Alrighty!
I'll start with the vinegar/alcohol method. It seems minimal, but i'll send some pictures just to be safe.

I've had signs of blue corrosion come back even on boards I've washed with vinegar. It is really difficult to get every last little bit off, especially inside the small vias. Part of my issue may have been do to soaking time. How long are we supposed to soak the boards in vinegar? I tend to scrub them with a toothbrush then poor more vinegar on it and only let it sit for 5 minutes. Is that not enough?

I've also had boards which did not contain barrel batteries still have blue corrosion on them. In those cases, it is usually on contacts of removable IC's. I suspect it is finger oil reacting over long periods of time. And in those cases, the blue corrosion still seems to follow the copper traces and spread out just like with the leaky battery scenarios.

These boards are getting so old now that I wonder if there should be a regular maintenance cycle to clean off the corrosion every x years for boards which have shown any sign of the corrosion in the past.

Skyscraper wrote:

Finally here is the MR BIOS for the "OPTI 386WB" a.k.a Shuttle HOT-307. […]
Show full quote

Finally here is the MR BIOS for the "OPTI 386WB" a.k.a Shuttle HOT-307.

Speedsys refuses to dump a BIOS without a working HDD in the system for some reason although it dumps the BIOS to its own the directory on the floppy... that's the reason for the delay.

I also made a new BIOS dump of the OPTI 391 i486 MR BIOS just in case something was wrong with the old one and replaced the file in the message two pages back. I will also post it here.

Both files are dumped with Speedsys using a clean DOS 8 boot disk. If for some reason Speedsys makes non functional dumps I will try to find a better utility.

OPTI 391 i386 MR BIOS. From a working generic OPTI 391 "OPTI 386WB" motherboard.

OPTI 391 MR BIOS i386 .rar

OPTI 391 i486 MR BIOS. From a non working generic OPTI 391 "ST0486WB" motherboard. The BIOS (chip) works perfectly fine with the Shuttle HOT-403 OPTI 391 i486 motherboard I used for dumping the file.

OPTI 391 MR BIOS i486.rar

As both motherboards seem to be reference design boards and they both have WB in the name I guess either WB dosn't stand for "Write Back" or more likely reference design OPTI 391 motherboards use a write back L2 caching scheme.

Don't try these BIOS files unless you have a way to recover your old BIOS in case it dosn't work!!!

Hey, how are you RARing these up? When trying to un-rar them with one utility on my system I'm getting a "Attempted to Read More Data than Was Available Error"; another decompressor (CLI version of 7Zip) extracts it successfully, but after flashing I'm getting a LH-LLL beep tone on power on, which indicates a ROM BIOS checksum error.

Can you perhaps try compressing them with the standard Windows context menu compression method, or 7-Zip? Alternatively, can you post the MD5 for the 386 ROM? The MD5 for my extracted version is: 1808a1fa726ccad34ad485908043b3df

Edit: Yeah, looks like your BINs are 1 byte too short. A 27C512 should be exactly 65,536 bytes long, yours are 65.535. Hmmm.

timb.us wrote:

Hey, how are you RARing these up? When trying to un-rar them with one utility on my system I'm getting a "Attempted to Read More Data than Was Available Error"; another decompressor (CLI version of 7Zip) extracts it successfully, but after flashing I'm getting a LH-LLL beep tone on power on, which indicates a ROM BIOS checksum error.

Can you perhaps try compressing them with the standard Windows context menu compression method, or 7-Zip? Alternatively, can you post the MD5 for the 386 ROM? The MD5 for my extracted version is: 1808a1fa726ccad34ad485908043b3df

Edit: Yeah, looks like your BINs are 1 byte too short. A 27C512 should be exactly 65,536 bytes long, yours are 65.535. Hmmm.

I'm using Winrar 3.91 x64. Dictionary size is set to 4096KB but seems to be 128KB for these files, delta compression is on. I never have any issues when unpacking my RAR files even when using other utilitys like 7-Zip. Oldest version of Winrar that can extract these rar files is Winrar 2.9.

The CRC32 for the i386 file is 10CBCA5 and for the i486 file B7961FC5

When it comes to the missing byte I have no idea, both BIOS files are the same size so this is apparently how they come out when dumped with Speedsys 4.70.

If Speedsys makes bad BIOS dumps I think many BIOS files found on the net are bad? Or perhaps it's just MR BIOS it has issues with?

Perhaps someone else knows if Speedsys 4.70 produces non working BIOS dumps?

I normally use Uniflash but these boards are too old. If someone could point me to an utility known to make correct BIOS dumps on 386 chipset boards I will redo the dumps.

I just have a hard time understanding how a common utility like Speedsys can produce bad BIOS dumps. It shouldn't be that hard to get it right one would think.

