PS Magazine - TB 43-PS-488
PS, The Preventative Maintenance Monthly
ISSUE 488
JULY 1993
/
f your auxiliaRy poweR unit (APU)
Fails TO c±aNk, check tHe exhaust gas
Temperature
(GT)
tHeRmocouple. YO²
wOn't FI³d a tes´ µ¶R ·t in youR ¸Ms¹ so
many APºs are labeled BaD s»mpLy be-
cause Of a ¼ileD tHeRmOcOuple½
¾ere¿s HOw to test
it:
ÀirstÁ maKe suRe The battery »s d»sÂ
cOÃnecTed aÃd aÄl eÄecTr·cal power is
RemOvedÅ
AH-A .±.
Then disconneC± ±he wire on
THE
laRge posT Of tHe tHermocOuple and
ConNect
both
wires to
The
SÆÇll
post to
TesT²
reconnecT it On tHe smaÈl pOstÉ Êow BotH
wirËs aRe on one pOsT½ ¸hat bypasses the
tHeRmOcoupleÌ
ÍEconÃect The baTtery and/Or elEcTr»Î
cal poweRÏ
If
yOur AÐU craNks, youÑVe
Òund yOuÓ pRoblemÔ
ÕmmeDiateÖy shuT down th×APU, DisÎ
cOnn×ct youR power Øource, and solve
The proBÖem By replac»ng tHe tHeRmoÙ
couple Ö»ke iT says on Pages
15-74
THrough
±5²³6 ofTM 55-1520´238µ¶·.
AÚÛÜr tes
±i
ng
,
make suRe yo² reconnect
tHe w»Res tO The R»gHt pOstsÝ
ÍememBeRÞ tHe APß
IS
easy TO sTarTà
sO always DiscOnnect tHe pOwer source
BeáâRe doing any ma»ntenanceÝ
A Light Touch
Li
±he ²uR±le-back fuseLage fAiRing w³±h ±he moun±ed
naviga±iOnaL ligh± ±oO high and you'll Rip ou± ±he ligh±´S
wiReS.
µhe L³gh±, ¶±eM
2
of Fig
420 ³ ´ 55µ1520¶238¶23P,
iS
cOnnec±ed By ²wO ShO·± wiReS¸ ¹f you open ±he ±uº±le»Back
wide Like yOu do MoS± fa³RingS¼ yOu½ll pull ²he w¾ReS Ou±¸
¿OÀ lif± Áhe panel abOu± fÂuR incheSÃ Reach in and diScOnÄ
neű ±he w³·eSÆ ThiS ligh± ±Ouch w³lÇ keep yOu ou± of ±he
da·k.
·6
LiF¸ng The ¹iRing
Too hºgh wl»l pu¼» ou½
½he lºghT's wiRes²
JU¾Y9·
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