DIY 16MB 30-Pin FPM SIMMs: Supercharge Your Vintage Hardware!

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Күн бұрын

This is a follow-up of my 4MB SIMM project. At that time, I created an altered version of SIMM PCBs that integrated a mod to operate EDO memory chips in FPM. A simple switch toggled between both modes and allowed me to get my 386 board to 32MB of system memory. Today, we are pushing the board to the limit! I will attempt to create 16MB SIMMs - the maximum supported capacity of 30-pin SIMMs. Let's see if I will be successful to get my 386 to 64 or even 128MB!
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▬▬▬▬ Timestamps ▬▬▬▬▬▬▬▬▬▬▬▬▬▬
00:00 Intro
01:36 Recap
04:43 Maximum capacity
05:31 Research
08:34 Preparation
09:45 Design PCBs
10:57 Unpacking
11:51 Building SIMMs
16:50 Final touches
17:19 Test
19:29 Where to get?

Пікірлер: 496

@bitsundbolts 7 күн бұрын

Hi there! I hope you like the 30-pin SIMM 16MB memory module. Would you be interested to get a set of 2, 4, or even 8 modules? I want to understand what the demand is for such modules. Hit the like button of this comment and reply with how many modules you would be interested in. This is not an order, I just want to know if I should make a few and utilize the memory modules you have seen in this video! Thanks everyone for watching, commenting, and liking! Cheers

@AttilaSVK 4 күн бұрын

This is awesome. I could use 8 such modules for my Macintosh SE/30 to max out the memory :) Btw, the Sound Blaster AWE32 also supports 16MB SIMMs, but the usable memory is limited to 28MB due to the 4MB ROM sharing the address space with the RAM.

@MarcoGPUtuber 4 күн бұрын

I know how to get chips for these so you don't have to desolder them from DIMMs.

@harvaldi 4 күн бұрын

@@AttilaSVK I would love to have 2 for my Sound Blaster AWE32! :D

@philpem 4 күн бұрын

I'd be interested in a set of four - I'm curious if my 386 boards can go as far as yours!

@BadManiac 4 күн бұрын

I'd absolutely be interested in a set of 4. Being able to switch between FPM and EDO would be invaluable for testing old hardware. Also can I please come visit your scrapyard one day? That place looks like heaven! :)

@0xTJ 4 күн бұрын

I love how cheap and fast PCB production has made creating custom modules like this, especially for non-standard things like the EDO->FPM adapter.

@bitsundbolts 4 күн бұрын

It is really easy! And the learning curve to my first PCB wasn't as steep as it might seem.

@Robin96 4 күн бұрын

The 64 MB RAM count was so funny i watched it several times. I really like the ram counting sound on old computers

@Spyd77 4 күн бұрын

I had a 8088 computer for way to long. I was young and had no money, so I saved all the money I got to upgrade my XT. The day I got enough, I bought a motherboard with an Intel 386SX, and 1Mb memory. The motherboard had 4 SIMM slots, and I wanted a single 1Mb module, but on the store they told me that I had to fill at least a bank (2 modules). My options were 4x256Kb, or 2x1Mb. No 512Kb modules. Having waited more than a year to be able to update my computer, I caved and got 4x256Kb, my options to upgrade gone. Then I had a 386sx (I think 25Mhz, don't remember), 1Mb of RAM, an Hercules graphics card, a green-phosphor monitor, a single 5,25" 360Kb floppy disk, and an MFM 20Mb hard disk. It wasn't much, but Windows 3.1 worked well and the CGA software emulation worked SOOOO much better.

@TheRaker1000 4 күн бұрын

your PCBWay ads are the only ads on YT that i actually watch. not even just letting the ad roll while i do other stuff, you have me paying attention and engrossed in the product. can we please make all advertising like this? relevant, informative, confident.

@bitsundbolts 4 күн бұрын

Oh well, thank you 😊. I usually get the opposite view about ads in general. But without PCBWay, I wouldn't be able to do all this. Not only do I get access to their services and products, but they also help a lot with their financial support. It wouldn't be feasible without sponsorships to run a channel like this. Thanks for your support! 🙏

@colinmoller4321 7 күн бұрын

Oh man, I have to agree, the black PCBs give it a really badass look!

@bitsundbolts 7 күн бұрын

It makes those modules look more premium. I'm looking forward to making these in larger quantities 😅

@tomasz89g 4 күн бұрын

I was happy with 5MB back in the day. 64MB is INSANE for a 386, nice job, pushing it to double the stated maximum!

@bitsundbolts 4 күн бұрын

I agree - 64MB is not really useful for a 386. Most of the memory is not usable by the software that runs on such a platform. As you said, the driver behind this project was to see what is possible. I learned a lot by going through the documentation and make sense of it. And finally also to understand, why we can only use those high capacity modules in memory bank 0.

@tomasz89g 4 күн бұрын

@@bitsundbolts RAMDisk would be very useful. Large smartdrv cache. But back in the day, this kind of system would have fetched a very high price. You are right, RAM was expensive!

