PC Archaeology: A left for dead XT clone
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- Опубликовано: 25 июл 2021
- When patron Justin dropped off the IBM 5170 which I featured on the main channel, he also dropped off some old neglected and abandoned XT machines. This is one of them -- what kind of things will we find lurking inside this computer?
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--- Instructional videos
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5:02 "I wonder what that says" - Google Lens says "Noguchi Electronics Ltd"
5:41 "very curious about what this one is" - it's probably a Monochrome Graphics Adapter (MGA), the precursor to both CGA and Hercules (a 3rd party higher resolution display) cards
source: was there at the time
6:24 "ST-225" - yep, slightly older than min - I had an ST-238R, which was a 235 with an RLL controller for 50% more storage
The Fastcard contained ROM so that you didn't have to install any TSR programs in conventional memory to access the EMS and caching functions offered by the card.
That was the coolest part of the video. First hardware EMS card I've ever seen with a ROM
A standard Hercules-like card is supposed to have 64K DRAM and a font ROM, typcially a 16K ROM containing two 8x8 fonts (unused on MDA/hercules) and a 9x14 font.
The presence of a 16K SRAM indicates that this card likely has some RAM font option. It's for sure *not* HGC+ (HGC RAMfont) compatible, because that card has a very elaborate RAM font system using 16K text mode RAM + 48K font RAM, and not just a 16K font chip. You likely need a proprietary utility to enable "font upload" mode and "use RAM font" mode.
"Page register hexadecimal address" is referring to the I/O port used to map EMS pages. It's not a memory address.
Those Seagate ST-225 sold so well. And for good reason, they are tanks!
The was a PCB maker in Miami Fl called "Tropical", IIRC they had a palm tree as their logo. IBM did design and FA&T their early PC's and XT's out of Boca Raton Fl.
Paradise was a video card brand as well… I don’t know if I still have mine - logo was a palm tree too
Those ST-225 hard drives are certainly built extremely well. I had 1 in storage for about 20 years from around 1998 when it was last used. It wasn't stored well and was dropped onto the floor at least twice. In 2018 I dug it out to test & possibly install in an XT build I was working on and I was able to recover about 95% of the data before hitting read errors. A low level format got it working like a champ again and it's still installed and working in my XT build today. They certainly don't make them like that anymore!
This is survivor bias. ST-225s were keeling over dead in the late 80s and early 90s. I was usually tasked with replacing them with ST-251, which at the time had a considerably lower failure rate. Once they got some wear on them, the reliability was only slightly better than the ST-225, and now it seems that the _very best_ ST-225 will outlive the _very best_ ST-251. But they weren't all like that.
they had no idea that Moore's law would drive people to upgrade every few years. DEC computers, from PDP line and maybe some Vax used MFM-RLL drives (actually I'm not sure exactly when RLL came out, all I know is that it doubled memory capacity.)
@@mal2ksc Yup, replaced a lot of ST-225s back in the day. Seagates always had a problem with stiction.
@@squirlmy RLL increased capacity by 50% over MFM.
This inspires lyrics on the song "Angel in the centerfold"
"... My blood ran cold,"
"The memory was just too old,"
"Battery leaked on the motherboard"
It's just "Centerfold", by the J.Geils Band ruclips.net/video/BqDjMZKf-wg/видео.html I have memories of when this song came out, they're not all good, frankly. I'm partly amused, but also part of me would like to let that song die.
VAR-TA NA-NA NA NA
In my experience, when dealing with corrosion on pc boards, watch for dark spots on the traces. The solder mask will have been breached and the copper exposed to whatever and the trace will likely have been eaten through. Sometimes you can save such traces by carefully scraping the compromised mask and trace underneath to get to virgin copper that can be built up with a bit of solder, else a bodge wire will have to be run across the break.
I love the XT content. Fond memories of learning the basics of DOS on them in school.
I still have my first XT compatible PC that I received from the now, long gone NRI (National Radio Institute) school of home study courses, for taking their digital electronics repair course. My late mom helped me pay for the course so it has sentimental value to me. I sure LOVED that course and I was able to do many things with that old XT that one would think it was incapable of doing! Thanks mom!! Love you and dad!! See you both in the future one day.....❤❤👍👍
The name 'Tandon' made me shudder -- I was unfortunate enough to own a Tandon Data Pac PC, and the disk controller was *almost* compatible with a normal one, but not quite enough to make stuff work reliably.
It is always pleasing to see useful old parts rescued!
I'm amazed how evenly that leakage spread out. It just gets *EVERYWHERE!*
I remember years ago, I had an old Seagate ST225 which had died, so I gave most of it to the local school, but kept that massive top cover back to use as a dish to feed my cat!
