I ordered G4 Sawtooth and i can't identify this expansion card that i will get with it

Update... tick tock tick tock 
This story is going to make me suffer  until the very end! :-)

The technician who was supposed to assemble the cable  is a nice  old  technician who has worked for 50 years on  radio and TV repairs and he said to me, "Oh Mario, I'm sorry, but  my hands and my eyesight  no longer allow me to do this kind of work. The  8 pins  to be soldered are too small, you need a steady hand.  Let's wait for the young guy who is just learning  the job to come back,  he's  away for a few days."
And I wait...

this makes sense, either you or your elves must have been doing that, as the hardware or OS9 will never do something like this.

however, it is generally not a bad idea to have a second system folder on the second disk, eventually a backup, but even better a juvenile, fresh install, so that you can easily boot from the second drive when something goes wrong with #1. (note that in order to boot OS9 from a drive, the boot partition may not exceed 192 gb.)

when you make backups from your system folder and do not want it to be bootable, use disc copy or toast to make image files, as this is much faster than using stuffit.

Of "some" possible interest here, in this matter...





                                               

This may be nothing at all, or it might provide some usable info regarding the J20 RAM slot problem.
(One of those ideas that has kept rattling around in my vacuous head.)

So far I know of five and possibly six individuals that have encountered this little J20 RAM slot bug-a-boo
AND maybe comparing the motherboard white labels of these machines might provide some other similarities.
And then again, maybe not.

See GaryN’s related comments here:
https://macos9lives.com/smforum/index.php?topic=7637.msg59356#msg59356

I’ve already requested such info / photos from @refinery and @blazer1878. That leaves @peeperpc
-- and an individual over on Reddit for me to contact and request this info / pic from.
I also have another MDD here, from which I also need to provide an image.

Again, this may all amount to absolutely nothing — but then again, maybe not?

Here’s the first such white label from @Mardeec’s MDD motherboard, below.



Seems rather odd to me that it looks like another, different label has been placed over the (original?) label
in the image above. Wonder if this might also be the case with the other J20 MDD here?

Anyway, everyone please humor me about this AND provide those requested label images here.

Thank ya!

Thank! 
As soon as I've solved the damn problem with the crossed serial cable (thanks again to Gary), I'll be able to start running the first scripts. If you like, and if you have time, I'll be happy to keep you updated (in addition, I'll be sure to seek your advice and suggestions).




(Southern Italy is a place that truly contains so much beauty layered over centuries of history)

Get a cheap heat sensor from aliexpress
It really helps with finding bad caps

Btw may that be issue with capacitors, exceptionally since i already trashed original psu because of this and this thing surely wasn't powered on for like 15 years minimum

Yes. Check for swollen (and possibly leaking) capacitors too.

"In the meantime, you can very closely inspect the mobo (top and bottom) looking for any signs
of overheating or other possible damage to the myriad of tiny electronic components and traces."

And now, before I really go to bed... while you're inside the thing, also please photograph the white
label on the mobo like this one below:



It looks like this one has a label pasted over a label. I've also another similar one to photograph here as well.

Btw may that be issue with capacitors, exceptionally since i already trashed original psu because of this and this thing surely wasn't powered on for like 15 years minimum

Searched your serial number @ https://appleserialnumberinfo.com/Desktop/index.php and came up with this:



Then searched same with EveryMac.com and it returned this info:

     

And for more detailed info on your MDD (like RAM specs, basic OS, etc.) check out:
https://everymac.com/systems/apple/powermac_g4/specs/powermac_g4_1.25_dp_mdd.html

And which RAM slot do you have the single 512 mb stick in? If it is not in J20, try also in other slots.
You might even try other RAM sticks in other slots, leaving the J20 slot empty. For more info see:
https://macos9lives.com/smforum/index.php?topic=7637.msg59231#msg59231

Or read that entire topic, beginning here:
https://macos9lives.com/smforum/index.php?topic=7637.msg59178#msg59178

Sure you might have a failing CPU or a damaged mobo but for the machine to only allow one stick of RAM,
well maybe you have the J20 slot problem too? If the single stick works in J21, J22 and J23, leave the J20
slot open and then test (one at a time) two other sticks along with the known working stick to see if it might
work with two or three sticks, total. (With the J20 slot left open.)

And maybe you’ve got mixed & matched RAM? PC2100 DDR and PC2700 DDR?

[I’m now going to bed!]

If you photograph the CPU, do please also photograph the entire open view of the mobo too.

AND I’ve sent you a PM. (In case you have not noticed it). Check “Messages” at top of opening page.

Cheers!