@OpenGL4ever 4 күн бұрын

@@bitsundbolts 64 MiB might be usable for compiling source code. You could benchmark it with 8, 16, 32 and 64 MiB to see if there is a difference.

@acubley 2 күн бұрын

@@bitsundbolts Back in the day I was super happy when I got my P90 system to 8mb. I put 4mb to a ram drive and had the autoexec.bat copy my current game there. 64mb would have been heaven. 😵

@philpem 4 күн бұрын

Nice work! I never thought I'd see a 386 with 64MB RAM. I always thought they topped out at 16. This absolutely blew my mind!

@bitsundbolts 4 күн бұрын

386SX systems seem to have this limitation of 16 MBs. Glad to hear that you have seen something new in this video! 🙂

@isaiasprestes 4 күн бұрын

Back there in 1992, our brand new AMD 386DX40 had 8Mb RAM. At some point, befere acquire a 486DX2, it was upgraded to 32Mb. Running on 8Mb we not really faced lack of memory. With 32Mb, it was such a paradise of RAM. This 386 was active until early 2000s as our local name server, firewall and NAT running Slackware Linux. One day, it's keyboard was not responsive, and I had already an AMD 5x86 spare on the corner. After more than 10 years of work, our beloved 386 (nick named AMaDo, beloved in Portuguese) retired.

@bitsundbolts 4 күн бұрын

AMaDo served you well! 32MB is quite a lot for such a platform and probably not that common.

@n.stephan9848 3 күн бұрын

8:55 That scrapyard is magnificent, I wish I had a place like that nearby with even a quarter of the stuff portrayed there.

@UpLateGeek 4 күн бұрын

Congratulations on such a successful project! Now people can finally stop bugging me to make 16MB SIMMs! Of course I'm kidding, I only got a few messages asking about them since I published that project so many years ago. But I'm glad someone finally took up the mantle and did what I never got around to doing. I had every intention of getting back to this project and making my own 16MB modules, at one point even tracking down a source for the requisite chips, but they were very expensive since they were NOS, so I never got around to ordering them. And then my career took the front seat and I've had neither the spare time or energy for such a project since then. But this is an even better design, since it's using chips that are basically scrap. The fact that you can use EDO chips really opens the door to potentially using other chips with a relatively simple modification to the design. So congratulations once again, you've really done some impressive work!

@bitsundbolts 4 күн бұрын

Thank you so much! Without you paving the way, I would have never picked up on PCB design. Your Gerber files and schematics allowed me to learn about those modules. Thank you for your work!

@xephorce 4 күн бұрын

I love this. saving chips that might have gone unused for the rest of time. this is something that needs to be done more often.

@bitsundbolts 4 күн бұрын

Haha, I am working hard on hopefully more projects like this in the future!

@BeniD82 4 күн бұрын

Years ago I ordered a number of 128MB 5v EDO DIMMs and the supplier shipped 3.3v modules instead. When I told them about the mistake they told me they'll send the correct replacement and to just keep the 3.3v sticks. Never had any use for them until now it seems. My chips are Micron parts but they appear to be 16Mx4 as well and are sharing the same pinout. Guess I should sacrifice a stick out of my pile to create a slew of 16MB 30pin SIMMs. It's a parity module too so two additional chips for an extra 30pin module... Awesome job!

@bitsundbolts 4 күн бұрын

Oh, wow. I always have to send stuff back 😅. Good for you - I guess you found a use case for those modules now! I wonder what you possibly could have used those EDO modules for otherwise (I guess you have the 168-pin version). I would rather use SD-Ram since it is probably a lot faster.

@argoneum 4 күн бұрын

Back in 1990s I had a borrowed Am386DX-40 machine with 4MB of RAM (and without FPU). It run Win3.11 For Workgroups on MS-DOS 6.22. There was Corel 5 and Corel 7 installed. Corel 5 was working fine, Corel 7 had trouble fitting in RAM and was swapping a lot. It was fun seeing Corel Draw 5 actually drawing the business cards when a file was opened.

@bitsundbolts 4 күн бұрын

Oh, I remember Corel. I think I had version 4. That was for Windows 3.1 if I'm not mistaken. It was slow if I remember correctly. Those vector graphics just took some time to be drawn on screen.

@2dfx 2 күн бұрын

When you started up that 386 for the first time with 64MB I had a huge smile on my face as I'm sure you did. What a really great achievement and just shows you that "official" and "supported" specifications may be two different things! Thanks for sharing.

@bitsundbolts 2 күн бұрын

I am working on an updated version that hopefully follows the specifications on the datasheet. I do it mostly to learn more. The current modules seem to work well and I got plenty of comments supporting both perspectives. There will be a follow up on this one very soon!