Never get sick of this type of content. It's always very interesting and informative. You are becoming the XT Guru.
In 1999 I used an XT as a text terminal for a Linux machine.
It's too bad that Linux didn't go early into multi-head configurations, even an XT or PC should be fit for more than a monitor & keyboard.
@@absalomdraconis That would have been cool if a ultra light GUI like GEOS was ported to the XT and if it's GUI could read X packets, or if X could read GEOS packets. Then yes, small machines like XT's or less could act as a sort of X Term.
@@absalomdraconis You could do multi head. My first multi head machine had a VGA display and a Hercules mono display each a separate instance of X. It was not seamless and you needed two keyboards and mice. So really, it was a dual console system. Also you could run as many getty's as you wanted against as many serial ports you could cram into the machine. I used to do as much as 8.
Might try to reflow the solder on that floppy power connector. Looks like a cold solder joint/cracked solder joint.
I was thinking the same
18:00 - 2 diskette drives lashed together: Love it! From back when people still thought half-height drives were a pretty neat idea.
Adrian, when you changed the video card to the VGA one, did you remember to set the DIP switches accordingly? If not, your "Error 04" might probably be just a video configuration error.
The two heads logo on the clock card is from Twinhead as I do have a branded Logitech serial mouse from them
10:00 I had similar damage on an XT clone I was working on. That slot might need to be replaced. For the rest of the board, soak it in a tub of cleaning vinegar and give it a good scrub.
OMG Norton Disk Doctor, Now that was a friend in very hard times now and again!
if only my memories of Norton Anti-virus were as good. Bulky, bloated, I'm not sure it was really any good for protecting from novel viruses, either.
@@squirlmy i remember it saving our butt a few times in the early days. It did get bloated over time and we went to a Symantec tool because we had a tech who used to work in their support dept. Yes. There was a time where we chose to use a Symantec product
@@squirlmy Lol, This is what I get for answering on my phone without my glasses. I give non-sequitur answers! You are absolutely right, Norton Anti-Virus was like using a sports car to tow a trailer full of horse manure!
On the card with 64 kB, the 64 k was for the video, but the static ram may have been for a print spooler/buffer. Just my guess. 🙂
Yeah that is possible -- although I think this card also has soft-font ability, so I bet the SRAM is for that
Hi Adrian,
Thank you for all the amazing content you put out! I'm interested in retro computers, but not enough to dive into it myself (I don't have enough room, and video game consoles are more my speed anyway). I love watching the effort you put into restoring and breathing life into old computers and components. I just appreciate that you put a camera on your work and share your knowledge with others.
Nice. Lots of good working stuff.. 👍
I think, that mainboard error 04 code may be caused by wrong dip switch settings for memory mapping..
The pin header on the controller at 3:00 is most probably a game port
You could gladly send one of those "boring" XT machines my way! I'd give it a good home. 😀
Maybe not a prob this time, but watch for proprietary floppy drives or cables. They often seem partly compatible, but can cause damage. I think 8BG discovered this on Tandy 200.
26:35 its like finding mold on your bread, its only appear if you study it 3 times.
Amazing video ! Really enjoy this content !
14:55 "Think the hard drive is kaputt"
that was random ;D
learning Germyn i see ;)
Some memory cards had ROM to support expanded memory. I am not familiar with this card, but had one foe PC-AT (16 bit slot) that went beyond the AT memory limits.
Yes, most likely EMS and has a BIOS so you don't need to load an EMS driver in DOS
Adrian - It looks like someone uploaded the Fastcard manuals and software to Minus Zero Degrees: minuszerodegrees.net/manuals.htm#THESYS . Looks like it's an EMS card which can also function as a RAM drive or a disk cache. According to the manual, the ROM is there to conserve memory -- so you don't have to load a DOS driver which would eat into the base 640K.
It says 野口電子工業株式会社, which is Noguchi Kogyo Co., Ltd., the name of the manufacturer. They're still in business today.
*sigh* how come I never find things like these in the attics I see? Great video as always! :)
@18:00 OMG, I remember using these brackets now that I see them again! It's been awhile :-)
The ST-225 and similar drives are actually self-parking.
The ST-225 doesn't self park, you are probably thinking of the later ST-251 and it's variants that use the inertia of the spindle motor on shutdown to move the head back to the landing zone. Although I am curious if the ST-225R was self parking?
