Turbo in a retro PC - explanation and repair.
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- Опубликовано: 2 ноя 2023
- Let's investigate and repair the turbo functionality on the Packard Bell PB430 / PB410 mainboard.
Music by Model Povedeniya
modelp.bandcamp.com/
Patreon:
/ necroware 
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I love this!! Amazing work and so interesting. I had never looked much into his turbo worked, so this was fascinating.
At least something interesting I could give back to you ;) Thank you Adrian.
amazing skills!! 😉
God-tier repair skills as always. Most people would have given up at this point. You should definitely archive your custom firmware until somebody dumps the real deal.
Certainly not an easy fix, especially when you first have to root out the cause.
That said, you don't absolutely need a PAL/GAL chip here. An 8-bit microcontroller could probably be made to do the job. The clock division alone could probably have been done with a multiple flip-flop IC chip.
Your retro repair skills are astonishing. Thank you so much for this PB video series!
amazing! Finding how the turbo worked was cool enough, writing a custom logic IC to replace the dead one is the next level! Thank you!
Excellent work, you never cease to impress with your repair skills.
While I have no need of the firmware personally, I do think the firmware you wrote should definitely be released, these old boards are going the way of the dodo and having the ability to keep them going for as long as possible is hugely important imo
Most people would just connect 5v to the affected pin permanently. Actually I take that back. Most people would know how to even find the problem. Please keep making these videos. They are very impressive and entertaining.
I wonder if anyone back in the day bought a new PC then hit the Turbo button and wondered why it ran so slow!
Everybody I think :)
I used turbo button to slow down. Once.
I lived through those days but never had the need to slow down.
I was young and foolish 🤠
I thought my parents had bought a faulty pc 😅
I think this is the first time I've encountered anyone programming a replacement PAL from scratch. That's some next-level work! It was also interesting to hear an explanation of the different implementations of turbo functionality.
What an amazing journey this was! Reverse engineering the chip for that turbo mode problem was just so cool to watch. So very well done!
"Rest in Peace, old PAL" 😁
That's priceless 😂
I really have to respect the skills and patience required to pull a repair like this off. From the last few episodes I was really looking forward to how you were going to repair these boards. Thanks for sharing!
Wow reverse engineering the PAL chip and writing a replacement firmware is next level! I loved seeing how you worked out the logic, great visualizations!
Also it made me realize that the PIO cores on the Pi Pico RP2040 are basically embedded PAL chips 🤯
A dead PAL chip is usually where most people figure it can’t be fixed. Reverse engineering one is incredibly impressive! From reading some of the FPGA recreation forums, it’s usually the custom PAL chips that hold up so many, that they end up trying to just use the original chips salvaged from ruined boards.
This was a great explanation of Turbo-Switching. I was never aware, that it was not just slowing down the clockspeed! At "rest in peace old PAL" i chuckled 😂
The analysis and problem solving is what i love about your channel. And even if i dont know a lot about electronic/electricity, i'm still learning and understanding HOW it works and im starting to follow along more easily!
Wow. Just wow. I don't want to say that your skills are godlike, you' said in some previous videos that you kind of involved in software development and this skill to "dig in" is essential for every good programmer. But you move forward further and go mess with hardware. And i think fighting this issue (in such elegant manner) is a great personal achievement.
And... from retro-hardware folks perspective what you did - is total magic. And... my hat tips and respect to your research and repair work. Nice show, thanks for your video!
I'd recommend archiving that reverse engineered firmware. Something tells me this particular implementation of a turbo controller has a high failure rate, due to choosing the cheapest IC they could get their hands on, based on the age of the hardware when it was manufactured.
Your tenancy is applaudable! 😊
Brilliant! Nice work reverse engineering that PAL too! Looks like a common fault, perhaps caused by the leakage =/
would more think the age of the board.
This was one of the best motherboard detective work videos I have ever seen. 😀
Great job!
Sorry for the loss of a pal of yours ;-) Great video!
Hoping it may come useful, here's a technique I use when investigating a logic signal on a PCB which is not behaving as expected: instead of shorting it to ground or to a supply rail, I always use a resistor. In this way you get more information about what's actually going on and, for example, you can discriminate between a dead short (like a solder bridge) or the lack of a driver winning over a pull-up/down resistor. It also avoid doing more damage or overloading the supply.
