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Old 09 November 2019, 01:04   #1
Vypr
Registered User

 
Join Date: Dec 2016
Location: East Kilbride, Scotland
Posts: 165
A500 memory issues

I recently bought an A500 cheap in the hopes of fixing it but I think it may be beyond me.
When I got it it was displaying a green screen at boot indicating a RAM issue.

I first swapped the Agnus chip for a known good one then swapped the RAM for known good chips but still the same issue.

I then replaced the Agnus socket and got a bit further. DiagROM gave me some serial output but was indicating serious problems reading from RAM (Output below) SInce then I have checked all traces on Agnus and the RAM for breaks and shorts and replaced U35 and U36 but no difference has been seen.
Any dieas on where to check next?

DiagROM output:

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 V1.1 - 27-Oct-18 - 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:
P1LMB P2LMB
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 FAILED
- Test of writing word $00FF to $400 FAILED
- Test of writing word $FF00 to $400 FAILED
- 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 FAILED
- Parallel Code $fd - Start of chipmemdetection

Addr $00000400 Write: $AAAAAAAA Read: $000000BF FAILED
Addr $00000400 Write: $55555555 Read: $000000BF FAILED
Addr $00000400 Write: $F0F0F0F0 Read: $000000BF FAILED
Addr $00000400 Write: $0F0F0F0F Read: $000000BF FAILED
Addr $00000400 Write: $00000000 Read: $000000BF FAILED
Addr $00008400 Write: $AAAAAAAA Read: $022C6100 FAILED
Addr $00008400 Write: $55555555 Read: $022C6100 FAILED
Addr $00008400 Write: $F0F0F0F0 Read: $022C6100 FAILED
Addr $00008400 Write: $0F0F0F0F Read: $022C6100 FAILED
Addr $00008400 Write: $00000000 Read: $022C6100 FAILED
Addr $00010400 Write: $AAAAAAAA Read: $000000BF FAILED
Addr $00010400 Write: $55555555 Read: $000000BF FAILED
Addr $00010400 Write: $F0F0F0F0 Read: $000000BF FAILED
Addr $00010400 Write: $0F0F0F0F Read: $000000BF FAILED
Addr $00010400 Write: $00000000 Read: $000000BF FAILED
Addr $00018400 Write: $AAAAAAAA Read: $022C6100 FAILED
Addr $00018400 Write: $55555555 Read: $022C6100 FAILED
Addr $00018400 Write: $F0F0F0F0 Read: $022C6100 FAILED
Addr $00018400 Write: $0F0F0F0F Read: $022C6100 FAILED
Addr $00018400 Write: $00000000 Read: $022C6100 FAILED
Addr $00020400 Write: $AAAAAAAA Read: $000000BF FAILED
Addr $00020400 Write: $55555555 Read: $000000BF FAILED
Addr $00020400 Write: $F0F0F0F0 Read: $000000BF FAILED
Addr $00020400 Write: $0F0F0F0F Read: $000000BF FAILED
Addr $00020400 Write: $00000000 Read: $000000BF FAILED
Addr $00028400 Write: $AAAAAAAA Read: $022C6100 FAILED
Addr $00028400 Write: $55555555 Read: $022C6100 FAILED
Addr $00028400 Write: $F0F0F0F0 Read: $022C6100 FAILED
Addr $00028400 Write: $0F0F0F0F Read: $022C6100 FAILED
Addr $00028400 Write: $00000000 Read: $022C6100 FAILED
Addr $00030400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $00030400 Write: $55555555 Read: $00000000 FAILED
Addr $00030400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $00030400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $00038400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $00038400 Write: $55555555 Read: $00000000 FAILED
Addr $00038400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $00038400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $00040400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $00040400 Write: $55555555 Read: $00000000 FAILED
Addr $00040400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $00040400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $00048400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $00048400 Write: $55555555 Read: $00000000 FAILED
Addr $00048400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $00048400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $00050400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $00050400 Write: $55555555 Read: $00000000 FAILED
Addr $00050400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $00050400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $00058400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $00058400 Write: $55555555 Read: $00000000 FAILED
Addr $00058400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $00058400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $00060400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $00060400 Write: $55555555 Read: $00000000 FAILED
Addr $00060400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $00060400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $00068400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $00068400 Write: $55555555 Read: $00000000 FAILED
