In case you cant find the seller (or end up at that Ebay one for 1500$) here is the manufacturer : http://www.rhinotools.com.au/vacuum-desolderi … ng-station.html

Old thread I know, but I recently got this board with a Cyrix 5x86 and 32MB of ram. It boots up, but unfortunatly it hangs at "Updating ESCD". I've read some regarding this issue and it could be dead battery in the RTC. If that is the case, is it as simple as ordering a new RTC from ebay? It's a Dallas DS12887A and they're available from several sellers from China.

The Biostar MB-8433UUD will not boot with a dead RTC battery. I do not think it is the fact that the battery is dead, but there are some settings in the BIOS which need to be changed to make the board boot properly. You can use MODBIN to change the default BIOS settings, flash the BIOS, and then be able to boot normally. This is much easier to do with an external FLASH programmer. Alternately, if your motherboard has a socket for the RTC, it is easy enough to replace the RTC module, otherwise, you'll need to desolder the RTC to replace it.

so.. the reason u socketed this RTC clock thing, is because they go bad?? and so u can swap a new one in for a bad one?

is there any chance of you helping other people repair any other similar boards that are on ebay as "for parts" ?? 😁

feipoa wrote:

The Biostar MB-8433UUD will not boot with a dead RTC battery. I do not think it is the fact that the battery is dead, but there are some settings in the BIOS which need to be changed to make the board boot properly. You can use MODBIN to change the default BIOS settings, flash the BIOS, and then be able to boot normally. This is much easier to do with an external FLASH programmer. Alternately, if your motherboard has a socket for the RTC, it is easy enough to replace the RTC module, otherwise, you'll need to desolder the RTC to replace it.

Got the new RTC now but it's still the same problem, stuck at "Updating ESCD..."

Marquzz wrote:

feipoa wrote:

The Biostar MB-8433UUD will not boot with a dead RTC battery. I do not think it is the fact that the battery is dead, but there are some settings in the BIOS which need to be changed to make the board boot properly. You can use MODBIN to change the default BIOS settings, flash the BIOS, and then be able to boot normally. This is much easier to do with an external FLASH programmer. Alternately, if your motherboard has a socket for the RTC, it is easy enough to replace the RTC module, otherwise, you'll need to desolder the RTC to replace it.

Got the new RTC now but it's still the same problem, stuck at "Updating ESCD..."

Are you using FPM or EDO? If you are using EDO, you need to select EDO from BIOS otherwise it will hang after "Updating ESCD...". I think it's in Advanced Chipset something or other in bios.

kanecvr wrote:

Marquzz wrote:

feipoa wrote:

The Biostar MB-8433UUD will not boot with a dead RTC battery. I do not think it is the fact that the battery is dead, but there are some settings in the BIOS which need to be changed to make the board boot properly. You can use MODBIN to change the default BIOS settings, flash the BIOS, and then be able to boot normally. This is much easier to do with an external FLASH programmer. Alternately, if your motherboard has a socket for the RTC, it is easy enough to replace the RTC module, otherwise, you'll need to desolder the RTC to replace it.

Got the new RTC now but it's still the same problem, stuck at "Updating ESCD..."

Are you using FPM or EDO? If you are using EDO, you need to select EDO from BIOS otherwise it will hang after "Updating ESCD...". I think it's in Advanced Chipset something or other in bios.

THANK YOU! 😁

*doing the Chandler-dance*

This thread was started in 2013 with the following remark

Mau1wurf1977 wrote:

The reason for this thread is to compile all the interesting aspects of this board in a single place!

Because I have this motherboard and have some problems with it I hope that it is ok to discuss them here.

