APC BACK UPC BR800I 220V DOESN'T GO ON LINE.

[BillP]

Hi to all.
I have 3 apc back ups br800i (220 v version) wich does't go on line.
I am an ing by myself and i have the original schematic diagram for this ups model and i want to repair it by my self with the help of your respective repplyers.
Or?-Can any one help me step by step with the repairing of this unit (i have 3 in total)
They show the same problem.
They'r history is as follows:

1. They have been exposed to an enviroment with generator use maby 1 day in 3 months and after 1 year and a half have shown this problem of not going online. (I supose that the generator is the responsabble thing for this type off error)
I have changed the fisical line with stabble input of about 210 to 220 volt (without generator line at all) (here in Albania we have the 220 volt standart on the wall plug) but not worthed!.
The strange thing is that they all have shown the same simptoms and i am 85& sure that the problem is with the part of circuit that calculates the incoming line (like input voltage, quality of input voltage, harmonic of input voltage and so on).
So to make it short i think that this area of circuit is partially or fully damaged, or the the signal that operates this circuit like supply voltage or powering on signal is damaged.

2. As i have controlled closely the schematics and the original board of 1 device i have seen some missing components in the board like r6 or q22 missing at all (i have supposed that maby is a fabrication thing wich should be normal because the projector isn't responsabble for the changings on the schematics after time goes by)

3.Now:
Should i measure all the components that are in the part of circuit wich is responsable for the incoming line detection or what?!!!!?.

Ps:
Thanks for your patience and i appologise for my bad english.
Ceers and a happy new year to all of you.

[BillP · Accepted solution]

Now:
Can any one help me with this type of problem or can poosibly give me a clue tip for repairing this 3 devices.

Thank you again.