Please put both boards side by side, clear your phone lens, put it on any suitable box, hold your breath and make a good photo.
May be you will get the best quality if take one by one photo.
It would be good to see chip names near the side connectors.
Also I would to discern dip switches near IC15 as well as chips in red circles.
I have usual Chinese phone. You can see the test photo below.
Your fist photo was very good.
From right, the two chips IC26/IC41 D72020GC-8
The center 8 chips, IC45,46,47,48,49,50,51,52 GM53C261 X8 Individual name is M51C262-10
Near CGROM 3 IC38 23C4001EJGZ
IC near GUNZE IC69 MB89363
The one near the MSDOS is JP4/JP6
MB89363/MB89363B, Fujitsu, 5V, Two data I/O LSIs with six ports of 8-bit parallel I/O
http://archive.computerhistory.org/resources/access/text/2013/04/102723432-05-01-acc.pdf (page 180)
MB89254, Fujitsu, Programmable Timer with three independent timer channels, DIP-24:
https://pdf.dzsc.com/autoupload/04ae79cd-5671-4a97-93a6-87bb2b912ffc.pdfhttp://bitsavers.informatik.uni-stuttgart.de/components/fujitsu/_dataBooks/1987_Fujitsu_8_16_Bit_Microprocessors_Microcomputers_Peripherals.pdf (page 818)
uPD23C4001E, NEC, 512K x 8 mask ROM, SOP-40 (equivalent to KM23C40018)
https://1www.bitsavers.org/components/samsung/_Databooks/1995_Samsung_MOS_Memory_DRAM_1110-4091.pdf (page 56)
These are all equivalent. They appear to be the ROM version of 27C4001 EPROM:
KM23C40008 (Samsung), uPD23C4001E (NEC), HN62335 (Hitachi), HN623448 (Hitachi), TC534000A (Toshiba), LH5341008 (Sharp), M5M23C401AP (Mitsubishi), MB834000A (Fujitsu), CXK384001 (Sony).
uPD72020GC, NEC, CMOS GRAPHIC DISPLAY CONTROLLER, QFP-52:
https://www.datasheetarchive.com/pdf/download/library/Datasheets-ZSAA1/DSAZSAA0006055.pdf?h=dbd324f5048e3bc420cdee7e3d2578a4%3A2caf4572a5cf3e36fee8%3A16029b4090d834c4a20d625f63f821ddLC3564B, BS, BM, BT-70/10, Sanyo, 64K (8192-word x 8-bit) SRAM, DIP-28:
https://pdf.datasheetcatalog.com/datasheet/sanyo/ds_pdf_e/LC3564BM-70.pdfM27C2001, STMicroelectronics, 2 Mbit (256Kb x

UV EPROM and OTP EPROM, DIP-32:
https://www.farnell.com/datasheets/72409.pdfGD75232, LGS, 3 RS232 drivers and 5 receivers, 5V, +/-15V, 20-pin:
https://www.ti.com/lit/ds/symlink/gd75232.pdfMB89255A, Fujitsu, Parallel Data I/O Interface, functionally compatible with the Intel 8255A:
http://bitsavers.informatik.uni-stuttgart.de/components/fujitsu/_dataBooks/1987_Fujitsu_8_16_Bit_Microprocessors_Microcomputers_Peripherals.pdf (page 819)
82C55A, Intel, CHMOS PROGRAMMABLE PERIPHERAL INTERFACE, 5V, PLCC-44:
https://www.alldatasheet.com/datasheet-pdf/download/66112/INTEL/82C55A.htmlGM53C261, Goldstar, 64K x 4 Bit Multiport Video RAM, 5V, 24-pin ZIP:
http://bitsavers.informatik.uni-stuttgart.de/components/goldStar/_dataBooks/1993_GoldStar_MOS_Memory.pdfMB89251A, Fujitsu, Serial Data Transmitter/Receiver, 28-pin:
http://bitsavers.informatik.uni-stuttgart.de/components/fujitsu/_dataBooks/1987_Fujitsu_8_16_Bit_Microprocessors_Microcomputers_Peripherals.pdf (page 817)
MB8464C, Fujitsu, 16K (2K x

