Zenith Z-148 rare retro PC Rifa repair & review
Вставка
- Опубліковано 28 тра 2024
- The Z-148 was Zenith Data Systems' unsuccessful entry-level PC, from 1985 to 1987. I explain its history, replace the failed Rifa capacitors in mine, give an overview of its design, and show it in operation.
Time flow:
0:00 Introduction
0:42 Zenith Z-148 history
3:14 Teardown
4:20 Roasted Rifa capacitors
8:56 CPU board
10:45 I/O board
12:32 System timing
13:55 Upgrades
15:41 Power-up & Zenith quirks
18:55 Floppy drives
20:28 MS-DOS in only 256K?
22:02 Keyboard
23:26 Zenith's nadir
24:06 A cure for upgraditis
Relevant videos:
BBC Micro X2 EVOX RIFA capacitors going POP
• BBC Micro X2 EVOX RIFA...
RIFA AC Filter Capacitor Blowup
• RIFA AC Filter Capacit...
Zenith Data Systems vintage 84-key AT keyboard
• Zenith Data Systems vi...
New SmartWatch+ clock module for Tandy 1000s & XTs
• New SmartWatch+ clock ...
Zenith eaZy PC review
• Zenith eaZy PC review
For more detailed technical information, here is the service manual for the Z-148:
www.mediafire.com/folder/a416...
#zenith #rifa #capacitor - Наука та технологія
RIFA actually stands for Reduces Itself to Fiery Ashes.
haha 😜
Yamaha actually did a product recall on a thirty year old amp using these as they didn't want peoples houses reduced to fiery ashes (although to be fair the capacitors are supposed to be flame proof).
Quiz: Where is the worst place a RIFA capacitor can go ?
Answer: In your vacuum cleaner. You won't see any smoke but the whole house will smell of it. Happened to me with an old Electrolux.
@@MrDuncl oof
Lol
@@MrDuncl 'proper' class X or X2 caps 'should' 'fail safe' , not causing any fire...
These were used by the US Government for a number of years. When I started in 1995 they had a ton of these. I came across the original purchase orders for them while cleaning out a filing cabinet - a lot were ordered by the group I used to work with in 1986. So we had these for about 12 years before we got new PCs. Amazing for the time we lived with these things until we had to upgrade to do something called Windows.
Proud part of Zenith Radio Corp. ZDS actually made a profit & was respected.
Old story that went around in the day. ZDS was sold to Bull, A B Dick was associated
some how. When you called ZDS the operator would say " Bull Dick how can I help you".
That lasted a week so they say. Now you need to get the Zenith 14" FTM CRT monitor.
Killer pix but prone to all kinds of cold PC joints. Had they used that jug in a 13" TV
it would have been an $800 TV. Flat & square just had to wait.......
LFOD !
My friend had one of the early Zenith flat-tube VGA monitors. It had a nice picture but compared to all the curved-tube CRTs we were used to at the time, the image looked concave.
I remember seeing a Groupe Bull Zenith computer in the mid-1990s for sale at a Detroit-based computer store, Computer City. It was running a Microsoft paint program named 'Fine Artist'. I remember thinking about how cool it was, and hoping my parents would buy it for me if they got a computer.
My parents bought a Macintosh Performa, and it turned out to have a copy of Fine Artist pre-installed. It was the best day ever.
In regards to policies behind universities trashing old equipment, it really varies. In Utah, for example, state funded schools are required to have guidelines (or even entire departments) on property disposal. The U of Utah has a Surplus and Salvage department that takes all furniture, computers, lab equipment, medical exam tables and anything else that could be resold to the public. A lot of what they get does, unfortunately, end up in an e-waste facility, but the rest of it gets put on shelves in their giant warehouse and sold off. I've seen some fascinating and really unique things there, like polymerase chain reaction (PCR) machines from 2011, a portable mid-90s data logger I picked up for $12 last week, and everything else you might have seen in an office or lab in the last 40 years.
