Valley FABRICATOR 251, Руководство по обслуживанию

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August 22, 2008
8-1
SERVICE MANUAL FABRICATOR 251
SECTION 8:
CIRCUIT OPERATION
CONNECTOR JE
Bu r nback potentiomete r
100k potentiomete r between pins
Terminal JE-1
bu r nback potentiomete r 0VDC
r efe r ence PCB common
Terminal JE-2
bu r nback potentiomete r app r ox 13VDC when
t r igge r on
r amps down to ze r o afte r t r igge r is r eleased
r efe r ence JA-5
8.01 Circuit Operation Of The Control PCB 7977964
Power Supply
24VAC is taken f r om the auxilia r y wi r ing of the fan. This voltage is then connected to the PCB 7977964 whe r e it is half
wave r ectified and filte r ed. This voltage is then fed to a zene r r egulato r to p r ovide the +15VDC supply fo r the elect r onics
on the ci r cuit boa r d
Inputs to the Control PCB
CONNECTOR JA
Terminal JA-1
t r igge r input=40VDC t r igge r open, app r ox 20VDC
t r igge r closed
r efe r ence JA-5
Terminal JA-2
t r igge r input=0VDC t r igge r open, app r ox 20VDCV
t r igge r closed
r efe r ence JA-5
Terminal JA-3
spot time r pot=12VDCV t r igge r closed 0VDC
t r igge r open
r efe r ence JA-5
Terminal JA-4
spot time r pot= r amps up to 12V f r om 0V when
t r igge r closed
0VDC when t r igge r open
r efe r ence JA-5
Terminal JA-5
PCB common
Terminal JA-6
ove r tempe r atu r e LED anode = app r ox 2VDC when
ove r temp led is ON, 0V when off
r efe r ence JA-5
Terminal JA-7
ove r tempe r atu r e switch=0VDC temp switch
closed, app r ox 15VDCV switch open
r efe r ence JA-5