I was completely wrong with my diagnosis of this IBM PC 5160 motherboard
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- Опубліковано 21 лип 2024
- Time for a break from the TRS-80 Model II. In this video, I give fixing a IBM PC 5160 motherboard a try. This motherboard stopped working in a previous video resulting in a black screen. Can I figure out what's wrong with it?
--- Video Links
Video featuring this machine:
PC Archeology: This IBM PC XT has a strange appendage
• PC archeology: IBM PC ...
Minuszerodegrees.net Resources
Beep codes for 5160:
minuszerodegrees.net/5150/post...
Diagnostic ROM for 5160: (and other machines)
www.minuszerodegrees.net/super...
DIP switch settings for 5160:
www.minuszerodegrees.net/5160/...
Adrian's Digital Basement ][ (Second Channel)
/ @adriansdigitalbasement2
Support the channel on Patreon:
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-- Tools
Deoxit D5:
amzn.to/2VvOKy1
store.caig.com/s.nl/it.A/id.16...
O-Ring Pick Set: (I use these to lift chips off boards)
amzn.to/3a9x54J
Elenco Electronics LP-560 Logic Probe:
amzn.to/2VrT5lW
Hakko FR301 Desoldering Iron:
amzn.to/2ye6xC0
Rigol DS1054Z Four Channel Oscilloscope:
www.rigolna.com/products/digi...
Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:
amzn.to/3adRbuy
TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)
amzn.to/2wG4tlP
www.aliexpress.com/item/33000...
TS100 Soldering Iron:
amzn.to/2K36dJ5
www.ebay.com/itm/TS100-65W-MI...
EEVBlog 121GW Multimeter:
www.eevblog.com/product/121gw/
DSLogic Basic Logic Analyzer:
amzn.to/2RDSDQw
www.ebay.com/itm/USB-Logic-DS...
Magnetic Screw Holder:
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www.harborfreight.com/4-inch-...
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
www.ebay.com/itm/14-16-18-20-...
RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
www.retrotink.com/
Plato (Clone) Side Cutters: (order five)
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Heat Sinks:
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Little squeezy bottles: (available elsewhere too)
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--- Links
My GitHub repository:
github.com/misterblack1?tab=r...
Commodore Computer Club / Vancouver, WA - Portland, OR - PDX Commodore Users Group
www.commodorecomputerclub.com/
--- Instructional videos
My video on damage-free chip removal:
• How to remove chips wi...
--- Music
Intro music and other tracks by:
Nathan Divino
@itsnathandivino - Наука та технологія
I was an IBM service technician.
This brings back so many memories.
Thanks for the nostalgic video.
nostalgic is an understatement :)
"so many memories"
i see what you did there
What do you do now?retired?
Nice work!
If you're a novice, Adrian, then many of us are toddlers. I really appreciate your methodic approach to diagnostics and explanations. Thanks!
Zygote level myself.
If he's a novice, I'm an amoeba lol
I'm a future sperm.
Adrian is one of the finest technicians this old technician has had a priviledge to witness.
Right _and_ wrong, your diagnostic videos are just the best. You explain your logic, why you move from component to component, as well as referencing the diagrams/docs and you show us ever bit of it. I really appreciate these videos. Thanks.
Pro tip: If you don't own a thermal camera spray isopropanol on all of the chips. The ones which are hot will have the liquid evaporate the fastest.
I like Adrian's joy when he solves a tough problem.
Really admirable for you to post all of the content of you going down the wrong diagnostic path. As you said, we are learning with you... it's totally normal to do these things and this is exactly the learning process. It can be frustrating at times but it's just how it works :) This sort of info is extremely helpful for us to not only understand how the computer works but to see that even the people we look up to as knowledgeable and experienced don't know everything and learn the same way we do. Love your videos man!
I agree, Adrian's videos are always honest that way. People can relate to his modus operandi because it's just what happens when you're troubleshooting. It's not Hollywood and the red herrings are everywhere, out to get you! ;-)
How many times have you worked on something and said to yourself, "I'm glad no one is watching me"?
@@scottlarson1548 wayyyy more than I'd like to admit 😂
This actually teaches way better than the person who edits their videos to make it look like they do no wrong. That's not how the real world works!
Not omitting false rabbitholes is indeed very commendable.
I think you should do a tour of your workbench area. It looks very cozy, and very well laid out with anything you need at any moment in arm's reach. But we don't know what everything is, or what things you have that are there but not apparent, or why you have certain things, or why the placement matters. It would probably help others (like me!) in laying out their own workbenches for working on not only vintage computers, but other electronics. Thanks for all the videos!
