I'm newbie like you, so I don't have answers to any of your questions. What I do happen to have is the exact same motherboard with a dead RTC and a necroware replacement that I haven't got around to doing yet. So, I'll just do it.

Mine has a Dallas DS12B887:

I've learned this lesson the hard way, so booting it up first to make sure it works:

All good. 👍 Can see the (blurry) CMOS battery failed error.

All right, what do we got:

Looks good to me!

This is mine third time soldering anything, so I'd say it's a pretty good little job for a newbie. Btw since you're worried about pins, you should know that I put a socket into the motherboard first, and I certainly didn't snip any pins on it.

Good work! SMD soldering of any kind can be challenging to newcomers.

nizce wrote on 2023-10-30, 21:43:

I’ve added some pictures of the ODIN, PIN number one is the top right one on the last picture. So 2,3,16,20,22 is “removed”. This doesn’t match up with the necroware which states the following pins should not be used: 2,3,16,20,21,22.

It should be fine.
Pin 21 is the RCLR# pin, used to wipe the CMOS info stored in the chip. On motherboards that supported this function there is a CLEAR CMOS jumper that connects this pin to ground. But gradually it stopped being supported and the DS12887A got rid of the pin.
All it means is that the CLEAR CMOS jumper on your board (if it has one) won't work with the necroware chip, but otherwise it will function the same as the ODIN.

(Are ODIN chips even sealed with epoxy? I know some of the other non-Dallas RTCs you can just pop the cover off and get access to the battery sitting on top of the DS12885...)

kingcake wrote on 2023-10-31, 02:26:

Good work! SMD soldering of any kind can be challenging to newcomers.

Oh no, I didn't mean to imply that I assembled the necroware RTC. 😓 That, I bought pre-built off eBay, much like I imagine the OP has.

No, the only soldering I did was just getting things in and out of the motherboard. I haven't even considered tackling any SMD stuff yet - though it's needed for so many of the cool projects out there, even the smallest ones like this here. Actually , this would a good one to start with... 🤔

jmarsh wrote on 2023-10-31, 03:16:

It should be fine. Pin 21 is the RCLR# pin, used to wipe the CMOS info stored in the chip. On motherboards that supported this f […]
Show full quote

nizce wrote on 2023-10-30, 21:43:

I’ve added some pictures of the ODIN, PIN number one is the top right one on the last picture. So 2,3,16,20,22 is “removed”. This doesn’t match up with the necroware which states the following pins should not be used: 2,3,16,20,21,22.

It should be fine.
Pin 21 is the RCLR# pin, used to wipe the CMOS info stored in the chip. On motherboards that supported this function there is a CLEAR CMOS jumper that connects this pin to ground. But gradually it stopped being supported and the DS12887A got rid of the pin.
All it means is that the CLEAR CMOS jumper on your board (if it has one) won't work with the necroware chip, but otherwise it will function the same as the ODIN.

(Are ODIN chips even sealed with epoxy? I know some of the other non-Dallas RTCs you can just pop the cover off and get access to the battery sitting on top of the DS12885...)

Sorry for late reply!
Thanks, then it should work 😀
I haven't tried to open the ODIN but I will, I just took for granted that it was sealed with epoxy 😁

I'll report back how it goes when it arrives hopefully next week 😀

ubiq wrote on 2023-10-31, 03:17:

kingcake wrote on 2023-10-31, 02:26:

Good work! SMD soldering of any kind can be challenging to newcomers.

Oh no, I didn't mean to imply that I assembled the necroware RTC. 😓 That, I bought pre-built off eBay, much like I imagine the OP has.

No, the only soldering I did was just getting things in and out of the motherboard. I haven't even considered tackling any SMD stuff yet - though it's needed for so many of the cool projects out there, even the smallest ones like this here. Actually , this would a good one to start with... 🤔

Look into the MHP30 mini hotplate, it's quite nice but really small. Can recommend it for small projects.
Have used it to assemble an expansion board called A314(the clockport variant) for my Amiga 1200 with alla SMD components.
Bought it after soldering one manually, it took a lot time to do it manually and a lot of bridges took some time to tidy up, but it was fun.