@sebastian19745 3 күн бұрын

I once got a set (4 pieces) of 4M 30-pin RAM modules. Man, I was so happy, I used them on my 486 with 2x16M FPM 72-pin RAM modules. Win 95 was very happy with that extra memory but, thinking now, it must have been quite slow because of the 30-pin/72 pin mix. However, I had 256k, 512k, 1M, 4M and I have seen 2M 30-pin RAM sticks but 16M is a first. Congratulations!

@Popclone 4 күн бұрын

Watching your retro upgrades is like watching NASA upgrade Voyager 1. Keep it up.

@bitsundbolts 4 күн бұрын

Haha, thanks for comparing my upgrades to Voyager 1 😅 - quite an honor! I'll try my best to keep the content interesting

@MarcoGPUtuber 4 күн бұрын

0:36 I found a 16-SIMM board in the scrapyard and a friend gave me another one. Very happy to own these.

@bitsundbolts 4 күн бұрын

They are no longer that common. I have many and not really any use for them. I prefer larger capacities. However, if you want to build a period correct system, those 1MB modules are probably the sweet spot.

@MarcoGPUtuber 4 күн бұрын

@@bitsundbolts I had never even seen one and wasn't aware they existed, I was going to make it one of my retro machines and max it out with what I could find. Once I fix the board though.

@pgtmr2713 4 күн бұрын

@@bitsundbolts It's weird to see "period correct." I'd say who cares. But the there's automotive, where original, oem, has the most value. There it makes sense since most can't build better than the manufacturer, and no one wants to buy junk used. I think we had 1mb in our 386 back in 92

@LellePrinter82 Күн бұрын

Impressive, great work. Impressive what u can salvage from old computer parts. That scrapyard looks like paradise to me, i've would've spent hours there. I have loved electronics since I was a young kid, it started when my dad bought his first pc with a 12mhz 286 cpu. Always been fascinated by computers and stereo equipment. I'm both into retro pc and retro stereo components, and I always will be. In highschool my teachers told me that I knew more about pc's than them, they were fascinated by my electronics/pc knowledge.

@ChrisR3tro 2 күн бұрын

Loved that bit about the meaning of SLC in the Opti chipset model name 😂

@mo0seboy 4 күн бұрын

I had a 486 DX2-66 machine with a weird motherboard that had 3 72 pin SIMM slots. I ended up populating it with 3x16MB modules for a total of 48MB of capacity. It was a fun machine to put slackware linux on.

@VVerVVurm 4 күн бұрын

My Atari had 1MB of memory and it was a lot! I remember reading in a magazine that althought the CPU was able to address 4GB of memory that this will never happen and extrapolated the power consumption from the 1MB and concluded that 4GB of memory would require about 200 amps during refresh cycle 😆

@bitsundbolts 4 күн бұрын

Haha, nice! And now we're considering 4GB unusable.

@bingusbongus9807 3 күн бұрын

16 MB is so cool, thats why i love the ez80, awesome 24 bit adress space

@stoojinator 4 күн бұрын

This is freaking awesome! What an awesome project!

@bitsundbolts 4 күн бұрын

Thank you 😊

@jamesrdgrs 6 күн бұрын

Another awesome video and another win for making this hobby a little more affordable! Thank you!!!!

@bitsundbolts 4 күн бұрын

Absolutely! It looks like I will have to make quite a few of those modules soon!

@blakecasimir 4 күн бұрын

Fantastic work as always.

@bitsundbolts 4 күн бұрын

Thank you!

@christ2290 4 күн бұрын

Man, you are LEGIT. Great work!

@bitsundbolts 4 күн бұрын

Thank you 👍😊

@Edmilho 2 күн бұрын

Excellent work! Congratulations on the video and success to the channel.

@Arti9m 4 күн бұрын

Please note that there have been reports on similar chips dying in 5V systems. On the other hand, I have a few SIMM72 5V modules made with 3.3V-only chips but indended for 5V boards. They don't even have the regulators, just two diodes in series to drop the voltage to 3.5-ish. Also there's another way of making 16M SIMM30 sticks. It involves 8 4x4 chips and a PAL chip for reorganizing the memory. Works kinda like SimmConn. I do have the PCBs drawn and firmware written for PAL but just don't have the time to build it 😢 Great video as usual!

@bitsundbolts 4 күн бұрын

Hey! Good to hear from you again! Thanks for pointing out the issue with the 5v issue. I'm going to research the topic and try to address the issue somehow. I have seen other SIMMs that also just have the voltage regulator and a few capacitors. I'm confused to be honest. But I'm researching level shifters at the moment.

@vitobelflores6510 Күн бұрын

Deja tu mujer y tendrás tiempo de sobra. Estos proyectos sí venden si los nostálgicos sabemos que existen.