Adrian you are a true expert as you refer to yourself as only a novice. A true expert knows there is always something new to learn. Someone could have extensive knowledge on this particular motherboard and repair it quicker but the real talent is in looking at something new to you and being able to troubleshoot and fix and make sense of it as you do. Every time you go over traces you are examining someone’s work from about 40 years ago which is very cool! It is amazing these devices can continue to work perfectly so many years later. Great work!
U84 can be fitted with a quad 2 input multiplexer, like a 74ls158. You can then if i'm not mistaken use 256x1kb chips in all memory Banks. Replacing U44 with a GAL with proper equations might even allow you to have as much as full 1MB and map RAM on UMB areas not used by hardware.
Seems that IBM was thinking ahead.
Yeah, I did a similar thing on my overclocked Compaq Portable board (the quintessential IBM 5150 clone). This thing, like the 5150 only has 5 expansion slots and 256k on board so maxing out the on board memory (to 640k in my case) comes in really handy as all my slots are populated with cards.
The 5160 has 8 slots so it's less likely to become overpopulated by expansion cards, leaving enough free slots for a memory expansion card in most configurations. It would a nice gimmick though to have a 5160 with a full 1mb (dude that's gnarly!) on board instead of that measly 64-256k :-)
@@pipschannel1222 Fun fact: In times of core memory the rule-of-thumb for good memory prices was "a dollar per bit".
IBM was always thinking ahead, at least back then.
It may also be that they were actually thinking _back._ While IBM had never done anything else that was compatible with the IBM PC, they _had_ made somewhat similar computers before (the IBM Datasette series I think?), so they certainly had experience with iterating on 8088/8086 designs.
@@absalomdraconis They actually contemplated the 6502, 8085, Z80, and 68000, as well as their very own CPU design for the IBM PC project. But for some reason, they selected the 8088. Perhaps because what you wrote and that they also used the slightly older 8085 and its support ICs. As you may know, several 8080/85 family ICs were used in the IBM PC. Pretty compatible with the 8088 (largely also with the 8086). Not sure it was the same designers though, as they had multiple teams.
Most of us that do electronics repair have gone down the rabbit hole many times. Good video.
The C, D or P in front of a device number on an Intel device denotes the package type. C will be standard ceramic, D will be dual layer ceramic and P will be epoxy. It's interesting that AMD used Intel's package type notation as well.
@Lassi Kinnunen 81 That is basically correct. Intel actually spun off AMD as a separate manufacturer of intel's chips to help with batch loads. That way Intel could keep up. Eventually AMD came up with their own designs and had to go their own way to make them since Intel didn't want the competition and tried to keep them for making their own chips. It's actually a lot more complicated than that but that's the general story.
Kudos for the patience for this... 1/3 of the way through this video, I was thinking I'd already have cut out that 245 and soldered in a socket.. I'm not used to seeing floating busses like that either so the scope signals definitely drove me in that direction.. I would REALLY love to see you read that dead ROM. it would be interesting to see what it has. Is one bit stuck on all bytes? Is it just random data? are just a few bytes wrong, or does it completely fail and read all 0 or ff? inquiring minds want to know!!!!!
I appreciate you showing the trouble shooting parts and not editing it out just to look better. Helps to show thought process involved in diagnosis.
I remember working on those back in the late 80s and early 90s. Thanks for the trip down memory lane.
lol, you're excitement when something works never gets old Adrian!
I enjoy your videos immensely, even when you go in the wrong direction it's worth every second. Keeping old tech history alive and learning new techniques along the way, thanks Adrian.
Going down the wrong path is frustrating but often illuminating and you rarely get tripped up the same way again, well done and thanks for sharing this oft overlooked part of the repair process!
The honesty in the process, mistakes, etc should be reassuring to everyone that runs into problems. Also how critical thinking can take you down all kinds of paths and ultimately down the right one if you're patient enough and persistent.
I work more on clockwork and electromechanical projects than electronics. It's fun to watch videos like these to go back to when I was doing electronic engineering and explore the problem solving process along with.
I seem to remember you repairing a C64 and it was the kernal rom that was taking the whole system down (even thought the kernal wasn't required to run the diagnostic). So i think you've been down this rabbit hole before.
Definitely although those MOS ROM failures are kind of expected. Normally, mask ROMs don't seem to fail.
I love your videos, not only because they're interesting, but because you leave in EVERYTHING, warts and all. It's nice to watch the process, even when you go off in the wrong direction. This is a fantastic channel!
You deserve to get funding from your government. Preserving the important history of computer development. Start a museum. Thanks for your efforts.
