74F151ASJ 74F151A SOP16 5pcs/lot
https://a.aliexpress.com/_mN19W9s

That might do the trick?

ChrisXF wrote on 2023-07-24, 22:41:

74F151ASJ 74F151A SOP16 5pcs/lot
https://a.aliexpress.com/_mN19W9s

That might do the trick?

Thanks! That does look like an exact replacement actually. I didn't think about Aliexpress. Someone over on VCFF recommended these as a TI made equivalent https://www.digikey.com/en/products/detail/te … 4F151BDR/562741

I ordered some of those for now just because its Digikey and I can get them in a couple of days vs Ali. But if they aren't the right thing I can fall back on those, thanks!

Basically with 74 series replacements you check the switching speed in nanoseconds, and check the fanout (number of other gates it can drive) and if it's better or same then swap away. F series were the best in the 70s, since then we've had ABT etc. A lot of Fs you can probably replace with AS but you gotta be sure that extra half nanosecond ain't too important.

I just wanted to add that I'm doing the EXACT same thing right now to my PB Legend that was our first family PC when I was a kid.

I asked this very question in a couple FB groups I'm in and was pointed to that exact eBay listing as a replacement. I ordered them, and successfully got one mounted in place, however I still have a few tiny trace repairs to finish before I can test it out.

I'll report back when I finish on whether or not that chip worked, for posterity if nothing else.

KNagle wrote on 2023-07-25, 05:12:

I just wanted to add that I'm doing the EXACT same thing right now to my PB Legend that was our first family PC when I was a kid.

I asked this very question in a couple FB groups I'm in and was pointed to that exact eBay listing as a replacement. I ordered them, and successfully got one mounted in place, however I still have a few tiny trace repairs to finish before I can test it out.

I'll report back when I finish on whether or not that chip worked, for posterity if nothing else.

Interesting, well at least I know if the digikey isn't happy I can try that one too. Does anyone know whats this chip actually does on this MB? So we know what to look out for to see if its its working right or not?

Hard to tell, looks like it's Mux-ing a few lines off the PAL there and piping it across the board somewhere.

My issue is not being able to press F2 to enter the bios settings. I found a random blog while researching this topic from a guy who again was doing the EXACT same repair, and also had the exact same symptoms I'm having: keyboard is working but pressing F2 to enter the BIOS does nothing.

Pressing F1 to retry works fine, but it just repeats the error again, and holding a key while it's booting gives me the stuck key error, so I'm pretty sure the keyboard is working fine.

After replacing the chip and repairing the broken traces, his was back to working again and was able to access the BIOS settings. I'm hopeful this will work for me too, and I'd be done already if these wires weren't so damn small 🤣.

KNagle wrote on 2023-07-26, 00:48:

My issue is not being able to press F2 to enter the bios settings. I found a random blog while researching this topic from a guy who again was doing the EXACT same repair, and also had the exact same symptoms I'm having: keyboard is working but pressing F2 to enter the BIOS does nothing.

Pressing F1 to retry works fine, but it just repeats the error again, and holding a key while it's booting gives me the stuck key error, so I'm pretty sure the keyboard is working fine.

After replacing the chip and repairing the broken traces, his was back to working again and was able to access the BIOS settings. I'm hopeful this will work for me too, and I'd be done already if these wires weren't so damn small 🤣.

That's actually quite helpful. I haven't even tried to boot mine yet, but once I do ill know that if F2 works then I did it right 🤣

Geetings...

I know this is an old post. But in case you have not found a solution you can use SN74F151B or SN74F151BDR. Both can be purchased from Texas Instruments -

[-] https://www.ti.com/product/SN74F151B
[-] https://www.ti.com/product/EN-US/SN74F151B/pa … ails/SN74F151BD

Cheers...