Identifying a component to fix welder

[phillrulz]

Hi guys at work im gonna try fix a welder cant remember which type, the "high frequency box" had a nice short across it not sure of the voltage of the board, board was fried as it had charred down to the fibreglass ( it failed and conducted) from what i remember the char was from R1 to R10 so skipped out 176k of resistance obviously blowing the resistor ( cracked ) in the past this board has been fixed from memory a track between two resistors blew out so there is a small bond wire between two resistors acting as the track. this schematic is purely from memory and should be taken with a pinch of salt there is 4 components which i labeled as diodes im not sure what they are, they look like diodes as they are black axial through hole components maybe 15mm  long where you would expect diode polarity line there is what i could describe as chevrons, see bottom right pcb picture, could anyone possibly help identify them, ive tried using a multimeter to check ( continuity across both ways diode check , resistance, capacitance ) problem is they are open circuit so i cant tell what they are...  the welder is obsolete so im the only chance it has of surviving.

[Rasz]

start with some pictures of damaged pcb

[phillrulz]

start with some pictures of damaged pcb

have to wait till friday not in the workshop till then.