This is the same in Georgia and Florida too.
A note on the "modern" 3.5" floppy drives and their drive select, some of them inside you can change through means of solder pads, most only have DS0 and DS1, but they are often set up to be selectable regardless, it just needs some soldering iron time... :)
Love your computer videos. I replaced the rifa in my 5160 with a brand new Rifa from mouser. People called me crazy, but the last one lasted almost 40 years and I only replaced it as a precaution. It didn't pop.
Your content shows respect and sincerity. Wish you more success and support, friend. ❣
Not sure why, but Zenith as a brand has something to it. Love the Zenith stuff. So thanks for this video. Too bad there are just so few out there.
It sounds cool and has one of the best logos ever.
@@GurtTarctor It sure does
I have one of these I bought several years ago. Neat little computer. Not sure what to do with it, but I can't get myself to sell it. It is handy for testing floppy drives since it's so easy to open.
A note on the labeling on those RIFA self-healing paper capacitors (which supposedly survive many power spikes before finally exploding): D in a circle means it has been certified to pass regulatory testing at the former Danish Electrical Material KOntrol authority DEMKO, whose lab facilities were sold to UL in the 1990s after being overshadowed by federal CE marking rules based on less strict enforcement. S in a circle is another such state approval from the 220V European grid. Unsure why RIFA would bother obtaining those approvals for their 110V capacitors, though technically they could be put in series instead of a single 220V RIFA capacitor for extra resilience
I've been meaning to say this after watching your videos for a few years; I love the scene transition jingle.
The ROM monitor is my favorite thing about this line of Zenith systems. You can use it to crack bootable games! Also love the smooth scrolling and 50hz options. Very cool and unique clone for its time. I have the portable/luggable version which looks like it came off a battleship.
BTW, I really enjoy your system reviews. You have a knack for taking a boring subject and keeping it interesting.
PS: You need to update your version of The CGA Compatibility Tester ;-)
Modern "safety caps" supposedly are guaranteed to fail open and not short. That's the problem with these Rifa caps, they fail shorted.
Very cool, nice to see this one is up and running again! It’s a good thing that the Rifa caps don’t cause any major damage, at least when taken care of. Even though the upgrade path for extra components is basically nonexistent, it does actually show how many of these systems were used when new. Top of the line hardware is fun, but it’s really the less expensive hardware that was available to more consumers. Unfortunate that many have probably been thrown out by now, but at least this one will continue to compute!
It's always a treat getting back to the basics with your vintage computer videos. I'll admit that quite a bit of the nitty-gritty flew well over my head, but an excellent in-depth overview regardless! Even though I already have two Model M's, I wouldn't mind getting my hands on that Zenith Keyboard just to get that key click beeper; too bad they're so rare and pricey.
2:14 Up until the late 2000s, when I ran a computing center at a university, the Psychology department still had what appears to be the HS-158 that ran some really old legacy software. In the early 90s, it also had some "chonky" 386DX Zenith machines that were for AutoCAD.
Psychologists are happy with SPSS and a word processor 😊
@@andic6676 Oh, I always had to have SPSS installed! Don't forget about Sniffy the Virtual Rat! ;)
Learned Pascal on one of these in 1986 at Cincinnati Technical College. Good times, good times!
I recall seeing Zenith PCs in a large lab over in then Stockton State College in southern NJ. I don't remember what model they were just that it was late 80s, had typical more yellow than beige case color, and amber phosphor monitors. I think they were part of the Z-286 series. Later I ended up with a differently styled ZDS 286 with an MFM drive because it was 1995/6 and La Salle was finally dumping the last of their non-Win3.1+ capable PCs and somehow as a Comp Sci major I didn't have a PC of my own at school. Couldn't do much but Lotus Works, Turbo C++, and the 2400 baud modem to connect to the school's Alpha still worked! It was quickly replaced by a shiny new Micron Millennia with more video RAM (4MB) than that 286 had for system RAM, because VB kind of didn't support that old clunker.