Addr $00068400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $00068400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $00070400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $00070400 Write: $55555555 Read: $00000000 FAILED
Addr $00070400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $00070400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $00078400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $00078400 Write: $55555555 Read: $00000000 FAILED
Addr $00078400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $00078400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $00080400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00080400 Write: $55555555 Read: $B800B800 FAILED
Addr $00080400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00080400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00080400 Write: $00000000 Read: $B800B800 FAILED
Addr $00088400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00088400 Write: $55555555 Read: $B800B800 FAILED
Addr $00088400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00088400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00088400 Write: $00000000 Read: $B800B800 FAILED
Addr $00090400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00090400 Write: $55555555 Read: $B800B800 FAILED
Addr $00090400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00090400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00090400 Write: $00000000 Read: $B800B800 FAILED
Addr $00098400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00098400 Write: $55555555 Read: $B800B800 FAILED
Addr $00098400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00098400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00098400 Write: $00000000 Read: $B800B800 FAILED
Addr $000A0400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000A0400 Write: $55555555 Read: $B800B800 FAILED
Addr $000A0400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000A0400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000A0400 Write: $00000000 Read: $B800B800 FAILED
Addr $000A8400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000A8400 Write: $55555555 Read: $B800B800 FAILED
Addr $000A8400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000A8400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000A8400 Write: $00000000 Read: $B800B800 FAILED
Addr $000B0400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000B0400 Write: $55555555 Read: $B800B800 FAILED
Addr $000B0400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000B0400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000B0400 Write: $00000000 Read: $B800B800 FAILED
Addr $000B8400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000B8400 Write: $55555555 Read: $B800B800 FAILED
Addr $000B8400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000B8400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000B8400 Write: $00000000 Read: $B800B800 FAILED
Addr $000C0400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000C0400 Write: $55555555 Read: $B800B800 FAILED
Addr $000C0400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000C0400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000C0400 Write: $00000000 Read: $B800B800 FAILED
Addr $000C8400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000C8400 Write: $55555555 Read: $B800B800 FAILED
Addr $000C8400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000C8400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000C8400 Write: $00000000 Read: $B800B800 FAILED
Addr $000D0400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000D0400 Write: $55555555 Read: $B800B800 FAILED
Addr $000D0400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000D0400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000D0400 Write: $00000000 Read: $B800B800 FAILED
Addr $000D8400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000D8400 Write: $55555555 Read: $B800B800 FAILED
Addr $000D8400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000D8400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000D8400 Write: $00000000 Read: $B800B800 FAILED
Addr $000E0400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000E0400 Write: $55555555 Read: $B800B800 FAILED
Addr $000E0400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000E0400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000E0400 Write: $00000000 Read: $B800B800 FAILED
Addr $000E8400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000E8400 Write: $55555555 Read: $B800B800 FAILED
Addr $000E8400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000E8400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000E8400 Write: $00000000 Read: $B800B800 FAILED
Addr $000F0400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000F0400 Write: $55555555 Read: $B800B800 FAILED
Addr $000F0400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000F0400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000F0400 Write: $00000000 Read: $B800B800 FAILED