@michvod 7 сағат бұрын

If I am not mistaken, those 168-pin EDO RAM modules can be very handy in some old Macintosh systems (like PowerMac 7200, etc.). They will also work in Pentium Pro and Pentium II systems, as those also support EDO RAM (the i440FX only supported EDO, later i440LX added SDRAM support, but it supported only 512MB of SDRAM, but 1GB if you used EDO!, same goes for i440BX). Those modules are really rare as we usually think of EDO RAM as an 72-pin SIMMs and not a SDRAM-styled 168-pin DIMM, but those do exist and are really rare

@br0wnd 4 күн бұрын

If I could go back in time and show one video to myself as a teenager, it'd be this one. I know I would have been in complete awe seeing this much ram on a 386!

@K10driver 4 күн бұрын

When the 386 counted up to 64MB the first time, I had to laugh like you did. Insane idea and great implementation! Another question: I am an earlytime member and from all the videos I have watched I might think you are German. There are some hidden words and things you did that make me think that. Am I wrong?

@bitsundbolts 4 күн бұрын

Yes, I am German - you are right. Listening to the memory test counting up is just great and I am glad those PCBs worked! Although, after making the 4MB SIMMs, it wasn't as challenging anymore.

@K10driver 4 күн бұрын

@@bitsundbolts Dann hab ich doch richtig gehört. Ich glaube es war in einem der P2B Videos wo Du ganz kurz auf deutsch geflucht hast.

@PhG1961 3 күн бұрын

What an awesome video and a great id!

@ileox4170 3 күн бұрын

Well Done ❤! I don‘t have any clue about FPM or EDO Memory at all but the explination is on point and the execution as well :D

@chrisrudi7162 4 күн бұрын

The project is very nice 👍 Really great, especially since it is very difficult to get really large modules. I also have a 386DX 40 MHz with 64 MB, but I bought these modules ready-made many years ago.

@Ale.K7 4 күн бұрын

Amazing!! :D That Cyrix FasMath FPU is gorgeous. I also find those COB SIMMs you showed at the start of the video pretty interesting! It's been a long time since I last played with my 386s, but I remember 4MB being the most I could use... So I think i don't have any module larger than 1MB (and there's also the possibility that I achieved said 4 megabytes on a board with 8 sockets and 512KB per module being my maximum!).

@bitsundbolts 4 күн бұрын

Most of my SIMMs are 1MB modules except for the ones I made myself. I think there must also be a few 256kb ones.

@lesar23 4 күн бұрын

What a LEGEND you are.

@rallyscoot 3 күн бұрын

saved the world

@mesterak 4 күн бұрын

This was simply amazing work!

@bitsundbolts 4 күн бұрын

Thank you very much!

@pongisan3658 3 күн бұрын

Holy crap this is so cool!

@viktorgorbunov 3 күн бұрын

I've remember how I switched from 1M ( 47$ for student was a good money ) to 4M, it was amazing.

@petrcvek Күн бұрын

Be careful when you buy EDO DIMM module. If it has 8K chips it will not work . An 8K chip will have 16M array, but it is not a symmetrical array (which would be 4K x 4K). 8K needs 13 bits of address, which is not defined on an SIMM module, so the highest bit will be floating and the motherboard will only see 4Kx2K array (which many chipsets don't support). Anyway awesome video!

@r4z4m4t4z 4 күн бұрын

nice vid, great work! 30 pin ram, so long ago, my 386 sx 33 struggling to get it going when adding more ram, so fun.

@bitsundbolts 4 күн бұрын

If I am not mistaken, a 386SX cannot support more than 16MB.

@UXXV 4 күн бұрын

This is like voodoo to me! Love it

@volkhen0 4 күн бұрын

Thanks for your effort!

@bitsundbolts 4 күн бұрын

My pleasure!

@christianhansen3590 4 күн бұрын

The audible sighs made me chuckle 😊 But a really cool project!

@argoneum 4 күн бұрын

SoundBlaster AWE32 (and AWE64 IIRC) supported 2x 16M modules, but could only use 24MB of RAM for soundfonts. Back in 1990s this was The Ultimate MIDI Setup. SB-Live! / Audigy soundfonts will work with it too. (yes, yes, didn't forget, there was GUS, and Holy Wars wars between some GUS and AWE users, I know ;)

@OpenGL4ever 4 күн бұрын

The SoundBlaster AWE32 was released in 1994. But later soundcards where much better MIDI setups. I had a Terratec EWS64XL in around 1997. This was still in the 90s and the EWS64XL was much better than the earlier SB AWE32 and still an ISA card for best compatibility to DOS games.

@ozzyp97 4 күн бұрын

@@OpenGL4everIn fairness, with full ram you can get very nice midi quality out of the AWE32, so long as you chosen DOS game will run under Win9x. Depending on the model they can also have real OPL3 FM, which is a nice perk as well.

@BarsMonster 4 күн бұрын

Great job! I think I can finally make myself some - I've got a box of old DIMMs that I can now put to good use :-)

@bitsundbolts 4 күн бұрын

I wonder how many of those SD-like modules with EDO memory chips exist. I have never seen them before. Just once, when I visited the scrapyard, I found all those modules and was like 'eh, let's take them. Maybe they will be useful in the future'... And here we go! I hope you can make good use of the PCBs!