I would try to read that damaged ROM using the programmer (if possible) - to see if just some contents are damaged, or what.. :D
Did anyone else get Eye of the Tiger to start up in their mind when he called that beautiful Motherboard a survivor? Great video! I'm so glad he could fix it!
Another awesome video Adrian, Love your thought process and diagnostics checking! but you always manage to get a positive result in the end and it must feel so rewarding! Keep all your brilliant video's coming please.
Nice shirt !
Love the way you apologised to the RAM! I feel old now as my first work pc was an IBM XT.
This channel is so unique to me as i don't understand anything yet sit and watch the videos from start to finish. I find myself wanting to buy an oscilloscope and look at waveforms!!
Thank you for the content
The ending result of this video blew me away. Good work Adrian!
It is interesting to watch your thought process in trouble shooting, and that alone is something people can learn from. But for me, having worked on these old PCXT systems, I was struggling watching you bark up all the wrong trees but I honestly share your excitement when you figure it out. This was a lot of fun!
As they say, it's not the destination that matters, but the journey.
Good save. Imagine those feelings, making this repair in it's time, when these motherboards used to costs even like 1000$ in todays money.
Wow! What a diag session, a marathon that ended up teaching so much.
Well done Adrian. Your normal forensic analysis has worked again. Loved the video. We all go off on tangents of course.....
Just noticed an interesting detail: Remember how Adrian initially recieved the "stack failure" message when trying to access the floppy drive? This must have been due to the same floppy reading routine failue (caused by the failed ROM chip) he expericenced with the diagnostic ROM installed. So the IBM ROM chip must have died in the time between Adrian accessing the drive with the cleaning disk inserted and him accessing it with the DOS 3.3 disk inserted. Or possibly even before that, as the drive obviously couldn't deliver valid data when trying to read the cleaning disk. I certainly wonder why and how the chip failed...
And of course great and especially well explained diagnostics, Adrian! Huge thanks for sharing the whole process, including when you went down that "rabbit hole". But just as a reference: I'm currently trying to repair a modern motherboard, and it's certainly possible that i've almost only gone down rabbit holes so far... Repairing really is a matter of experience, and thus i'm really grateful for being able to learn from you. Keep up the good content!
This is one of my favourite ADB videos yet, Adrian. The reason is because you go through the diagnostic process in a very natural way. It also covers more familiar territory for me: IBM stuff
Falling down rabbit holes is all part of the investigative adventure & I find it rather intriguing!
It may sound weird, but this was a pretty exciting diagnosis process. Thanks for all the detail.
I made the same mistake troubleshooting a C64. All the diagnostics pointed to bad ram...ended up being a bad Kernel ROM. Spun my wheels a lot that day. Congrats on getting that board working!
I really don't understand much of what you were doing but I worked doing electrical diagnosis for a large Toyota dealership and did work with basic test equipment and sometimes with an old Tectronic analog scope and later a digital scope to analyze wonky signals from various EFI sensors. I also built early computers from parts starting with 286's running DOS and later 386's, 486's etc. So I know what the inside of a PC looks like and have a rudimentary understanding of the various components inside one. I just like watching people diagnosing any type of electronic equipment. I liked the way you explained your process as you went along. I imagine it was a game changer to be able to program and use an EPROM to stand in for various faulty chips. I was watching a group of techs try to bring to life an actual Apollo guidance computer and they had some young kid who was able to program FPGA's to stand in for faulty and otherwise unobtainable hardware modules. Anyway the bottom line is the Mounties got their man and found the problem. Will be watching and learning from more of your videos in the future.
Just found out about your channel and went down a deep dive into your videos! Love them!
I wince though, every time you handle motherboards/cards/chips without a ground strap!
Your basement temps is around 25C-26C based on some vids of yours and that would likely mean your relative humidity will be very low in a basement in Oregon.
Low RH means you are likely a walking static bomb, frying cmos/mos parts as you go!
Please check your RH and meybe think of a ground strap for one of your wrists.
Love the channel, love your work, subscribed and sharing it!
A very good example of fault finding. You call yourself a novice, but i think you undersell yourself, which is a humble character trait and certainly no bad thing. Keep the great memory lane videos coming!
Thank you for showing the problems and you actually working threw the issues. This helps teach all of us
Great episode (again). I wouldn't have suspected the ROM myself.
I like learning with you Adrian. Well done, mistakes and all. Glad you don't edit that out.
Magically fantastical Infotainment - an immediate "classic" - Thank's so much! You RoCk (post editing skills were off the chart!)
