I forgot to mention, the repair in this video was temporary for test purposes. You shouldn't follow it as a how-to! It'll be redone professionally before the next Compaq 386s video. Stay tuned for that in the not too distant future.
Right around when you were posting this wonderful series (what initially brought me to your channel) I had just purchased a Deskpro 386/20e (DX at 20Mhz w/32kb cache). I finally found the matching monitor and it arrived yesterday, but after 20-25 minutes one of the RIFA capacitors let out the magic smoke! Ironically at the moment it happened I was explaining to my wife how these capacitors would eventually go and would make a horrid smell (and the RIFA did not disappoint)! Luckily the picture was excellent before the catastrophe, so at least it is a worthwhile repair. I immediately thought of your videos and revisited them for a refresher -- keep up the great content! By the way, the closest mouse I found that matches these systems is a Logitech manufactured M-SF14-2 (there are at least 2 versions, the earlier one having the same Compaq logo with line underneath). It looks right at home next to the appropriate keyboard.
This is still one of my favourite computers, and I get it out regularly for various things. There will definitely be some more videos on the channel about it eventually. The main problem I have with my monitor now is it is out of focus (nothing to do with the RIFAs). I need to find time to pull it apart again and get it focused up. Your 386/20e sounds pretty nice. I bought bits and pieces of a later machine at some point but it isn't in a state of repair. In the end I became quite interested in these SX machines due to the obvious limitations they had, which I find fascinating to try and overcome through clever coding.
I completely agree with it being a favorite. Even 25+ years ago I thought these second generation Deskpros were beautiful machines but was never able to get my hands on one, then with the lockdowns of 2020 I actually found retro computing to be a very apt hobby (albeit an expensive one). I also have a Deskpro 386s that I initially purchased as a parts system shortly after acquiring the 386/20e, but have since changed my mind and am slowly gathering parts to bring it back as well. I look forward to more content (especially with the Deskpro) and thanks again for sharing your knowledge, findings, and expertise!
Have the exact same PC on my desk, with the exact same monitor, and the exact same issues (smoke / cmos setup issues / ......). Funny to see :) Great video !
Ah that is quite the coincidence. I didn't get a chance to watch your hard disk videos yet but I'm looking forward to seeing if you were able to make any progress with those. I once had a hard drive recovery expert watch one of my videos on that topic. He was not best pleased with my approach!
Just picked up one of these - the VGA card on the motherboard looks the same, I'm pretty sure there isn't any cover missing - this was one owner from brand new. Has a 40MB hard drive, the official Compaq joystick adapter card (for two joysticks) and a very proprietary 4MB RAM expansion too!
@@PCRetroTech our parents had a Packard Bell 386/16 with 1MB RAM/105MB as our first ever PC so fairly similar spec on this! I buy and sell retro kit and this came in as part of a largish bundle, it's cleaned up near perfectly but it's not my bag really, I'm into vintage Commodores and early IBM stuff. Mine is just the base unit as well, no keyboard, mouse or monitor sadly.
It definitely says SX on the chip. It's possible the Compaq VGA implementation was really fast or something like that. I'll try running Timeless on some other hardware and see if there's a noticeable difference. I have a few different VGA cards and at least one other 386 machine.
@@PCRetroTech No need, it is possible I am misremembering. Tran coated most of his stuff for a 386 SX16 because that's what he had. His home motivation to create pmode was to gain back the time lost due to db 66 and DB 67 opcodes required in real mode, made especially important due to the 16-bit bus of the 386 SX.
@@JimLeonard There's definitely going to be a followup video on this machine. Benchmarking it will certainly be part of that. In this video I mentioned there was this probably apocryphal story of MS engineers using these machines because of their speed. But I now think that was the original Compaq 386, not this 386SX. So now I really am curious how much difference there is. I am not even sure what other 386 chips/boards I have, so that will be fun to play around with in a later video.
@@PCRetroTech Be sure to include 16-bit real mode and 32-bit protected mode memory transfers in your benchmarking, as you will see the most difference in that area. Topbench can handle the 16-bit part to save you some time.
Those Rifa capacitors that blew are Y-class. Those connect between line and ground and are there to filter out RF emissions. The Y-class is a special kind and designed to fail open when they fail. The capacitors you put in are not Y-class but just ordinary impulse capacitors.