Doesn't look like it... I still remember parking my ST-238R with park.com :D
ST213/ST225/ST238R - The read/write heads may be parked by issuing a seek to any cylinder between 615-670
ST225R/ST250R - The read/write heads may be parked by issuing a seek to any cylinder between 667-670
At power-on the drive will recalibrate to Track 0. If the heads are parked while power is still applied, any step pulse will cause the unit to recalibrate to Track 0.
The ST-225. With these Seagate 5.25" drives, if it self-parks, you definitely *WILL* hear it. It sounds like an 18-wheeler tractor trailer using its Jake Brake.
They must have gutted the board of the RAM chips leaving just the bare minimum which will let DOS load but nothing else.
That old hard drive working is amazing. Good job :)
Look back at the video.. The power was not attached when you tested the floppy controller the first time and you thought it was bad... I went back and looked when you had doubts that it was plugged in, it was not...
Thanks for the Videos, I'm a big fan.
You got some cool PC expansion boards out of that. Let's hope the Mother board is an easy fix. :)
Good video! very well explained!
Woo-yeah, incoming repairs!
"PC TURBO BIOS Error #4... super nondescript" You made my day, Adrian.
I thought it was going to boot from the cleaning disk. I was bummed and then felt stupid, oh well.
The palm tree on that video card means it can play Crysis.
A petition to Adrian Black.
That upsidedown TDK D60 drives me crazy for a very, very long time.
Please, fix this.
PLEASE!!!
7:20 it has empty EPROM-sockets due to the lack of ROM BASIC... (i never met sb retrofitting it into an XT clone)
I did come across one Turbo XT clone which had an illegally copied version of IBM BASIC in ROM.
@@vwestlife Corona Data put out a Portable PC Model PPC-400, and Eagle Computers put out the Eagle 1600 series with copied IBM BIOS. IBM threatened lawsuits, but settled, and not for fixed dollar amounts, just mandated changes, and a piece of profits from remaining stock. I need to add that it wasn't sure that US Courts would uphold firmware copyrights until Apple vs Franklin in 1983. I think IBM feared the courts might rule that code, or any machine code, was not covered by existing copyright (or exceptions would be made). Apple v Franklin set precedent. So, it was immoral or underhanded copying, sketchy, but not necessarily illegal, at least not in US law, before '83.
@@vwestlife and was that BASIC from Microsoft? They made BASIC for all sorts of home computers of the time.
@@squirlmy It was directly copied from the IBM BASIC ROM, including the IBM copyright message.
@Adrian's Digital Basement ][ .. At 29:08 floppy power disconnected 🤔.......... but wait.... then at 25:30.. the other floppy controller 😦.... was the power disconnected the all time..??? 😯😯
"Yes none of the chips are hot".. yeap.. look at 26:24 when rotate the board.. 🙆♀️ .. the power connector loose at the side.. 🤭
"Not to mention, the chips are completely off the shell.".... YES and at 27:15 .. the floppy power connector is also off........ off of power connector !!.. 🤦 🤦♀️
this one is for the bloopers reel..... 🤣😂.... we love you Adrián !! 🤗
David Jones Says Murphy will get you every time.
Somehow my reply disappeared......
4:59 That 野口電子工業株式會社, while sound very Japanese, might be a Hong Kong company (with the English title "KENTECH COMPUTER (H.K.) LIMITED", C.R. No. 154889) after all. 會 is the kyūjitai ("old character") compatible with traditional Chinese, while 会 is the shinjitai ("new character") after 1946 and compatible with simplified Chinese.
I think you might be correct about that... I am certain it is not Japanese company at least
The Hong Kong company existed from 1985-07-23 to 2001-11-09. Various electronic components associated with this company, such as pin adaptors and a manual for Zilog Z80-based single board computer "TP801A," can still be found on Taobao and some Chinese electronic fora, all with the kyūjitai / traditional Chinese character 會.
On the other hand, there is a Japanese company 野口工業株式会社 but is specialized in providing sheet metal for automobile industries.
I guess one place to start with the MB is ensuring all signals make it across the damaged area, just in case something broke under the connector.
na it's fine just hit it with a hammer and shes off to the races
@10:15 "Now I am become Varta, the destroyer of PCBs"
why are these so damn relaxing?!
... got 50 mins before I have to go to bed... this pops up.... I click ;p
Speaking of stuffed slots, I just bought a motherboard with busted pins in the PCI slot and now have to change it out without a de-soldering iron - lol -.
Wow the ST-225 got a bunch of bad sector back in 1991 when I try to format it, and the metal clicking sound of the head seeking.
low-level format? By the way these aren't "data transferable". In a new computer, it requires low level formatting, starting from scratch, so to speak.
@@squirlmy Low level format and adjust best interleave is the basic of installing RLL and MFM hard drive.
