Around 2000, I repaired the TV for an old lady and saw this computer sitting near the door. When I asked, she sait that it was prepared to be thrown away. Of course, I asked if I can have it and she gave it to me. It came with its original power supply, its monitor (Hercules mono compatible) that was amber. It came with the same game ports that I replaced with a modem card. It had the HDD unit that I repaired the power supply. I used it to host a BBS and occasionally as a terminal with Procomm. I also used a VGA card in that ISA slot and to my surprise it worked (it was a 16bit ISA card mae by Oak). I sold it to a person from Germany that claimed to be from a museum and was in search for that specific model.
One way to salvage chips with damaged pins is to place the chip into a loose socket and solder its pins to those in the socket, giving you undamaged pins to insert into the socket on the board. (can cause issues with height inside casing) Good start to a difficult fix!
Nice video. You may find the service manual googling it. The keyboard controller is a MC6805U2. It is possible to replace with a MC68705R3L. Details are available at the “forum Classic-computing de”, posted by LVR. This IC also controls the reset line, so its kind of important…. The FQP is a highly integrated CGA controller from Paradise (not required to boot). The biggest challenge is the “JIM”, a Toshiba gate array that manages the I/O, also a possible point of failure, it is very near the varta, and it controls the enable/select lines. I think that “post diag cards” are close to useless in the majority of 8088 machines, and in particular this one, because the BIOS is proprietary. Hope it helps and looking forward for part 2 ...
Thanks for watching. I could not find the posting about the MC6870 ? I do have 6805U2 OTP Microcontrollers, but I don't have the module for reading out the old code, I don't even know if the code is readable. But If someone has reverse engineered this that's great. Yes I am aware of the reset problem, and this is not the only chip that is performing "actions" to the reset signal in one way or another. This is not the biggest problem anyway as the Faraday chip set has a serial keyboard input that can be hooked to a std DIN keyboard. My next instalment will be going through the service manual. I just found a good copy.
*TIP* There are long single inline IC sockets strips that are quite cheap, which can be "snapped or clipped to length" that are now sold by most high end Electronics outlets, To install them cut to length and place them onto the IC to be installed, Solder the ground leads or each corner and remove the IC to solder the rest of the pins in, and once done reinsert the IC. APU I dropped a 👉👍👈
How are they when it comes to removal? It seems like single inline strips of this type might be easier to desolder and remove without damage. Are the pin sockets single-wipe, dual-wipe, or machined, or are all types available?
Thanks for watching, and for the TIP. I actually have ordered tree different single line strips from Mouser, Digikey and some Aliexpress shop, but I don’t think they give the same good tight fit around the legs on the IC as the actual DIL sockets do. But they do work, it just sems like the chip is looser than in the DIL sockets with round holes. Round hole socket’s is the way to go for all DE soldered chip’s For other purposes a good dual grip / Swipe sockets keeps the chip’s in the sockets with good contact.
Great vid, thanks. Reminds me of my struggle with my EuroPC. Although downloading schematics first would save you the "wild goose chase", it is clear there that pin 7 on the DIN connector (the "green wire") is ON signal and is connected to the ON/OFF switch on the MB 😉
I don't know why, but at first I could not find the schematics for this version of the Euro PC. only the AT kind, But after i filmed that segment I actually found not one but three different downloads of the exact same PDF. So this time it really was by accident, normally it's because you sometimes can't grab and understand the whole schematics in one go.. But take one bit at a time, and the geese will line up.
So the color monitor looks like the Atari SC1224 too. I was given an EuroPC for repair and it came with a mono monitor that looked like the Atari SM124, but it had an amber screen. The Paradise chipset is Hercules / CGA (IIRC Plantronics). The battery has eaten through the enable / direction inputs on the 74LS245 on the left of the battery and two data lines to the JIM as well as every single line to the RTC chip. And then probably some lines to the serial/parallel IO chips, because the owner told me these weren't working. I didn't test those... my bad. But hey, it booted and let you play games. It didn't like the Y2K fix hack BIOS though. My method of troubleshooting this machine was a bit lazy, I just turned it on and measured signals near the battery, looking for floating signals. Then I checked what they should have connected to and patched a wire in.
