try looking here https://theretroweb.com/motherboards/search/

It is a socket 7 mainboard only. that socket you describe as slot 1 is actually for a Cache module. your chipset is an intel 430 fx.

edit: couldn't find it there myself.
if you can boot it and post the bios id code here, the manufacturer could at least be identified. the code is listed at the bottom of the screen during the memory test.

someone thinks it may be from RECTRON. as for booting I am waiting for ram for the board, but what CPU will this support? Intel? Amd?

also, you said: " your chipset is an Intel 430 fx." I would like to understand how/where you saw this.

TxSnipper wrote on 2023-06-15, 12:54:

someone thinks it may be from RECTRON. as for booting I am waiting for ram for the board, but what CPU will this support? Intel? Amd?

also, you said: " your chipset is an Intel 430 fx." I would like to understand how/where you saw this.

its the number on one of the big chips on the board SB82437FX66
I guess your best bet for this is a pentium 1 cpu without mmx, Intel P54C

soldermask color, bios sticker and use of ODI chip scream Soyo, but Soyo would slap big sticker in there and they never used Molex connector next to CPU socket.

google only found one reference for the Rectron RT-512X

I only now noticed the text between the isa slots.

weedeewee wrote on 2023-06-15, 13:33:

I only now noticed the text between the isa slots.

oh wow 😮 I even looked at the zoomed in version and missed it, probably due to angle

weedeewee wrote on 2023-06-15, 13:33:

google only found one reference for the Rectron RT-512X

https://www.reddit.com/r/vintagecomputing/com … e_max_vrm_mods/ that tower of power is a cool ghetto mod

yeah I will have to find a Pentium or AMD K6 to try on it. and see whats what. and score some ram for it 😀

an amd k6 can't be used without extra modifications to the mainboard since it requires a lower cpu core voltage.
your best bet for this is a pentium 1 cpu without mmx, Intel P54C

weedeewee wrote on 2023-06-16, 05:57:

an amd k6 can't be used without extra modifications to the mainboard since it requires a lower cpu core voltage.
your best bet for this is a pentium 1 cpu without mmx, Intel P54C

K6 Model 6 CPUs will be fine at 3.3V. Their power draw may become an issue for some mainboards though.

Doornkaat wrote on 2023-06-16, 06:15:

weedeewee wrote on 2023-06-16, 05:57:

an amd k6 can't be used without extra modifications to the mainboard since it requires a lower cpu core voltage.
your best bet for this is a pentium 1 cpu without mmx, Intel P54C

K6 Model 6 CPUs will be fine at 3.3V. Their power draw may become an issue for some mainboards though.

Up until the 233 they seem to not have split voltage, higher than 233, Vcore & Vio are split. So while it runs it will definitely run hotter
correction: some lower speeds ones also have a slighly lower vcore.

weedeewee wrote on 2023-06-16, 09:04:

Doornkaat wrote on 2023-06-16, 06:15:

weedeewee wrote on 2023-06-16, 05:57:

an amd k6 can't be used without extra modifications to the mainboard since it requires a lower cpu core voltage.
your best bet for this is a pentium 1 cpu without mmx, Intel P54C

K6 Model 6 CPUs will be fine at 3.3V. Their power draw may become an issue for some mainboards though.

Up until the 233 they seem to not have split voltage, higher than 233, Vcore & Vio are split. So while it runs it will definitely run hotter
correction: some lower speeds ones also have a slighly lower vcore.

AMD K6 Model 6 has a Vcore spec of 2.9V (+/-0.1V) on the 166MHz and 200MHz models and 3.2V (+/- 0.1V or 0.145V) for the 233MHz models. They're all made on 0.35nm process and will run fine at 3.3Vcore. 3.3Vcore is even within spec for the 233MHz models.
Obviously you'll need a decent cooler with a ~30W max TDP chip.😎

The AMD K6 Model 7 (Little Foot) chips are 0.25nm parts that require lower Vcore and will not last long at 3.3V.

Not all 200MHz&233MHz K6 will be happy at 3.3V. Only Model 6 chips can handle that.

I hope this clears things up. 😃👍

Doornkaat wrote on 2023-06-16, 11:22:

AMD K6 Model 6 has a Vcore spec of 2.9V (+/-0.1V) on the 166MHz and 200MHz models and 3.2V (+/- 0.1V or 0.145V) for the 233MHz m […]
Show full quote

weedeewee wrote on 2023-06-16, 09:04:

Doornkaat wrote on 2023-06-16, 06:15:

K6 Model 6 CPUs will be fine at 3.3V. Their power draw may become an issue for some mainboards though.

Up until the 233 they seem to not have split voltage, higher than 233, Vcore & Vio are split. So while it runs it will definitely run hotter
correction: some lower speeds ones also have a slighly lower vcore.

