Charging problem

**miked** · February 18th, 2016 05:19 PM

isuzu tfr 4ja1

before: 13.8 -14.3 volts (full load to no load)

tapos naging below 12.5 volts and below. kahit na irev mo ng mataas e hindi na masyado lumalampas ng 12.5 volts.

so inassume ko na pudpod na carbon brush. so ayun baklas ng alternator at nung nakita ko carbon brush e abnormally short na yung isa tapos mahaba pa yung kapares nya na brush. so ang ginawa ko pinalitan na lang. kasama rin syempre yung oil seal.

tinesting ko rin yung stator at coil for continuity, etc. kaso mabilisan dahil may lakad sana ako netong hapon.

kaso ganun pa rin yung charging voltage after nung supposed to be "repair"....

dalawang beses din pumutok yung fuse controlling the charge relay at fuel cut solenoid.

kapag icoconnect ko na ang battery e nagki-click yung charge relay kahit naka-off sa susian. aba e 2.5 amperes din yung current draw nung sinukat ko. pero kung disconnected yung B (charging) terminal nung alternator e hindi nagki-click yung charge relay.

ang nakakawindang pa ay nawawala ang battery warning at fuel sedimentor warning lamps kapag isasalpak ko yung fuse sa circuit (kung saan nagkaroon ng 2x na blown fuse)

ewan ko. mejo pagod pako kaya tinigilan ko muna.

ayoko lang kasing palitan agad alternator at malaman na simpleng wiring problem lang pala.

nangyari na ba sa inyo ito mga kaibigan? kung oo, anong ginawa nyo?

tulong!!

**ParticleX** · February 19th, 2016 09:06 AM

Could be the IC / voltage regulator? Dunno how to test this without consulting a electrical shop. Guess lang since you have done an extensive troubleshooting already

**dr. d** · February 19th, 2016 09:21 AM

"IC" inside alternator. i had it checked by an alternator shop. replacement of the IC solved the problem (non-isuzu vehicle, me).

**miked** · February 19th, 2016 10:57 AM

Originally Posted by dr. d

"IC" inside alternator. i had it checked by an alternator shop. replacement of the IC solved the problem (non-isuzu vehicle, me).

removed the alternator again. bawat isa sa tatlong diode ay chineck ko ang continuity

488 ohms tapos 1238 ohm with the test leads reversed. bawat isa sa tatlong diode ganyan ang reading. hindi ba dapat zero ohms tapos infinity?

tapos chineck ko uli yung wiring ng charge relay. with the test lead connected to the negative battery cable, zero ohms (continuous) ang reading when connected to the terminal socket #30 and #87. ayon sa aking pagkakaalam, ang 30 & 87 is the load circuit. tapos 30 is connected to the positive side and 87 is to the load. pero bakit continuous?

pinapanalangin ko na nga sana ic or diode lang para straightforward pero parang maghahanap ako ng short to ground neto ng matagal.

namomonkey wrench nako a.

**jick.cejoco** · February 19th, 2016 11:08 AM

Originally Posted by miked

removed the alternator again. bawat isa sa tatlong diode ay chineck ko ang continuity

488 ohms tapos 1238 ohm with the test leads reversed. bawat isa sa tatlong diode ganyan ang reading. hindi ba dapat zero ohms tapos infinity?

tapos chineck ko uli yung wiring ng charge relay. with the test lead connected to the negative battery cable, zero ohms (continuous) ang reading when connected to the terminal socket #30 and #87. ayon sa aking pagkakaalam, ang 30 & 87 is the load circuit. tapos 30 is connected to the positive side and 87 is to the load. pero bakit continuous?

pinapanalangin ko na nga sana ic or diode lang para straightforward pero parang maghahanap ako ng short to ground neto ng matagal.

namomonkey wrench nako a.

try using a digital multimeter. in diode check mode,
forward bias should read approximately 5v
reverse bias should read OL or infinity

if reading/s are off even on one diode out of the rectifier bridge, the rectifier bridge assembly is shorted.

