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WORD RAM PART (ICll, IC12)
Check the functions related to the word RAM (ICll, IC12).
The word RAM executes programs and performs data processing
for graphic rotation etc. Causes of Error here can include
·the G/A (IC2) and word RAM parts.
Cause of Error: the surroundings of G/A (IC2) and word RANG
(ICll, IC12), pattern disconnection between
the two.
• if there are some passing items in the followings, the
possibility of pattern disconnection is considered to
be low.
1. 2M mode R/W check
2. 2M mode select check
3. Graphic mode check
4. Graphic overwrite mode check
5. Graphic underwrite mode check
6. lM mode R/W check
7. lM mode swap check
8. lM mode overwrite mode check
9. lM mode underwrite mode check
10. VRAM
image check
11. Word RAM to VRAM DMA check
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PERIPHERAL IC
Check peripheral res. One is to check the access to the PCM
RAM (IC13, 14), and another is to check the function of the
backup RAM (IClO).
1. PCM wave memory R/W check
Cause of Error: the surroundings of PCM IC (IC3) and PCM RAM
( IC13, 14)
2. Backup RAM check
Cause of Error: the surroundings of Backup RAM (IClO),
battery (BTl), backup power control IC (IC9)
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CD INTERFACE PART
Check whether the interchange with the CD drive can be carried
out properly, or whether the CD drive itself operates properly.
Cause of Error: the surroundings of G/A (Ic2), CNl, the connect
-ing cable between CNl and CD drive etc.
3
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