A1200 no chipmem

[imi2003]

Hi all

Trying to repair my a1200, it was not showing any signs of life before, even with diagrom. I started by retouching the solder on the alice chip.

I am now get some display with diagrom some raster bars with flashing green background.
I'm now also getting the following through the serial output

Garbage before this text was binary numbers: 1, 2, 4, 8, 16, 32, 64,  @???U

Garbage before this text was binary numbers: 1, 2, 4, 8, 16, 32, 64, 128, 240, 15, 170 and 85
To help you find biterrors to paula. Now starting normal startuptext etc
Amiga DiagROM V1.2 - 13-Aug-19  - 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 $00008400   OK  Number of 32K blocks found: $01
Chipmem Shadowram detected, guess there is no more chipmem, stopping here

Startaddr: $00000400  Endaddr: $00007FFF
- Parallel Code $fc - Trying to find some fastmem (as no chipmem found)
- Parallel Code $fb - Memorydetection done
- Parallel Code $80 - NO Chipmem detected
- NO MEMORY FOUND - HALTING SYSTEM

The board looks ok with no obvious damage or broken traces, I have retiuched all the other chips as well fresh solder and flux.

I assumed it was bad ram, so i also desoldered all the ram and put in 2 good chips in U16 & U17 only, but it still shows the same problem.

Any help or pointers would be greatly appreciated

[Firthy2002]

Could be an issue with Gayle.

[imi2003]

Tried another Gayle, it got even worse would not even show any serial output.
The board is a rev 1A, I'm guessing there is something seriously wrong with this board.

I've got a reamiga 1.4 on order, I'm going build it up with sockets for the custom chips and see how it goes.

[fitzsteve]

Good luck with the build, when my ReAmiga was put together there was initially an issue with no chip ram, resoldering the Alice sorted.

Originally there was garbage serial output, resoldering the budgie sorted that and was how the chip ram issue was diagnosed