**miked** · February 19th, 2016 12:00 PM

Originally Posted by jick.cejoco

try using a digital multimeter. in diode check mode,
forward bias should read approximately 5v
reverse bias should read OL or infinity

if reading/s are off even on one diode out of the rectifier bridge, the rectifier bridge assembly is shorted.

i have a dmm with a diode check but reads ohms i think. not volts. it reads 1206 and 460 . diode trio is still connected to field coil and regulator.

what puzzles me is that the 15 amp fuse (code CB-3) for the charge relay, alternator, fuel cut solenoid, thermo switch keeps blowing.

with the key on (engine off), the battery (charge) and fuel sedimentor warning lamps goes off when i put in a fuse on CB-3. these two lamps comes back on when i remove the fuse. btw, these two lamps are connected to each other via the charge relay.

**miked** · February 19th, 2016 12:26 PM

Originally Posted by jick.cejoco

try using a digital multimeter. in diode check mode,
forward bias should read approximately 5v
reverse bias should read OL or infinity

if reading/s are off even on one diode out of the rectifier bridge, the rectifier bridge assembly is shorted.

hmmmm

kung shorted ang isa man lang sa mga diode or lahat ng diode, magchcharge pa rin ito right?

kung open naman ang isa o lahat, hindi na magchcharge right?

**miked** · February 19th, 2016 03:29 PM

Originally Posted by jick.cejoco

try using a digital multimeter. in diode check mode,
forward bias should read approximately 5v
reverse bias should read OL or infinity

if reading/s are off even on one diode out of the rectifier bridge, the rectifier bridge assembly is shorted.

let me correct myself on some of my errors sir.

studied the diagram of the charging circuit and i was able to separate the rectifier diodes (ac to dc) from the diode trio (for voltage regulation). the diode trio for volt regulation all reads approximately 480 ohms and 1240 ohms. so i assume they are good.

the rectifier diodes are similar to the one on the left on this pic borrowed from the internet: Auto Rectifier, Alternator Rectifier Diode, Automobile Diode, Press fit Diode, Avalanche Diode manufacturer ......mas maliit nga lang.

did some continuity test on the rectifier diodes. the 3 diodes connected to the "B" (charging) terminal all reads the same even with the test leads reversed. continuity on both sides. while the "negative/ground" side diode pack reads 446 ohms and infinity (OL).

am i lucky? but what are the odds of these 3 diodes fail at the same time?

**Flipo** · February 19th, 2016 11:28 AM

Originally Posted by miked

removed the alternator again. bawat isa sa tatlong diode ay chineck ko ang continuity

488 ohms tapos 1238 ohm with the test leads reversed. bawat isa sa tatlong diode ganyan ang reading. hindi ba dapat zero ohms tapos infinity?

tapos chineck ko uli yung wiring ng charge relay. with the test lead connected to the negative battery cable, zero ohms (continuous) ang reading when connected to the terminal socket #30 and #87. ayon sa aking pagkakaalam, ang 30 & 87 is the load circuit. tapos 30 is connected to the positive side and 87 is to the load. pero bakit continuous?

pinapanalangin ko na nga sana ic or diode lang para straightforward pero parang maghahanap ako ng short to ground neto ng matagal.

namomonkey wrench nako a.

With regards to the diodes, it looks okay. Nang tinest mo nakakabit yata sa circuit? Try to test a diode with an ohm meter that is disconnected from the circuit just for comparison.

Ilang taon na yung battery? Ito kasi ang malaking load sa alternator.

**miked** · February 19th, 2016 11:50 AM

Originally Posted by Flipo

With regards to the diodes, it looks okay. Nang tinest mo nakakabit yata sa circuit? Try to test a diode with an ohm meter that is disconnected from the circuit just for comparison.

Ilang taon na yung battery? Ito kasi ang malaking load sa alternator.

wala pa isang taon ang battery....good thing may ininstall ako na voltmeter sa sasakyan kaya nakita ko agad at naiuwi pa ng bahay. kung hinde e hinila na ito somewhere.

yup nakakabit pa sa field coil at regulator yung diode trio nung chineck ko.