Hello there! Thank you so much for devoting time to this. I have the same computer that i'm trying to restore :) Thankx to your video i managed to confirm my suspicious... the power brick needs a load to start... Now i have just finished desoldering the real clock batery, and yes, it leaked :( ... Let's see how it goes. It's a shame that your channel does not have more subscribers, your content is really helpfull. Ohhh and i really like your bunker... You call it a shed, but that door looks like a bunker door... What's up with that? :)
Hi, thanks for watching. I actually have tree locations where I do work on retro stuff. Down in the bunker I have a small workbench and I do spend quite some time there. This is actually an old Cold war area bomb shelter in a downtown commercial building that got decommissioned when the rules changed some years ago. Here I have my main storage. The shed is just that, a small 12 Square meter shed in my garden, here I often bring the pieces I need to work with over time. It’s just a small walk, so I can drop out there for 10 minutes if I got an idea, or find the time. In the wintertime there is periods where it’s to cold to work from there, so then I have my residential basement workbench. This is cozy and indoors, but here I compete for space with the kids, and it’s often noisy and difficult to film. In fact, I am editing av new part in this series now, and that is mostly filmed in the basement.
Thanks for watching, yes I might take you up on that.. Although KOJRO merch is quite a bit in the future I did actually run a company called KOJRO, and in fact still do but on a micro scale. So I do still have some T-shirts and jackets with the KOJRO logo on... The bigger screwdriver indeed..
Varta damage is a real pain to fix. I had to add half a dozen bodges to fix my EuroPC. Someone should design a reproduction mainboard for these computers.
Around 2000, I repaired the TV for an old lady and saw this computer sitting near the door. When I asked, she sait that it was prepared to be thrown away. Of course, I asked if I can have it and she gave it to me.
It came with its original power supply, its monitor (Hercules mono compatible) that was amber. It came with the same game ports that I replaced with a modem card. It had the HDD unit that I repaired the power supply.
I used it to host a BBS and occasionally as a terminal with Procomm. I also used a VGA card in that ISA slot and to my surprise it worked (it was a 16bit ISA card mae by Oak). I sold it to a person from Germany that claimed to be from a museum and was in search for that specific model.
Thanks for sharing. Excellent work!
Thanks for watching !
Oh that was a sad looking machine. Hope to see it fixed in the next episode. Good work!
Thanks for watching !
One way to salvage chips with damaged pins is to place the chip into a loose socket and solder its pins to those in the socket, giving you undamaged pins to insert into the socket on the board. (can cause issues with height inside casing)
Good start to a difficult fix!
Nice video. You may find the service manual googling it.
The keyboard controller is a MC6805U2. It is possible to replace with a MC68705R3L. Details are available at the “forum Classic-computing de”, posted by LVR. This IC also controls the reset line, so its kind of important….
The FQP is a highly integrated CGA controller from Paradise (not required to boot).
The biggest challenge is the “JIM”, a Toshiba gate array that manages the I/O, also a possible point of failure, it is very near the varta, and it controls the enable/select lines.
I think that “post diag cards” are close to useless in the majority of 8088 machines, and in particular this one, because the BIOS is proprietary.
Hope it helps and looking forward for part 2 ...
Thanks for watching. I could not find the posting about the MC6870 ? I do have 6805U2 OTP Microcontrollers, but I don't have the module for reading out the old code, I don't even know if the code is readable. But If someone has reverse engineered this that's great. Yes I am aware of the reset problem, and this is not the only chip that is performing "actions" to the reset signal in one way or another. This is not the biggest problem anyway as the Faraday chip set has a serial keyboard input that can be hooked to a std DIN keyboard. My next instalment will be going through the service manual. I just found a good copy.
*TIP*
There are long single inline IC sockets strips that are quite cheap, which can be "snapped or clipped to length" that are now sold by most high end Electronics outlets,
To install them cut to length and place them onto the IC to be installed, Solder the ground leads or each corner and remove the IC to solder the rest of the pins in, and
once done reinsert the IC.