@Adrian's Digital Basement ][ .. At 29:08 floppy power disconnected 🤔.......... but wait.... then at 25:30.. the other floppy controller 😦.... was the power disconnected the all time..??? 😯😯
"Yes none of the chips are hot".. yeap.. look at 26:24 when rotate the board.. 🙆♀️ .. the power connector loose at the side.. 🤭
"Not to mention, the chips are completely off the shell.".... YES and at 27:15 .. the floppy power connector is also off........ off of power connector !!.. 🤦 🤦♀️
this one is for the bloopers reel..... 🤣😂.... we love you Adrián !! 🤗
I think that extra loud beep happened because of that "error #4" that was popping up. If it booted normally I don't think it would be that loud maybe 🤔
Im the one who uploaded the FC4 stuff on VCFED. Its archived on minuszerodegrees. If you have questions let me know. I have the disks and manual stuff. it should be archived. I just moved the link :) the google link died when google killed all shared links in the past I think.
Wasn't the palm tree the logo for Paradise Systems (absorbed into WD in the mid to late 80s)?
Want to see the other two ewaste XTs!
PMI Fastcard Software is here (scroll down to 'PMI Fastcard IV'): archive.org/download/Wigglesworth_DOS_Floppies_Collection_01
I probably installed thousands of ST225s back in the day
I know I'd love to see any of the Atari IBM compatible PC's. The made PC1,2,3,4,5 and ABC (Atari Business Computer).
This card seems to give the XT more than 1Mb max of RAM, hence the need for some firmware (ROM) tweaks, this is my humble shot at a guess, let me know if I am right. (Don't see an XT since my teens working part time building and repairing PC's)
Likely so. There were a couple of standards that provided such.
That's one sturdy HDD...
Found this Super PC/Turbo XT BIOS at github(dot)(com)/andreas-jonsson/pcxtbios
The BIOS may give a "System Error" code at bootup. This error code is a
combination of the following codes:
01h - Bad system BIOS checksum
02h - Bad RAM in main system memory
04h - Bad RAM in video card
10h - Bad RAM in vector area (this also in main system memory)
20h - Bad expansion ROM checksum
Why are those slots with the copper green crap ruined? It should be able to be cleaned out. Maybe some vinegar and some deoxit.
Those ST225 hard drives are well known for their reliability. Congrats! They are nice. Looking for one myself if I ever get an XT machine set up. the 30MB drives are known for high fail rates. Maybe just reflowing the formerly green solder joints on that IBM type FDD controller would undo any corrosion.
Error #4 - BIOS settings needed!!
---
That Seagate HD is not longed for. I know, I worked for them in the '90's. They had baring problems!!! JUNK!
this was from the 80s. The Seagate drives that came out with the first IBMs were pretty good. The fact that they work today is impressive. I think you worked for them when their hard drives were going downhill. And you seem bitter about it, too!
@@squirlmy- YES! They were a terrible company to work for!!
Populate that EMS card. Unleash the fullest power of that system. Even if not much uses it. If you have it to spare at least.
I’m sure you’ve already found this but error 4 on the Turbo BIOS is video RAM error, which is odd given the card you were using 🤔
The mainboard shouldn't check the video RAM if the DIP switches are set to "no CGA/MDA card installed". This setting is sometimes named "EGA/PGA/VGA", or "none". If you DIP configure the mainboard to 80x25 color, you actually instruct the BIOS to run the builtin 80x25 *CGA* on that card. So "error 4" might very well be fixed by correcting the DIP switches.
DIP switch settings are generally cloned from the original IBM mainboard, so you don't need a mainboard specific manual to find the video card switches.
Given he took a ram chip out of that card earlier, the RAM error makes sense.
Get some rubbing alcohol & deoxidizer in that green port, and on the green card connector that was in it.
I haven't finished the video yet, but do you ever check the dip switches for video/floppies on XTs that you work on?
Switches 5 and 6 On for VGA. (Video Adapter w/onboard BIOS).
00 = MDA (Or Hercules)
01 = CGA (40 Col)
10 = CGA (80 Col)
11 = EGA/VGA (Video Adapter with onboard BIOS)
There is an old TSR you can run to inhibit flicker. Can't remember the exact name of it.
Was that shipped to the US from the UK as I recall seeing one in the Data Processing Room after the OLIVETTI BCS 3030 was got rid off,
At 30:09 and other places, is that a ceiling camera that obscures the upper right part of the monitor?
Dry joint on the floppy power connector?
A weird, random question, but as your name is familiar, I will chance it. Does "Hartsdown" ring any bells for you? If my suspicion is right, it should present quite the learning curve.
