Marshall Mosfer Lead 100 diy repair help

[Roly]

That colour rendition can't be too hot 'coz I would read C22 as;

Brown = 1
Black = 0
Orange = 3 = 000
White (9) "tolerance band".  Since resistors don't use a white tolerance marking this is a clue that it's a cap not a resistor. {another clue is that it would test as open circuit rather than 10k ohms}

This would make it 1,0,000 and it would be pF, so 10,000pF or 10nF, exactly as they are marked on the circuit.  I suspect that if they have been replaced it may have been because of the type rather than the value.

For reference the values of the resistors in your pic are;

R18 = brown, black, orange, (gold) = 1,0,000 5% = 10k 5%
R19 = yellow, violet, orange, (gold) = 4,7,000 5% = 47k 5%
R20 as R18
R21 = brown, black, yellow, (gold) = 1,0,0000 5% = 100k 5%

[jjonas]

That colour rendition can't be too hot 'coz I would read C22 as;

Brown = 1
Black = 0
Orange = 3 = 000
White (9) "tolerance band".  Since resistors don't use a white tolerance marking this is a clue that it's a cap not a resistor. {another clue is that it would test as open circuit rather than 10k ohms}

You're right that one of the bands is black and not green, I don't know why I wrote green, because I did see it was black as well. Sorry for that.

As to the tolerance band, probably it's white as you say, that perhaps makes the most sense, but personally I can't really tell for sure whether it's yellow or white just by looking at it.

[J M Fahey]

Don´t worry, I was also misled by that at the beginning.
And even though the PCB silscreen clearly labels them as "Cxx" I thought they were an assembly or previous repair error .... until I measured them and found that they actually were Caps.
That C22 in your picture is brown black orange meaning 10000 or 103 or .01uF .

EDIT: and the 4th band in a cap is not tolerance but voltage.

Yellow would be a reasonable 4(00) V
White would be 9(00)V, a very unusual rating.