For example using a 10k from 5V, 0.5mA is enough to pull the signal to ground and this current should not be a problem for anything. If the signal is lifted to 2.5V you know that the net is connected to something equivalent to 10k.
Again, really impressed with your perseverance and skills!
This is the kind of content we're here for. Other channels be like: "Yeah, motherboard iz half-ded, it's for parts, too bad". Necroware be like: "Lets reverse engineer the PAL and write new firmware." And he proceeds to do it. WHAT. Amazing.
Terrific work on the reverse engineering! So much knowledge about these custom programmed logic chips is lost to the annals of time, and it makes repairs like yours all the more difficult! Very well done :)
Thank you for all your efforts. If possible, please archive your work. This may help others even with different motherboards that use similar chips. Great video.
You sir are a master of the old x86 days. Well done. And yes, it deserves archiving.
I've thought about this video multiple times today after watching it yesterday. Fantastic. This is excellent content, and very relevant. There are fewer and fewer of these machines, and the problems will continue to happen. So please, more content like this!
You Sir, are very clever guy! Truly are THEE Necromancer of electronics...
"Rest in peace old PAL" - I see what you did there ;-)
very interesting repair! I've never come across anything like that.
Because of your channel I took a foto of my Advantech industrial sbc pentium board and sent it to the retro web 😊
Congrats on another fantastic repair!!!!
Absolutely great detective work. :) I might have socketed the PLCC chip when it was desoldered anyway... but then the chance of that same defect happening again in the same place is low. Although, since 2 boards have failed on the same chip, it may be more common than one would think, hmmm...
And TBH, you have already released the programming of the chip since we can see your PAL equations in the video. :D
Wow, your patience and technical know-how are amazing - makes me believe I could achieve the same one day. Most motherboards are a black box to me, so this was a very interesting and easy to understand video, thank you.
I am amazed by your skills and reasoning: please keep this up. It is inspiring.
That is taking repair to another level, very impressive.
What a smooth 'n soothing episode, enjoyed it with ma Coffee.
that was very interesting how you worked out where the problem was, and even more interesting was that you managed to build up the PAL with no knowledge of what needed to be programed in there, only what it should produce on the outputs, I guess you have a fair bit of background knowledge of programing these devices.
Yes it would for sure be useful to have access to the programming file for the PAL/GAL for archival for fixing others of these motherboards and also learning from the source.
Incredible work, I enjoyed this very much!
The PAL stuff was very interesting, first time I've seen someone reverse-engineering one of those.
Keep up your wonderful videos man, you're a gem. :)
I really appreciate this kind of deep diving for fixing things, superb!
This level of repair is absolutely incredible!!!
I'm just repeating what everyone else has already said, but really good video. Educational and entertaining. Love these deep dives.
Even if many people write similar kind words, this is still very motivating and helps the channel to grow. Thank you very much too!
@@necro_ware least we can do :). Keep it up and hope all is well mate.
Excellent video and troubleshooting work as always! I learned a lot about turbo functionality and PALs too. 👍🙂
You, sir, are a genius! 🧠
I have to call my neighbor from downstairs so he retuned my jaw back! 😮 Astonishing job!
LOL :)
Seriously, your determination has no bounds. Quite enjoyable video. Thank you.
So much trouble for such a little thing! Another great video, I always learn something with them.
Incredible work! Congratulations!
My friend and I both worked at PB writing tech docs during the time of these boards. That document you found was very likely written by him or he was involved in its creation. What you found was probably a webified version of the one created in the early 90s before PB even had a website - the info would be sent to service centers on 3.5" floppies that we hand created. I remember this board but it was replaced shortly after with the PB450. If you ever run across one, many had a quirky BIOS that caused them to slow down when you added the cache chips! :D :D
Necroware necromancer skills!
Being able to reproduce the code on these PAL chips is a huge deal, since it's frequently the point of failure that takes these old boards down for good. A lot of old Macintosh computers have multiple programmable logic chips that can die, and their opaque contents also impedes reproduction board efforts, something that's ongoing in the retro mac community.
Fantastic stuff! Nice to see the logic / process you went through to get to the fix.
Really solid work, well done!
Amazing work!! That's why i come here.
That is some next level repair! Great job!
Great reverse engneering of that PAL. I always considered the turbo as a slowdown-button, as by default the systems would run in Turbo-mode.