Thanks for the great video Adrian. do you have a link to the rgb to hdmi converter you used on the mono card please?
It's a RGB2HDMI -- can't really link to a place to buy them right now as I don't know.
@@adriansdigitalbasement2 .. At 29:08 floppy power disconnected 🤔... then at 25:30.. the other floppy controller?? 😦.... was the power disconnected the all time..??? 😯😯
"Yes none of the chips are hot".. yeap.. look at 26:24 when rotate the board.. 🙆♀️ .. the power connector loose at the side.. 🤭
"Not to mention, the chips are completely off the shell.".... YES and at 27:15 .. the floppy power connector is also off........ off of power connector !!.. 🤦 🤦♀️
this one is for the bloopers reel..... 🤣😂.... we love you Adrián !! 🤗
well, it more a sway than a shake
Someone used it in 1999? Maybe an early retro-gamer .
My first IBM style computer (after a series of 8-bit Ataris) was a 286 clone which looked a LOT like the 5170 in your other videos, even down to the shape of some of the plastic mouldings, and that had an ST-238R RLL 30Mb drive in it, which at the time was bleeding edge technology. It sounded exactly like its older brother the ST-225 and those boot sounds and your recent videos have been triggering a lot of nostalgia! My 286 machine taught me DOS programming in Turbo C and QuickBASIC, and a lot about PC hardware in general. I accidentally destroyed my ST-238 by plugging it in the wrong way round on one of the connectors, which also taught me a lot about the importance of backups.... but by then larger, faster hard drives were available (I beleive IDE had come out) and after a dalliance with a 20Mb Hard Card I upgraded to an incredible for then 170Mb Western Digital drive......
error 04 is a problem with the Programmable interrupt controller
You can clean that card with vinegar and just unsolder that slot and put a new one
As someone who’s allergic to cigarette smoke, I’m not a fan either.
Haha, I'm pretty sure no-one is a fan of it.. but some people are definitely more tolerant of it, especially the rare few who still smoke traditional cigarettes (vs. vapes) and don't notice the horrible residue smell.
I thought I was allergic to cigarette smoke as a kid, my eyes would water and I'd get congested. Eventually I started smoking menthols as a teen, and cured that condition! lol
Hey Adrian - is there any chance you can dump the rom from that board to put online? I actually just got a Modular Circuit Technologies MCT-Turbo board, which appears to be almost identical to the one in this machine - except someone DID harvest the EPROMs from it. Trying to get my 5160 up to 8MHz to be able to run my MCT MOD-EMUP-A programmer at optimal speeds, and to recreate as well as I can my childhood turbo XT clone. Thanks in advance, and thank you for all your videos and inspiration to start my own channel. Currently have probably 20-30 hours of video of various system repairs and upgrades queued up to edit and post.
Can you explain what the procedure to "wash" PCB/motherboard
from what I can find from github.com/andreas-jonsson/pcxtbios about the error 04 is that it might be a bad or incompatible RAM chip on the video card
It's always a Varta.
You need to retest the MB with the know good components.
I miss my XT, I wish I could get a working one with green monochrome monitor.
you certainly can. Working XTs start at about $400 on eBay which is less than Model M or F keyboard. Monitors are heavy and increase shipping costs quite a bit, and at this age are likely to have serious problems. I think valuation is going to go up from here. They are now "vintage collector's items". There's a "mint" condition IBM 5150 (advertised as XT) going for $2200, $99 shipping right now. Its very doable if you have that kind of money to throw at it.
Glad that I'm not bothered by smoke but wonder if smoke smell will still linger after almost 40 years or is it a Pavlovian effect? Biologically potent stimulus (e.g. cigarette smoke/cigarette tar odor) paired with a previously neutral stimulus (e.g. yellow stained IBM model NNNN).
computer expert or neurologist? ;) Is the smoke smell really 40 years old, or has that smell been building up for 39 years, last of it relatively fresh? Idle thoughts. I'm impressed how you bridged those worlds, though.
Once it gets into electronics, it's incredibly difficult to remove it....
Japanese reads: Noguchi Electronics Manufacturing Co.
The motor for the HDD heads may need a bump and some oil
Ooops, too young a drive.
The left side of the Japanese says Noguchi electric.
I see "XT clone", I click 'Like'.
the error might be just the missing RTC
Looks like a Hercules clone of some kind.
Ok the missing top cover is not a problem in this day and age that's what a 3d printer is for
What about unsoldering that PCB Socket and replace it with another PCB socket.
I would at least remove the corroded slot, just to make sure it doesn't short out the system later
Eek! Varta! Enough said.