First of all, take care of the corrosion. It doesn't look very bad now, but leave it like this and it will get worse. Use vinegar and a small brush or cotton swabs, keep the board tilted so it doesn't spill towards the center. After removing the green oxidation as much as you can, rinse the area with isopropyl alcohol and let dry.
The external battery connects to pin 1 and 4 of that header, and since you've already discovered the GND pins it's clear which one will be the positive (the one that goes to the anode of CR3 😀 )
You will have to try and find the best voltage for the external battery, some boards work with 3 volts, others require 4.5 or even 6 volts. You might not need to change any jumpers for the external battery to work.
For the 80286, notice that the socket has a notch (left side in your photo). The chip should have the same notch, just align them properly and you're good to go.

Cleaned the board. Using 3 1.5V AA battery with tape and a connector, now, BIOS params stay.
BUT. I lost the HDD... Disk Failed to initialize, or HD Controller Failure, not always the same message.
Tried with an IDE-PCMCIA converter, I can fdisk, format, copy files on the SDCard but not boot from, and not read again (Drive not ready). Tried with 2 or 3 card that works in my HP200 or Fujuitsu Stylistic, no way.. The card I boot my 486 from does'nt work either.
I may have fried the HD controler... Or the IDE-PCMCIA do not work.
I do not have any suitable IDE disk (or those I have are 40 Gb...).

Damned...

jvernet wrote on 2020-03-21, 10:37:

Hi,

I need help to indentify, if possible, this card from a KENITEC 286/16. Working, but leaking battery. I need help to:
- in wich way should I insert a 80287 ? U49 in the left.

The notch in the socket tells which way to install it. BTW you need a 10Mhz or faster 80287 as most boards run the 287 at 2/3 speed of the cpu unless you have jumpers to set it's clock at a different rate. I see the 32Mhz XTAL for the cpu and a 40Mhz Xtal so am guessing the 287 runs at 10Mhz (no other reason to have a 40Mhz Xtal unless the board supports a 20Mhz 286). Either way make sure you get a fast 287.

added:

jvernet wrote on 2020-03-21, 22:16:

I may have fried the HD controler... Or the IDE-PCMCIA do not work.
I do not have any suitable IDE disk (or those I have are 40 Gb...).

It's a 286 board with no onboard controller I can see. So how are you adding the IDE controller ? Most 286 boards do not like IDE unless specifically made for them or using a good 16bit addon like a Promise EIDE Pro card, XT-IDE, etc.

Horun wrote on 2020-03-22, 04:56:

The notch in the socket tells which way to install it. BTW you need a 10Mhz or faster 80287 as most boards run the 287 at 2/3 speed of the cpu unless you have jumpers to set it's clock at a different rate. I see the 32Mhz XTAL for the cpu and a 40Mhz Xtal so am guessing the 287 runs at 10Mhz (no other reason to have a 40Mhz Xtal unless the board supports a 20Mhz 286). Either way make sure you get a fast 287.

I bought a 80287 XL from china,brand new, never used. inserted in the correct way, it's working perfectly ! 2 time faster than a stock 287.

It's a 286 board with no onboard controller I can see. So how are you adding the IDE controller ? Most 286 boards do not like IDE unless specifically made for them or using a good 16bit addon like a Promise EIDE Pro card, XT-IDE, etc.

The machine have a CCAT200A ISA card. Wich is not fried: using the second drive of my 486 and it work. The LPS105AT HD seems to be dead: plugged to the 286, it prevent Drive 1 initialisation. The 486 won't even go to de POST, only a black screen when plugged. I may have inverted the IDE cable at some stage... It doesn't like the 3$ IDE-PCMCIA either (I need to test it in the 486, as I have the same adapter).

Now, i have sometimes (with BCC) a parity memory error. I've added 4 1 MB SIMM, may be one is defective, but Checkit 3.0 Memory tests do not report any error.

Other problem: I CAN'T ACCESS the setup BIOS once eveything is ok. None of the known key (DEL,INS, F1, F2, F10....) let me access the setup.... I had a similar KENITEC back in time, and was able to access the BIOS without problem...
Below, the BIOS (as 86Box can emulate this machine). May be someone can dissasemble it and see which key may work. Or it's a setting of the mobo...

It is possible that only way to change BIOS settings is to run dedicated program for it. I had Amstrad 2286 which works this way.
However you may try to use program like 'cmoser.exe' for modifying CMOS settings. Just run in from diskette.

Also some PC-test programs have such a function, i.e. PC-PRO 6.0 <- from my Dropbox

jvernet wrote on 2020-03-22, 11:33:

I bought a 80287 XL from china,brand new, never used. inserted in the correct way, it's working perfectly ! 2 time faster than a […]
Show full quote

Horun wrote on 2020-03-22, 04:56:

The notch in the socket tells which way to install it. BTW you need a 10Mhz or faster 80287 as most boards run the 287 at 2/3 speed of the cpu unless you have jumpers to set it's clock at a different rate. I see the 32Mhz XTAL for the cpu and a 40Mhz Xtal so am guessing the 287 runs at 10Mhz (no other reason to have a 40Mhz Xtal unless the board supports a 20Mhz 286). Either way make sure you get a fast 287.

I bought a 80287 XL from china,brand new, never used. inserted in the correct way, it's working perfectly ! 2 time faster than a stock 287.

It's a 286 board with no onboard controller I can see. So how are you adding the IDE controller ? Most 286 boards do not like IDE unless specifically made for them or using a good 16bit addon like a Promise EIDE Pro card, XT-IDE, etc.

The machine have a CCAT200A ISA card. Wich is not fried: using the second drive of my 486 and it work. The LPS105AT HD seems to be dead: plugged to the 286, it prevent Drive 1 initialisation. The 486 won't even go to de POST, only a black screen when plugged. I may have inverted the IDE cable at some stage... It doesn't like the 3$ IDE-PCMCIA either (I need to test it in the 486, as I have the same adapter).

Now, i have sometimes (with BCC) a parity memory error. I've added 4 1 MB SIMM, may be one is defective, but Checkit 3.0 Memory tests do not report any error.

Other problem: I CAN'T ACCESS the setup BIOS once eveything is ok. None of the known key (DEL,INS, F1, F2, F10....) let me access the setup.... I had a similar KENITEC back in time, and was able to access the BIOS without problem...
Below, the BIOS (as 86Box can emulate this machine). May be someone can dissasemble it and see which key may work. Or it's a setting of the mobo...

KENITEC.zip

you did extract the bios rom dump?

Found this Setup util for Phoenix BIOS (the attached BIOS above is "phoenix 80286 ROM BIOS PLUS Version 3.10". Also inside one of texts says:
"If the system has an older Phoenix BIOS and a built-in setup program, it is most likely accessed by pressing CTL-ALT-ESC or CTL-ALT-S during POST.
On newer Phoenix BIOSes, setup is accessed by pressing F2 during POST. On some systems F1 is used instead.

Warning: this Setup.com can wipe the settings on some motherboards, use at your own risk !