Repairing An Explosive Compaq Portable I
Рет қаралды 20,844
Күн бұрынOnce again, I've been summoned to perform computer necromancy, in this case, in the form of a Compaq Portable I who my friend sirocyl "helpfully" brought to my apartment. The Portable I is an interesting piece of history given it was the machine that marked the end of IBM's monopoly over the personal computer, and was the first "fully compatible" IBM PC clone.
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While IBM would face early challenges with "functionally compatible" and "DOS compatible" machines, COMPAQ was the first to proudly proclaim 100% compatibility. In what would be a famous case of reverse engineering, Compaq fully documented and re-engineered the BIOS of the 5150, and created their own functionally identical replacement of IBM's code. This, combined with a licensed copy of DOS and GW-BASIC made the Compaq almost perfectly compatible with the 5150, with the only truly notable difference being the lack of cassette port. Compaq would also go as far to create their own clone of IBM's Color/Graphics Adapter in the form of the Video Display Unit, or VDU card.
This specific Portable was found on Goodwill Auctions by sirocyl in unknown condition. It's also one of the rarer, two floppy drive models, and a look at its system board shows that its one of the earliest revisions of Compaq Portable. Included is a full 256k of RAM, and BIOS chips from 1986.
When I got it, the Portable was entirely dead, and required extensive work even to determine what was wrong with it. This is also not including problems with the power supply, VDU card, or shorted capacitors which all made themselves known throughout the process.
Interesting Timestamps:
00:00 - Intro
01:00 - COMPAQ and the PC Clone Wars
02:50 - Initial Machine Exploration
05:45 - Machine Teardown
07:30 - Locating Short Circuits
08:40 - PSU Troubleshooting
13:10 - Exploring PSU Schematics
15:21 - Amateur Electrical Explanation
16:15 - C81 Capacitor Replacement
18:00 - Isolating New Faults
20:33 - Compaq Portable ATX Replacement
21:40 - Inspecting the Damage
23:00 - The Final Smoketest
24:05 - In Closing ...
Music provided by Epidemic Sound, in order of appearance:
- Chef Extraordinaire - Trabant 33
- Jam Street - T. Morri
- Thief - Rossier
- New York Minute - T. Morri
- Extravaganza - Jules Gaia
- Ain't No Thing But To Swing - Jules Gaia
- Midnight Swing - Jules Gaia
- Swagger Stagger - Lucas Pittman
- Feeling Alright - Gavin Luke
- Glitz At The Ritz - Jules Gaia
- Mama Swing - Lucas Pittman
#Compaq #VintageComputing #Restoration #Explosive
@NCommander 3 жыл бұрын
Figures I only catch "I try" later ... I just need to learn to stop using title cards ...
@schmatzler 3 жыл бұрын
You never get used to exploding caps, no matter how prepared you think you might be. :D
@NCommander 3 жыл бұрын
I was a line firefighter, so I turned the psu off, then my brain processed what just happened
@nickwallette6201 3 жыл бұрын
What are you talking about? I just wanted to see my room from the ceiling, that's all.
@NCommander 3 жыл бұрын
Obviously the correct solution is to mount your desk so you can solder while lying on your back.
@o_o-_-8639 2 жыл бұрын
Electroboom: Hold my beer!
@kevinlkoehler 2 жыл бұрын
I think you should have to ground the board when soldering.
@tsbrownie 3 жыл бұрын
Not called "portable" by those of us who carried them home every night or took them on planes. We preferred the term "luggable", and that also applied to the Kaypro and Osborne.
@NCommander 3 жыл бұрын
Well, it was formally called the Compaq Portable, although that is stretching the definition of Portable ...
@LaskyLabs 3 жыл бұрын
I leave DVDs on my friend's front porch. Your friend mails you an explosive computer. Just saying, I'm open to finding more friends.
@NCommander 3 жыл бұрын
My friend got a massive kick out of this. I on the other hand realize that I know far too many people who like to see things explode ...
@LaskyLabs 3 жыл бұрын
@@NCommander I'm not against it... But I'd much rather share my pira-- not pirated music with my friends. If you don't tell the FBI and RIAA then we can be good friends.