Ah! With building a PC via a Heath-Kit . . . it's one thing to cobble together a bunch of electrical parts, it's a whole another matter with venturing into the murky waters of getting it all to run with MS-DOS, as there were DIPS switches and 'interrupter' aspects when getting the hardware to harmonize with the OS and software apps.
No joke, I am currently in the process of binging your computer videos, and this is definitely gonna be another good one! Never heard of this computer by the way, so this will definitely be interesting!😁👌
The Zenith was the first PC I used in college in 1987, in the same year, I discovered the Macintosh. The Mac blew my mind and I never looked back.
Yes this is the very machine that I used back in high school for typing practice using Typing Tutor IV.
I remember the flashing K logo when you started up the program.
The machine I used had a hard drive in the right drive bay as well as the 5.25 floppy drive.
In 1985, I wrote an inventory/point-of-sale/accounts-receivable system that ran on a Z-148 with two floppy drives and 256K of RAM, so you could do a lot. 256K is really a lot of memory-when you're not trying to drive a graphical user interface.
Random off-topic fact: that jingle you use for title screens between sections was used heavily in a kids television program in Australia called the Curiosity Show. There are episodes on UA-cam if you want to check it out.
Amazing what some of these early machines had in ROM, although now it’s still there in some form in spirit in the form of some of the system restore options and BIOS UIs.
I'm always sketched out by older capacitors in general cause of electrolyte drying out over time. I've seen it happen but honestly unless the machine somehow becomes unstable or does something screwy under load I'm more apt to leave them alone cause sometimes its not worth replacing them. Parts shortages are still a major issue now and its unnecessary busy work for a machine that looks like only get used infrequently.
dont worry too much about it, ones from this sort of era arent as bad as more modern ones, such as from late 90s to late 2000s, eg. 'capacitor plague' years .. i have some electrolytics 50+years old still good , admittedly not used under high power/temperature/ripple conditions, but still......
That's really cool there's a machine language monitor built into ROM on that Zenith! Presumably that was the continued influence of Heathkit on the Zenith products.
I love all the jumper options. Plug n play is nice but sometimes you just want to force something to do things the way you want it to for compatibility and such.
Another great and informative video; thank you VWL. I especially enjoyed the part about the capacitors.
That smooth scrolling is very cool.
Love how tech had more variety and passion back then. Now: flat pads, everything.
I remember taking a class for BASIC language programming on a mainframe in the early 80's. In the back of the lab was a room with about 20 of these. I thought they were so cool.
Great rescue of an iconic Zenith machine.
Your videos with transition tones are the best!
That capacitors you put in will hold up for much longer than those RIFAs did. They aren't impregnated metalised paper, but a Polypropylene foil and ceramic. Those were even made in the 1960s, but cost much more, and you guessed it: they still hold fine till today. But the paper ones from the 1960s and newer are all leaky and would explode if placed from L to N :)
yep, paper dielectric caps are in general shorter lived than poly ones , but its the epoxy cracking that starts the problem, allowing atmospheric moisture in , which paper of course absorbs....
@@andygozzo72 I was pleased to see that he didn't fit the same type. People have found the epoxy cracking on old RIFA capacitors that have never been used or even soldered into a board.
@@MrDuncl yep, i dunno whether i'd dare fit a modern RIFA of that type 😉 i DID fit clear epoxy cased ones in an AT PSU that blew, but dont think RiFA branded...it was about 20 years ago!
i have a good used epoxy cased RIFA that seems ok, at the mo.. but its a 'low' voltage type, 10uF 63v dc and pretty sure poly dielectric..
That’s great to know, ceramic caps last forever barring some external shock strong enough to crack the internal structure and cause a short. (Which sadly is quite common with the very tiny surface mount ceramic caps, but these of course are not those!)
