[Techtoolslist] Cat box, and fluke usage..

[Kevin Moore]

Well I was following the seqeunce given in the manual, which is Address
lines, then Data lines, then Ram etc..

I'll run the bus sigs now, and see what I get.

Thanks,

Kevin


2009/11/25 John Robertson <jrr at flippers.com>


> Kevin Moore wrote:

>

>> Hi all, in my quest to learn more about using these tools, I've actually

>> come up with a problem, and could use a little explanation.

>>

>> I'm working on a liberator board, and was using the atari cat box. The

>> first

>> two tests in the liberator manual have you check address lines. Well those

>> checked out good. Next was the Data lines. This is where things fell

>> apart,

>> and I'm not sure what I'm seeing.

>>

>> Punch in address 0000, and write AA check the D0-D7 lines going to the

>> ls245

>> well half the incoming lines are the wrong state, and the output of the

>> ls245 is non existent. Ie pins 2-9 have no output.

>>

>> So I hook up my fluke 9010a thinking there may be something wrong with the

>> catbox, since this is the first time I've used it. Did the same basic

>> setup

>> wddis grounded, and Φ0 Φ2 shorted together. Do a write to 0000 with AA and

>> use my logic probe to check. Same results.

>>

>> Am I to assume Bad memory at location 0000.??

>>

>>

> Yes.

>

> Did you do the BUS Test first? That will show if any address or data lines

> are misbehaving.

>

> If BUS Test is OK, and you get this problem for RAM @ 0000h, then try the

> next RAM set - say @ 0800h or 1000h (if RAM present - check Memory Map). If

> other RAM all checks OK, or ANY RAM checks OK, then the RAM @ 0000h is

> certainly suspect.

>

> If the RAM is 4-bit, then which bits are locked will tell you which RAM to

> replace.

>

> John :-#)#

>

> --

> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 Call

> (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)

>                www.flippers.com "Old pinballers never die, they just flip

> out"

>

>

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