@botchedrepair1542 3 жыл бұрын
@@NCommander yep i love seeing things explode, but even apart from that your video is amazing
@ncot_tech 3 жыл бұрын
See that's how you make an interesting start to a video. I like the computer's response of "FF" though.
@NCommander 3 жыл бұрын
Nobody: Nobody At All: Capacitor: *EXPLODE* Past NCommander: *startled*
@Damaniel3 3 жыл бұрын
I've seen enough Compaq Portable repair videos (and early IBM PC/XT videos) to figure there was going to be a tantalum filter cap involved, and this one didn't disappoint. Removing those should be high on the list of 'first things to do during a restoration'.
@NCommander 3 жыл бұрын
I did check that cap specifically with the DMM and ESR and it tested good. I only figured out it was a filter cap after it exploded
@adamsfusion 3 жыл бұрын
Yeah, everything I bring in gets a proper recap. Tantalum and aluminum caps never fail to give me surprises.
@nickwallette6201 3 жыл бұрын
Absolutely. I don't even turn stuff on anymore until all the old electros are replaced, a new fan in the PSU, and if it's older than a 386, the tantalums gotta go too. Although I'm convinced IBM was trolling people with those 3-pin caps with the legs bent under the PCB.
@chriswareham 3 жыл бұрын
If the PSU board itself looks undamaged, I'd suggest replacing the electrolytic caps and giving it a chance. I've rebuilt a few PSUs in synths and samplers with good results - as long as there's no catastrophic damage then it's usually just the bigger caps drifting out of spec (and the dreaded RIFA caps if they're present).
@NCommander 3 жыл бұрын
No RFIA's I could fine, but there is a sealed metal can with the IEC plug on it; no way to open it, although no one has reported a RFIA explosion from one of these.
@NewRepublicMapper 2 жыл бұрын
0:08 That timing when you almost explode the F Word and the FF appears
@MatroxMillennium 2 жыл бұрын
I was so stoked to see that cursor pop up at the end of the video!
@varno 3 жыл бұрын
I would try getting the old psu to work. For such an iconic machine, best to try to keep as much circuitry original as possible.
@nickwallette6201 3 жыл бұрын
Absolutely. PSUs seem to fail in one of a few common ways, and you can go a long way with _minimal_ know-how and testing equipment. First, replace all the electro caps, then look for the large-package diodes and transistors. Remove those from the circuit and test them with a multi-meter. If they don't test out OK, replace them and just try it again. There's a good chance it'll fire right up. But just in case, you might want to buy a couple extra. They're usually pretty cheap.
@NCommander 3 жыл бұрын
I'm hesitant to do this on the basis that this PSU design uses quite a few zener diodes to downstep the voltage (the 5V rail is generated that way). It's pretty much a single component failure from frying the entire PC. I didn't realize quite how bad it was when I first started with this project.
@nickwallette6201 3 жыл бұрын
I understand the sentiment, but I think the more you work with power supplies, the more you realize you are _always_ one component failure away from catastrophy. haha Zeners don't tend to be regulators themselves. More often, they are used in a voltage reference circuit. So, you pass +12V through a resistor (to limit current), and then into a Zener with a breakdown of ~5V, then to ground. The junction between R and Z is going to be around 5V, and so you can use that as one input to a comparator that's in the feedback loop of the 5V regulation circuit. It's not handling any current to speak of. External to this, there's usually a protection circuit that's monitoring the voltages produced by all the rails, and when they exceed a margin of error, the drive signal to the main switcher is cut off, or something similar. So, if that Zener goes open and the 5V reference voltage is suddenly at 12V, the over-voltage protection circuit should put the kibosh on things _right quick._ Suffice to say, nothing lasts forever and there are never any guarantees that the whole thing won't just pass rectified mains straight into your motherboard. But, there are checks and balances to prevent that from happening. If the output caps are in good shape, the secondary rectifier diodes are working properly, and the LM339 (or whatever is monitoring the rails) hasn't been blasted apart, you're probably as safe as you can get with _any_ PSU -- new or old.
@NCommander 3 жыл бұрын
@@nickwallette6201 true, but there's a world of difference when said component is mostly new, vs. 40+ years old.