Damark! I haven't thought about that in over a decade! Great video, as always!
"Oh beepbeepbeepbeepbeep". I remember seeing a lot of Zenith equipment as the company I worked at in 1999-2004 bought the Bull service department in Scotland. (Groupe Bull/Zenith/NEC)
Very nice old zenith. Brings back memories, thanks for sharing!
I think this is the computer my family had when I was little, but it's hard to find quality info on the different Zenith computers, especially this one. I definitely remember the Function keys being arranged like that on the left (I remember an Asteroids game using F9/F10 for Rotate Left/Rotate Right), and the turbo button. I also remember it having a "demo program", the kind a store would set up for a display unit, that cycled through different features. But I haven't been able to find that specific demo since. (I remember it showed off Turbo by having a stick figure walk, and it showed a drawing of a fountain and played a little song over the speaker.) I'd been trying to find more info on this machine recently, so I guess it's serendipitous timing that this video just went up.
Love your channel. I chuckled when I saw the section title "Zenith's Nadir" as they are astronomical antonyms.
Oh wow, this is the system I still have from my childhood. Have not tried turning it on for like 20 years... Clearly I should keep this in mind for any future efforts
I had one of these. Control Data got employees a discount. It's a little disconcerting when you were "back in the day". That keyboard was a mixed blessing, great to type on, but to this day, I need a mechanical kb to hit my best speed.
Love the graphics and music on this one
That Zenith price point of nearly $2K in 1985 would equal that of $5,500 dollars in 2022; so those early PCs were not commonly found household items in the 1980s.
😀Wow such a lovely video, great job! So cool having that built-in monitor too
It's Rifa Madness!
Oh, the memories. My parents bought one of these new in 1985. We packed it with the 768K... none of my friends who used computers would believe it had so much memory. Four years later, I was surrounded by Zeniths working in the computer labs in college... and being Zenith-knowledgeable really gave me a leg up. Those Zeniths really held up to the abuse. Unfortunately, there was a regime change, and the new labs got these flimsy plastic junk systems. I can only imagine the Zeniths soon ended up in the trash. I'm trying to track down my original Zenith and hope it hasn't suffered damage in the last 25 years, but I suspect it has.
My Aunt had a Zenith, can remeber witch one, but it was a 386 I remeber that.
BTW I like your early 90s style scene transitions. :D
I’m surprised Zenith even made computers, I know them for making TVs, they look like imitation of Tandy computers, but it’s really cool you’re able to repair that Zenith computer!
They had large contracts with the US government in the mid 1980's. My first machine when I started work at a defense contractor was a Zenith 386SX16 desktop machine.
@@dennisp.2147 that’s cool, Zenith is like RCA, they were both making machines for the defense industry! And then both companies declined and were sold off!
I believe they had a large educational presence. My University in the late '80s/early '90s almost exclusively used Zenith for their PCs (although there was a large Apple Macintosh presence outside of the Comp Sci department as well).
The comp sci dept. even had some of the "Heathkit" PCs that had it's ISA Expansion configured as a bread board on top of the machine's case, so you could rig up your own custom ISA "expansion card" while learning computer electronics!
Ultimately Zenith couldn't compete in the market by the time the margins got super thin in 90s and Zenith Data Systems was sold to NEC who also owned Packard Bell, by that point they were selling Zenith and Packard Bell machines that were pretty much the same other than branding. There was also Zenith Network Systems that was acquired by Motorola which was eventually swallowed up by Arris that's now owned by Commscope, ZNS made one of the first cable modems.
@@irinotecanhcl Zenith was lucky to even have the educational market, because in the 1980s, we never had any of their computers in my school, it was mostly Apple II and the classic Macs, IBM, and Tandy computers! Only some colleges had them for cost reasons.
The two voltage ratings on those Y caps are for DC and AC voltage.
I've been looking for the expansion daughtercard for one of these for almost 20 years now. I'm not sure that they were ever sold in large numbers. I did not know there was an aftermarket version though!
