User Guide

47
Service Manual NeoTherm 80 - NeoTherm 285
Tools and equipment required:
• Volt-Ohmmeter
• Phillipsheadscrewdriver(size#1)
• Deepsocketfortransformermountingnuts
Test Procedure:
Itissimplesttotestthetransformerbycheckingthe
voltagesatotherpointsontheNTunit.
1. Turnonpowertotheunit.
Warning! Youwillbeworkingwithsectionsof
themachinethatwillcarry120VAC.Donot
attemptthisprocedureunlessyouhavebeen
trainedinsafetechniqueswhenworkingaround
“live”electricalparts.
2. RemovethetopcoversontheNTunitsoyou
canreachthetransformer.
Fig. B30-2 - Reset switch on bottom of transformer
(viewed from below)
Servicing the Transformer (continued)
3. TryresettingtheResetswitch.IftheResetswitchtripsagain,thereisashort-circuitinthe24VACcircuitryor
insidethetransformeritself.
4. Ifthepowerremainson(Resetswitchdoesnottrip),youcancheckfornormalvoltages:
 120VACinput:
 BlackwireonTB1(120Vhot)towhitewireonTB2(neutral)
 24VACoutput:
 BluewireonTB3(24Vhot)toyellowwireonTB4(common)
 Ifthemeterindicates120Vinput,butthereisno24Voutput,thisindicatesabadtransformer.Ifthereisno24V
ACoutput,theoperatordisplaywillnotlightup.
Replacement Procedure:
1. TurnoffthepowertotheNTunit.Usethepowerswitchlocatedabovethecenterofthecontrolpanel.
2. Disconnectthefourwireswhichruntothetransformer.Beforeremovingeachwire,carefullynotethewayitis
threadedthroughtheNTunit.
 • blackwiretoTB1
 • whitewiretoTB2
 • bluewiretoTB3
 • yellowwiretoTB4
3. Removethetwoboltswhichattachthetransformertotheframeofthemachine.
4. Toinstallthenewtransformer,reversetheprocedurewehavejustdescribed.Oncethepowerhasbeenturnedon
again,youmayneedtopresstheResetswitchonthebottomofthetransformer.
Reset
switch
B30
cont.