Wow, that board looks like it should be fun to use, with PCI and EISA. Good job catching the bad capacitors before they could do more damage 😀
Also that big regulator looks like it's missing the heatsink. Is that just while fixing it or it's really missing? It looks very similar to the heatsink on my AN430TX Intel board

appiah4 wrote on 2023-11-26, 09:36:

kingcake wrote on 2023-11-25, 20:02:

I bought a UV-C rechargeable toothbrush holder/sanitizer for $19 on black friday, chopped the toothbrush holder part out, and now I have a portable EPROM eraser. It's working great!

image_50425857.jpg

Does it actually work? I have one of these and tried to erase EEPROMs with it, and it did nothing..

Maybe it needs a couple of runs through? If it's a UVC lamp tube it should work.
Looking around I can see that UV sterilizer boxes for phones / small stuff are a thing and they have UVC lamp tubes in too - but no one's buying them so they're super cheap now, £4. I'm getting a UVC lamp type box and a UVC LED that's rechargeable to see how well they perform 😀 I've got a few UV eraseable EPROMs that I've never been able to do anything with.

EEPROMs with two Es are Electrically Erasable... you're not gonna wipe those in a UV box. Single E are Erasable with UV.

Now UVC is the most highly energetic and you get your EPROMs erased in a short time. UVB will still do it but it will take a lot longer, even UVA will eventually do it. It's also a function of distance to the source so you get the most energy per unit area.

It's a bit like toasting marshmallows on a camp fire. If you've got a really roaring large fire that you can feel your hair crinkling if you get within a couple of feet of it, you can get your marshmallow toasted very quickly and you don't even have to get it that close, starts happening a foot away. That's like UVC... Then say a "normal" small fire, you have to get it a lot closer, find the right glowing coal and carefully rotate and expose marshmallow to heat. UVB.. then there's a tealight candle... you can theoretically roast a marshmallow on it, but you have to get it super close and it takes a very long time. UVA

So if you get a UV cleaner and it gives times in minutes for cleaning, it's probably UVC and keeping the window exposed at a close distance to the source will erase the EPROM in minutes also. If it gives times in hours, it's probably UVB and doing single EPROM per source, with it right up to it, will clear it over many hours. ... UVA is probably not worth bothering with vs leaving chips on a window ledge in full sun for a few days.

nhattu1986 wrote on 2023-11-26, 10:34:

today i tried to recap the dual socket 5 motherboard since the cap i order had been arrived de-cap the cap 23-11-26 14-39-49 14 […]
Show full quote

today i tried to recap the dual socket 5 motherboard since the cap i order had been arrived
de-cap the cap
23-11-26 14-39-49 1499.jpg
the old electrolyte cap is leaking and eating the pad...

23-11-26 14-40-15 1500.jpg

at least, i can somewhat clean it up
23-11-26 14-47-28 1501.jpg

done with the replacement.
23-11-26 15-36-50 1503.jpg

a quick fix for the cap with ripped pad due to damaged in transit.
23-11-26 16-56-52 1504.jpg

since i don't have cpu, a quick power up show no firework so i can consider it should be good enough for now.

That voltage regulator (or whatever it is) that is close to the memory slots looks like it has some thermal paste on it; somebody likely has removed the heatsink for it.

Been working a tad more in my grandfather's old laptop where I am having a pretty weird error, which is something I play around with.

While doing various installations and checkups, I've also worked a bit on a small project of mine: making diskette labels for my platforms, I am not sure which design I like best. Any preferences from you guys?

Apart from this I am simply going through my "mystery diskettes" one by one to see what is on it - and which platform it belongs to! Starting with PC and then I will move over to other.
I also found a few Apple Formatted diskettes which I can see have been used for PC so those will be reformatted in my Macintosh SE30 later - and get one of those nice diskette labels ones I chose a standard.

appiah4 wrote on 2023-11-26, 09:36:

kingcake wrote on 2023-11-25, 20:02:

I bought a UV-C rechargeable toothbrush holder/sanitizer for $19 on black friday, chopped the toothbrush holder part out, and now I have a portable EPROM eraser. It's working great!

image_50425857.jpg

Does it actually work? I have one of these and tried to erase EEPROMs with it, and it did nothing..

Like I said, it's working great. This has a real UV-C tube in it. I put two 90s era 27c256s in it that were programmed and after 20 minutes they showed blank in my reader. Lots of these UV disinfection devices have "UV LEDs" which will not work. Wrong wavelength and not enough output power.

