While testing things at an electronic manufacturer, a co-worker showed me something new, the LEEPROM (Light Emitting EPROM). He plugged an EPROM in the socket backwards, and when power was applied a tiny light appeared in its window, then went out. Needless to say, *that* EPROM no longer worked! The sad part is that he did it once, then did it again to show me! He didn't realize he had it in backwards. This was back when EPROMs were not cheap, and these were special ones, higher capacity in a 24-pin DIP.
I remember tripping over a network cable once which pulled out a PCI NIC from its slot (not screwed in) - I just pushed it back in and Windows 98SE (I think) just re-detected it and carried on working :)
I can see where this can come from. Pretty much every card (PCI, PCIE) I have is inserted with the component side down. Without the bracket, this would sure happen to me too without thinking. Thanks!
Edman yeah with isa cards it’s usually the opposite where the components are on top. I also had the case backwards (backside oriented towards me). Made it extra confusing. Especially at 1am :)
I remember the first time I bought a PCI card. I was sooo confused and thought somehow the i/o bracket was somehow placed on the wrong end because i was so used to putting cards that had the components facing up. It felt so strange to insert a card that appeared upside down.
Kinda surprised it didn't take out the '688. Guess those comparators are more robust than the EEPROM chip. For anybody still confused, having +5v going into a data/address pin won't harm anything on a 5v chip. But A6 and A8, which were crossed with the +12 and -12 can have disastrous effects on a 5v chip, especially one that only needs 5v to program. Learned that one the hard way under different circumstances.
Can one of these cards be used in a 486 PC to get around the BIOS size limit? I tried using the XT-IDE BIOS on a network card and it would bring up the menu, but the system still didn't see the correct drive size. I also want to use the existing IDE port on the system if possible, because it is probably faster than the one on the ISA card.
I put in a POST diagnostics card the wrong way the other day. The reset, clk, power, etc.. LEDs lit up some but no POST. Luckily it still managed to function.
I didn’t see it, but sometimes it can ne subtle. But there is no visual damage on the chip itself, and the computer didn’t shut down. Think some of the internal data lines on the flash rom just got so damaged that it didn’t do anything anymore.
If the voltage were any higher than +12/-12 (crossed to A6 and A8), there probably would be. The 47LS688 comparator also takes input from A6 and A8, so I'm kinda surprised that it took that without frying.
Very nice work. I probably would have missed disabling shadow RAM (I tend to flash mine directly in my XT systems when possible as I configure the XUB for the installed CPU).
Thanks for pointing that out. Wouldn't you want to change the settings back on the machine you used to perform the flashing? I could see where you might not, since it's your machine and you know about it. I just meant for other people, in general, they'd want to restore the settings back to "normal". 😉
Not really. Diodes are good for reverse current protection, but won't help in this case, because the problem isn't reverse current, but over voltage on the A6 and A8 lines from the +12/-12 pins. Resistors could prevent overcurrent, but would also have the effect of dropping it too low for signal integrity. Really, the solution is to either add a bracket, or just pay attention.
@@RetroSpector78 Very true! I think in my case it fried something else as well but either way, can't be that bad. I didn't know you could flash from the card directly either, that makes a huge difference - I'll dig it back out and give it another shot. Thanks!
Yeah ... really convenient. You will be able to download the flash utility and images from lotech (its on their wiki). The other chips on the board can withstand quite a bit. It’s just the flash rom that is a bit sensitive and took most of the hit when inserting it backwards. Hope you get it up and running again.
that's why pc manufacturing companies have created standarts that plugs only go in one way and that pc parts can be used with various machines and so on
Very useful 👍 video. I think I just fucked up mine XT ide running some int13 and int3 commands using debug.exe. after that I am getting "external bios d8000 chechsum error." Do you think I should flash the eeprom ?
Many years ago a friend had a 8088 Clone and it stopped seeing the Hard Drive and he attempted to fix it. The Controller card had no bracket and sure enough he put it in backwards and fried it. Even though the card was old as dirt even for that time it cost him $200 bucks for a replacement from a Computer repair shop.
And if you insert cache chips on backwards for a second, they get hot. Did that once before years ago and the computer still runs. Another thing is, the PCI cards can also be inserted in backwards as well if you're not careful or absent mindedly insert a PCI card in an ISA slot and cause sparks to fly. Did that once myself, including overvoltage on a CPU socket, but I didn't know what would happen at that time. Had a power supply blow out magic smoke 7 years ago (cheap AT PSU fan shot itself in the foot).