@DOSdaze 3 жыл бұрын
Just had a similar cap blow on me too on my 5150, then immediately caught the board on fire. Fortunately I was able to quickly pull the power and blow the small flame out, but it sure made me glad I was in the room at the time... and realize I shouldn't leave my old-timers on unattended. I would be very curious at what it might take to refresh that old PS. I like using the original units in my old machines when I can, but I know its only a matter of time before something goes.
@NCommander 3 жыл бұрын
I'm semi-debating replacing all the capaciters, although I feel like I run more risk of damaging the board than not ...
@javaguru7141 2 жыл бұрын
@@NCommander Get yourself a Hakko resoldering gun.
@Bianchi77 7 ай бұрын
Nice video, well done,thanks :)
@amdintelxsniperx Жыл бұрын
these things are worth sooo much in working condition . even when not working you can see them online for 1k or more
@bytetravell3r402 3 жыл бұрын
I noticed that at 19:50, the voltage showed on the multimeter keeps dropping, from my experience, I think that suggests the PSU is still partially shorted.
@NCommander 3 жыл бұрын
There's a lot of things that can be causing that. Diode reverse bias failing, flaky caps, zener cap having issues (since zeners are what generate the 5V rail). It's a giant mess of issues which is why I *really* just don't want to repair it.
@angieandretti 2 жыл бұрын
If you need to create the -5v rail, one EASY solution that comes to mind: I think it was called the Voltage Blaster - a tiny (modern project) 8-bit ISA card that generates that rail, feeding it back into the mobo. Have you done any more work on this project since the video? I'd love to see how it turns out!
@NCommander 2 жыл бұрын
I got the machine working again, but I didn't film a part 3 as these videos didn't do very well. However, I use three slots in regular operation, and with five total, a voltage blaster isn't really an option sadly.
@007KnightBond 2 жыл бұрын
Hello loved your video do you have something written down that shows how you connected the new power supply to the adapter car you got off of eBay?
@SoulcatcherLucario 3 жыл бұрын
oh hi Michael, i'm really really excited for this :3
@AstralPhnx 2 жыл бұрын
HELL YEAH BLOWING UP CAPACITORS WHOOOOO. Honestly blowing up caps is something I find infinitely hilarious because sometimes it's like "Fuck I dunno what's broken I'ma just try to blow the wonky part up on purpose". The nuclear option
@hasithloolbadduwa52 Ай бұрын
NCommander, Great video. 👍 I’m in a process of trying to get my Portable 2 back to life. But I came across that C13 cap is blown on power supply. Tried to locate a circuit diagram for PSU and no luck. Do you know what cap is in used C13? Without knowing the details will not be able to order a replacement. Thanks
@dieSpinnt Жыл бұрын
Thanks for the video and reviving(so far) this jewel. Your journey was a really entertaining watch, NCommander:) Now to the woman-splaining part(You asked for tips! Hehehe): You treating that dead capacitor with kindness and respect gave me a smile:) Just a thought (and THE OBVIOUS? **g** ) that gets more and more important if you have components with more than two legs and no $2000 de-soldering equipment. If a component is dead and you know it for sure ... use an electronics-side-cutter (not some "plumper-pliers", they just stress the PCB pads) and CUT the legs off. Then you use needle-nose-pliers and your soldering iron to easily de-solder the left in pins without any stress for the copper pads and traces. Cleanup can be done with de-soldering braid or a de-soldering suction pump. Of course, that only applies if you don't want to open a museum for old broken capacitors:))) BTW this is meant in the context of that we RESTORE and PRESERVE old/retro hardware. Which implies that we do not stress the "patient" more than needed. Older PCBs and components or connections, etc do not get better over time. The opposite is true. Also assumptions (seen very often in the retro-community/KZfaq) will stab you in the back. Like "Good, the over-voltage protection of the (40 years old!) PSU kicks in ...". That are "famous last words", hehehe. But does it kick in fast enough? At all rails? Does the over-current protection work? Oh and ask yourself: How did you know, that the protection worked? Yes: Because it didn't catch fire and took all other components including those you wanted to preserve with it into the Nirvana. That was a lottery game, think about it! Proper testing and repair work HAS to be done at a place with at least a working laboratory power supply with current limiting. Not taking these precautions is to beg for disaster ... for devices there is possibly no more spare parts to find out there in the wilderness. This should not be a criticism or an accusation and the following is not directed at you personally: Many (too many) do repairs the brute force way and don't even know the professional approach to certain tasks. It's a job that you have to learn. Good luck with repairing (even the professionals need luck) and tinkering with the hardware. Thanks:)
@tschak909 Жыл бұрын
cap just said "FUCK IT, I AM _DONE_!"
