Cab 50. Cab50

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New Member
Oct 23, 2023
Ive looked at most of the posts with a similair problem.
Purchased a used cab 50.
Feeds pellets and lights.
Green led never comes on so no pellets are fed after initial start up unless reset hit.
Pressure switch has continuity with vac hose hooked up open with hose off.
Snap disc switches seem to funtion properly.
Replaced thermal couple(it was wired backwards but I corrected)
Im at the control board at this point unless someone has any idea what im missing.
Also any idea where i can get a schematic for the board. I found a wiring diagrahm but no schematic so far . Also there is a pick off to ground off the red thermal couple wire at the blade connector what is its purpose? Can i just ground red wire to test? Seems like yellow would be pof signal if red is tied to ground. Thanks in advance

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Also board knows when thermal couple disconnected or backwards it flashes amber in either of those conditions and red light under main fuse is on all the time calling for more pellets. Wiring appears in good condition but havent ohmed it out yet
I ordered a new control box ..I read 3mv between pins 1 and 3 of blade connector from thermal couple. I also ordered an I/C chip to see if I can repair this control box that part is $3 .
Ill update once either of those arrive and i have a chance to test
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After replacing the control box the unit still would still start up but no green light. I reversed the thermal couple leads back the way it originally came wired (yellow to red and red to yellow) and the heater now runs perfect.
i guess reading ahead that some thermal couples are wired backwards threw me off in this case. Although wire colors were backwards electricaly the part was correct...