@Mr Guru The Tl866 is pretty nice for newer EEPROMS, and GALs, and is also handy in diagnosing 74xx series logic chips, but I don't think it supports the 8051.
@@RetroSpector78 Do you have any Memory expansion cards for XT Systems? I'm interested in freeing up conventional RAM and resolving conflicts with my Tandy, to increase its abilities. I do alot of networking.
Be sure to subscribe for updates. Once I hit 1k subs I can also post text msgs and should pop up in your feed. But difficult for new channels to get momentum.
I just got Lo-Tech's 1MB RAM board for my XT, but I had to shuffle cards around to make it fit. I was very careful to point the label Tex-Elec put on the ROM saying "PC Rear ->" toward the PC rear, though thinking that I didn't remember the components being on the other side of the board. Yeah, I had the PC 180° from how I was thinking it was. So now I'm here watching this video. I guess Mouser is going to get some more money from me soon. xD
That Xt-Ide card looks alot more easy to build that the one from glitchwrks, does some one knows what the differences are between these two ? Btw Excellent video as usual !
@@marzi_kat I get the cost savings, though it sounds like they do need it based on this video and the comments below about other people frying them by putting in backwards. I know I would pay an extra 5 bucks or whatever for one that comes with a bracket to prevent that and also keep it securely in the slot. That said, the card is nothing short of a miracle - amazing that such a great product has been made for the retro computing world!
Zankuhaaa! No there wasn’t. Added the caption on the thumbnail for dramatic effect. Already had my share of exploding caps and power supplies. This one went down silently :)
this card is intended for old computers (primarily XT or early 286 systems) that only have 8 bit isa slots. A 400 Mhz server will probably have 16 bit ISA / PCI where you can get standard IDE cards for.
@@RetroSpector78 will these drive an AT/16 IDE on an XT ? Originally XT IDE was a different standard and the drives were not interchangeable . it was a nightmare when people would fry a 40mb 16bit IDE drive by connecting it to an XT IDE board.
@@ruben_balea not entirely sure what you mean by XTA.. IDE/XT ? . Ive worked in the industry since the days of MFM and RLL then on to ESDI . ( scsi ran concurrantly to all of these but at a much higher price point) To the best of my memory , from the changeover period around 1988, XT IDE drives were forwards compatable with IDE/AT . you could even go the other way and put IDE/AT drives on an XT IDE controller if you had the required software tools which were NOT distributed. ..if you did manage to get the proper tool , it allowed re-low-level-formatting back to XT IDE standard. It didnt seem to be a hardware level issue at all other than drive bios and interleve settings... With the tool it would compensate for that. Maybe they were using an FPGA ? But it specifically applied to WD and Miniscribe IDE devices. . . If you didnt have the tool, you trashed the drive and had to send it back for repair. And it was considered a non warranty issue. . xt ide controllers itself would even work in 16 bit pcs but wouldnt handle either drive properly. We had quite a while where drives would be labeled incorrectly, especially miniscribe IDE/AT drives were coming labeled as XT and vice versa . it was a huge deal bc we were selling DIY kits and people were thrashing the drive and miniscribe didnt want to honor warranty. We had enough buying clout at the time that they eventually gave in .. And then sent them back labeled "refurb." Which was another issue. But our corporate stood behind them assuring everyone we would honor the full 3y warranty ... and i only saw 1 come back as a premature failure. As soon as Connor was able to ramp up production we made the switch .
@@ruben_balea if you compare pinouts and read thru the forums, not even mentioning working in the industry thru that era, the XTA drives can be made to work on ATA cards after some hobbyist level rework like flipping the pinout on the ribbon and flashing the bios table of the controller. Which seems to be in line with that i said about needing thw drive manufacturer's internal-use toolkit. The reverse is not true , though, without re-engineering an ata card. You cant put an ATA native drive on an XTA controller which is something i also said. Basically if you had an xt with an xta drive and bought a 386 you could frankenstein a cable and flash the controller table and not have to reinstall everything. Remember this is the era of win386 1.0 and Geos ..both of which were dos shells. So no reload required.
Every one? Unless I'm missing something, the only lines crossed with the +12 and -12 are the A6 & A8 lines. Those only connect to the EEPROM (which are very sensitive to overvoltage), and the '688 comparator.