Addr $000F8400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $000F8400 Write: $55555555 Read: $B800B800 FAILED
Addr $000F8400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $000F8400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $000F8400 Write: $00000000 Read: $B800B800 FAILED
Addr $00100400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00100400 Write: $55555555 Read: $B800B800 FAILED
Addr $00100400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00100400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00100400 Write: $00000000 Read: $B800B800 FAILED
Addr $00108400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00108400 Write: $55555555 Read: $B800B800 FAILED
Addr $00108400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00108400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00108400 Write: $00000000 Read: $B800B800 FAILED
Addr $00110400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00110400 Write: $55555555 Read: $B800B800 FAILED
Addr $00110400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00110400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00110400 Write: $00000000 Read: $B800B800 FAILED
Addr $00118400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00118400 Write: $55555555 Read: $B800B800 FAILED
Addr $00118400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00118400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00118400 Write: $00000000 Read: $B800B800 FAILED
Addr $00120400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00120400 Write: $55555555 Read: $B800B800 FAILED
Addr $00120400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00120400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00120400 Write: $00000000 Read: $B800B800 FAILED
Addr $00128400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00128400 Write: $55555555 Read: $B800B800 FAILED
Addr $00128400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00128400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00128400 Write: $00000000 Read: $B800B800 FAILED
Addr $00130400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00130400 Write: $55555555 Read: $B800B800 FAILED
Addr $00130400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00130400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00130400 Write: $00000000 Read: $B800B800 FAILED
Addr $00138400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00138400 Write: $55555555 Read: $B800B800 FAILED
Addr $00138400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00138400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00138400 Write: $00000000 Read: $B800B800 FAILED
Addr $00140400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00140400 Write: $55555555 Read: $B800B800 FAILED
Addr $00140400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00140400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00140400 Write: $00000000 Read: $B800B800 FAILED
Addr $00148400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00148400 Write: $55555555 Read: $B800B800 FAILED
Addr $00148400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00148400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00148400 Write: $00000000 Read: $B800B800 FAILED
Addr $00150400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00150400 Write: $55555555 Read: $B800B800 FAILED
Addr $00150400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00150400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00150400 Write: $00000000 Read: $B800B800 FAILED
Addr $00158400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00158400 Write: $55555555 Read: $B800B800 FAILED
Addr $00158400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00158400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00158400 Write: $00000000 Read: $B800B800 FAILED
Addr $00160400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00160400 Write: $55555555 Read: $B800B800 FAILED
Addr $00160400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00160400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00160400 Write: $00000000 Read: $B800B800 FAILED
Addr $00168400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00168400 Write: $55555555 Read: $B800B800 FAILED
Addr $00168400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00168400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00168400 Write: $00000000 Read: $B800B800 FAILED
Addr $00170400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00170400 Write: $55555555 Read: $B800B800 FAILED
Addr $00170400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00170400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00170400 Write: $00000000 Read: $B800B800 FAILED
Addr $00178400 Write: $AAAAAAAA Read: $B800B800 FAILED
