[Techtoolslist] Midway Sea Wolf with Fluke

[Andrew Welburn]

Rom is 0000-1fff - so you can't run a ram test on it, its read only.

Ram is 2000-3fff - rams are used in pairs on each bit, on alternating 
addresses. I do not use the 9010 but i'm pretty sure you can't 
dicriminate down to individual 8080 rams in this arrangment. If you can 
ramtest with a bitmask, you can isolate which is the failing bit, this 
will give you two rams to suspect, then its 50/50 luck replacing them.

4000-5fff isn't anything you need to look at, especially not with the 
ram test.

Andrew Welburn
http://www.andys-arcade.com

On 08/04/2013 19:00, Theron Troxel wrote:

> Just started using my Fluke for the first time.  Decided to work on a Sea Wolf that quit working on me.  Ran a bus test, which came back fine.  Then did a short RAM test, and got the following errors:

>

> Range 0000-1fff

> R/W ERR @ 0000 BTS FF - loop?

>

> Range 2000-3fff

> RAM DCD ERR @ 2000 Bit 11 - loop?

>

> Range 4000-5fff

> R/W ERR @ 4000 BTS FF - loop?

>

>

> Looking into the manual, I found the errors, but not quite sure what they are telling me.  I somewhat get the RAM DCD error.  It's saying at 2000 there is a problem with the address 11, which would be pin 3 on the RAM.  Is that correct?

>

> One of my questions, is how do you know what RAM goes with what error?  If there are 16 RAM chips on the main pcb, how do you tell which ones are between 0000-1fff and which one goes with 0000?

>

> Not sure what the R/W error is stating.

>

> Any help would be greatly appreciated.

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