@tezinho81 4 күн бұрын

I use a SIMM from my very own first 486 pc (1995 iirc) as a keyfob. It's a link to my past that I carry every day.

@GadgetUK164 4 күн бұрын

Fantastic work! One potential problem, having to fit 3.3v regulators for 3.3v RAM, the RAM may have a shorter life as any clamping diodes are driven frequently by 5v logic levels of the chipset. It's also possible the chipset could die when interfacing 3.3v and 5v. It's possible the RAM you are using is 5v tolerant? I see you scoped the address and data levels there, and they look right - but probably because of the clamping. It's worth measuring that same way with 5v RAM fitted - see what levels you get. Don't be put off by this btw - the chances are it will work reliably even if the clamping is an issue. It's just one of these things that I am sure will get pointed out.

@bitsundbolts 4 күн бұрын

The ram I'm using is not 5V tolerant. In the data sheet it says absolute maximum voltage is 4.75 or something. I am wondering and will do some additional tests before starting a mass order of those PCBs. In case there are 5v signals, would a simple voltage driver be enough?

@GadgetUK164 4 күн бұрын

@@bitsundbolts What you might be able to do - since it says the RAM can go up to 4.75v, try measuring the data and address bus levels with a 5v SIMM, lets say the levels are around 4v - that would mean you could perhaps try and regulate the RAM VCC to 4v ish, and in theory the RAM would work safely as its under its 4.75V limit, and clamping would be (I think) less likely as the logic levels are within the VCC level.

@radionicretrofit 4 күн бұрын

I wondered same issue, chip lifespan will be reduced with 5v operation. I am not sure how tight timings on address bus but maybe level shifters are fast enough to use on this modules?

@bitsundbolts 4 күн бұрын

Would a simple voltage divider do the trick? I might have to get like 40 small resistors on the board if I understand that correctly.

@bitsundbolts 4 күн бұрын

I'll try to understand this more. I already got details regarding level shifters. More things for me to learn and definitely a thing to look at before I order larger quantities of those modules. Thank you for all the great hints!

@Choralone422 4 күн бұрын

Excellent work! It would have been incredible (and expensive!) to have that amount of memory in a 386 system back in those days!

@bitsundbolts 4 күн бұрын

Oh absolutely!

@oldconsolegaming 22 сағат бұрын

Thanks so much I had a ton of sim modules that where from a different pc that did not physically fit in my 486 pc now I can use them (I believe they where server or smth else) and now I can put them to use without throwing them out!

@bitsundbolts 18 сағат бұрын

I'm working on an updated version of the PCBs. They should better support 3.3 volt memory chips.

@retropcscotland4645 4 күн бұрын

I loved Soyo back in the day. I used those branded boards all the way up to socket 478. They recently started up again in China.

@ruben_balea 3 күн бұрын

My first computer (386SX-16 from late 1991) came with 1MB in four 256kB SIMMs and that was more than enough when most games only used conventional memory and only a few could use EMS. Later I got some programs that needed Windows 3.1 in 386 enhanced mode to run and I added another four 1 MB SIMMs to end up with 5 MB.

@JonBrase 3 күн бұрын

What I'd really like to see for retro machines is an all-in-one storage adapter: SATA connectors and maybe a network port on one side, multiple GB of RAM for caching in the middle, and legacy connectivity on the other side (PATA/Floppy and/or ISA or PCI). Board runs Linux, you connect storage on the modern side, it reads disk images off that storage and presents those images as floppy or ATA disks on the legacy side. There are already SATA/PATA adapters, which allow a modern disk to be presented to an old system, but there are issues with old BIOSes choking on large disks. Using images would allow for keeping presented disk sizes to something BIOS can handle while using the capacity of the underlying modern disk to provide a multiboot environment with multiple legacy OSes without having to squeeze all of them into the size of whatever number of small disks will fit in the chassis.

@christophero1969 3 күн бұрын

Very awesome!

@bitsundbolts 3 күн бұрын

Thank you for your support! 🙏

@jefersonfischer 4 күн бұрын

Very Cool video!

@bitsundbolts 4 күн бұрын

Thank you so much for your support! Glad to hear that you liked the video and the project!

@HBAVHS 4 күн бұрын

Perfekt. Dann werd ich gleich mal Platinen bestellen. Dank dir. Hammergeil!

@bitsundbolts 4 күн бұрын

Haha, kein Problem! Viel Spaß damit!

@cheaterman49 3 күн бұрын

Next time you order black PCBs, take the ENIG finish instead of HASL, trust me you won't regret it 😁

@lantapaukku7629 3 күн бұрын

I had a 386sx25 back in early 90's. I had an ISA card that had 16 slots for 30 pin memory modules and I salvaged a pile of 256kb modules. It gave +4 MB of total memory in addition of those 2MB already on mainboard. Interesting video though.

@AG-jj3lx 3 күн бұрын

Awesome!