Amazing. You never cease to impress me. Thank you for sharing these gems. It is a joy to watch and learn in each of these journeys.
You're a genius! Another amazing repair video. Thanks for your time.
You 're an 007 agent of old systems. Kkkkkk
Brilliant video as always, thanks for sharing this and all your thoughts about what is going on and how it works! 😉👍
amazing video, Necroware. you're talking alien language to me but i enjoy it so much :)
well done, all to the end! i'm 100% sure i had ended it by pulling the pin high thus enabling full speed permanently 😄
That would be too easy :)
It's nice that you made a replacement chip. I would have probably been happy to just remove it and have the system run at full speed all the time.
Outstanding effort. Thanks for showing it to us.
👏 Very interesting. I had been wondering how the turbo button worked. Now I have a pretty good idea. If anyone can benefit then I think it is worth while publishing the PAL firmware.
Wow. Really enjoyed the video. I appreciate the time and effort in making it too 😊
I have a soft spot for the turbo button and went to great lengths to find a turbo capable motherboard for my primary PC. Turbo in general is a poorly documented and esoteric topic, this video was enlightening.
turbo button + 7 segment led ❤
you are the best friends of mine, thank you so much..
thank you for the nice video and some new knowledge about turbo mode :)
I like the PLCC to DIP "adapter" :)
Super cool overview of turbo implementations. Also, major kudos on thr reverse engineering and fix. Get yourself and ice cream. You deserve it
Thanks for video. Big respect for problem solution
As i told on the phone. This is really over the top.
This is fantastic work! I'm so glad you figured this out! As I said on the previous video I have a particular interest in these mainboards as my first PC had a PB410 mainboard in it and I learned a LOT while using the machine for several years.
I love your content and looking deep into actual issue!
Great work, brilliant detective work on the Turbo functionality, thanks for sharing I think that will be very useful for other people struggling with broken Turbo functionality on their machines. Also makes me wonder if implementing 'Turbo' (slow down) on other machines that don't have it might be possible so that some speed sensitive games could work better.
This is just incredible.
Perfect work!
Просто нереально крутое видео: здесь и скилл реверс инжениринга, и объяснения принципа поэтапного делителя частоты, и самостоятельное написание прошивки для PAL/GAL. На моей памяти это, верятно, лучшее видео на тему ремонта ретро-платы!
Я считаю, что выложить прошивку для GAL на theretroweb - отличная идея.
BTW, насколько я понимаю, в некоторых случаях возможно считать прошивку из PAL/GAL. В данном случае, вероятно, производителю было нечего скрывать, и считать прошивку со второй платы возможно? С целью бэкапа, разумеется.
Спасибо! Рад, что видео понравилось. К сожалению, большинство ГАЛов закодированы и вычитать прошивку не вариант. При записи на ГАЛ шифровка - стандартная установка, которую активно надо отключить. Большинство производителей не парятся и зашивают так, чтобы вычитать было не возможно.
My very first pc was a 386SX25 with a turbo button. If I remember rightly it dropped from 25MHz to 14MHz when it was used. It also had 2 Meg of RAM (soldered to the mobo as 8 256k chips) and a massive 50 Meg hdd.
As a (software) reverse engineer with only basic hardware/electronics skill, I love these vids and so much of the process & approach is the same as with software.
Your vids also taught me not to be as intimidated by 'chip blackboxes' as I used to be. Since I have a very talented 'hw buddy' I always let him do his thing for complex stuff, kinda selling myself short in hindsight.
I'm a software developer and have actually no clue about hardware ;)
@@necro_ware Now I'm impressed even more !
Very impressive repair!
That was pretty intense.
Incredible! And I'm just afraid of unsoldering a damaged floppy connector😂
Absolutely incredible work!!!!
Man, great work! Thank you for share with us.
Just awesome work.
Nice work! This was a very informative video.
As always Necroware provides us with quality and interesting content. Thx Necroware ❤
Excellent video
Digger, we had that on the Amstrad back in the late 80s
once again i must say your videos are amazing to watch and your skills are just out this world. thanks for the content :)
Nice work, as always. Cheers.
Excellent job!
I like retro repairs video cool to learn something new 😃
Amazing - great fix!
Excellent video and work, thank you for sharing this.
Very nice video
Great video lerned a lot, as always.
Awesome troubleshooting!