@GeoNeilUK 3 жыл бұрын
As soon as I heard EEVBlog mentioned I immediately thought "There's your problem, meate. You broke the law! You turned it on, when you shoulda took it apart!"
@NCommander 3 жыл бұрын
I did take it apart! It exploded while on pieces!
@mdw21111 3 жыл бұрын
I'd vote for the original PSU + recap everything -- it's your project though so whatever you decide is fine! Thanks very much for the enjoyable content.
@NCommander 3 жыл бұрын
I may end up doing a full recap; I haven't decided yet, would like to see if I can get the rest of it working before doing so though ...
@Hans-gb4mv 3 жыл бұрын
Regarding the PSU, you could attempt to track down someone who is willing to have a proper look at it and does have the right knowledge to do so. Since we are talking old tech, I wonder if CuriousMarc would be willing to take it on. Given that the basics of the system work, it would be a shame not to restore it to its former glory.
@NCommander 3 жыл бұрын
I plan on holding onto the psu board with hope that happend
@T3hBeowulf 3 жыл бұрын
If you check out Phil's Computer Lab, he worked with his audience to design a board for using converted modern ATX supplies on older systems. If you search for "phil's computer lab voltage blaster" and click "I'm Feeling Lucky", you'll see the article with a very short parts list and the gerber files for the ordering a PCB. When built, it slots into an ISA slot and provides the -5V rail for cards in the system that require it.
@NCommander 3 жыл бұрын
That solution works, but this system only have 5 ISA slots, and nothing built in. I'm likely using 3-4 slots just for basic functionality, so I'm better off with soemthing that eats a full slot.
@JVHShack 3 жыл бұрын
Here's an easy way to go about the PSY issue: Mean Well. I know that it can cost some, but there's bound to be a solution that will fit into the allotted space. Even if you have to get 2 small ones (in physical size, stacked) to get the voltages required, I strongly recommend this. Tip: go for the ones that are designed for medical devices as they don't have any enclosures from Mouser or equivalent vendors. The ATX adapter can still be used in conjunction with the Mean Well PSU(s), just desolder the ATX connector and run the wires to there.
@NCommander 3 жыл бұрын
I've seen someone who basically did this for the Portable. The PSU is going to be the last thing I tackle in this project, but I'm keeping ideasa in the back of my mind ...
@atatopatato 3 жыл бұрын
Imo keep the modifications. this is history!
@systemchris 3 жыл бұрын
Sometimes you gotta blow some capacitors to make a pc omelette
@NCommander 3 жыл бұрын
Scrambled or sunny side up?
@ryjelsum 2 жыл бұрын
Bursting caps are one thing, I once had a whole trace on a motherboard catch on fire..
@mattsqwrl Жыл бұрын
Boy a lot of this is familiar from my Portable III
@cloudii_fnf 2 жыл бұрын
21:24 Cute Things Exploding!
@Hammerjockeyrepair 2 жыл бұрын
to remove your psu easily, remove the little nut on the plastic case side of that big bolt
@garryadamson8507 3 жыл бұрын
I think Dave Jones was working on a similar machine on the EEV blog, might be worth a look for a few troubleshooting tips.
@NCommander 3 жыл бұрын
He did, and I used it for reference but he didn't get it further than I did. His psu also didn't have cracked capacitors
@TheMrDeeJay 3 жыл бұрын
oh neat new video
@Fry09294 2 жыл бұрын
Did you/will you ever make a part 2? My compaq portable PSU seems to be totally dead...