Really enjoy your troubleshooting vids, even if you go down the wrong path before finally finding the cause. 👍
Dude, your modesty is admirable. However your digital hardware debug abilities are supreme. Fantastic content. Cheers
Hi Adrian. Really enjoyed this video. It was great. Thanks for sharing your troubleshooting process. Please keep making this type of video so we can learn with you.
this is more like detective work.. you got trown out on wrong path, but got on track.. well done!
Always a pleasure to watch your videos! By digging for the root cause, as you said, we both learn new and interesting things. Great content!
I really appreciate you showing the IC was backwards; makes me feel much better about the socket I put in backwards while putting the Harlequin ZX Spectrum together :-)
Good job again Adrian, as usual it was a pleasure to watch. I sincerely learn something from it every time:)
Mistakes are the only way I truly learn. Doing things completely right can reenforce thinking that might be rightish but not completely right.
Excellent job troubleshooting! Had the same issue with my Apple IIe. Ended up swapping the RAM only to realize that the issue wasn't the memory but rather one of the ROMs having failed *facepalm*
"I'm still quite the novice". Oh, come on, being humble honors you, and I appreciate it. But it is not exactly like many true experts in repairing those very early PCs in this time and age exist anymore. At present, for nearly everyone, it's about finding your way through it, and we love watching the problem solving process, and the convoluted way that leads to an exciting FRIGGIN' WORKS finale! You're the hero of our favourite tech adventures, keep up the great work.
I love seeing the full experience incl. the false paths (something Usagi Electric also does a lot). I have definitely been there and given up too early. However, I can see that I probably need to get an (E)EPROM reader/programmer as that's very likely an issue I'm facing with my 1981 Nascom 2.
You may have gone down the wrong path, but you quickly found your way to the right path. Nice work.
I was testing an Altos CPM computer in the 80's which had ceramic ram chips and found the faulty chip when I left my finger print behind on it as it must have been so incredibly hot. At the time I thought my skin would not grow back normally but after a couple of years I was back to normal. From that point on I put a sheet of paper on the chips first to feel if they where cool enough to touch with bear fingers so watch out! It always was a good diagnostic test. Also reseating the chips in sockets.
Adrian - i love this! i am a IT tech for last 26 years and this stuff was before my time but i love it. this video makes me feel stupid coz you are so smarter than me! but its awesome. and we all make mistakes, it is cool to watch this stuff! Keep it up!
lol adrian the mobo on your thumbnail blends in and looks like a mobo christmas sweater
also the expression on your face makes me think of doc brown GREAT SCOTT haha
It's good you have electrical engineering education and experience of some form I have been doing ee as a hobby for a while now I find myself fixing Pentium iii and IV or even earlier motherboards the newer Post lga 775 boards have their idiosyncrasies I was given one with a celeron d allegedly a PC tech said it was unrepairable well just as you do I fixed it but it was a different issue but good work mate keep the videos coming I always learning from your videos
@Adrian
You're better a bench-tech than you think you are. Novice you are not. BIOS chip failures are very rare and can often lead to odd diagnosis results like what you experienced. Trust me on this poing, compared to most people who work on computers, you have a high level of expertise. But you on the humble side of things and clearly have a desire to continue learning. Hang on to that desire. It will continue to serve you well!
You said it failed while you were using it, maybe it was a seating issue that showed up after the components warmed up and expanded. Maybe even dust in the socket? It would be fun, as others have said, to see what that rom Holtz. Maybe it is something that will work for other boards, even though EPROMs are a dime a dozen. It may in fact be un-x-orable. I always dig your videos! Keep up the great work.
Very nice video.
Very nice and lovely fixing for the first PC.
Congratulation :)
1x vote for a video attempting to fix USB issue on your modern motherboard!! Also if it is just front end ports check the connector/header, they and be annoyingly fragile. Awesome content as always! :)
This channel is gold.
Not gonna lie, even if your diagnostics were down the wrong path, seeing the process is still rewarding! :D thanks so much! :)
Fantastic, once again. I really enjoyed this. Learned so much!
It's good to learn and breakthrough with new way of thinking, learn from mistake feel good.
Well, the sticker on the ROM is better for identification more than preventing erase, since I can't program the 2716 with the TL866II, I've switched to use EEPROM equivalent (I made adapter for 27c512 to 2716/32) , for faster erase and programming, the ultra violet thing waste lot of time, I keep some EPROM for collection but try not to use them.
Victory is sweet! Congratulations! (and thanks for showing the whole process)
Great video, a little bit beyond me in some areas but still really enjoyed it. Thanks
I didnt understand almost half of this video, but it was very interesting and i will review it once again! thanks!
Very good troubleshooting! I totally thought it was a RAM controller chip or something just up from the RAM.
Great analysis, even if it was way off initially. One can learn a lot from such mistakes. Thanks.
