Well the cracked IC is a Signetics 74LS245 , really really common and cheap IC... for example: http://www.ebay.co.uk/itm/121129742430
No matter what make 74LS245 IC you get it will work just stick to 74LS245 and you'll be fine

It's actually a 74ALS245, the ALS types have a shorter delay than the regular LS which the board might require.

You should use a 74ALS245 or 74F245.

I agree with the other posters. Please make sure you get the right replacment chip, don't just buy any 74xx245 chip.
General speaking, some 74 series chips do also have a non pin compatible but functional identical counter part.
I vaguely remember that I had this issue myself with a 74Fxx(?) chip.

In case of doubt, it's better to check the data sheets or ask the dude in your local electronics shop first
(the type of shop who sells caps and resistors, not television sets).

Try this shop. I bought some parts there a couple of years ago, they are cheap and postage was good.

http://standby-shop.eu/go/_search/full_search … =74f245&x=0&y=0

Jo22 wrote:

In case of doubt, it's better to check the data sheets or ask the dude in your local electronics shop first
(the type of shop who sells caps and resistors, not television sets).

Yeah, sounds great, but there is no electronics shop in 100 km radius around my house, so, it's gonna be hard... 😁

Imperious wrote:

Try this shop. I bought some parts there a couple of years ago, they are cheap and postage was good.

Sadly, they doesn't have anything that matches requirements, but thanks!

https://www.aliexpress.com/item/DM74ALS245AN/ … 7b-6d8b4a2edd1c
This looks like the same item and it costs half the price. I know it is not much, but I am a student and it is very hard to gain even coins.

GoblinUpTheRoad wrote:

It's actually a 74ALS245, the ALS types have a shorter delay than the regular LS which the board might require.

You should use a 74ALS245 or 74F245.

Good catch, absolutely correct 😊

74 series ICs are really common and cheap now days so pretty much every reputable place to get them is fine

krivulak wrote:

Yeah, sounds great, but there is no electronics shop in 100 km radius around my house, so, it's gonna be hard... :D […]
Show full quote

Jo22 wrote:

In case of doubt, it's better to check the data sheets or ask the dude in your local electronics shop first
(the type of shop who sells caps and resistors, not television sets).

Yeah, sounds great, but there is no electronics shop in 100 km radius around my house, so, it's gonna be hard... 😁

Imperious wrote:

Try this shop. I bought some parts there a couple of years ago, they are cheap and postage was good.

Sadly, they doesn't have anything that matches requirements, but thanks!

It does. The bottom one is a 74F245 which will work. 74F are the fastest 74 series ic's.

krivulak wrote:

Jo22 wrote:

In case of doubt, it's better to check the data sheets or ask the dude in your local electronics shop first
(the type of shop who sells caps and resistors, not television sets).

Yeah, sounds great, but there is no electronics shop in 100 km radius around my house, so, it's gonna be hard... 😁

Ah, that' makes sense. I was just pointing out that it is better to check details twice. 😉
Even though the 74 series is well known and modern CMOS parts can often be used as replacements, there might be small incompatibilities here and there.
The chip in my case was an 74FxxN and the replacment chip was not the 74Cxx, but a different one. That's why I mentioned it.
Anyway, it shouldn't hurt to always be careful when using replacement chips..

If you use the CMOS version, I'd go 74HCT245 - the T in HCT means it uses TTL voltage signalling, the HC use CMOS style voltage signalling - while the two MAY be compatible in some circumstances, the output "high" of TTL has limited margin for CMOS input high, and the output "low" of CMOS has limited margin for TTL input low.

Hi Krivulak, greetings from Brno.
Could you please tell me what RAM chips are on your LM-103 / 103FS board?
I have the same board, but with all the RAM chips missing.

Did you manage to replace the cracked 74LS245AN?

Does anyone have the BIOS ROM images for this particular board at hand?
I've got exactly the same board here with missing ROM chips and unfortunately I couldn't get any AMI BIOS for HT12/A working on it so far.

Thx,
Vasco

There are at least 4 variations of AMI BIOS for the HT12 chipset. I found all of them would work on my HT12 board. I mirrored them on my own site a while ago, along with a description of the major differences between the BIOS versions:

https://www.target-earth.net/wiki/doku.php?id … erence_material

The main summary being:

- BIOS in the 2hlm006.zip - supports 0-wait-state, BIOS shadowing and fast ISA bus BIOS settings.

- the BIOS in the 2hlm008.zip - supports BIOS option to partition RAM into XMS or EMS in 64KByte chunks, but loses the speed optimisation settings from 006.

You can still use EMS memory if needed, through the use of the HT12MM.SYS EMS driver (linked from my page above), so actually the 008 BIOS is entirely unnecessary.

Thanks, Megatron - coincidentally those were the BIOSses I tried so far (at least 2hlm006 and one for BI-025C). 😀
Maybe I should give the others a try too.

Nonetheless, I was just wondering if the original BIOS of the board pictured above (which is visually exactly the same LM-103 REV2.1 [with sticker 103FS on top if it] as I have here) would have some peculiarity which makes it different to the various HT12/A with AMI, Quadtels and Eurosofts around (I have three others).
But maybe mine is just broken and that's why it hangs very early during at POST codes 0x10, 0x0c which should be lower 64K initialization.
I simply had hoped it's just a BIOS issue..

Hmm, that doesn't sound too good. Any possibility of damage or corrosion? Does it happen with both SIMM/SIPP modules and DIP chips?

Slight corrosion in the battery area yes, but the traces make contact. Already cleaned that with Isopropanol, same to the contacts of the PLCC CPU and the socket pins.
Rest of the board looks good from visual inspection, no scratches not much dust etc.
It was my first idea to test with DIPs too (some HT12 boards require DIPs be mounted even when SIMM/SIPPs are used).

megatron-uk wrote on 2021-02-06, 10:02:

There are at least 4 variations of AMI BIOS for the HT12 chipset. I found all of them would work on my HT12 board. I mirrored th […]
Show full quote

There are at least 4 variations of AMI BIOS for the HT12 chipset. I found all of them would work on my HT12 board. I mirrored them on my own site a while ago, along with a description of the major differences between the BIOS versions:

https://www.target-earth.net/wiki/doku.php?id … erence_material

The main summary being:

- BIOS in the 2hlm006.zip - supports 0-wait-state, BIOS shadowing and fast ISA bus BIOS settings.

- the BIOS in the 2hlm008.zip - supports BIOS option to partition RAM into XMS or EMS in 64KByte chunks, but loses the speed optimisation settings from 006.

You can still use EMS memory if needed, through the use of the HT12MM.SYS EMS driver (linked from my page above), so actually the 008 BIOS is entirely unnecessary.

Very well documented. Bookmarked in case I ever work with a similar board.

Wow, that is necroposting and a half...
Anyway, after the years I found out that this kind of a board is a piece of $#!t... Had 5 of them in my possesion, all of them dead with no apparent reason. Seems like the chipset tends to die somehow.