I can give you an answer to "what happens if.. you plug your AGP video card in backwards" - It lets out the magic smoke and never works again. You may scream at your screen while vigorously foaming at the mouth "That's impossible!" I present to you late 90s motherboard with backwards AGP: i.imgur.com/B4iH8Lv.jpg
While testing things at an electronic manufacturer, a co-worker showed me something new, the LEEPROM (Light Emitting EPROM). He plugged an EPROM in the socket backwards, and when power was applied a tiny light appeared in its window, then went out. Needless to say, *that* EPROM no longer worked! The sad part is that he did it once, then did it again to show me! He didn't realize he had it in backwards. This was back when EPROMs were not cheap, and these were special ones, higher capacity in a 24-pin DIP.
I remember tripping over a network cable once which pulled out a PCI NIC from its slot (not screwed in) - I just pushed it back in and Windows 98SE (I think) just re-detected it and carried on working :)
Pull out, plug in and play :)
Did it redetect it ? Or just not notice ?
I can see where this can come from. Pretty much every card (PCI, PCIE) I have is inserted with the component side down. Without the bracket, this would sure happen to me too without thinking. Thanks!
Edman yeah with isa cards it’s usually the opposite where the components are on top. I also had the case backwards (backside oriented towards me). Made it extra confusing. Especially at 1am :)
I remember the first time I bought a PCI card. I was sooo confused and thought somehow the i/o bracket was somehow placed on the wrong end because i was so used to putting cards that had the components facing up. It felt so strange to insert a card that appeared upside down.
Damn you're underrated. I'd like to see you doing tutorials on solving problems with modern systems too.
Kinda surprised it didn't take out the '688. Guess those comparators are more robust than the EEPROM chip.
For anybody still confused, having +5v going into a data/address pin won't harm anything on a 5v chip. But A6 and A8, which were crossed with the +12 and -12 can have disastrous effects on a 5v chip, especially one that only needs 5v to program. Learned that one the hard way under different circumstances.
Always wondered why you say "Lord and behold" ... it's actually "Lo and behold"
Can one of these cards be used in a 486 PC to get around the BIOS size limit? I tried using the XT-IDE BIOS on a network card and it would bring up the menu, but the system still didn't see the correct drive size. I also want to use the existing IDE port on the system if possible, because it is probably faster than the one on the ISA card.
I put in a POST diagnostics card the wrong way the other day. The reset, clk, power, etc.. LEDs lit up some but no POST. Luckily it still managed to function.
where to get the xtide flash utility and such?
I wonder if there was actually any 'magic smoke' when the power was first applied? I always hated 'magic smoke'.
I didn’t see it, but sometimes it can ne subtle. But there is no visual damage on the chip itself, and the computer didn’t shut down. Think some of the internal data lines on the flash rom just got so damaged that it didn’t do anything anymore.
It's always bad to let the smoke out.
If the voltage were any higher than +12/-12 (crossed to A6 and A8), there probably would be. The 47LS688 comparator also takes input from A6 and A8, so I'm kinda surprised that it took that without frying.
Very nice work. I probably would have missed disabling shadow RAM (I tend to flash mine directly in my XT systems when possible as I configure the XUB for the installed CPU).
First time i tried flashing it it was on this machine. Spent about an hour and a half figuring out why it would not flash :)
Thanks for pointing that out.
Wouldn't you want to change the settings back on the machine you used to perform the flashing? I could see where you might not, since it's your machine and you know about it. I just meant for other people, in general, they'd want to restore the settings back to "normal". 😉
Hmm. I wonder if there's a way to either put a fuse or even a diode to prevent damage
Not really. Diodes are good for reverse current protection, but won't help in this case, because the problem isn't reverse current, but over voltage on the A6 and A8 lines from the +12/-12 pins. Resistors could prevent overcurrent, but would also have the effect of dropping it too low for signal integrity. Really, the solution is to either add a bracket, or just pay attention.
I fried an XT CF a few weeks ago this same way. RIP
At least it is an easy fix. These card are usually pretty expensive over here (50 EUR range). So a 1.3 EUR fix is always welcome ;)
@@RetroSpector78 Very true! I think in my case it fried something else as well but either way, can't be that bad. I didn't know you could flash from the card directly either, that makes a huge difference - I'll dig it back out and give it another shot.
