current analysis short/konslet nokia bb5. . . godluck. . . . . click the image to open in full size.
for handphone bb5 yg use ic rf ahne, use processor rapgsm v1.1 not rap3g.
rapgsmv1.1 this belong dlm cmos processor (mosfet) yg be combination series field effect transistor vdd(drain) sbg teg. the positive and vss(source) sbg negative.
in rapgsm this want 2 active pressure kinds as follows:
tension microprocessor vcore=1,4v
data tension signal processor vio=1,8v
in rapgsm this is found 19 foots yg get positive tension vddcore 1,4v(drain) from tahvo and 19 negative tension foots vsscore(source) to ground.
with 11 foots yg get tension vddio 1,8v.
well from almost fifty tension foots input (vdd/vss) to rap that, often experience problem short in kaki2. therefore biggest possibility is caused by rapgsm this.
but when want to do measurement carefuler short or not it in rapgsm this is when done by inject tension and heat feeling (feel yg hot). or called inject tension (gives teg. work yg appropriate, direct from power supply, not again from ic regulator retu& tahvo that, and see current consumption reaction pd power supply).
why? caused by in module ic rapgsm in input vdd/vss found protection mengode sbg switching moment shorting. so that in rap yg short sendiripun tdk feeled hot, but hot happen in regulator yg give tegangan(retu/tahvo). so that can happen wrong detection, hot at retu doesn't mean retu yg short.
as to manner eliminates to detect which component yg short as follows:
(manner eliminates memutus tension towards one of [the] component yg suspected, then compare the current returns in power supply. )
1. eliminate tahvo
pull l2302, if pulled so vcore will lost. cheque returns. does condition msh same? if yes sign tdk there problem dgn vcore for rap.
if hot sdh normal, 100% problem from rapgsm (part microprocessor he).
pull l2301&l2306, if pulled input tahvo from vbat will broken off, rangkain charging tdk work. cheque returns. condition stills same? if yes sign tdk there problem dgn tahvo. if hot sdh normal, problem from tahvo.
2. eliminate pa
pull z7520, so teg. vbat to pa will broken off. cheque returns. if current consumption is normal, so 100% problem in pa.
3. eliminate ic rf (ahne)
pull l7502, teg. vbat to ahne will broken off, if current consumption is normal, so 100% problem in ahne. if tall permanent current, problem not in ahne, reset l7502.
4. eliminate bluetooth ic
pull l6077, so teg. vbat to bt ic will broken off, if current is normal, so ic bt vb4.
5. eliminate camera ic regulator
pull l3303, if current is normal, so problem at camera or camera ic(d3300),
if current stills tall, pull l3304, current is normal, so 100% problem at regulator camera(n3300)
camera ic often also vb4 short.
for part dsp from rapgsm yg get teg. vio. manner eliminates with lift rapgsm. then see to return current reaction pd ps, or feel to what retu still hot. if sdh normal, so sign rapgsm vb4. if retu msh hot/ps the current stills tall, problem sign not from rapgsm.
while short in rapgsm there two possibilities can from kaki2 bga yg evoke short, can also from module rapgsm itself.
if kaki2 bga yg vb4, can be lifted to print (reball)
but if after mereball, current returns to jump up, retu hot. so sign rapgsm sdh broken.
while shorting in handphone, there 3 categories:
1. direct short so pair batt/ps. (current in ps direct jump up)
2. short after depress switch on/off. (current ps rise after depress on/off)
3. short moment do calling/transmit. (current rises tall moment do calling)
condition 1, easiest guess it. investigate eliminate component yg direct get tension from vbatt. spt pa, retu, tahvo, rf ic, bt ic, etc. .
condition 2. rather difficult the detection. investigate eliminate component yg get tension from regulator(retu, tahvo, camera regulator, led regulator, etc)
condition 3. usually damage from pa. . because pa work moment call in//out.Out.
percobaan
9 tahun yang lalu