Using the hotplate sure went faster, but it was still a learning curve, used waaaay to much soldering paste the first time 😁
Still got bridges that had to be solved with a soldering iron, but at it saved a lot of time compared to manual soldering, and it's quite soothing to see all the components just "snap" into place when the paste melts 😀

But I'm quite new to this, so I guess someone who is experienced with a soldering iron will be faster than using a hotplate.

mine p55t2p4. 32,768hz quartz + 30yr battery from famicom cartridge (its still 3v+).
sometimes everything can be done with improvised means and without waiting for deliveries)

nizce wrote on 2023-11-02, 22:19:

Look into the MHP30 mini hotplate, it's quite nice but really small. Can recommend it for small projects. Have used it to assemb […]
Show full quote

ubiq wrote on 2023-10-31, 03:17:

kingcake wrote on 2023-10-31, 02:26:

Good work! SMD soldering of any kind can be challenging to newcomers.

Oh no, I didn't mean to imply that I assembled the necroware RTC. 😓 That, I bought pre-built off eBay, much like I imagine the OP has.

No, the only soldering I did was just getting things in and out of the motherboard. I haven't even considered tackling any SMD stuff yet - though it's needed for so many of the cool projects out there, even the smallest ones like this here. Actually , this would a good one to start with... 🤔

Look into the MHP30 mini hotplate, it's quite nice but really small. Can recommend it for small projects.
Have used it to assemble an expansion board called A314(the clockport variant) for my Amiga 1200 with alla SMD components.
Bought it after soldering one manually, it took a lot time to do it manually and a lot of bridges took some time to tidy up, but it was fun.

Using the hotplate sure went faster, but it was still a learning curve, used waaaay to much soldering paste the first time 😁
Still got bridges that had to be solved with a soldering iron, but at it saved a lot of time compared to manual soldering, and it's quite soothing to see all the components just "snap" into place when the paste melts 😀

But I'm quite new to this, so I guess someone who is experienced with a soldering iron will be faster than using a hotplate.

Thanks for this - no idea such a thing even existed. I'll probably stick with simple through-hole stuff for now but yeah... I'm eager to level up!

Speaking of improv, I made a CR2032 holder out of the top of a water bottle and a drawing pin. cut the screw part off the bottle, put the drawing pin through the cap, tacked a wire on the pin of the drawing pin, trapped a wire under the screw "sleeve" I cut off the top of the bottle, and trapped the CR2032 against the drawing pin on the cap with it. Need a small diameter bottle neck though, regular soda/pop bottle size is a tad too large.

overdrive333 wrote on 2023-11-02, 22:20:

mine p55t2p4. 32,768hz quartz + 30yr battery from famicom cartridge (its still 3v+).
sometimes everything can be done with improvised means and without waiting for deliveries)

Nice work ! Looks very good ! I have modded a few RTC Dallas and Benchmark too and once you do one, it is easier than some may think.
Only quirk seen is sometimes if you need the Xtal, getting the proper one can be tricky (there are diff pF capacitor loading factors which could come into play)
Good job !!

overdrive333 wrote on 2023-11-02, 22:20:

mine p55t2p4. 32,768hz quartz + 30yr battery from famicom cartridge (its still 3v+).
sometimes everything can be done with improvised means and without waiting for deliveries)

From the other photos, you probably could have traced the battery supply pins back to diodes and used the existing battery location on the board rather than bending the chip's pins up.
(Often there's a blank spot on motherboards for a crystal connected to pins 2+3 too.)

jmarsh wrote on 2023-11-03, 07:00:

overdrive333 wrote on 2023-11-02, 22:20:

mine p55t2p4. 32,768hz quartz + 30yr battery from famicom cartridge (its still 3v+).
sometimes everything can be done with improvised means and without waiting for deliveries)

From the other photos, you probably could have traced the battery supply pins back to diodes and used the existing battery location on the board rather than bending the chip's pins up.
(Often there's a blank spot on motherboards for a crystal connected to pins 2+3 too.

There are no battery or crystal place on p55t2p4. It was designed to use all-in-one dallas 12887 (hate it)