@NCommander 2 жыл бұрын
I entirely replaced it, and while I have some footage for a potential Part 3, I'l likely never make it. This was just a soul crushing project
@sus7732 2 жыл бұрын
you sound like mjd for me lol edit: its the first time i watch ur video
@andriangarces2760 2 жыл бұрын
The exploded cap is the exact same one 8 bit guy Run into lol
@shaunclarke94 2 жыл бұрын
After seeing the damage to that power supply, I would have stopped using it immediately to not risk further damage.
@riikkatheiceprincess_she_h8725 2 жыл бұрын
So your friend's been mailing explosive devices, hmm? ;P Also, do you even /have/ a "normal" computer? Y'know, AMD64, DDR, Radeon/Geforce, mid tower/notebook case, that sort of thing? *half expecting NCommander mains a SPARCstation or something :'D*
@NCommander 2 жыл бұрын
My video editing rig is fairly mundane by my standards :)
@TylerFurrison 2 жыл бұрын
I mean, it is called a smoke test... but damn, not an explosion test, save that for the Gigabyte PSUs
@SkynetCyb 3 жыл бұрын
Will you upload a copy of that service manual? If only so people don't have to pay 22 bucks for it later?
@NCommander 3 жыл бұрын
Its still available for sale, so I can't justify doing so
@SkynetCyb 3 жыл бұрын
@@NCommander Is it being sold by Compaq then? OR people on ebay/auction websites?
@FlavorPhx 2 жыл бұрын
Should have yelled "CLEAR!" before you flipped the switch.
@tech34756 3 жыл бұрын
Display FF to pay respect.
@NCommander 3 жыл бұрын
What is FF? I know f to pay respect, but this is new
@tech34756 3 жыл бұрын
@@NCommander In the video at the beginning, the diag card displayed FF literally just after the explosion. My comment was meant to be a reference to ‘press F to pay respect’.
@Logan_935 2 жыл бұрын
The fan running in a COMPAQ Portable isn’t indicative of the machine running because the fan runs off of AC power regardless.
@DistrosProjects 2 жыл бұрын
Michael MJD sent me
@NCommander 2 жыл бұрын
Enjoy your capacitor explosions :)
@adamsfusion 3 жыл бұрын
I second the notion of using an ATX adapter to power older equipment. Old power supplies are well beyond their safety lives and are ticking timebombs. We've come a long way in power supply technology since the 80's and 90's and are much more safe and reliable to the point where I'd trust a modern ATX supply for several decades. While I understand the argument for keeping the circuitry original, the PSU, in my mind, is nothing more than a means to an end. It has little significance and utility outside of basic power supply.
@NCommander 3 жыл бұрын
That's kinda how I'm leaning although a lot of people want me to stay with the original PSU, but this PSU design is basically a single zener diode from deliver 12V to the 5V components ...
@nethoncho 3 жыл бұрын
Adrian's Digital Basement sent me here
@NCommander 3 жыл бұрын
NCommander's Analog Apartment welcomes you :)
@cromulence 3 жыл бұрын
Regarding the -5v issue, someone has worked this out already - you can buy a Voltage Blaster to put into an ISA slot - www.philscomputerlab.com/voltage-blaster--5v.html
@NCommander 3 жыл бұрын
On a system with only 5 slots, and at least four used for basic functionality, bit of a tall order :/
@cromulence 3 жыл бұрын
@@NCommander ah crap! I forgot that literally nothing is onboard! You could replicate the functionality of the Voltage Blaster and solder it to one of the already populated ISA slots perhaps?
@NCommander 3 жыл бұрын
That may be what I end up doing, although very few isa cards need -5v. There is a pin on the atx adapter for -5v, so its an easyish mod
@rasz 3 жыл бұрын
fully open short you say? :) The soldering iron you are using looks like the $10 "soldering kit" special from Amazon. Dont do that, you will only think soldering is hard. Its unregulated (has basic light dimmer instead of temp control) and shittiest smallest possible tip. Buy a $15.32 "Digital Soldering Iron Station Temperature Controller Kits For HAKKO T12 Handle" on ebay. It uses very good T12 cartridges (same as >$300 stations, integrated heating/sensing element), is easy to assemble, and only requires old 19v laptop power supply and random case for the controller pcb to function. That, or proper FX-951.
@NCommander 3 жыл бұрын
It's a cheap iron, but it was more nerves than anything else that made it difficult. I'll probably look at replacing it.