@tony359 7 күн бұрын

TAKE MY MONEY! 💰💰💰💰💰💰💰💰

@bitsundbolts 7 күн бұрын

😂

@harvaldi 4 күн бұрын

Easy Tony, easy... Beath slowly and deeply :)

@adriansdigitalbasement 3 күн бұрын

Just awesome! I would love to see if any 386 boards support 128mb on board using 8 of these.

@bitsundbolts 3 күн бұрын

Thank you Adrian. I hope to find a board that supports 128MBs!

@thebishtable 4 күн бұрын

I'd recommend ordering PCBs with Gold ENIG. It's worth the extra few bucks.

@darklore7566 4 күн бұрын

That 386 was like umm i am not sure what to do with all this RAM I can only uses about 1/4 of it 😂 like to see the temps of the multitasking with that 386 lol.

@itstheweirdguy 3 күн бұрын

A great video as always! With how much data we can send with our busses on the computers now, it's pretty pathetic how little our computers can do in 2024 taking into consideration we're sending multiple GB/sec even with storage now.

@ajdothack 4 күн бұрын

Omg I have a ton of scrap arcade boards full whit those ram chips, I am soo going to try this on mi vintage 386 and 486 PCs thank you!

@bitsundbolts 4 күн бұрын

You're welcome!

@wildorb1209 4 күн бұрын

This is so wild!!!! :-D

@olek4182 2 күн бұрын

Back in the day (1990) I had an Amiga 500 with 2.5 MB RAM (which was an incredibly large amount of RAM :) .

@ukmk3supra 4 күн бұрын

I'm just constantly in awe of these scrap yards - nothing like this in the UK :(

@bitsundbolts 4 күн бұрын

Ah, I am really fortunate to have access to one in my area and regulations are almost nonexistent! Paradise for scrap hunters 😊

@Darkstar2342 4 күн бұрын

@@bitsundbolts what country is that scrap yard in? I'm guessing central europe somewhere (because some of the modules in your video had German labels on them) but here it's almost impossible to get access to a scrap yard as mere mortal...

@RetroShare2 4 күн бұрын

@@bitsundbolts where is that scrapeyard?

@evandrochaves9596 4 күн бұрын

UAE, not in europe

@bitsundbolts 4 күн бұрын

I live in the United Arab Emirates. The scrapyard is here. But it's more like independent scrap dealers accumulated in one area.

@dav1dbone 3 күн бұрын

A successful and worthwhile project. There were some mainboards from this time that used zipp sockets for memory, do you know of any PCBWay or public domain solutions for an adapter pcb to enable reusing dram from scrap simms to solder onto?

@AlexanderWeurding 3 күн бұрын

Epic!

@Robert.Czarnik 4 күн бұрын

That's awesome! I have to check my memory connection I have. Maybe I have some of those. If not I'll be interested too.

@bitsundbolts 4 күн бұрын

I hope you'll find some of those chips. Making those modules yourself is just so rewarding!

@Robert.Czarnik 4 күн бұрын

@@bitsundbolts unfortunately, I don't have those. I'm interested in 4 modules.

@ruediix 3 күн бұрын

Very cool design. If you want to expand further you may be able to hotwire a secondary memory controller into a piggy-back board right on the CPU. This would also allow you to use even faster memory such as SRAM. High density (by late 80s standard) SRAM is now dirt cheap as it is used in some microcontroller use. You can easily get 4MBit modules for relatively cheap.

@KomradeMikhail 4 күн бұрын

8:54 "Scrapyard to the rescue." Holy smokes !... Your local scrapyard is so much better than mine. How much to buy the whole lot ?

@betomanske477 4 күн бұрын

Brilliant work. Would it be possible to use these modules on Sound Blaster cards such as the CT3600?

@MonochromeWench 3 күн бұрын

Never needed more than 4x1MB in my 386, it was enough to run doom and command and conquer poorly, but they actually ran so I was happy. C&C should not have worked at all on a 4MB 386 but somehow it did. By the time 8MB games were common I had a 486 with 8x1MB.

@Nukle0n 4 күн бұрын

My favorite PCB look is black substrate with clear solder mask, so you can see all the copper traces-

@bitsundbolts 4 күн бұрын

Ohhhh, interesting... PCBWay has that option... Maybe I should try those.

@kjamison5951 3 күн бұрын

Thank you for this! In theory, my Macintosh SE/30 could easily get its 128MB RAM maxed out!

@TexasAgg2003 4 күн бұрын

such an awesome video. The black PCBs look great. I can imagine how much something like this would have cost back in the day. besides a ram drive, are there any applications that would have utilized this amount of ram? Maybe some type of simulation software?

@bitsundbolts 4 күн бұрын

Thank you! Maybe some industrial applications or CAD software could have utilised such amounts of memory. I wouldn't know what to do with that much memory.

@ceruleanserpent387 4 күн бұрын

I love maxing out 386 board with more ram than possible in the day, SSD, other tech to see how competitive it can be even with the CPU bottleneck!