Someone should reverse engineer it and make it open source!
@@ricardog2165 If only someone could find the service manual for it, which hopefully would have the pinout for that ribbon connector, it would be possibly to make a replica of the expansion daughterboard.
@@vwestlife My first thought would be that we just need to map the lines to the known ISA spec. 1) Use a multimeter to get the power lines.
2) Visually check where the other lines go
3) Check the rest with an oscilloscope
4) Then hook up a POST board to check
Maybe I'm missing something?
@@ricardog2165 I could probably try and whip up a very rough proof-of-concept if I had some schematics and one of these to try it on.. If it's anything like the Tandy 1000EX's ISA pin header, that should relatively be straightforward to do.
@@Alexis_du_60 There's a guy supposedly selling schematics. Google "retrotechnology zenith manuals". He's in NJ, VWestLife's state.
Great video, as always!
I graduated high school in 1982, and went to the first school in the country to be equipped with Zenith Data Systems. Every time I see that logo, I recognize it.
I have one of these on a shelf that I have yet to get around to repairing, this Christmas for sure..
Such interesting information about clock speeds and how they were derived.
Some turbo XTs also run at 9.54 MHz. Can you figure out how they derived that speed?
@@vwestlife I taught grad students about computer architecture and design and still learning, but off the top I’d say there was a clock doubler involved since 4.77 * 2 == 9.54. Or not divided by 2…
@@5cyndi Hint: It's divided from the 14.31818 MHz crystal I showed.
I loved the PC Junior once I figured out that I could actually play Space Quest 3 on it.
beautiful relic. reminiscent of an amstrad 1512. ready for fractal graphics!
built the Heathkit version of this computer a couple of months before heading off to college. Went ahead and topped it up to the full 640K +, and then picked up the expansion riser a year or two later. Used it for ~ 8 years, still have it, but I probably need to check the PS caps before I try to turn it back on. Cut a lot of TurboPascal code on that box, and a bit of Smalltalk...
excellent 80s computer..even if without flash....great review kevin...
I really likes vintage PC unfortunately LG killed Zenith I miss the Z ⚡ thanks for bringing me back in the past
I will never forgive Gold Star for killing Zenith. Probably just after all the HDTV
patents Zenith had, most of them.
LFOD !
Different Zenith. The PC part of the company was sold to a French company called Groupe Bull in the 1990's. From there they ended up with Packard Bell and whoever now owns that company.
@@dennisp.2147 Correct. Packard Bell was purchased by NEC and later sold to Acer who still sell computers under the Packard Bell name in Europe.
Zenith made some nice stuff back then. I have one of their alps switch mechanical keyboards from back in the day.
A typically excellent review of this system. I just can't get excited by it, but then I feel the same way about the PCjr. I do love my Z-159, however, which uses the same heavy, clicky keyboard.
Not just in power suplies, I once had a Rifa blow its' guts out inside a Hoover Junior U1104, used as a noise suppression cap across the motor, even after cleaning the mess up that vac stank for ages afterwards... :S
I had the same in an Electrolux. You don't see any smoke due to the high airflow but you certainly smell it. In am still annoyed about my Mums expansive Husquvarna sewing machine. She thought the motor had blown so threw all the accessories in the trash, then next time I visited asked me to take it to the tip. When I looked it was just a RIFA capacitor across the motor that had smoked out.
Regarding the 3,5" Floppy drive issue.....EVERY 3,5" Drive can be turned into a Drive 0 drive. Even if you have to remove a trace on the PCB and rewire that. I found manuals on how to change ALL my 3,5" drives and it worked flawlessly every time. Many of the newer ones can be even adapted to Amiga, if you're willing to re-route some more wires on the drive PCB.
A nice video! Thank you!