APU I dropped a 👉👍👈
How are they when it comes to removal? It seems like single inline strips of this type might be easier to desolder and remove without damage.
Are the pin sockets single-wipe, dual-wipe, or machined, or are all types available?
Thanks for watching, and for the TIP. I actually have ordered tree different single line strips from Mouser, Digikey and some Aliexpress shop, but I don’t think they give the same good tight fit around the legs on the IC as the actual DIL sockets do. But they do work, it just sems like the chip is looser than in the DIL sockets with round holes. Round hole socket’s is the way to go for all DE soldered chip’s For other purposes a good dual grip / Swipe sockets keeps the chip’s in the sockets with good contact.
Great vid, thanks. Reminds me of my struggle with my EuroPC. Although downloading schematics first would save you the "wild goose chase", it is clear there that pin 7 on the DIN connector (the "green wire") is ON signal and is connected to the ON/OFF switch on the MB 😉
I don't know why, but at first I could not find the schematics for this version of the Euro PC. only the AT kind, But after i filmed that segment I actually found not one but three different downloads of the exact same PDF. So this time it really was by accident, normally it's because you sometimes can't grab and understand the whole schematics in one go.. But take one bit at a time, and the geese will line up.
Nice job Kojro !!. Amazing repairing. Cannot wait to watch the next instalment 🙂
Thanks for watching !
So the color monitor looks like the Atari SC1224 too. I was given an EuroPC for repair and it came with a mono monitor that looked like the Atari SM124, but it had an amber screen. The Paradise chipset is Hercules / CGA (IIRC Plantronics). The battery has eaten through the enable / direction inputs on the 74LS245 on the left of the battery and two data lines to the JIM as well as every single line to the RTC chip. And then probably some lines to the serial/parallel IO chips, because the owner told me these weren't working. I didn't test those... my bad. But hey, it booted and let you play games. It didn't like the Y2K fix hack BIOS though.
My method of troubleshooting this machine was a bit lazy, I just turned it on and measured signals near the battery, looking for floating signals. Then I checked what they should have connected to and patched a wire in.
Hello there! Thank you so much for devoting time to this. I have the same computer that i'm trying to restore :) Thankx to your video i managed to confirm my suspicious... the power brick needs a load to start... Now i have just finished desoldering the real clock batery, and yes, it leaked :( ... Let's see how it goes. It's a shame that your channel does not have more subscribers, your content is really helpfull. Ohhh and i really like your bunker... You call it a shed, but that door looks like a bunker door... What's up with that? :)
Hi, thanks for watching. I actually have tree locations where I do work on retro stuff. Down in the bunker I have a small workbench and I do spend quite some time there. This is actually an old Cold war area bomb shelter in a downtown commercial building that got decommissioned when the rules changed some years ago. Here I have my main storage. The shed is just that, a small 12 Square meter shed in my garden, here I often bring the pieces I need to work with over time. It’s just a small walk, so I can drop out there for 10 minutes if I got an idea, or find the time. In the wintertime there is periods where it’s to cold to work from there, so then I have my residential basement workbench. This is cozy and indoors, but here I compete for space with the kids, and it’s often noisy and difficult to film. In fact, I am editing av new part in this series now, and that is mostly filmed in the basement.
6:43 That might be the new Kojro merch store T-shirt design "When in doubt, get a bigger screwdriver."
Thanks for watching, yes I might take you up on that.. Although KOJRO merch is quite a bit in the future I did actually run a company called KOJRO, and in fact still do but on a micro scale. So I do still have some T-shirts and jackets with the KOJRO logo on... The bigger screwdriver indeed..
This is what I used in 1988/1989...EuroPC/CM14...my first PC...but I think the MM12 was the better choice.
Varta damage is a real pain to fix. I had to add half a dozen bodges to fix my EuroPC. Someone should design a reproduction mainboard for these computers.
Could you dump the ROMs?
Thanks for watching, yes I will try to dump them. This will be in a week or two, as I am a lot on the road this autumn.
It needs a battery to boot :)