Addr $00178400 Write: $55555555 Read: $B800B800 FAILED
Addr $00178400 Write: $F0F0F0F0 Read: $B800B800 FAILED
Addr $00178400 Write: $0F0F0F0F Read: $B800B800 FAILED
Addr $00178400 Write: $00000000 Read: $B800B800 FAILED
Addr $00180400 Write: $AAAAAAAA Read: $000000BF FAILED
Addr $00180400 Write: $55555555 Read: $000000BF FAILED
Addr $00180400 Write: $F0F0F0F0 Read: $000000BF FAILED
Addr $00180400 Write: $0F0F0F0F Read: $000000BF FAILED
Addr $00180400 Write: $00000000 Read: $000000BF FAILED
Addr $00188400 Write: $AAAAAAAA Read: $022C6100 FAILED
Addr $00188400 Write: $55555555 Read: $022C6100 FAILED
Addr $00188400 Write: $F0F0F0F0 Read: $022C6100 FAILED
Addr $00188400 Write: $0F0F0F0F Read: $022C6100 FAILED
Addr $00188400 Write: $00000000 Read: $022C6100 FAILED
Addr $00190400 Write: $AAAAAAAA Read: $000000BF FAILED
Addr $00190400 Write: $55555555 Read: $000000BF FAILED
Addr $00190400 Write: $F0F0F0F0 Read: $000000BF FAILED
Addr $00190400 Write: $0F0F0F0F Read: $000000BF FAILED
Addr $00190400 Write: $00000000 Read: $000000BF FAILED
Addr $00198400 Write: $AAAAAAAA Read: $022C6100 FAILED
Addr $00198400 Write: $55555555 Read: $022C6100 FAILED
Addr $00198400 Write: $F0F0F0F0 Read: $022C6100 FAILED
Addr $00198400 Write: $0F0F0F0F Read: $022C6100 FAILED
Addr $00198400 Write: $00000000 Read: $022C6100 FAILED
Addr $001A0400 Write: $AAAAAAAA Read: $000000BF FAILED
Addr $001A0400 Write: $55555555 Read: $000000BF FAILED
Addr $001A0400 Write: $F0F0F0F0 Read: $000000BF FAILED
Addr $001A0400 Write: $0F0F0F0F Read: $000000BF FAILED
Addr $001A0400 Write: $00000000 Read: $000000BF FAILED
Addr $001A8400 Write: $AAAAAAAA Read: $022C6100 FAILED
Addr $001A8400 Write: $55555555 Read: $022C6100 FAILED
Addr $001A8400 Write: $F0F0F0F0 Read: $022C6100 FAILED
Addr $001A8400 Write: $0F0F0F0F Read: $022C6100 FAILED
Addr $001A8400 Write: $00000000 Read: $022C6100 FAILED
Addr $001B0400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $001B0400 Write: $55555555 Read: $00000000 FAILED
Addr $001B0400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $001B0400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $001B8400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $001B8400 Write: $55555555 Read: $00000000 FAILED
Addr $001B8400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $001B8400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $001C0400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $001C0400 Write: $55555555 Read: $00000000 FAILED
Addr $001C0400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $001C0400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $001C8400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $001C8400 Write: $55555555 Read: $00000000 FAILED
Addr $001C8400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $001C8400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $001D0400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $001D0400 Write: $55555555 Read: $00000000 FAILED
Addr $001D0400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $001D0400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $001D8400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $001D8400 Write: $55555555 Read: $00000000 FAILED
Addr $001D8400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $001D8400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $001E0400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $001E0400 Write: $55555555 Read: $00000000 FAILED
Addr $001E0400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $001E0400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $001E8400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $001E8400 Write: $55555555 Read: $00000000 FAILED
Addr $001E8400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $001E8400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $001F0400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $001F0400 Write: $55555555 Read: $00000000 FAILED
Addr $001F0400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $001F0400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $001F8400 Write: $AAAAAAAA Read: $00000000 FAILED
Addr $001F8400 Write: $55555555 Read: $00000000 FAILED
Addr $001F8400 Write: $F0F0F0F0 Read: $00000000 FAILED
Addr $001F8400 Write: $0F0F0F0F Read: $00000000 FAILED
Addr $001F8400
NO Chipmem detected
- Parallel Code $fc - Start of non autoconfig fastmemdetection (as no chip found/startup check)
- No fastmem found, Autoconfig ram NOT checked
- Parallel Code $fb - Memorydetection done
- Parallel Code $80 - NO Chipmem detected
- NO MEMORY FOUND - HALTING SYSTEM
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Old 09 November 2019, 01:50   #2
solarmon
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Have you checked the data path traces to/through/under U10 to U13 chips?

