Nice board, manual is easy to find on the 'net, so please make sure your jumpers are properly set for the CPUs you are using.

Are the CPUs getting warm after a minute or so?

That transistor, if defective, could prevent your board from working with 3.x - 4 volt processors. But both your CPUs are 5 volt so they should work regardless.

I think the capacitors are ok, I've never seen defective caps on any 486 board (except for phisically broken).

The BIOS chip sure looks like an EPROM (UV-erasable), and to find its type you must peel back the sticker a little bit. LX5BZ000E seems to be a date code or something. It would help if you have some means to read its contents, check if it's not corrupted. Also, a cheap POST diagnostic card would be very useful.

I don't have any experience with this particular board, but there are some that don't start with EDO ram. Is yours FPM? Maybe start with no ram at all, speaker should give some beeps.

Edit: on a quick look, your JP28 jumpers seem to be rotated 90 degrees from what they should be. But please double-check with the manual.

but if you are trying a 66mhz and 40mhz cpu are you setting the correct fsb frequency? 66mhz should run at 2 x 33 and 40mhz at 2x20 (I think)

Easiest would be rechecking jumpers - always look thrice. Then maybe use a diagnose card - which if everything else has failed seems to be a must.

A handy cpu for testing is a DX50 because it mostly fires up even if the fsb is too high for a clock doubled chip. The already mentioned check for EDO vs FPM is also essential since many modern boards do not support EDO.

I have this board (Rev 2.1 though) and it doesn't work with EDO memory unfortunately. It could be the culprit.

I just have to say ... that board is adorable. It's just long enough for the ISA slots!

I've never heard of Tomato. Are they relatively modern boards? As in like, industrial or just a budget brand for those that had not moved on to P-MMX by then?

Hi guys 😀

Thank you for your interest.

So, first I checked the transistor TIP32C NPN, is work 100% ok . Next, I changed the all capacitors - work 100% ok. (470uf/16V)
I took out the electronic circuit.
BIOS is TMS JL 27C010A-15 with windows UV. Unfortunately, my programmer is too new because I have Sofi SP-8A programmer. I think I need a Willem'a programator. I work in this topic.

This configuration worked(1996 - 2005 year). This RAM memory worked with this mainboard. It is from the producer. The processor heats up after some 15 seconds. Is warm. FSB is 33Mhz. - Jumper Settings.
Mainboard without RAM - Speaker is be quiet
Mainboard without GPU - Speaker is be quiet
Jumper Settings JP28 corrected but not change.

I need new BIOS for testing. I bought a diagnostic card today (PCI, ISA diagnostic card)
If I get it, I'll let you know what happened

Edit:

I have another motherboard, but is dead. Maybe processor is wrong ? Must be Intel ? AMD - not ?

thanks, and sorry my english is bad

That's a strange programmer. Looked through the supported devices list, quite useless for vintage hardware. I'm using the TL866CS, perfect for this purpose.

Diagnostic card could prove useful for both boards, but you'll have to wait ~1 month if you ordered it from China.

I have some old board (OPTi 495sx chipset) that only starts with Intel 486 DX or DX2 CPUs, could be the same with yours. But again, on closer look, that second board is missing its BIOS chip.

SirNickity wrote:

I've never heard of Tomato. Are they relatively modern boards? As in like, industrial or just a budget brand for those that had not moved on to P-MMX by then?

I've heard quite a bit about them, mid to late 90s, but maybe they were more common around here (Eastern Europe). I think they are the same with Zida.

thigobr wrote:

I have this board (Rev 2.1 though) and it doesn't work with EDO memory unfortunately. It could be the culprit.

My RAM is: Infineon Portugal 8MB 72-pin EDO DRAM SIMM (KM44C1000CJ)

This memory RAM worked with this board. but I read that they must be 2 same bones and only in pairs. Solo will not work. maybe one of them is damaged. I have ordered 2 new ones, we will see.

thanks for the suggestions.

I did corrupt BIOS once on this motherboard by experimenting with different CPU settings and CPUs so if CPU votage/type/freq. are set correctly and CPU does get warm, BIOS corruption just might be the culprit here.

SSTV2 wrote:

I did corrupt BIOS once on this motherboard by experimenting with different CPU settings and CPUs so if CPU votage/type/freq. are set correctly and CPU does get warm, BIOS corruption just might be the culprit here.

Do you know if it is a replacement?

Original is TMS 27C010A-15

I have from another board (k5) eeprom BIOS : ASD AE29F1008-15
I think that my TMS 27C010A-15 is damaged.

Yes, ASD AE29F1008-15 is compatible with this motherboard. I know that, because I went the same diagnostic route, by borrowing an easy to program Flash ROM from a working motherboard.

If you can read contents off a UV EPROM, it's not damaged.

SSTV2 wrote:

Yes, ASD AE29F1008-15 is compatible with this motherboard. I know that, because I went the same diagnostic route, by borrowing an easy to program Flash ROM from a working motherboard.

If you can read contents off a UV EPROM, it's not damaged.

I dont know becouse I dont have compatible programator. I'll go to the electronics on Monday and get the BIOS.

If I insert the FLASH system, I need to change the jumper from EEPROM to FLASH on the board ?

A very stupid question maybe. But did you put the psu power cables in the right order? The black cables should be next to each other.

Radar41 wrote:

If I insert the FLASH system, I need to change the jumper from EEPROM to FLASH on the board ?

JP4 is used for Vpp pin of UV EPROM, it allows to select either 5 or 12V as programing voltage and has no use for flash memory. Always set it to 5V if you are using UV chip, else unstable systems might corrupt BIOS. For Flash memory, JP4 can be left unjumpered.

Even for frash the jumper should be at 5V. 12V should only be set only for the duration of flash update IF the chip needs 12V for programming (vast majority don't and will die instantly if 12V is given to them, possibly taking the rest with it).

Hi

A have new BIOS : 1.72. I have JP4 on Pins 2 & 3 closed - BIOS type select EPROM - is correct ?
I connect the power supply correctly.
Unfortunately, the mainboard still does not work. No beep without RAM , No beep without GPU. CPU is warm.

Tomorrow I should have a diagnostic card, we will see what will show

It will also load another v4.00A BIOS

Let me know what the card will show

Hi

I have a card diagnostic and such results.

+12V - OK
-12V - OK
+5V - OK
+3,3V - nd

CLK - OK
IRDY- OK
FRAME - OK
RESET - (if button ON )- OK

On the screen only dashes. ;/

BIOS: 1.72 and 4.00A (I have a three bones - 2x EEPROM and 1 Flash).

Hmm, BIOS not started ? Hmm, What would you advise to check?

In ISA only + 12 light ON why ?

You inserted it backwards in the ISA slot. There's a marking on it, "rear", it goes to rear of the case (where the bracket is on a normal card). Please check if the analyzer still works by plugging it in a working motherboard, because it is possible that you fried it.

You are right. Thanks

Fortunately, it works.

In ISA:

+12V - ok
-12V - ok
+5V - ok
+3,3V - ok

CLK - OK
IRDY - not light
Frame - ok
Reset - Ok if button switch ON.

Soł.

PCI - IRDY - light on but 3,3V is light off

ISA - IRDY - light off but 3,3V is light on

Conclusions ? 😐