@rasz 3 жыл бұрын
@@NCommander Novice instinct is small elements(especially smd) means I need small tip, this leads to bad heat transfer and loss of confidence. On the video you were using the smallest sharpest tip, all the cheap soldering irons ship with it for no apparent reason, its useless. Use the largest chisel tip suitable for the job and everything will go smoother. T12 cartridge soldering stations, no matter if original ~$300 Hakko or $15 DIY kits, give you even more confidence by providing greater temp control and heat capacity, means you can use lower temperature and everything still melts instantly without danger of destroying pads or lifting traces. Oh, and dont put the random Chinese industrial waste flux paste with your finger, at least not the same one you use for eating or scratching your eye 10 minutes later :) This is nasty corrosive stuff.
@TrolleyMC 2 жыл бұрын
I'd say use a modern PSU, or atleast a PSU manufactured today without any suspicious parts.
@nickwallette6201 3 жыл бұрын
Just watched the intro so far. As someone currently in an extended epic slap-fest with a PS/2 Model 70, I can relate. It hates me. I don't know what I did to offend it, but I know with absolute certainty that it hates me.
@NCommander 3 жыл бұрын
Working on PS/2 machines are a downright pain since IBM really went out of their way to make everything as different as possible, and you basically need everything to work just to be able to install the reference disk and boot.
@InconsistentManner 3 жыл бұрын
Tantalum go POP.
@NCommander 3 жыл бұрын
It did indeed.
@superchiaki 2 жыл бұрын
Press 0xFF for respect
@gettingpast4391 2 жыл бұрын
Doesn't need to be this dramatic. You just start clipping one lead of each tantalum cap until it powers on. Then you replace the one which was shorted and re-solder or replace the others. This whole process takes about 60 seconds. You don't even need to desolder it. Clip the leads and solder the new one to the old leads.
@northof-62 2 жыл бұрын
We can see the pain, but luckily not feel it. Or can we?
@NCommander 2 жыл бұрын
bbiab, writing an RFC for Pain-over-HTTPS standard now.
@morganwortman3408 2 жыл бұрын
the 8 bit guy had the same problem ask him
@RonLaws Жыл бұрын
a self resolving fault :)
@dennislindqvist5461 2 жыл бұрын
Please dump the crazy music for the next part.
@chaoticsystem2211 2 жыл бұрын
Don't you like the pain?
@kuro68000 3 жыл бұрын
I love those machines, can't wait for part 2. That modem does look amazing, would be great to get that working. Maybe don't mention EEVblog/Dave Jones though, given his mocking of BLM, misogyny and doxing he's probably best avoided.
@NCommander 3 жыл бұрын
Wait, what happened? I don't watch eevblog regularly so I missed this entirely
@NCommander 3 жыл бұрын
I'll look this up when I get home, but thats just ugh if thats the case
@kuro68000 3 жыл бұрын
@@NCommander he was mocking BLM on Twitter, parodying the phrase "Black lives matter". His misogyny has been going on for years, all that "in like Flynn" stuff. He doxed me a few years back too. Oh and let's not forget the racism too, "one hung low" and all that. It's sad because he made some decent content. His forum is sometimes useful, although there is a lot of that kind of stuff on there so. He enables the guys there to behave badly. As often as not genuine questions just get trolled though.
@NCommander 3 жыл бұрын
Crap, I legitimately don't know any of this. I only glanced at a few EEVblog videos from time to time, but I've never gone on his forums or interacted with his community. The actual EEVBlog website appears to be down ATM, but I found some posts on Twitter which was him mocking BLM which ... yeah ... Frustratingly, I couldn't even find anything without trying pretty specific search terms, so this seems really under the radar. I def. woun't have brought him up by name had I realized this in advance. Thank you for the heads up. EDIT: (I'm probably going to pin a comment on this, but I want to do a bit more searching, and not write something when I'm literally nodding off at the keyboard, I don't want to yank the video since its a passing mention, but I'll keep it in mind for the future.)
@NCommander 3 жыл бұрын
@TheTechChannel 1 Neither did I. At least I know for the future now.
@atatopatato 3 жыл бұрын
first!
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