From the DiagROM output, there's quite obviously a chip memory problem.
For a start, it consistently reports:
- Test of writing byte (even) $ff to $400 FAILED
If you're using a terminal in ANSI/VT220 mode, this will appear in red, to highlight the problem.
It then correctly reports the memory address range, and correctly decides on a base address of $ECCEA:
Startaddr: $00000400 Endaddr: $000FFFFF
- Fastmemcheck skipped as we found chipmem
- Parallel Code $fb - Memorydetection done
Using $000ECCEA as start of workmem (Base)
But the base address is then somehow reported as $EEEEAAAA:
Detected Chipmem: 1024kB
Detected Motherboard Fastmem: 00kB
Basememory address: $000EEEEAAAA
Of course there's no memory at that address, so it could never work with that. It's more likely to be an issue with the string being written as EEEEAAAA instead of the expected ECCEA.
In fear of sounding like a broken record, this looks exactly like a chip memory fault, which is probably caused by one of the eight soldered in 256k x 4bit DRAMs being defective, but it's not easy to pinpoint which DRAM has the issue. Fortunately they're not that hard to find new and were around $3ea when I last bought some. Your cheapest and easiest route from here would be to buy eight new 256kx4 DRAMs in ZIP package, find someone local who is very good at through hole component soldering work, and get them to replace all 8 DRAMs. Note that these parts are different from the 1Mx4 DRAM as used for A3000 fast memory.
As a source of DRAMs, contact Michael M (mechy on Amiga.org) who may have stock of these in America. I can share his Email address privately if needed.
And FYI, I quickly ran DiagROM v1.2.1 in a good A1200 for a comparison of what to expect on a correctly working machine:
[With A1200, 2MB memory, DiagROM v1.2.1]
Garbage before this text was binary numbers: 1, 2, 4, 8, 16, 32, 64, 128, 240
5, 170 and 85
To help you find biterrors to paula. Now starting normal startuptext etc
Amiga DiagROM V1.2.1 - 16-Jul-20 - By John (Chucky/The Gang) Hertell
Testing if serial loopbackadapter is installed: <> NOT DETECTED
- Parallel Code $ff - Start of ROM, CPU Seems somewhat alive
Checking status of mousebuttons for different startups:
Set all Interrupt enablebits (INTENA $dff09a) to Disabled: Done
Set all Interrupt requestbits (INTREQ $dff09c) to Disabled: Done
Set all DMA enablebits (DMACON $dff096) to Disabled: Done
Testing if OVL is working: OK
- Parallel Code $fe - Test UDS/LDS line
- Test of writing word $FFFF to $400 OK
- Test of writing word $00FF to $400 OK
- Test of writing word $FF00 to $400 OK
- Test of writing word $0000 to $400 OK
- Test of writing byte (even) $ff to $400 OK
- Test of writing byte (odd) $ff to $401 OK
- Parallel Code $fd - Start of chipmemdetection
Addr $001F8400 OK Number of 32K blocks found: $40
Startaddr: $00000400 Endaddr: $001FFFFF
- Fastmemcheck skipped as we found chipmem
- Parallel Code $fb - Memorydetection done
Using $001ECCEA as start of workmem (Base)
- Parallel Code $fa - Starting to use detected memory
Testing if serial loopbackadapter is installed: <> NOT DETECTED
Detecting if we have a working raster: DETECTED
Detected Chipmem: 2048kB
Detected Motherboard Fastmem: 0kB
Basememory address: $001ECCEA
As a very fast test of variablearea working this SHOULD read OK: OK!
- Parallel Code $f9 - Detected memory in use, we now have a stack etc
- Doing Initstuff
- Setting up Chipmemdata
- Copy Menu Copperlist from ROM to Chipmem
- Copy ECS TestCopperlist from ROM to Chipmem
- Copy ECS testCopperlist2 from ROM to Chipmem
- Fixing Bitplane Pointers etc in Menu Copperlist
- Copy Audio Data from ROM to Chipmem
- Do final Bitplanedata in Menu Copperlist
- Initstuff done!
Set Start of copper (COP1LCH $dff080): Done
Starting Copper (COPJMP1 $dff088): Done
Set all DMA enablebits (DMACON $dff096) to Enabled: Done
Set Beam Conter control register to 32 (PAL) (BEAMCON0 $dff1dc): Done
Set POTGO to all OUTPUT ($FF00) (POTGO $dff034): Done
- Parallel Code $f8 - Starting up screen, text echoed to serialport
Amiga DiagROM V1.2.1 - 16-Jul-20 - By John (Chucky/The Gang) Hertell
Doing ROM Checksumtest: (64K blocks, Green OK, Red Failed)
$5A39AC3E $C5724DFE $7C779F2B $00000000 $00000000 $00000000 $00000000 $006C00
CPU: 68EC20 FPU: NONE MMU: NOT CHECKED
Checking for fastmem
Pressing left mousebutton will cancel detection (if hanged)
Checking if a 24 Bit address cpu is used: YES
- Checking for Memory in 24 Bit area (NON AUTOCONFIG)
- Checking for Memory in Ranger or Fakefast area