AMD K6 Model 6 has a Vcore spec of 2.9V (+/-0.1V) on the 166MHz and 200MHz models and 3.2V (+/- 0.1V or 0.145V) for the 233MHz models. They're all made on 0.35nm process and will run fine at 3.3Vcore. 3.3Vcore is even within spec for the 233MHz models.
Obviously you'll need a decent cooler with a ~30W max TDP chip.😎

The AMD K6 Model 7 (Little Foot) chips are 0.25nm parts that require lower Vcore and will not last long at 3.3V.

Not all 200MHz&233MHz K6 will be happy at 3.3V. Only Model 6 chips can handle that.

I hope this clears things up. 😃👍

It's not a problem nor confusion for me, but that many possibilities to check is exactly why I suggested to go for a simple pentium 1 without mmx.

Indeed.

Just to be complete, seeing as OP seems unfamiliar with this period of computing:

The minium you need to test/use this board:

- a Socket 7 CPU for single voltage 3.2V-3.5V. Pentium non-MMX is the safest and easiest option. Various AMD, Cyrix and IDT CPUs will probably also work, but if you're new to this game, keep it simple for now.
- a heatsink for on top of the CPU. A fan is only necessary if the heatsink is very small. Socket 5, 7, 370 and A essentially all share same heatsink clips, so you can use whichever is easiest.
- two identical 72p SIMM memory modules. The board supports both older FP and newer EDO types. If your CPU runs at 66MHz bus speed, you need at least 60ns memory, otherwise 70ns is fine (lower is better). For best compatibility, choose 60ns SIMMs. They need to be installed in pairs of two.
- an AT power supply to connect to the P8 and P9 connectors between keyboard port and SIMM slots. Be sure to put the black wires together in the middle. If you don't have a (working) AT PSU you can use an ATX PSU with an adapter cable. This may give weird problems with sound cards because of missing -5V voltages, but for testing it's fine. If you want to use an ATX power supply permanently, get an adapter cable with -5V voltage regulator to give all required voltages.
- an AT keyboard. Note that AT is electrically identical to PS/2, so you can use a passive PS/2 to AT adapter. USB is quite different, but there are active USB->PS/2 adapters that let you use USB keyboards. Note that XT keyboards also exist with same connector as AT, but different protocol. These will not work. Easiest is just to get an AT keyboard.
- a video card. A PCI VGA card is simplest, cheapest and will give best performance. Ideally go for one from same period as motherboard (1996-ish, so S3 Trio or S3 Virge is easiest). Be aware that very new PCI VGA cards (from after 2002) may require 3.3V on PCI bus, which these old boards don't supply.

Check the manual for jumper settings, install hardware, connect monitor, keyboard and power, and then power up 😀

dionb wrote on 2023-06-16, 12:04:

Check the manual for jumper settings, install hardware, connect monitor, keyboard and power, and then power up 😀

I agree with all the rest but have to comment on that last statement of yours.
Check the manual for jumper settings will be fricking hard since it seems the manual or any other documentation is nowhere to be found. 😉

weedeewee wrote on 2023-06-16, 12:09:

dionb wrote on 2023-06-16, 12:04:

Check the manual for jumper settings, install hardware, connect monitor, keyboard and power, and then power up 😀

I agree with all the rest but have to comment on that last statement of yours.
Check the manual for jumper settings will be fricking hard since it seems the manual or any other documentation is nowhere to be found. 😉

Not so sure - take a look here:
https://theretroweb.com/motherboard/manual/km … 88832981330.pdf

This is for the Kaimei KM-T5-2, which is supposedly a synonym of Rectron RT-5xx

The pic in OP isn't perfect, but I think I can make out JP12 by the blue jumpers above the tag RAM to the right of the CPU socket. Above that, the two solid yellow caps are next to the clock crystal, so whether or not they are JP13/14 as in this manual, they almost certainly do the bus speed. If you want to be certain, read the name of the PLL/clock gen chip and look up its datasheet, but three of the four options are going to be 50, 60 and 66MHz. The fourth will almost certainly be 55MHz. Most likely the diagrams will be correct even if the name isn't.

As it's a single-voltage board, the other jumper to the left of CPU socket next to the Molex connector will most likely be for VS/VRE (3.2V vs 3.45V). As VRE is within tolerance of VS parts, you can safely guess this and correct afterwards if it turns out to be the other way round.

There are two jumpers above the DS12885 RTC/CMOS. One will be for clear CMOS, the other probably toggles BIOS writeable yes/no.

Only jumper I'm less sure about is JP6 next to the PLB cache chips on the lower left. It might be to select between onboard and COAST cache.