@joetoney184 2 күн бұрын

I need to lay out a DDR4 DIMM footprint QDR SRAM board, this video inspired me to get it done! Now I just need to prep my wallet for buying $300 of ebay SRAM to get some low capacity memory to practice soldering down since they are BGA.

@bitsundbolts 2 күн бұрын

Glad to hear you found some inspiration! Good luck!

@Stratotank3r 4 күн бұрын

Das muss der Hardwarehimmel sein! 386er, die normalerweise 4MB und höchsten 8MB hatten auf 32 und jetzt 64MB zu pushen! Genial. Musste damals meinen 486DLC von 4 auf 8MB aufrüsten und 300DM löhnen. Bin froh, dass ich 4*4MB habe. Bei 486ern dürfte es sicherlich klappen auf 128MB zu kommen. Dazu einen 5X86-133 und Win2000 drauf. Der POD ist zwar besser aber die Boards, die den POD unterstützen, nutzen sicherlich 72pin Module.

@bitsundbolts 4 күн бұрын

Ja, diese großen 30-pin Module werden wohl eine kleinere Nische beglücken. Ich werde da auf jeden Fall noch etwas herum experimentieren.

@netzwerk-werkstatt332 4 күн бұрын

Great 👍

@OSkar000se 3 күн бұрын

Interesting video as usual :) Got some ideas to make 4mb modules out of old 8mb EDO modules in the same way since I got plenty of them laying around here. Not sure if its possible though. In the end of the life of my 386DX 33 it had 20mb of ram, enough to run Windows 95 a bit better then how it ran on 8mb that I had before. I had that computer until the end of 1998 when I got a chance to upgrade to a Pentium 133,

@chimebirdplayer3327 3 күн бұрын

I once had a Soyo motherboard that came with it's own proprietary software (that ran in Windows) which allowed the customization of the Energy Star logo; but as with the software you demonstrated in this video, it wasn't easy to control the colors.

@sleveee 2 күн бұрын

i remember saving up from my grocery store job to pay over $100 each for 2 sets of 2MB modules for my 386sx. ended up with right at 5MB with the onboard RAM.

@micksta 4 күн бұрын

Declaring my interest in such memory modules please :)

@bbjunkie 4 күн бұрын

With the responses you're getting i'm sure i'm too late! Just getting into retro computing, would love a set of 4 to use, am addicted to building circuits and bodgery like this!

@bitsundbolts 4 күн бұрын

Haha, oh no. Since the PCBs are available to anybody, you're never too late. And I am not selling them now anyway - I just want to see if there is demand for them. The main problem for me would be the logistics to ship modules worldwide due to cost.

@Roadkill7878 4 күн бұрын

My first PC was a Pentium 90 with 4mb of ram. I remember paying £240 for an extra 4mb! Back in 1995 memory was stupidly expensive

@OpenGL4ever 4 күн бұрын

I upgraded my 486DX from 4 MiB to 8 MiB in June 1995 in Germany. I paid without tax around 46.37 Dollar (64.35 DM) per 1 MiB SIMM Module. Thus 185.48 Dollar in total and 213.31 Dollar with 15 % tax.

@bitsundbolts 4 күн бұрын

15% Mehrwertsteuer 😂 that was the time! Crazy how expensive RAM was!

@OpenGL4ever 4 күн бұрын

@@bitsundbolts And yet it was worth it just to be able to play Dark Forces. My friend from school followed suit, he also wanted to be able to play Dark Forces. It was my first game, that required 8 MiB, the next was Warcraft 2 Tides of Darkness. The computer was too slow for the later games, but the upgrade was still useful for Windows 3.1.

@JVAmorim 4 күн бұрын

Very cool!!!! In another project, make a Edo memory!

@timc3600 4 күн бұрын

Nice project. As you already have surface mount soldering capabilities, order the stencil with the PCB. The non-framework ones are cheaper and easier to store. Then use solder paste and an old plastic card to apply. This makes manufacturing of the boards a lot quicker and easier. A gold edge connector would also be a good upgrade as it would reduce the risk of corrosion over time.

@bitsundbolts 4 күн бұрын

This is the plan! Stencil and solder paste. I wish I could order those modules gold plated. But it's quite pricey.

@timc3600 4 күн бұрын

@@bitsundbolts I agree it doesn't work at low numbers, but you can play with the options to find a sweet spot that might work for you. For fun, I just ran a quote with a non-framework stencil (metal sheet without a frame around it), 20mm x 100mm PCB using the edge connector option and choose immersion gold(ENIG), then increase the quantity up to say 50. This came out at £79.90, so $1.60 a card. Changing the quantity to 100 gives $107.60, so $1.07 a board. The equivalent costs without gold edge connectors were 50 off $45.64, 100 off $75.05, so the costs are much lower overall. This could work if you are planning to sell on ready made modules or even blank boards. Note that these all included a cheap shipping cost too The other option is to look at gold plating solutions that can be added once the boards are manufactured. They are either brush on or dipped. There are many on-line. 50ml for £30 was one example I found. I note that some have hazardous chemicals in (cyanide), so be really careful if you go this route. Take a look at the newer fluids that don't have problem.