That's correct. It's a temporary repair for testing. The replacement RIFA's are on the way, but didn't make it in time for filming. In fact, I don't think the seller even dispatched them yet. I don't like the fact that they are too large either. But all will be rectified soon. I actually didn't know if there was anything else wrong with the monitor, so it made sense to test before getting too worried about dotting I's and crossing T's. :-)
Very nice system ! I have its little brother (quite litterally) the 386s/20N which worked but had lots of bad caps and a broken hdd. 3:08 "You need specialist tools and equipment" * see a hammer and a saw in the backrground * :))) Ah RIFA caps ... Apparently they're a common failure on old hardware. The reason is that their plastic gets brittle over time and the stuff inside don't like oxygen or something which shorts them and make them run hotter and hotter until they blow up. Something similar happened to my ICL 286 the other but unfortunately no RIFA cap in sight ... I have no idea what died there but it made a crazy purple smoke and the computer turned itself off. On a totally different topic, I have created a website which can probably interest you : www.win3x.org/uh19/ It's a database of over 6000 oldschool motherboards :) (more infos about the project over here : www.vogons.org/viewtopic.php?f=46&t=74070)
I think the orange tantalum capacitors are the next most common failure, then the electrolytics (with the silver tops), then voltage regulators. I can't imagine anything else making smoke. Wow, that website really is something! I'm impressed!
@@PCRetroTech Well it's the PSU that smoked. But I haven't seen anything that looked bad despite the burned electronics smell and the large amount of smoke that came out of it. I really need to investigate. As for the website, thank you :) As you can guess, we're planning next to add expansion cards of all sorts. Considering all the video cards you own, you'll probably be able to help us (if you want to)
@@Dxceor2486 Hopefully I can find some time to help. I have taken on some other very big projects lately, which you'll hear about on the channel eventually. So finding time is actually quite a lot harder than it used to. But this is such a great project I'm sure I'll at least contribute something.
Those replacement caps are probably fine, but the originals were y class caps... Edit: you can still find replacement Dallas RTC chips, I think the chip code ends in B now but its the same chip.
Well spotted. I want to replace them with smaller caps, so they'll end up being the right kind in the next iteration. These are literally just what I could get in time for filming. As for the Dallas chip, I've seen people referring to external batteries in these Compaqs. So I have to look into whether there is a connection for that somewhere. I'm really not sure how that would work and details are scant. But yes, I'll probably get a replacement Dallas chip otherwise.
I bet the reason why windows 3.x doesn't start and complains about not enough memory is that you have no memory manager loaded to access that memory above 640k.
I think there is one, but there's a whole load of other things loaded in config.sys which are probably using up memory. Windows 3.1 apparently has a minimum requirement of 2mb, so it should be possible to fix this when I film part 2.
wait... what's so special about this computer? why the bidding frenzy? it looks like a pretty bog standard 80s/90s era pc from the big box guys. i don't get it.
I have the 25 sx mhz version of this PC and it's fairly unique for it's age, including a socketed Dallas RTC chip for easy replacement and 72-pin FP memory slots (up to 16 megs supported). A significant number of 386 and early 486 motherboards self destructed due to leaking rechargeable motherboard batteries, not to mention being poorly documented, so these tend to be much better candidates for restoration since they buck both of those trends. I did find a pair of the same monitors in a gaylord of bad CRT's at a recycler, wonder if they are worth fishing out and repairing to have a complete set...
Oh no, that's not the issue. If you update to the latest Windows 7 security patches it's been disabled from the GUI. You can now only format them from the command line, which means looking up the exact commands format a: /T:80 /N:9 every time I want to do it. Not very convenient! The reason this was an issue here is that the program that I was using to make floppies from .img files had two options: 1) format disk and write image 2) write image only. The first option no longer works, so it was necessary to first format the disk from the command line, then use option 2. As far as I can tell, Windows 7 is mostly crippled these days. The browser works intermittently, there are always problems with the floppy drivers and the thing is so slow it is almost unusable.
In fact, I am going to abandon my Windows 7 machine, as it only allows one floppy drive to be attached, which is really inconvenient. I frequently need stuff transferred to 3.5" and 5.25" floppies so I actually have to switch the drive over in the machine, set it up in the bios and restart. It's amazing that the designers of the late motherboard that I have didn't support two floppies! (I can't recall the problem, whether it only allows a single drive on a cable or if it is just that the cable won't reach from the 3.5" bay to the 5.25" bay and there is only a single floppy connector on the mainboard. Either way, it is too much hassle.) Instead I am going to download stuff on a modern laptop with secure browser, and transfer it via USB stick to a much older machine with both 3.5" and 5.25" floppies. I'm sick of all the hassles my Windows 7 machine has been giving me.
@@PCRetroTech Oh I see. I haven't used Windows 7 in 2 years so that's why. I wish there was a __cheap__ way to connect floppy disk drives to USB with a non crippled controller.
