Lights flash 10 times failure, repair bad reference tip is terminal board or DS board. Once maintenance commercial PDP 11 series, SD plate/SC/P board failure, indicator light will flash 10 times. Due to no relay protection, immediately and voice fault area in P or D plate can be determined.
 
First, remove P plate test (test method training materials have, don't repeat here) is normal. Determine fault in D plate, only then can be removed to the DS terminal board components, maintenance of the line of sight is very intuitive.
 
Considering no relay and first measured the CPU working conditions, STB3.3 V normal, there are about 2.9 V voltage, 24, 25 feet data X9000 crystals XO and XI have 1.77 V and 1.73 V, oscillation is normal.
 
 
Measuring 75 feet only 0.7 V, the normal boot should be about 3.2 V. Not very sure is bad CPU, remove CPUIC9003 and replacement of the CPU on another piece of D board, commissioning, troubleshooting.