Edit

Mystery solved... or so I hope at least. It seems Speedsys indeed produces bad BIOS dumps. NSSI to the rescue!

OPTI 391 i386 MR BIOS

OPTI 493 i486 MR BIOS

I will replace the files in the earlier posts aswell.

/Edit

I've used Navrátil System Information (NSSI) 0.60 to dump all my 386 and 486 BIOS contents.

jesolo wrote:

I've used Navrátil System Information (NSSI) 0.60 to dump all my 386 and 486 BIOS contents.

Thanks!

NSSI (0.60.45) produced files with the correct file size.

I will replace the BIOS dumps with new ones made by NSSI.

I find it very odd and sad that Speedsys fails to produce valid BIOS dumps on two different motherboards, I even find it unacceptable as it can cause serious issues for people.

Skyscraper wrote:

Thanks! […]
Show full quote

jesolo wrote:

I've used Navrátil System Information (NSSI) 0.60 to dump all my 386 and 486 BIOS contents.

Thanks!

NSSI (0.60.45) produced files with the correct file size.

I will replace the BIOS dumps with new ones made by NSSI.

I find it very odd and sad that Speedsys fails to produce valid BIOS dumps on two different motherboards, I even find it unacceptable as it can cause serious issues for people.

Yeag, while brushing my teeth a few minutes ago and was thinking it might be a Speedsys issue so I was going to recommend NSSI, as I've had good luck with that in the past. Glad to see you got it sorted!

Another thought I had: Do you happen to have ROM Shadowing turned on for the BIOS range? I know for a fact that has caused issues with certain chipsets and BIOS flashing/dumping utilities for me in the past.

Anyway, (at least) the 386 BIOS seems to be valid based on the checksum information stored in the ROM and the checksum I just computed for the file appear to match. I don't feel like pulling the whole system apart again right now, so I'll test it tonight. 😀

By the way, the AMI BIOS from my OPTi 391 based 386WB is available here, if anyone needs/wants it: http://retro.timb.us/ROMs/

Skyscraper wrote:

Thanks! […]
Show full quote

jesolo wrote:

I've used Navrátil System Information (NSSI) 0.60 to dump all my 386 and 486 BIOS contents.

Thanks!

NSSI (0.60.45) produced files with the correct file size.

I will replace the BIOS dumps with new ones made by NSSI.

I find it very odd and sad that Speedsys fails to produce valid BIOS dumps on two different motherboards, I even find it unacceptable as it can cause serious issues for people.

I also want to add that NSSI is also able to dump your graphics card's BIOS (I've used it on my old Tseng Labs, Cirrus Logic, etc. ISA cards).

I'll for sure try that BIOS out once the system is up and running.
But back to the corrosion thing, more of the corrosion here is black and not blue.
What does that mean?

feipoa wrote:

I've had signs of blue corrosion come back even on boards I've washed with vinegar. It is really difficult to get every last little bit off, especially inside the small vias. Part of my issue may have been do to soaking time. How long are we supposed to soak the boards in vinegar? I tend to scrub them with a toothbrush then poor more vinegar on it and only let it sit for 5 minutes. Is that not enough?

I've also had boards which did not contain barrel batteries still have blue corrosion on them. In those cases, it is usually on contacts of removable IC's. I suspect it is finger oil reacting over long periods of time. And in those cases, the blue corrosion still seems to follow the copper traces and spread out just like with the leaky battery scenarios.

These boards are getting so old now that I wonder if there should be a regular maintenance cycle to clean off the corrosion every x years for boards which have shown any sign of the corrosion in the past.

That's interesting. I haven't noticed this on my boards, but i started collecting only a few months ago. Given the years/decades, i guess the spill from the battery penetrates deeper than i thought, and so a simple scrub or even soak isn't enough to neutralise everything.
I also seen corrosion on boards without barrel batteries (or far away from the battery, if there was one). I guess they were stacked on top of each other, and i remember reading that, in time, the fumes from the spill are enough to corrode exposed metal. On some Socket 7 boards I've also seen some nasty corrosion from electrolytic capacitor spills...

My first step for cleaning up battery corrosion is a bath in warm water with Dawn dish detergent and a liberal amount of baking soda; I literally cover the board in it in extreme cases. Not only does the baking soda help neutralize the acid, it also acts as a micro abrasive when you’re scrubbing with an anti-static brush. I’ve also got a set of long, sharp dental picks that are great for cleaning vias!

Now, this is usually enough to take care of most battery corrosion issues, however if it’s really bad you have to get extreme. That involves literally scraping the corrosion off the board. Again, I like to use dental picks for this (the same sideways implements they use for gum scraping, in fact). Basically you’re going to scrape the solder mask off any affected traces, until the copper turns shinny, then you tin the traces with your soldering iron for protection (if the traces are super thin and too close together for you to tin, simply apply clear nail polish over the bare copper to help seal them).

