Apple IIe System Test Fails

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Apple IIe System Test Fails

I get "RAM 00100000" on my screen when I hold both Apple keys down during boot.  I can remove all cards and get the same thing.  I have replaced the 3rd of 8 RAM chips, after desoldering suspect RAM and soldered in a socket before putting new RAM in.  The 4th and 5th chips are also socketed and I tried swapping those as well.  I can enter and run a BASIC program, but booting from floppy doesn't work.  Help!

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Joined: Jun 16 2020 - 16:58
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Himaybe there is a broken

Hi

maybe there is a broken trace? If not mistaken those chips run in parallel. You should be able to quickly check continuity between the corresponding legs of the memory chips.  

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Hi,You can also swap the

Hi,

You can also swap the original suspect RAM chip with another socketed one and see if the Diag behave differently.

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It is entirely possible what

It is entirely possible what whoever put in the sockets broke a via. 

 

If you want to go through the effort:

 

Desolder all RAM and sockets. 

Install machine pin sockets and solder both the back side, and the front side, as this creates new vias through the sockets. 

Install new RAM. 

 

The cost and time here may not be worthwile.

 

Before you do this, do you have a RAM EXP acard in the EXP slot? If so, remove this ere running the HW test, and report the results. 

 

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