The board:
------------------------------------------------------------------
Biostar MB-8433UUD
Award 1.0A // Bios v4.50gp
UUD951222S.
12/05/95-UMC-881E/886B-2A4X5B08C-00
----------------------
time chip:
DALLAS - DS12887A
REAL TIME
----------------------
EPROM B061684
M27C1001
-12F1
BHHAQ
9540E
----------------------
Am5x86-P75-S at 133 Mhz
64 MB memory
------------------------------------------------------------------

The Problems:
-----------------------------
Does not install Windows 3.11 / Windows95 / Windows98SE
The installs break off with reported errors on loading:
COMM.DRV
GDI.EXE
USER.EXE
-----------------------------
Erratic recogniton of CD-ROM drive - appr. 50/50 (set at 'NONE' in BIOS)
-----------------------------
Does not boot in turbo mode
-----------------------------
Shows erratic behaviour (hangs) in certain programs.
-----------------------------
I did some software testing too:
-Cachechek v7 reports that if I think to have an L2 cache that I probably have fake cache chips
-Speedsys v4.78 however recognizes an L2 cache that works at 7.45 Mb/s

Over the last two months I have done some serious homework on understanding this motherboard better - that is: on a lay person's level - via reading multiple threads on VOGONS and other internet sources.
Over the last couple of weeks I have tested this board with two different CPU's, with two
different sets of memory sticks, with three different GPU cards, with two different PSU's, and with different sets of DOS and Windows 3.x software. The system is virus-free.
The board looks pristine. I do not know the history or if it ever worked ok. It came to me in a
bag and when I got it it was overclocked (this is one of the things I learned) at 160 Mhz for the AM5x86 in the socket.
I would very much appreciate suggestions that may lead to solving the problems with this board; I do not hope to end up with a world champion speed- or gaming 486 but it would be very nice if it could be fixed so that it does the most basic stuff most of the time.

Does it behave better if you disable the onboard IDE controller and use an ISA one? It will be slow, but at least it can help you isolate the problem.

I just tried but I cannot get past 'hd fail (80)' when I define the harddisk [LBA mode 4] via the USER option - it only offers NORMAL and AUTO mode for user settings.

If L2 is at 7 MB/s, it sounds to me as if your turbo jumper is set incorrectly. Please check the speedsys L2 speed in turbo and non-turbo mode and report back.

Also, please post images of all your BIOS pages.

What type of memory are you using? EDO or FPM? I suggest you start with using MemTest 86+ version 4.00 to determine if your system is incompatible with your memory sticks.

What version number is printed on your motherboard's PCB? if there is no version number next to MB-843UUD-A, then you have version 1.0, which I found to be a less than ideal version. I have a thread of the version 1.0 board on vogons somewhere. I recall it not letting me keep the PCI frequency at a 1:1 ratio with HOST even when using a FSB of 33 MHz. If you are using a verison 1.0 board, try setting the HOST-PCI freq. at 1:2/3.

feipoa wrote:

What type of memory are you using? EDO or FPM? I suggest you start with using
MemTest 86+ version 4.00 to determine if your system is incompatible with your memory sticks.

Wow! You hit the nail on the head with that first question... Although it was mentioned just 2 weeks ago in this very same thread I totally missed the point that the board does not install EDO by default - plus of course that I did not have a clue if I had EDO ram on board or what it meant anyway. After your inquiry I set the BIOS to install EDO ram and successfully installed Win95 which is a significant move into the right direction.
Thank You !!!

ps The memory consists of two TM893GBK32I-60 sticks.
The chips are marked TMS417409ADJ.
According to the Texas Instruments website they are EDO.

feipoa wrote:

If L2 is at 7 MB/s, it sounds to me as if your turbo jumper is set incorrectly.
Please check the speedsys L2 speed in turbo and non-turbo mode and report back.

Pins 23 & 24 on the J15 connector are jumpered.
I will try the turbo versus non-turbo mode later and get back with the result.

feipoa wrote:

What version number is printed on your motherboard's PCB?

Yes, sorry for the incomplete info earlier on. It is an MB-8433UUD-A VER:2.

feipoa wrote:

If L2 is at 7 MB/s, it sounds to me as if your turbo jumper is set incorrectly. Please check the speedsys L2 speed in turbo and non-turbo mode and report back.