Thanks!
Yeah ... really convenient. You will be able to download the flash utility and images from lotech (its on their wiki). The other chips on the board can withstand quite a bit. It’s just the flash rom that is a bit sensitive and took most of the hit when inserting it backwards. Hope you get it up and running again.
Press F to pay respects
that's why pc manufacturing companies have created standarts that plugs only go in one way and that pc parts can be used with various machines and so on
I know, but without a bracket an isa card can still be put in the wrong way. The isa slot / spec does not prevent that.
Very informative indeed. Thanks!
So can you hook up a normal IDE hard drive and not use a flash card? or SSD I guess if there cheaper.
Yes, and also much larger drives than the original BIOS supported.
Very useful 👍 video. I think I just fucked up mine XT ide running some int13 and int3 commands using debug.exe. after that I am getting "external bios d8000 chechsum error." Do you think I should flash the eeprom ?
Thx. Definitively worth a try to reflash it !
Just found this video today. Very informative!! Thanks for covering this.
Many years ago a friend had a 8088 Clone and it stopped seeing the Hard Drive and he attempted to fix it. The Controller card had no bracket and sure enough he put it in backwards and fried it. Even though the card was old as dirt even for that time it cost him $200 bucks for a replacement from a Computer repair shop.
Ouch .... lot of money back in the day .... yeah mistakes are easily made. Thankfully 99% of the cards have brackets.
And if you insert cache chips on backwards for a second, they get hot. Did that once before years ago and the computer still runs. Another thing is, the PCI cards can also be inserted in backwards as well if you're not careful or absent mindedly insert a PCI card in an ISA slot and cause sparks to fly. Did that once myself, including overvoltage on a CPU socket, but I didn't know what would happen at that time. Had a power supply blow out magic smoke 7 years ago (cheap AT PSU fan shot itself in the foot).
Is it possible to utilize this board to programming any bin such as a 8051 program?
@Mr Guru The Tl866 is pretty nice for newer EEPROMS, and GALs, and is also handy in diagnosing 74xx series logic chips, but I don't think it supports the 8051.
Can you assist me on the use of EMS Ram on the Tandy 1000 TL?
Don’t have an EMS card unfortunately to try :( but would gladly accept donations and post a video on it :)
@@RetroSpector78 Do you have any Memory expansion cards for XT Systems? I'm interested in freeing up conventional RAM and resolving conflicts with my Tandy, to increase its abilities. I do alot of networking.
Got some xt expansion cards. Need to see if they fit inside the Tandy case. Will give it a try somewhere next week.
Be sure to subscribe for updates. Once I hit 1k subs I can also post text msgs and should pop up in your feed. But difficult for new channels to get momentum.
@@RetroSpector78 Will do.
why didn't they add a bracket than to stop someone from putting in back words like all other cards do now....
Ah funky, I remember soundblasters not showing all pins on a side of the board. Now I know why.
I just got Lo-Tech's 1MB RAM board for my XT, but I had to shuffle cards around to make it fit. I was very careful to point the label Tex-Elec put on the ROM saying "PC Rear ->" toward the PC rear, though thinking that I didn't remember the components being on the other side of the board. Yeah, I had the PC 180° from how I was thinking it was. So now I'm here watching this video. I guess Mouser is going to get some more money from me soon. xD
That Xt-Ide card looks alot more easy to build that the one from glitchwrks, does some one knows what the differences are between these two ? Btw Excellent video as usual !
Julian Pacheco this one is specifically made for easy soldering (all through hole). Lo tech has a wiki that shows all of their offerings and specs.
i have the same issue and burned every single ic on the board, to fix it replace them all
Very helpful. I also fried one of my chips by putting my XTIDE card in the wrong way once.
Could you do a video of "What happens if: you put the motherboard chips randomly?"
So, I have to ask. Why don't these cards actually have brackets?
Doesn't need one so it's cheaper that way.
@@marzi_kat I get the cost savings, though it sounds like they do need it based on this video and the comments below about other people frying them by putting in backwards. I know I would pay an extra 5 bucks or whatever for one that comes with a bracket to prevent that and also keep it securely in the slot. That said, the card is nothing short of a miracle - amazing that such a great product has been made for the retro computing world!
Going to do what happens if you remove your cpu while its working ?
I did that once, sparks and arcs and burnt off a couple of pins from the massive amount of current draw.
