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solidcore · 06 June 2018, 16:21

Firstly let me brief you with the condition of the a500 plus .

The a500 plus has had its leak and was donated to me by indigolemon who told me that the a500 plus looked as if it had been thrown down some stairs .

Secondly the damage of the leak had spread locally about a few inches from battery and with light spotting across a foot in length . Cleaned up and found a trace has been eaten away to the left of battery , fixed that and what was once
A black output become a flashing green.

Anyway green means memory so I pushed on to replace ram and sockets for Paula, Gary and local u* chips below Gary and right of ram .

Hooked up diagrom over serial and saw that the memory was random each boot and didn't reflect the input data .

Using a logic analyser I discovered _WE (RRW) is stuck high , all other signals to ram is fine .

Followed to u35 pin 3 and 17 , still nothing , back to agnus pin 21 still nothing still stuck high ! Tried without u35 same deal!

Replaced agnus 8375 pal for a500+ ,

Replaced u35 . Booted up , same green screen same situation with diagrom.

Any ideas ? Suggestions welcome.

06 June 2018, 16:21	#1
solidcore Registered User Join Date: Sep 2017 Location: birmingham, uk Posts: 548	A500 plus agnus _WE stuck high. Firstly let me brief you with the condition of the a500 plus . The a500 plus has had its leak and was donated to me by indigolemon who told me that the a500 plus looked as if it had been thrown down some stairs . Secondly the damage of the leak had spread locally about a few inches from battery and with light spotting across a foot in length . Cleaned up and found a trace has been eaten away to the left of battery , fixed that and what was once A black output become a flashing green. Anyway green means memory so I pushed on to replace ram and sockets for Paula, Gary and local u* chips below Gary and right of ram . Hooked up diagrom over serial and saw that the memory was random each boot and didn't reflect the input data . Using a logic analyser I discovered _WE (RRW) is stuck high , all other signals to ram is fine . Followed to u35 pin 3 and 17 , still nothing , back to agnus pin 21 still nothing still stuck high ! Tried without u35 same deal! Replaced agnus 8375 pal for a500+ , Replaced u35 . Booted up , same green screen same situation with diagrom. Any ideas ? Suggestions welcome. Last edited by solidcore; 06 June 2018 at 19:14.