LEM procon 1800 plus
repair/popravilo
Procon 1800 plus
Replacing transistors
Q226B(2.ch) 2SC5200 and Q227B (2.ch) 2SA1943 output failed-protect/menjava
tranzistorjev Q226B (2.kan) 2SC5200 in Q227B (2.kan) 2SA1943 izhod ne deluje-protect
Zaradi
dotrajanosti ali kakšnih napak omrežja,breme manjše od 4E (v mostiču manj kot
8E) itd…se nam lahko večkrat zgodi da odpove izhod.Na
končni stopnji ne deluje izhod 2,vklopi se indikator protect.
Due to wear
or what network errors,load less
than 4E (bridge less than 8E) , etc. .. can often
happen to failed output. On
power end 2. output does not work,the protect
light on.
Previdno odvijemo zgornjo panel plošče z vijaki.
Carefully unscrew
the top panel boards with screws.
Ker je
napetost v kratkem stiku ne je moremo zmeriti.Preverimo
izhodne trazistorje med B in C na obeh kanalih.
Regarding the
voltage is in short circuit can not be checked. Check
the output transistors between C and E on both channels.
Ugotovimo
da je na kanalu 2 v kratkem stiku plus pol napajanja na maso. Odvijemo
kompletni blok z hladilnikom in odstranimo konektorje.
Pozneje bomo preveri tudi negativni pol.
We find
that on channel 2 is short-circuited positive half power
supply on gnd. Unscrew complete
block with a cooler and remove
the connectors. Later, we will
check the negative power supply.
Ko smo
odstranili kompletni blok 2 kanala si označimo barvo kablov na vezju in odspajkamo žičko za bridge
povezavo.
When we
removed the complete block of 2. channel ,label color wires
in the pcb, and unsolder wire
for bridge connection.
Sedaj
nastopi del,kjer se lahko gremo malo loterije. Malokdaj vsi tranzistorji
prebiti,ponavadi sta dva para ali celo en par. Odščipnemo sponke kolektorja in na vezju merimo upornost med C in E,ter tranzistor.
Now comes
the part where you can go a little
lottery. Rarely all the transistors
are failed,usually two pairs of
even one pair. Disconnect the collector terminal and measue the resistance
on pcb between C and E, and transistor.
Ko smo
ugotovili kateri tranzistor je v kratkem stiku,ga zamenjamo. Preverimo tudi
upornosti ostalih tranzistorjev,če zelo odstopajo je to znak da lahko prebijejo
med delovanjem. Najbolje jih je zamenjati z novimi.
we
When we
find out which transistor is short-circuited, we have to replace
it. Check the resistance of the
other transistors if very deviate
it is a sign that they can fail during
operation. We have to replace them with new
ones.
Preden končno
stopnjo sestavimo,vklopimo aparat,protect indikator
mora ugasniti. Preverimo simetrično napetost,ta mora biti približno +-110V. To
je znak da je v z napajanjem vse v redu. Po potrebi lahko nastavimo tudi
mirovni tok (sledimo navodilom-service manual).
Before you
assemble the power-end, switch
on the unit, protect indicator should light off.
Check symmetrical voltage, it should be about +-110V. This is a sign that the power supply
is OK. If necessary, you can adjust
the offset current (follow instructions-service manual).
Opozorilo:AudioLogs ne odgovarja,da ne bo
prišlo do napake med postopkom ali za škodo ki se lahko zgodi. Preden se lotite
popravila izlključite aparat iz omrežja. S posegom v
aparat lahko poškodujete vezje. Bodite previdni pri menjavi transistorjev,ker
lahko poškodujete ploščo tiskanega vezja. Če tega posega niste vešči naj za vas
to opravi strokovnjak.
Warning: AudioLogs is not responsible, that there will be no errors during the procedure or damage that may occur. Before you start to repair,plug
out unit from the network. By intervening in unit could damage the circuit. Be careful when frepacing transistors because they can damage the pcb. If you are not skilled in this practice
should be done for you an expert.
AudioLogs,November2013,info@audiologs.com
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