Re: VX 724 black screen green light flashing
HI Rtech, If is was sorry, couldnt let it go
Got my VX912 off Ebay, same board as the VX724, but screen is 2" bigger, it had the 2 seconds to black flashing , simple fix, swapped about 4 domed caps over and Bobs your Uncle
YEEE now got a 2 screen set up
stevepw
Member
Last Activity: 09-29-2013, 03:02 PM
Joined: 11-03-2010
Location: Hartlepool England
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Re: VX 724 black screen green light flashing
HI All
just an update , got some new caps to day to replace a duff H154 put them in and WOW a working screen again, been on for an hour now looks good with no funny smells..
to get it working I replaced
5 domed caps on the power board
one burnt transformer (many thanks rtech, I would have struggled without this )
The 2 small transisitors underneath above
both of the H154 caps one of which had gone
Thanks for the diagnosis, tips, help ive enjoyed the learning...Leave a comment:
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Re: VX 724 black screen green light flashing
Many thanks Rtech
looks ok, outsides common , from centre pin to either outside pins gives 198ohms and swopping leads gives open reading both ways.
for the brown H154 J there are some with 150nF is this the same as 0.15UF both rated at 250V these are blue too , does it matter , seebelow
[url]http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6689961[/url]Re: VX 724 black screen green light ...rom centre pinLeave a comment:
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Re: VX 724 black screen green light flashing
I have just removed the two brown radial polypropylene caps near the transformers
Rtech you mentioned these on another thread thyre H154 J , with my meter set on 2UF
i get 0.141 on the good side and 0 on the one nearest burnt out transformer
I have somne transistors ordered from RS , shoukd be in in next 2 days
It may be worth checking the shottkey diode MBR101100CT, as this has been highlighted as an issue on threads does this need to be removed from board to do it properly,Leave a comment:
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Re: VX 724 black screen green light flashing
Rtech and Plainbill
I was wondering what bit if any started the chain of events leading to failure to work,
transformer getting hot making transistor fail or vice versa
electrolytics going domed and causing above to fail
or the other caps... brown , blue , yellow even
i read on another thread asjemb? who seemed to replace everything just to be sure
if the transistorsand transformer are replaced would another duff cap just make them fail again?Leave a comment:
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Re: VX 724 black screen green light flashing
hi
Yes tested both transformers
T1 next to shorted transistors all readings between 0.7-1.6ohms
T2 shows
1-2 746ohms
1-3 746ohms
1-4 746ohms
1-5 746ohms
1-6 0
2-3 0
2-4 0
2-5 0
2-6 556ohms
3-4 0
3-5 0
3-6 559ohms
4-5 0
4-6 559ohms
5-6 559 ohms
guess T1 is a goner!...Leave a comment:
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Re: VX 724 black screen green light flashing
Thanks it looks like it could work
there are some other numbers on the side SPI 8T J00029
0523 1 FC
i will have a look at some Uk suppliers...Leave a comment:
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Re: VX 724 black screen green light flashing
Hi Rtech
thanks for that,having a closer look with eyeglass the underside of the transformer is burnt just where the Q6 transistor is, Q6 also seems to be pitted on top.
so transistors Q6 and Q7 need replacing and a new transformer it has EPC19 stamped on it , would this be the part number hopefully
thanks retiredcaps ill have a look for the transistors...Leave a comment:
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Re: VX 724 black screen green light flashing
hi jetadm guessing its just the three small connectors, i changed the multimeter setting for3and4 as they appeared open on 200ohm
testing from Left to right with pin 1 at top
MMset at 200ohm MM set at 2k ohm
PINS No1 No2 No3 No4
1-2 37.8 38.3 0.500 0.500
1-3 36.7 38.3 0.563 0.564
2-3 1.1 1.4 0.559 0.559Leave a comment:
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Re: VX 724 black screen green light flashing
HI
The part number of the board is AS02B012D75
all 4 resisitors have DK QR on them
to test for shorts am i just checking the 3 small connections on the right of each transistor or the fat one on the left tooLeave a comment:
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VX 724 black screen green light flashing
HI Guys
My Viewsonic VX724 monitor died a few weeks ago, following a few hours where it smelt of burning, it now gives the black screen, green on/off button flashes. (im not an electronics bod but i know which end of the soldering iron to hold!)
I have replaced 5 domed caps on the power board, the green board caps look ok. The button still flashes green.
following previous threads and a bit more troubleshooting, there is 12.3v on the connector that joins the 2 boards with power lead connected.
There are two small connectors at top left...Last edited by stevepw; 12-12-2010, 12:49 PM. -
Re: New Members - please post your introductions here
HI All
I'm Steve
Im from hartlepool England, my job is civil engineering but im quite handy with mechanical items and a soldering iron and I like to fix things rather than chuck them out, no experience of electronics, I found this great forum searching about fixing viewsonic monitors, but thats for another thread
regards
SteveLeave a comment:
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