[Coco] Transplanting 512K RAM expansion?

Stephen Castello zootzoot at cfl.rr.com
Thu May 25 13:10:05 EDT 2006


On Thu, 25 May 2006 18:14:26 +0200, Fedor Steeman
<petrander at gmail.com> had a flock of green cheek conures squawk out:

>Two small questions before I proceed:
>
>1. How can I, from BASIC, check whether the RAM has been properly installed.
>I know PRINT MEM doesn't work, so aren't there some POKEs and PEEKs that I
>can use?
>
>2. Where on the circuit board can I find C65? There is almost a hundred
>capacitators there, and they are not placed in orderly manner according to
>number.
>
>Thanks in advance,
>
>Fedor Steeman

NTSC: C65 is next to IC17.
PAL: to right of CN4, which is next to IC17.  CN4 is one of the
connectors the 512k board plugs into.

Test program from the service manual:
(it doesn't test every location)

10 WIDTH 40:PALETTE 0,0:PALETTE 7,63: CLS8
20 POKE&HFFD9,0
30 FOR A=&H00000 TO &H5FFFF STEP 512
40 D=RND(255)
50 LPOKE A,D
60 B=LPEEK(A)
70 LOCATE 10,2: PRINT"ADDRESS=";A
80 LOCATE 10,4: PRINT"DATA=";D
90 IF B<>D THEN 130
100 NEXT A
110 LOCATE 10,10: PRINT"RAM TEST IS GOOD!"
120 POKE&HFFD8,0: END
130 LOCATE 10,6: PRINT"ERROR!"
140 POKE&HFFD8,0:END

Stephen
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