In the most extreme cases you’ll have to scrape the copper away completely and replace it with 28 or 30AWG wire. I like to use tiny spots of super glue to adhere the wire (applied with the tip of a toothpick) to the original path the trace took. If there’s no pad or via to solder the ends to, I’ll simply scrape away a bit of solder mask and make my own pad.

Doing this type of restoration takes tremendous soldering skill, patience and determination. Boards with significant damage can take dozens of hours to repair.

You don't use acetic acid (vinegar) at all? About what volume (e.g. teaspoons, tablespoons, etc) of dish soap and baking soda (e.g. grams or tablespoons) do you use per volume of water? Before and/or after scrubbing, how long do you let this solution sit on the board? Do you only use water to rinse, or do you use any contact cleaner as the final rinsing stage? Do you de-solder any components which have corrosion around them, e.g. the DIN-5 keyboard connector, DIP sockets, DIP IC's?

Can the blue corrosion make its way into the transistors of the IC's and affect gate conductivity? I have experienced issues with an RTC crystal oscillator circuit loosing precise timing with continued growth of corrosion. Many years ago, I cleaned up a board which experienced battery acid leakage. The clock timing as off. I replaced the crystal and small capacitors around it. This seemed to fix the clock timing issues. Then years later, the clock timing issues returned. I am not positive if it is due to corrosion, but over those years, some signs of blue corrosion had returned. So I was wondering if some of that corrosion can hide in IC's and components which do not get properly cleaned.

I found the best way to solder 30 AWG wires to traces is to use a flux pen, though it is still time consuming. I usually trace the broken trace from end to end and solder the new wires on component through-holes.

Back in the early 90's, super glue worked like magic. That stuff would bond within 15 seconds. I have not been able to find the same kind of super glue these days. Today's "super glue" and "krazy glue" seems to take minutes to bond and doesn't hold as well as the stuff from decades past. Was the original "super glue" banned in certain regions of the world?

I have an assortment of solid-core wires gauges from 20 to 30 AWG, in 2 gauge steps. I usually use these wires to "floss" vias which have been corroded. It seems like tapered tips, like dental instruments, don't scrape the centre of the via all that well, although I usually start with tapered tips to clean the outermost part of the via.

I have a SiS Rabbit board, a Chaintech 340SCD, which I repaired many years ago which I would like to redo the wiring on so that it doesn't look so messy. I'd like to use 30 AWG wire on this re-repair. It seems like the acrylic conformal coating may hold down the wires if applied thick enough.

The battery stuff can get into the pcb, beetween layers.
You really need to desolder everything and neutralize this stuff by putting the whole pcb inside vinegar for some time.

i also have a handful of boards i fixed, some of it have now broken via's.. i used a ultra fine drill and fine wire to fix them.
i did not clean everything 100% which now takes revenge, years after.

Also had the same clock problem with a 486DX50 Mainboard, the clock seemend to work faster then slower..
replaced capacitor and clock crystal, and it worked again, but not perfect.
i had to replace the RTC Chip too.
The stuff also gets inside the glass of the diodes and eat them up.

Ón a Compaq LTE Laptop Capacitors leaked and destroyed traces inside the PCB.. very annonying repair..
Capacitors make much more Damage.. i now have a Sanyo 386 Laptop here also with leaking capacitors..

Skyscraper wrote:

Thanks! […]
Show full quote

jesolo wrote:

I've used Navrátil System Information (NSSI) 0.60 to dump all my 386 and 486 BIOS contents.

Thanks!

NSSI (0.60.45) produced files with the correct file size.

I will replace the BIOS dumps with new ones made by NSSI.

I find it very odd and sad that Speedsys fails to produce valid BIOS dumps on two different motherboards, I even find it unacceptable as it can cause serious issues for people.

Success!

I’m getting a massive speed boost with this MR BiOS compared to my original AMI BIOS for some things, especially SCSI reads off my Cheetah. I suspect this has to do with nice DMA tuning options that the MR BIOS provides. Thanks for posting this, I’m liking it a lot so far! (I’ll post side by side Speedsys results later.)

By the way, the 486 MR BIOS still doesn’t work for my board and I think I figured out why. I don’t think it’s for the OPTi 391 chipset at all! Looking at the BIOS strings of the bin file in a hex editor, it shows it’s for the OPTi493 which was an early 486 chipset consisting of the 82C493, 82C392 and 82C206. Looking back at the pictures of your 486 boards you posted earlier in this thread, the one with the MR BIOS chip in it does appear to use those very chips. So I guess that explains that. 😀

timb.us wrote:

Success!