When I worked at Gateway 2000 the 486DXLB motherboards were coming back bricked (no post). My coworker and I thought we would try something radical. We pulled the BIOS off of other bad boards of the same model and plugged them in the bricked ones. It fixed them every time. Oddly, service did not have a way to burn blank bios chips.
That is a smashing tie you got there in the thumbnail
I watch this channel for Adrian's enthusiasm when he succeeds fixing some old piece of electronics.
Adrian
Don't forget to cover the window over the 27??? EPROM, as I was using them in the early days and if they were not covered we found that strong uv light would currupt the data.
We used to put a rectangular one on with programm title issue and number of EPROM.
I think the max we used was somthing like 12, but it was a number of years ago app 40.
It think it was when NASA was taking nearly all the manufacturer of special 74 series chips for the Saturn moon shot.
I think it was the 7414 schmitt-trigger ones and others.
The early IBM XT and AT models were brilliant our problem at Vauxhall (GMC) in Luton UK was sending the larg amount of data on the engine tests, back to Flint USA it was a nightmare, the systems would go down, regulary.
It would have been quicker to fly the data there.
Component level fault finding was my fortay, even used hot 🔥 fire lighters to diagnose faults on Ferranti computer boards the ceramic chips would work up to fantastic temperatures. Or freeze them.
Thanks for another informative 👍 technical video.
We’ve all been led down the wrong path when trying to chase down a fault in a circuit board, Adrian. It can be a mix of a DOH 🤦♂️ moment followed by a “it freaking works” moment when you find the actual problem and fix it…
Thank you, so much, for covering the erase window on the chip.
Good to see its notmjust me who.goes off in tangents! Really enjoyed seeing the thought processes
Really like your videos, even though I don't understand anything about repairing computers. Cheers! :)
When I was restoring a certain 386 motherboard I decided to populate the board with filtering capacitors where the manufacturer cheaped out on them. All the spots where the power lines, except a single spot where it was 2.5V. Turned out it was IRQ2 line and it was pulled with 10k to GND and +5V at the same time.
Wow, a roller-coaster ride through a twisty diagnostic path! It was compulsive viewing.
Maybe start with the diagnostic ROM in the first place. That helps you eliminate bigger swaths of potential faults from the get go. Good job fixing it.
Very funny, I made the same mistake troubleshooting my Commodore PC 10. Swapped the RAMs and the 245 but still the same. In the End there was no fault, was a bad Program Version that caused Freezes. And the half height Levels we're normal. Spended two days fixing a perfectly working machine. 🤣
Splendid investigation!
Good practice, and a nice catch before you wandered down the wrong road! :)
Thanks for sharing the whole process. Great video!
Great video, Adrian!
I'm sure I mirror alot of people here when I say this, even the most experienced have moments like this. It's easy to get dragged down the wrong path, what's important out of all of that is that you did not give up and found the answer.
That right there is what separates good tech troubleshooters versus the ones that are bad :)
Loved this video. Greatly appreciate the humility and the passion.
I was kinda waiting for you to try and read the bad ROM in the minipro :)
Thanks for the interesting video once again.
40:10 Good to hear I'm not the only one that has things break randomly.
I remember fixing these "Top of the line" PCs in darkest Africa when they first came out, WHITHOUT the aid of the diagnostic ROMs. Use to have a working set of the pluggable IC's that we swopped out until I found the faulty one before I went full out Rambo and started cutting out chips.
Fine time with you ... Thank you
Chips can be the most resilient piece of hardware or can fail just by touching them if you have some static on you. On that regard, I learned that the hard way with a bios on an 3d gen Intel Core motherboard about 5 years ago, and that hurt because it was my main PC. Fortunately I already had the same IC programmer as you and I ordered the same bios chip so I could repair it, but also ordered an anti static strap and I always work with it every time now.
Love you Adrian but the thumbnail had me looking at Richard Dreyfuss wearing a motherboard. Lol. Keep up the good work. 😑
An awesome video. Thanks Adrian.
Coincidentally I acquired a 5160 base unit last week and was today giving it a good clean up and inspection. It all appears to be functional, at the moment LOL
Memories. I remember making trips to micro center in Orange County California. I built my first ibm clone 1989, I remember 200mb hard drive was $2,000 or so. I was working for Santa Fe energy in Santa Fe springs which they wanted a presentation using dbase , lotus 123. I created some paratio charts and production charts. Remember word perfect . I remember first time, I completed my project for about $1,000 and then, I needed DOS. DOS is still used today. Today, i use 12.9 IPads and phone. I haven’t used a. Pc for the last ten years.. thanks for research .. Downey California