Also check data and address traces to/from the CPU.

I would also suggest reseating the CPU and Gary chips, ckeaning the pins and sockets whilst you're at it.

Was there a expansion memory card in it that had a leaking battery? There may have been corrosion from that which got to the motherboard and may have damaged traces, sockets, pins and components.

Post so clear and closeup pictures of your motherboard so that we can assess better.
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Old 09 November 2019, 16:57   #3
Vypr
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Join Date: Dec 2016
Location: East Kilbride, Scotland
Posts: 165
Quote:
Originally Posted by solarmon View Post
Have you checked the data path traces to/through/under U10 to U13 chips?

Also check data and address traces to/from the CPU.

I would also suggest reseating the CPU and Gary chips, ckeaning the pins and sockets whilst you're at it.

Was there a expansion memory card in it that had a leaking battery? There may have been corrosion from that which got to the motherboard and may have damaged traces, sockets, pins and components.

Post so clear and closeup pictures of your motherboard so that we can assess better.
U10 - U13 are all fine, there is continuity to where they are supposed to go.

I've reseated Gary, Paula and the CPU , I've even replaced the sockets for Gary and Paula just to be on the safe side and tried known good chips from a spare board
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Old 09 November 2019, 19:58   #4
solarmon
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Quote:
Originally Posted by Vypr View Post
U10 - U13 are all fine, there is continuity to where they are supposed to go.
Well, continuity to the chips is one thing, and the chips themselves is another - i.e. how the signals are processed going through and out of them.

You could try removing U10 - U13, putting them sockets and get some new chips to test/compare against.

EDIT: I had to do that to U10 and U12 with my A500+, but I think that was more to do with corrosion to the chip pin holes and issues with traces underneath them.
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Old 11 November 2019, 01:58   #5
Vypr
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Posts: 165
Well, replacing U10-U13 did not change anything. Looks like I'll have to get the multimeter out and start checking continuity on all the traces . See you guys in a month or so.
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Old 11 November 2019, 05:02   #6
r.cade
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I recently replaced all the RAM on my A500 (all 16 chips) and tore up at least 3 traces/vias. I noticed a couple of them, but not all of them.

Go through the schematic - almost all of the lines are parallel on all the RAM chips except a couple. Make sure all lines are good everywhere on every chip. Mine had breaks and I missed them on double check and finally found on 3rd or 4th check. Due to the way they are connected to each other on the board you can get contiunity to all other chips except one and you will miss it. Triple check, quadruple check... even have someone else check behind you.
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Old 11 November 2019, 11:48   #7
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Originally Posted by r.cade View Post
I recently replaced all the RAM on my A500 (all 16 chips) and tore up at least 3 traces/vias. I noticed a couple of them, but not all of them.

Go through the schematic - almost all of the lines are parallel on all the RAM chips except a couple. Make sure all lines are good everywhere on every chip. Mine had breaks and I missed them on double check and finally found on 3rd or 4th check. Due to the way they are connected to each other on the board you can get contiunity to all other chips except one and you will miss it. Triple check, quadruple check... even have someone else check behind you.
Yep, I second, and third, and fourth that!

I use http://www.amigapcb.org/ and https://www.amigawiki.org/doku.php?i...ice:schematics to methodically check each trace from each chip pin, in numerical order. You may cover the same trace several times (in reverse), but doing it methodically and in order allows you to keep track of where you are.
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Old 12 November 2019, 00:48   #8
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I checked every trace in the RAM as I remember having probelms with an A2052 card with broken traces but all the traces are fine. Followed them all the way to Agnus and Paula as well as U10-13, they are all fine.
I decided to break out the oscilloscope to see what was happening and I have found that the 5V line is showing a lot of fluctuation, we're talking between 5.43 and 3.4 V, the scopeis showing an average of 4.22V
I'm going to try replacing the caps on the 5V line and see if that helps.
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Old 12 November 2019, 10:52   #9
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It might not be the caps on the motherboard, but the caps on the PSU itself.

Have you got another PSU to test with.

Or test the PSU without the Amiga connected - although testing without a load is not accurate so you need to try to put a 5V or 12V load on it somehow.