I remember these as well as many others, my father back in the 80s and 90s used to buy used computers from people and places like the flea market and thrift stores. I used to play with just about every old computer he had so many of them. If he olny kept them until today he might be a millionaire if he sold his entire collection on ebay. Sadly in the late 90s he moved and ended up getting rid of most of them. By that time windows 95 became the standard and the older pcs kind of lost their charm. But here we are 20 to 30 years later and suddenly they are super valuable again!!
6:38 Second retro computing video I've seen with exploding RIFA caps lol
The Rifa in my dad's Quad amp blew too, luckily easily fixed
I'm not sure if I've ever seen a zenith computer until now, I mean I must have at some point right? 😅anyway dope video!
Amazing video
Nice I remember those computers !
Sweet! You can play some Attack of the Petscii Robots though. That's for sure. :D
But, did you ever show us how Lotus 123 took benefit from the 287 co-processor? I was waiting to see before and after.
From what I've seen on David's site, Attack of the PETSCII Robots requires 640K RAM and a high-density floppy drive, however Planet X3 should be able to run in 256K and from 5.25" 360K floppy disks. I did a video about the 8087 showing that it doesn't really benefit most uses of a vintage PC these days, but it's nice to fill the empty socket anyway.
@@vwestlife Ah you’re probably right. I’ve gotten lost in all these numerous ports he made. I just do the box designs and manuals and not really memorising the specs. 😂🙈
Yeah, I was thinking the math processors never really do that much for us in these settings.
Good to know about capacitors being constantly energized even while the power is off, something to watch out for.
And by the way, this isn't required or common for X capacitors, unless they are inside the power input socket itself
I had one of these. I loved it. The keyboard was very good. I think mine had a 7 MHz V20 CPU.
Documentation! I just found mine. (I no longer have the computer, but somehow, I still have the documentation.) 5, vinyl bound, 8-1/2" ring binders. (Not as classy as IBM's cloth-bound binders, but more useful.) MS-DOS Version 3, Z-140 PC Series Owner's Manual, MS-DOS Version 3 Programmer's Utility Pack (Volumes 1 and 2), and MS-DOS Version 2. The binders are labeled with both "Zenith Data Systems" and "Heath".
Mechanics and technicians have a simple saying that matters a lot: if it's not broke, don't fix it. If those other capacitors are in good shape and still working, leaving them alone is the best bet.
Cool machine ! It is pitty that not so meny survived
Today I love the aesthetic of PCs of this era. Funnily enough I didn't back in the day, I really wasn't into computing, more into music, so had no interest.
However although they look so cool they are so slow I really wouldn't use it but that still doesn't prevent me from admiring from afar.
A lovely thing. Good choice, good job.
You could always just swap out the components inside to more modern hardware. There's probably a video on YT on how to mod the case.
Holy transitions!
Luckily in my experience the RIFAs fail open :-) at least that saved my tektronix scope which blew up with a nasty smell bu kept working… Thank you for the great video!
I've had 2 Rifa's pop in 2 days in Apple 2 PSU's....man that SMELL
There was ZERO ads for the Zenith if I recall, unlike IBM which had a plethora of TV commercials and ads for their products held around the same time. A Charlie Chaplin character played in them.
"Oh, F-" *[BEE-EEE-EEE-EEE-EEP]*
LOL!
I also put forth the motion that the "Zenith Beep" become the official censor beep for this channel & related videos.
All in favor?
That was the best part of the video 😂
At least Amstrad got it right with their 1512 and 1640 in that it had standard 8 bit ISA slots and 512 or 640k of ram as standard, even if the PSU was in the monitor.
As for the RIFA's, modern polyester? capacitors will last longer, esp. if from a reputable manufacturer. They are also an issue in older Numatic vacuum cleaners and most people (incorrectly) just remove them.
Lastly, the LED's in the lock keys was a feature on some of our Acorn Archimedes machines, the keyboard wedge ones at least.
