it should work. It may need a good quality voltage regulator though and you would also need to populate all the capacitors on the socket blaster, which I haven't done yet :). Some folks in the comment section have mentioned some good quality ones. I will give it a try and I will get back to you.

Would it be possible to extend the PCB an add circuitry for L2 cache? I swear I have seen such a thing for sale once on Ebay. I remember is used those weird chips that had a width that was between a normal cache chip and, say, a typical keyabord controller.

@scrap_computing

Жыл бұрын

Great idea! if I am not mistaken the cache is managed by the chipset so there would need to be some additional logic to get it to work. But yeah, that would be awesome!

@davidschaper3238

Жыл бұрын

@@scrap_computing Normally it's managed by the chipset, but Sony made a complete solution with a single chip, it attaches directly to the 486's bus. The chip is the Sony cxk784862q, you can easily find the datasheet for it. For instance Compaq used these on certain 486 machines.

What music soundtrack are you using? My shazam isn't able to identify...

@scrap_computing

Жыл бұрын

It is track Stalker from the Duke Duke Dance Party Album by the Space Quest Historian. spacequesthistorian.bandcamp.com kzread.info/dash/bejne/ZIKIpNWjYNHOgto.html

Is anyone selling these pre-assembled and tested? I like soldering projects but feel nervous thinking about this one!

@scrap_computing

Жыл бұрын

If you have some soldering experience it shouldn't be too hard. You just need to take your time to make sure that you don't spread solder all over the place. There is a great video by @Epictronics1 that shows some nice tips on how to assemble it.

You intend to run a 100MHz Dx4/486 without a heat sink? do let me know how that goes for you, because I am actually looking at one right now and it says HeatSink Req. It's not on the cpu it self but on a red sticker stuck to it.