I’m getting a massive speed boost with this MR BiOS compared to my original AMI BIOS for some things, especially SCSI reads off my Cheetah. I suspect this has to do with nice DMA tuning options that the MR BIOS provides. Thanks for posting this, I’m liking it a lot so far! (I’ll post side by side Speedsys results later.)

By the way, the 486 MR BIOS still doesn’t work for my board and I think I figured out why. I don’t think it’s for the OPTi 391 chipset at all! Looking at the BIOS strings of the bin file in a hex editor, it shows it’s for the OPTi423 which was an early 486 chipset consisting of the 82C423, 82C392 and 82C206. Looking back at the pictures of your 486 boards you posted earlier in this thread, the one with the MR BIOS chip in it does appear to use those very chips. So I guess that explains that. 😀

That's great!

About the 486 BIOS. I probably just looked at the matching 82C392 and 82C206 chips and assumed the last chip was an 82C391 in the non optimal lighting.

"My eyes are dim. I cannot see."
//
"My legs are grey. My ears are gnarled. My eyes are old and bent."
//
"My eyesight is bad. My eyes are poor. My nose is knackered."

The correct name seems to be the OPTi 493 (82C493) chipset?. My quick Google returned both 386 and 486 results so I guess it's also a chipset used for both 386 and ISA only 486 motherboards.

The OPTi 391 MR BIOS probably works on both 386 and any 486 boards with OPTi 391 chipset and the OPTi 493 MR BIOS probably also works on both 386 and 486 boards only with OPTi 493 chipset. Both versions are MR BIOS V1.30 from early 1992 ("Port OPTI324" vs "Port OPTI428").

Things would have been less confusing if OPTis reference designs weren't more or less identical for most of these ISA only OPTi 3xx and OPTi 4xx chipsets.

I'd sure like to get hold of MR BIOS for VLSI Topcat chipsets (VL82C330/331/332). If anyone has one, please post it!

Indeed. It would be nice to have that one, but seeing that the Topcat was not widely used outside of OEMs, I doubt it's ever going to pop up.

timb.us, please post speedsys results of your OPTI391 after the MR BIOS is installed and tuned.

The nice thing about these MR BIOSes is that they seem to have native PS/2 mouse support built-in, so no TSR or BIOS hack needed when adding a PS/2 mouse onto the keyboard controller. Unfortuntaely, my Topcat board is the only AMI BIOS-based board I have which does NOT work with the PS/2 KBC mod, so having alternate BIOSes to test, especially a MR BIOS, would be an asset.

Anonymous Coward wrote:

Indeed. It would be nice to have that one, but seeing that the Topcat was not widely used outside of OEMs, I doubt it's ever going to pop up.

timb.us, please post speedsys results of your OPTI391 after the MR BIOS is installed and tuned.

Will do! I just need to figure out why Speedsys is locking up during the memory test. It’s either an issue with HimemX/FreeDOS or one of my RAM sticks is bad (though I did 2 hours worth of extensive memory tests via Micro-Scope 7 last night and it came back clean). I’ll try it from a DOS 6.22 boot disk tonight.

feipoa wrote:

I'd sure like to get hold of MR BIOS for VLSI Topcat chipsets (VL82C330/331/332). If anyone has one, please post it!

FYI, it seems Intel also made versions of a lot of VLSI chips under different part numbers. For example, the VL82C320/VL82C331 are interchangeable with the i82343/i82344. So, that might help when searching for BIOSes.

Skyscraper wrote:

That's great! […]
Show full quote

That's great!

About the 486 BIOS. I probably just looked at the matching 82C392 and 82C206 chips and assumed the last chip was an 82C391 in the non optimal lighting.

"My eyes are dim. I cannot see."
//
"My legs are grey. My ears are gnarled. My eyes are old and bent."
//
"My eyesight is bad. My eyes are poor. My nose is knackered."

The correct name seems to be the OPTi 493 (82C493) chipset?. My quick Google returned both 386 and 486 results so I guess it's also a chipset used for both 386 and ISA only 486 motherboards.

The OPTi 391 MR BIOS probably works on both 386 and any 486 boards with OPTi 391 chipset and the OPTi 493 MR BIOS probably also works on both 386 and 486 boards only with OPTi 493 chipset. Both versions are MR BIOS V1.30 from early 1992 ("Port OPTI324" vs "Port OPTI428").

Things would have been less confusing if OPTis reference designs weren't more or less identical for most of these ISA only OPTi 3xx and OPTi 4xx chipsets.

Whoops, you’re right! It’s the 493, not 423. I guess I can’t see either!

By the way, do you mind if I mirror your MR BIOS dumps on my site? I credited you in the text files that accompany the ROMs, but I just wanted to make sure it was OK with you first.