I wouldn't connect the PSU to the Amiga anymore if it is suspect.
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Old 12 November 2019, 11:04   #10
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If you're getting that kind of fluctuation on the 5V line, I would also suspect the capacitors in the PSU itself rather than the Amiga (though changing them won't make it worse). But it's also worth checking the power connector itself - if it's making poor contact or has a bad solder joint, you can get voltage fluctuations like that as the cable moves slightly.
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Old 12 November 2019, 11:51   #11
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If you're getting that kind of fluctuation on the 5V line, I would also suspect the capacitors in the PSU itself rather than the Amiga (though changing them won't make it worse). But it's also worth checking the power connector itself - if it's making poor contact or has a bad solder joint, you can get voltage fluctuations like that as the cable moves slightly.
The power suypply itself should be OK, I use it to run am A500+, and A600 and an A1200 with no issues.
I'll double check the line filter and the power connector though.
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Old 13 November 2019, 03:23   #12
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OK, Caps C811-C816 have been replaced, 5V line now settled at around 5.14V but still no joy. Now getting a light grey screen at boot. Checking the RST and HLT lines show both as High so there's still something I'm missing.
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Old 13 November 2019, 09:08   #13
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OK, Caps C811-C816 have been replaced, 5V line now settled at around 5.14V but still no joy. Now getting a light grey screen at boot. Checking the RST and HLT lines show both as High so there's still something I'm missing.
OK great!

So no green screen now? At least hopefully that means your memory is OK and it has passed the test to now get to a white/grey screen.

What are the behavior of the POWER and CAPS LOCK LED? Do they flash/pulse?

Can you do a CTRL-Amiga-Amiga keyboard reset?

A few things you could try:

1. Remove the CIA chips - it should still boot without them. Try known working CIA chips.
2. Try a known working kickstart ROM.
3. Try a known working CPU chip.

Also, what does Diagrom now show?
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Old 13 November 2019, 15:08   #14
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OK, had some issues, managed to kill my DiagROM 1.1 chip (Always check chip alignment before powering on D'oh!)
DiagROM 1.2 just gives a screen with green and red lines.
Burned a new 1.1 chip, ran out of 24C400's and had to use a 24C800, got the following serial output. Video out is just a purple screen:

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 V1.1 - 27-Oct-18 - 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:
P1LMB P2LMB
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 $00080400 OK Number of 32K blocks found: $10
Chipmem Shadowram detected, guess there is no more chipmem, stopping here

Startaddr: $00000400 Endaddr: $00080000
- Parallel Code $fc - Start of non autoconfig fastmemdetection (as no chip found/startup check)
- No fastmem found, Autoconfig ram NOT checked
- Parallel Code $fb - Memorydetection done

Using $0006CD00 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: 512kB
Detected Motherboard Fastmem: 0kB
Basememory address: $0006CD00
- Parallel Code $f9 - Detected memory in use, we now have a stack etc
We are in a nonchip/nodraw mode. Serialoutput is all we got. colorflash on screen
is actually chars that should be printed on screen. telling user something happens


Doing ROM Checksumtest: (64K blocks, Green OK, Red Failed)
$6946ACF4 $B526F1B8 $E967DADB $00000000 $FFFFC000 $FFFFC000 $FFFFC000 $FFFFC000

I think I'll try replacing the rest of the capacitors first.
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Old 13 November 2019, 20:23   #15
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She lives!

Replaced all the capacitors except the ones on the audio filter and VCC was now showing a stable voltage (+/- .1V), DiagROM serial output was (kind of) working and at least I could see the menu on the serial output but still getting garbage on the screen. Decided to swap the CIA's for known working ones and found that the odd CIA had been put in upside down!

Looks like someone had previously had a go at this as at least one capacitor had already been replaced as it was a different colour to the rest. Whoever it was must have tried swapping the CIA's and made a boo-boo (I swear it wasn't me)

Switche dit around and now everything works as it should.

Last edited by Vypr; 13 November 2019 at 20:24. Reason: spelling and grammar mistakes
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Old 13 November 2019, 21:05   #16
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Glad you got it working!

But that was unexpected!
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Old 13 November 2019, 23:30   #17
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Good deal. Another one saved from the scrap heap. Mine still has a keyboard that will not come out of reset that I need to look at.
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Old 14 November 2019, 01:33   #18
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I recently bought an A500 cheap in the hopes of fixing it but I think it may be beyond me.
How cheap?!

Well done on getting it working! A gratifying feeling I'm sure when you see the changing colour boot screens followed by KS 1.3.

I would consider using SysTest to check hardware e.g. sound.
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