Where do I can find this card?
Similar results if you put the EEPROM chip in the XTIDE backwards, ask me how I know that lol.
Haha. Yeah .... luckily you can get new ones cheap and flash them easily.
Apparently those 5v EEPROMs are a tad sensitive to overvoltage.
When in doubt look at the other ISA cards in the system.
Was there any smoke?
Zankuhaaa! No there wasn’t. Added the caption on the thumbnail for dramatic effect. Already had my share of exploding caps and power supplies. This one went down silently :)
Just did that with a pair of eeproms in my 5170. Not backwards in a slot, but backwards in the sockets. 🤦♂️
Oops! 😅 Hope I never need to follow this tutorial! 😁
yeah ... realised very quickly what I had done wrong. In the end just lost 1 flash rom chip , but gained some insights + a video here :)
i have an old server with 2 400 mhz cpus but only scsi could i use this card to get ide on it?
this card is intended for old computers (primarily XT or early 286 systems) that only have 8 bit isa slots. A 400 Mhz server will probably have 16 bit ISA / PCI where you can get standard IDE cards for.
@@RetroSpector78 thanks you :)
@@RetroSpector78 will these drive an AT/16 IDE on an XT ? Originally XT IDE was a different standard and the drives were not interchangeable . it was a nightmare when people would fry a 40mb 16bit IDE drive by connecting it to an XT IDE board.
@@ruben_balea not entirely sure what you mean by XTA.. IDE/XT ? . Ive worked in the industry since the days of MFM and RLL then on to ESDI . ( scsi ran concurrantly to all of these but at a much higher price point)
To the best of my memory , from the changeover period around 1988, XT IDE drives were forwards compatable with IDE/AT . you could even go the other way and put IDE/AT drives on an XT IDE controller if you had the required software tools which were NOT distributed. ..if you did manage to get the proper tool , it allowed re-low-level-formatting back to XT IDE standard. It didnt seem to be a hardware level issue at all other than drive bios and interleve settings... With the tool it would compensate for that. Maybe they were using an FPGA ? But it specifically applied to WD and Miniscribe IDE devices. . . If you didnt have the tool, you trashed the drive and had to send it back for repair. And it was considered a non warranty issue.
. xt ide controllers itself would even work in 16 bit pcs but wouldnt handle either drive properly.
We had quite a while where drives would be labeled incorrectly, especially miniscribe IDE/AT drives were coming labeled as XT and vice versa . it was a huge deal bc we were selling DIY kits and people were thrashing the drive and miniscribe didnt want to honor warranty. We had enough buying clout at the time that they eventually gave in .. And then sent them back labeled "refurb." Which was another issue. But our corporate stood behind them assuring everyone we would honor the full 3y warranty ... and i only saw 1 come back as a premature failure.
As soon as Connor was able to ramp up production we made the switch .
@@ruben_balea if you compare pinouts and read thru the forums, not even mentioning working in the industry thru that era, the XTA drives can be made to work on ATA cards after some hobbyist level rework like flipping the pinout on the ribbon and flashing the bios table of the controller. Which seems to be in line with that i said about needing thw drive manufacturer's internal-use toolkit.
The reverse is not true , though, without re-engineering an ata card. You cant put an ATA native drive on an XTA controller which is something i also said.
Basically if you had an xt with an xta drive and bought a 386 you could frankenstein a cable and flash the controller table and not have to reinstall everything. Remember this is the era of win386 1.0 and Geos ..both of which were dos shells. So no reload required.
I did this as well. Fried the ROM chip.
yeah ... luckily an easy fix.
have gone that route and burned every single ic in the card have to replace them
Every one? Unless I'm missing something, the only lines crossed with the +12 and -12 are the A6 & A8 lines. Those only connect to the EEPROM (which are very sensitive to overvoltage), and the '688 comparator.
More What If!!
I can give you an answer to "what happens if.. you plug your AGP video card in backwards" - It lets out the magic smoke and never works again.
You may scream at your screen while vigorously foaming at the mouth "That's impossible!"
I present to you late 90s motherboard with backwards AGP: i.imgur.com/B4iH8Lv.jpg
I can smell the magic smoke from here. Lol....
w-what if w-w-we.. put our xtide card in backwards😳😳😳😳😳😳🙈🙈🙈
Try putting it in a pci slot.
This are little designers design
*e x p l o s i o n*