@bitsundbolts 4 күн бұрын

I would not want to deal with chemicals - as you point out, the gold option may be feasible! I didn't check those options yet, but it may be worth it for some high quality SIMMs. Let's see how this project continues! Thanks for checking the quote btw!

@Inject0r 4 күн бұрын

Nice! I thought I was special with my 4MB modules :p Have you tried to tighten the memory timings? Those timings are probably the most important feature of EDO memory :D

@bitsundbolts 4 күн бұрын

I haven't done much with those modules yet, but I'm planning on doubling the cache on the board and also exploring what's possible with that amount of memory.

@Thelemorf 3 күн бұрын

I had a whopping 24MB in my 486 dx4 100, and also a p83od

@ccanaves 4 күн бұрын

Amazing video with great insight. What are C1 and C3 for? You left them unpopulated.

@bitsundbolts 4 күн бұрын

Those capacitor pads are for the input voltage to the regulators. You could add some additional capacitors to smoothen the input voltage - I left them because I have a good power supply and don't think it would make a difference.

@Sigmatechnica 4 күн бұрын

Nice! i remember having a 386 with a whole 2MB RAM. It wasn't enough. didn't get 64MB until i got a k6-3 several computers later :(

@bitsundbolts 4 күн бұрын

Yeah, that sounds like a more reasonable platform to put 64 MB on 😅

@shanent5793 3 күн бұрын

There's a problem with connecting the 3V chips to a 5V bus. The DQ[3:0] pins are bidirectional, so they have both an input and output circuit. While the input is a high impedance circuit and can probably tolerate over 5V, the output has a clamping diode pointing to the 3.3V supply. Your particular chipset is only driving the bus to 3.4V, which is not enough to make the diode conduct, but there are worst-case scenarios that can cause high currents in the diode. The 3.3V supply could be as low as 3.0V, while the 5V supply could be 5.5V, which might drive 3.9V (3.4+0.5) to 5.0 V on to the bus and exceed 3.0+0.7=3.7V on the 3.3V output, causing the diode to become forward biased. The 3.3V supply doesn't turn on instantly, so it's possible that it may not be ready before the chipset starts driving signals onto the bus. One mitigation is a series diode between the outputs to reduce the current. If we assume a worst-case difference of 5.5V the resistance may be quite large, which together with the input capacitance will filter out the edges and violate the rise time. If you can guarantee that the 3.3V supply comes up before the signals are applied, then this will reduce the voltage and you can use a smaller resistor. Bidirectional level translators are available, they usually block until the power comes up on both sides and will convert the voltages to the appropriate levels. They have around 5ns propagation delay so you will have to verify the timing, as well as figure out a way to drive the direction input. An 8-channel device should cost fifty cents in quantity. The input-only pins are more tolerant because they are only connected to a high-impedance MOSFET gate, so you may only need one 8-channel translator per module (4 data pins per chip x 2 chips).

@NaoPb 4 күн бұрын

This is great! I will surely be giving this a try sometime in the future. I do have a silly request. Could the modules be updated with solder pads to attach two SMD LEDs? I have some Geil Dragon Ram (DDR1, DDR2, etc) that has an LED on the left and the right side of the front, symetrically. And I thought it would be funny to add that effect to these modules. Could it be that it also needs a resistor?

@bitsundbolts 4 күн бұрын

That's probably small SMD LEDs on that module. They most likely need a resistor to most probably get a voltage around 2v.

@sandmanxo 4 күн бұрын

It's insane to even think of 64mb on a 386. At the end of the 486 era I had 16mb and that was overkill. I think that was around 1996 with my overclocked amd 5x86. Still cool to see it can boot up with that much ram.

@bitsundbolts 4 күн бұрын

There must be a 386 chipset that supports 128mb 😅

@sandmanxo 4 күн бұрын

@bitsundbolts I would think a board that supports both 386 and 486 cpus would have the best chance, but then again I'm not that familiar with it. Always fun to see if an old cpu with handle an absurd amount of ram though!

@--Lam 4 күн бұрын

Wait, 20 years ago I had 96 MB FPM in a 486 system. I was moving about a lot and at that time, got myself a P4 or whatever and stored that 486 back at my parents'... so my mom promptly recycled it. WOMEN! I still can't forgive her, for this and also my pimped out 386 router with a Hercules console :( Anyways, 32 MB FPM sticks not only existed, not only I had them, but they were scrap when I got them . The world already moved from EDO SIMMs to DIMMs, I was simply too poor for any of that and had to actually research what was actually fast, and my resulting 486 pwned!

@bitsundbolts 4 күн бұрын

Noooooo! Ah, I am so sorry. This must have been something like "ah, why does he keep this old stuff around. Let's make some space."