This is what Speedsys now reports in non-turbo mode:
ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
System Speed Test Ver 4.78 Report file - created on 15-01-1998 22:08:58

CPU is in V86 mode: No
Processor : AMD Am5x86WB(tm) 110 MHz
CPU speed index : 49.54
Total memory size : 64 MB
Memory Bandwidth : 21.26 MB/s

Cache/Memory Benchmark
// Read // Write // Move // Average
Cache Level 1 // 119.31 MB/s // 3.55 MB/s // 141.69 MB/s // 88.18 MB/s
Cache Level 2 // 14.15 MB/s // 3.54 MB/s // 6.70 MB/s // 8.13 MB/s
Memory // 10.62 MB/s // 3.66 MB/s // 4.90 MB/s // 6.39 MB/s
ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo

This is in turbo mode:
ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
CPU is in V86 mode: No
Processor : AMD Am5x86WB(tm) 133 MHz
CPU speed index : 49.63
Memory Bandwidth : 72.41 MB/s

Cache/Memory Benchmark
// Read // Write // Move // Average
Cache Level 1 // 126.32 MB/s // 42.39 MB/s // 163.25 MB/s // 110.65 MB/s //
Cache Level 2 // 56.78 MB/s // 42.26 MB/s // 28.38 MB/s // 42.47 MB/s //
Memory // 28.24 MB/s // 43.21 MB/s // 11.10 MB/s // 27.52 MB/s //
ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo

Looks like your turbo is functioning as it should. If you plan on maxing out your RAM or using FSB's above 33 MHz, you should use FPM RAM.

feipoa wrote:

Looks like your turbo is functioning as it should. If you plan on maxing out your RAM or using FSB's above 33 MHz, you should use FPM RAM.

Yes, thank you very much for your help. It seems that all the software problems that I had are gone.
Further tuning is certainly an interesting road to explore if the pc keeps behaving appropiately.

With [FSB's above 33 MHz] do you mean overclocking the AMD5x or installing an actual
40 MHz CPU ? Or both ?
FPM ram does not seem very common over here in the dutch marketplace. What is the type of software that will likely perform better with FPM Ram ?

Also, I have a question re the actual RAM installation of the board. In the manual it reads that the access time is 70ns. The EDO ram that I have installed is 60ns. Does that have any effect, and if so what kind of effect ?

Any CPU which runs with a 40 MHz front-side bus. If you want to use 40 MHz, it is best to use only 256 KB of double-banked L2 cache so that you can keep your L2 timings as fast as possible. Also, FPM memory was the most reliable in this circumstance. The least amount of sticks the better. I recommend a single stick of 64 MB FPM, then download my BIOS hack, which allows you to set the L2 cache into write-through mode.

For a 50 MHz FSB, you have to put your L2 timings on slowest for reliable operation, so there is little benefit in this speed option. However, at 50 MHz, you have a 2/3 PCI multiplier option, which allows you to run your PCI cards in spec, at 33.3 Mhz.

It is not software which will perform better with FPM. Actually, I have not seen any recordable difference between FPM and EDO in terms of real world performance, but using FPM does allow for faster BIOS timings when using a 40 MHz+ FSB. In that sense, it is faster.

RAM speed has an effect on your BIOS memory latency times - the lower latency, the faster. 60 ns should let you run at 0 ws read/write for 40 MHz FSB. I'm not sure about 50 MHz. I know at 66 MHz, you need 2 ws read latency and 0 ws write latency. Perhaps 50 MHz requires 1 ws latency for the memory read?

Thank you (again) for your considerations and suggestions. I will certainly save this post and start looking for an FPM stick. Alas, I cannot use your BIOS hack (which I already downloaded some time ago) because the EPROM on my board is not flashable and replacing it is beyond my ability.

If you cannot upgrade your BIOS, then your L2 cache will be stuck in write-back mode. If you are using 256 KB of cache, then 32 MB is the most that is cacheable. To install more RAM than is cacheable will reduce system performance. In which case, a single stick of 32 MB FPM would suffice.

Do you have the required BIOS ROM that should be used?
Also, besides socketing the ODIN chip, does adding the 4th oscillator selector do anything? And what chip should be used for 1MB of cache? I cant find one anywhere. I know you were using an 2MB mod.

What do you mean by 4th oscillator selector?

I am using 1 MB cache in my mod. This board only accepts up to 512 KB, single-banked cache.