CMOS Static RAM, 5V, DIP-28:
http://www.bitsavers.org/components/fujitsu/_dataBooks/1984_Fujitsu_Memory_Data_Book.pdf (page 204)
PALCE16V8H, AMD, Universal Programmable Array Logic, 5V, 20-pin:
https://www.silicon-ark.co.uk/datasheets/PALCE16V8H-datasheet-amd.pdfPALCE20V8Q, AMD, Universal Programmable Array Logic, 5V, 24-pin:
https://www.tomek.cedro.info/files/electronics/doc/ic_various/GAL20V8.PDFM51C262, OKI, multiport 64K x 4 (256K bits) DRAM, 5V, ZIP-24:
https://bitsavers.org/components/oki/_dataBooks/1990_OKI_Memory_Data_Book.pdf (page 738)
CXK5863BP, Sony, 64Kbit (8K x

SRAM, 5V, 28-pin:
https://www.datasheetarchive.com/datasheet/3271000e66c77fe3?type=O&term=CXK5863BPConnectors
CN1 /CN2/ CN3: These are used for a controller and RS232 serial ports, facilitating communication with peripheral devices and ensuring robust data transfer capabilities. It is used for RS232 serial communication, ensuring reliable data transfer between the motherboard and connected devices.RS232/ RS232/485 /RAS
CN4: It is used for printer
CN5:
CN6:
CN7: It is used for card slots, connected via a small PCB, allowing the integration of various expansion cards.
CN8:
CN9:
CN10: It is the main power for motherboard.
CN11: It is connected to another board which is a PCB, that's the main board for card slots, there is error in card slots if this have problem.
CN12: This connector is designated for a 12V fan, crucial for maintaining optimal thermal conditions within the system.
CN13: Not used in most boards as far as known.
CN14: This connector is linked to a display monitor that includes a PCB, ensuring effective video output and control.
CN15: No connector
CN16: It is used as video outputs connected directly from the other components, the big machine. Analog RGB
CN17: It is used for mouse
CN18: It is a keyboard connector.
NF could be noise filters, ie ferrite beads.
DA could be ESD protection diode arrays.
RA is probably a resistor array.
TA is NPN transistor arrays.
All ICs
IC 1 (MB3771)
IC23(D4990A)
IC54(TLC27L7)
IC53(74HCT374)
IC22(74LS174)
IC6(74F74)
IC7(74ACT08)
IC15 AND IC16(MSDOS BIOS)
IC21 / IC24 (74LS07)
IC72 / IC73 / IC63 (74HC04A/74HC14A)
IC69(MB89363)
IC70(GUNZE AHL-51A)
IC74(MB89254H)
IC75(MB89251A)
IC28/ IC77 (74LS125A)
IC38(23C4001EJGZ)
IC66(PALCE20V8Q)
IC14(LC3564BS-70)
IC83 / IC61 / IC60 / IC62 / IC82/ IC84/ IC25 (74LS244)
IC87/ IC88/ IC68/ IC89/ IC86/ IC67/ IC30/ IC31(74LS245)
IC2(P79AJ 74F04)
IC56/ IC57/ IC58/ IC59/ IC80/ IC33/ IC32/ IC34/ (PALCE16V8H-15SC/4)
IC85 (74LS373)
IC3 (74HC132)
IC18 (74LS14)
IC64 (74HC244)
IC26/ IC41 (D72020GC-8)
IC27 (MB89255A)
IC19/ IC20/ IC79 (GD75232D)
IC76 (74LS38)
IC78 (74LS153)
IC81 (SN751177N)
IC45,46,47,48,49,50,51,52 (GM53C261 X8).It consists of 8 IC, which is M51C262-10 IC.
IC36/ IC37/ IC39 (CXK5863BP-35)
NOTE: Its a Old Board, lots of IC Markings are gone, I barely can see.