no one can tell you the value of R20 and D8 according to your pictures as they are not populated. Why are you interested in this particular components?
Which kind of problem do you have? What kind of malfunction?
What happened to the board? Why is it so dirty?
The housing of both relays look like if they are damaged. Also the two electrolytic capacitors C1 & C9 look damaged (uplifted cap?).
BR
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I had a second look on the pictures, it seems there are the remainings of D8. I think it should be the same as the diode below, shown on your second picture (1605968064898699642010).