Both of those machines came out 18 months after the Z-148. They were also not fully 100% IBM compatible. The Zenith came out a bit more than two and a half years after the Commodore 64 and it's 64 K (38.9 usable) and the same year as the Commodore 128. So it's amount of RAM was certainly commensurate with machines that it was competing with. Remember, the IBM XT's motherboard didn't officially get a 640K capable revision until a year after this machine's introduction.
Apparently that computer was made in Mexico, in the city of Reynosa Tamaulipas
My family had the Zenith Z-158 in the early 90s, it was sold as surplus from a nonprofit and the only software we had was WordStar so I wasn't very interested in it.
I'd like to see some tests playing with the wait states on Landmark or other tests.
Hmm, I wonder if there are any of those Rifa capacitors in my ZF-152? (By contrast, many of those systems seem to have survived.) I wasn't a big fan of the Zenith keyboard because it had a noticeable metallic echo when the keys were struck. Something about the sound it made just bugged me.
Thanks for the Control-Alt-Insert tip! With any luck, Zenith left that functionality intact in later BIOSes and it might shed some light on a Zenith 386 desktop I've got that won't finish POST.
That power supply bears a lot of physical resemblance to those that Zenith made for the Model 50, 50z and 70 PS/2s. I always thought it odd that they didn't put their name or logo in a readily visible place on those power supplies as the other manufacturer (Astec) did.
Funny how the passage of time makes one forget things. In looking back at the comments on the ZF-152 video, you (vwestlife) mentioned the Control-Alt-Insert thing. I guess I should try it!
@@uxwbill There's also Ctrl-Alt-Enter (or Return as Zenith called it) to enter a CPU debug mode.
Also jam in new smaller low impedance power supply electrolytic caps. New ones are smaller too.
First computer I ever had was a Zenith with a Winchester hard drive from this era. Ironically I got it for free from a school along with an IBM 5150. They simply placed their old PCs out back and let anyone take what they wanted.
I appreciate the "if it ain't broke" philosophy, but those electrolytics almost definitely have superior modern substitutes.
Totally agree
I have an amplifier from the 80's with capacitors that measure better than the modern substitutes.
Theoretically, there’s probably something better out there from Nichicon or Rubycon.
Practically, unless you have unlimited budget, it’s much better to only replace the ones that fail.
Even a midrange modern one could be worse, and a cheap one almost definitely would be. Even if they technically measure better at first, modern cheap ones show all signs of being worse on longevity (smaller casing, denser electrolytes, reducing tolerance for thermal expansion being one factor no matter how good anything else is).
@@kaitlyn__L I would say unlimited budget and excellent soldering ability otherwise you may end up doing more harm than good - overheating the board causing delamination, lifting traces, etc. etc.
@@TheErador that’s an excellent point! I always assume the people saying this have experience and confidence in their soldering ability, since I’ve been doing it for 13 years, but you’re right that a loooot of people attempt this after just watching one or two videos and mess up their PCB.
7:40 did the USA have stricter EM emissions requirements than Europe in the 1980s? I had a similar era Ericsson PC and it's monitor that would interfere with the MW and LW radio bands respectively.
My BBC micro's rifa caps went, It made a very loud buzz and the smell was unbelievable, really acrid. Its hard to get across just how nasty it is.
Do you have manuals? I am working on a z-138 luggable, which appears to use the same mainboards, but I don't have any documentation for it.
I'd be thinking about designing a clone of the ISA adapter.
18:53 The CRT monitors make zap sound.
It happened to me before as a 6 years old boy, I just got zapped by touching the front screen of that Akira CRT TV.
I know it's electrostatics, but how it can zap people and why it is acting like that.
It's static electricity, just like when taking off a wool sweater. It's thousands of volts, but the current is so low that it doesn't hurt you.
APPRECIATED
It looked like there was moisture or fluid in there! Leakage from the caps? Looked pretty juicy.
Modern poly caps basically last forever and don't suffer from leakage, both physically and electrically.