R34 is also a 100K Ohm resistor, and I change these as well. They can eradicate the "flicker" that sometimes affects these displays..
The changing of the digit resistors should be manditory - as Owen has pointed out.
Reflowing the headers pins abd the display pins solves most of the problems with these displays..
My apologies for preempting anything points you wish to make, Owen - I actually enjoy repairing displays.. I used to buy them faulty off eBay just for the fun of repairing them !!