Thermalwrong wrote on 2023-11-26, 14:38:

Wow, that board looks like it should be fun to use, with PCI and EISA. Good job catching the bad capacitors before they could do […]
Show full quote

Wow, that board looks like it should be fun to use, with PCI and EISA. Good job catching the bad capacitors before they could do more damage 😀
Also that big regulator looks like it's missing the heatsink. Is that just while fixing it or it's really missing? It looks very similar to the heatsink on my AN430TX Intel board

appiah4 wrote on 2023-11-26, 09:36:

kingcake wrote on 2023-11-25, 20:02:

I bought a UV-C rechargeable toothbrush holder/sanitizer for $19 on black friday, chopped the toothbrush holder part out, and now I have a portable EPROM eraser. It's working great!

image_50425857.jpg

Does it actually work? I have one of these and tried to erase EEPROMs with it, and it did nothing..

Maybe it needs a couple of runs through? If it's a UVC lamp tube it should work.
Looking around I can see that UV sterilizer boxes for phones / small stuff are a thing and they have UVC lamp tubes in too - but no one's buying them so they're super cheap now, £4. I'm getting a UVC lamp type box and a UVC LED that's rechargeable to see how well they perform 😀 I've got a few UV eraseable EPROMs that I've never been able to do anything with.

Don't waste your time with LED based devices. Real UV LEDs are mega expensive. The LEDs in those cheap devices are more purple than UV.

kingcake wrote on 2023-11-26, 20:20:

Don't waste your time with LED based devices. Real UV LEDs are mega expensive. The LEDs in those cheap devices are more purple than UV.

I have a LED based UV sterilizer. I've used it to erase EEPROMs and can confirm it works.

BitWrangler wrote on 2023-11-26, 15:38:

EEPROMs with two Es are Electrically Erasable... you're not gonna wipe those in a UV box. Single E are Erasable with UV. […]
Show full quote

EEPROMs with two Es are Electrically Erasable... you're not gonna wipe those in a UV box. Single E are Erasable with UV.

Now UVC is the most highly energetic and you get your EPROMs erased in a short time. UVB will still do it but it will take a lot longer, even UVA will eventually do it. It's also a function of distance to the source so you get the most energy per unit area.

It's a bit like toasting marshmallows on a camp fire. If you've got a really roaring large fire that you can feel your hair crinkling if you get within a couple of feet of it, you can get your marshmallow toasted very quickly and you don't even have to get it that close, starts happening a foot away. That's like UVC... Then say a "normal" small fire, you have to get it a lot closer, find the right glowing coal and carefully rotate and expose marshmallow to heat. UVB.. then there's a tealight candle... you can theoretically roast a marshmallow on it, but you have to get it super close and it takes a very long time. UVA

So if you get a UV cleaner and it gives times in minutes for cleaning, it's probably UVC and keeping the window exposed at a close distance to the source will erase the EPROM in minutes also. If it gives times in hours, it's probably UVB and doing single EPROM per source, with it right up to it, will clear it over many hours. ... UVA is probably not worth bothering with vs leaving chips on a window ledge in full sun for a few days.

Can confirm. I have a medical certified UVA tube device for spot treating Psoriasis. I tried to erase an EPROM with it (EPROM Window directly against tube) and after an hour it had no effect.

Shponglefan wrote on 2023-11-26, 20:23:

kingcake wrote on 2023-11-26, 20:20:

Don't waste your time with LED based devices. Real UV LEDs are mega expensive. The LEDs in those cheap devices are more purple than UV.

I have a LED based UV sterilizer. I've used it to erase EEPROMs and can confirm it works.

Maybe after two week of exposure. I'll leave it as an exercise for you to calculate the output of that little led.

kingcake wrote on 2023-11-26, 20:27:

Maybe after two week of exposure.

It takes 15 minutes. I've timed it.

kingcake wrote on 2023-11-26, 20:27:

Shponglefan wrote on 2023-11-26, 20:23:

kingcake wrote on 2023-11-26, 20:20:

Don't waste your time with LED based devices. Real UV LEDs are mega expensive. The LEDs in those cheap devices are more purple than UV.

I have a LED based UV sterilizer. I've used it to erase EEPROMs and can confirm it works.

Maybe after two week of exposure. I'll leave it as an exercise for you to calculate the output of that little led.

