XG-P20XE (serv.man5). Service Manual Part 2 - Troubleshooting, Block and overall diagrams - p36-87 - Sharp Projector Service Manual (repair manual). Page 5

Are there signal inputs at 
SC8405, SC8502, SC8404? 
Are voltages applied to EA 
connectors?

Check IC1401,Q1401,Q1402, 
Q1403 and their peripheral 
circuits.

Are there signal outputs at
pins (18) (16) (14) of IC1401?

Are there signal inputs at 
pin(44) and (47) of IC1101, 
IC1102, IC1201, IC1202, 
IC1301 and IC1302?

Check IC1101,IC1201,IC1301   
and their peripheral circuits.

Are there signal outputs at pins 
(17), (19), (21), (28), (30) and 
(32) of IC1101, IC1102, 
IC1201, IC1202, IC1301 and 
IC1302?

If there is no signal input at 
pins (15) and (30) of  
SC1101, SC1102 and 
SC1103, check IC1001, 
IC1004 and their 
peripheral circuits.

If there is no signal input at 
pins (1) and (31) of  SC1101, 
SC1102 and SC1103, check 
the switching circuit and 
amplifier circuit of IC1101, 
IC1201, IC1301, IC1102, 
IC1202, IC1302 and their 
peripheral circuits.

Are there signal inputs at 
SC1101, SC1201 and 
SC1301?

Check IC1558, IC1559, 
IC1551~IC1556 and their 
peripheral circuits.

Check the R, G and B panels.

If there is no signal at EA 
connector or SC8404, SC8405 
and SC8502, go to Checking 
the power unitblock.

If there is no signal at P4302, 
P4303 and P4301, go to 
"Checking the video system". 

Check IC2102, IC2202, 
IC2302 and their peripheral 
circuits.