I was checking some youtube videos on this and apparently even a 0.1w 250nm LED works when left for a bit and it's actually a that frequency: https://www.youtube.com/watch?v=m0y9IO95PRU&t=335s

This guy has done some good research on it too: https://mattpilz.com/uv-phone-sanitizers-erase-eproms/
The 1st comment on that video confirms that the device I bought for £5 - the Homedics UV sanitiser's LED does actually work for clearing EPROMs when it's not got a controller limiting the on time 😀

A week or so ago I won an auction for a Compaq Contura Aero 4/33C which I didn't realise at the time was pretty broken. Specifically while the motherboard seems to be just fine, it's missing the RAM cover and the are no functional friction hinges on this thing - the screen is still attached but it just flops up and down. It's not even like some part is broken, that must've been removed long ago since there's just a nub where the right hinge should be inside it.
To solve that I was initially okay with putting a heavy object behind it to hold up the screen but today decided to make a real solution, so I made an external hinge that screws onto where the right hinge screws to the case, that gives it a strong metal area of the chassis to attach to:

It folds out of the way for storage:

Perfect!

And because I hate CR1220 batteries and this laptop had no battery - the CMOS battery is relocated with a much more available CR2032 cell 😀

Thermalwrong wrote on 2023-11-26, 20:57:

The 1st comment on that video confirms that the device I bought for £5 - the Homedics UV sanitiser's LED does actually work for clearing EPROMs when it's not got a controller limiting the on time 😀

The sterilizer I bought is intended for sterilizing pacifiers. It was about $20 USD.

It has a 1 minute timer built in. This is how I know it takes 15 minutes to erase an EEPROM because I had to restart the timer 15 times. 😁

Sorting heatsinks.

I have another box like the one on the right down in the basement. A lot of intel 775s.

Thermalwrong wrote on 2023-11-26, 14:38:

Wow, that board looks like it should be fun to use, with PCI and EISA. Good job catching the bad capacitors before they could do more damage 😀
Also that big regulator looks like it's missing the heatsink. Is that just while fixing it or it's really missing? It looks very similar to the heatsink on my AN430TX Intel board

Oh, i removed that heatsink to access the small capacitor underneath the regulator, after done with the recap and cleanup the board, i put it back together 😁

Shponglefan wrote on 2023-11-26, 21:03:

Thermalwrong wrote on 2023-11-26, 20:57:

The 1st comment on that video confirms that the device I bought for £5 - the Homedics UV sanitiser's LED does actually work for clearing EPROMs when it's not got a controller limiting the on time 😀

The sterilizer I bought is intended for sterilizing pacifiers. It was about $20 USD.

It has a 1 minute timer built in. This is how I know it takes 15 minutes to erase an EEPROM because I had to restart the timer 15 times. 😁

Sorry, I just don't believe a fake UV LED from China that just makes purple light and draws 0.1A will erase any EPROM in 15 minutes. It defies physics.

Well the 0.1W example I linked to the youtube video for said he left it around half an hour and who knows if it was that long or if he was overdriving the LED.
The UVC LEDs in products like sterilisers, who knows what the wattage would be of those. Looking forward to getting this homedics thing now - found a post on how to double its power output: https://old.reddit.com/r/FluorescentMinerals/ … pest_uvc_light/

kingcake wrote on 2023-11-27, 00:55:

Sorry, I just don't believe a fake UV LED from China that just makes purple light and draws 0.1A will erase any EPROM in 15 minutes. It defies physics.

Dunno what to tell you, but it erased an EEPROM in 15 minutes. ¯\_(ツ)_/¯

Testing another Pentium Pro motherboard, a DataExpert EXP8P61.

This one has a soldered clock chip, a M48T86PCI.

From what I have found online, I think this should be Dallas DS1287 pin-compatible? I'll guess I'll find out once I remove it and install a replacement.

Does...

Does mixing Oddworld's main themes (from Abe's Oddysee and Exoddus) with H.P.Lovecraft ambiental horror count?

Basically spent all of sunday repairing and prepping the returned old 486 for it's second run on e-bay again. Quite a pain in the Ass. Wound up going with a 210MB HDD because that seemed to be the most reliable option. Had to fix the CD-ROM Drive (it was fixable, tray was jammed by a CD that was in it and off it's track - works great now), and fixed the seven segment display to now show 100/33 when changed.

Now have been setting up a Windows 3.11 for Workgroups setup in DOS GPL 7.01, going to try this out. If I don't like it, I might buy another 8.4GB Seagate Drive and duplicate the setup I had before. I used the 8.4GB in the Compaq Deskpro 386s/20 machine. Got sick of deleting stuff just to run something else on there.