The tv is working for longer times but it still goto standby , i tried to lower the brightness and contrast by a lot but it still shut down after few minutes or randomly , plz guide me where to check
thanks
GraphicMan
Senior Member
Last Activity: Yesterday, 08:54 AM
Joined: 08-06-2018
Location: Cairo
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it looks like the main cap was the problem, i did replace it with a 450v 330uF instead the original 450v 150uF, according to my LCR the replacement was giving me 303uF but a bit less ESR, however it does have a belly on above and have been sitting for years with no use it looks like it did the trick, at the begining the tv did goto sleep but soon went back on by itself, the more i test the less the turning off, i know from experience that old caps need time to wake up again, only time will prove that
the other subject is that it seems like i cant find the right spots to measure voltages,...Leave a comment:
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yes the 300v is about 334v ( i think while on sleep) i have pulled out the biggest cap on the psu and measured it good, i can replace also just to make sure, it is difficult to measure the voltages while on because the tv now barely turns on, it just switch back to sleep almost instantly giving me no time to measure anything, i dont have the schematics , do you mean i should looks for C509 and C531 and replace then where they are? or they might have different numbers?...Leave a comment:
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21SF8XEL 21" CRT TV Turns off by itself
Hello
The chassis number is kd -331 (v1.0) sh12144
Tv once plugged in it shows the red led normally, once clicked on ch+ or ch- it does show the normal blue screen with no issues, but that is when it was left for few hours Off, then shortly it goes back to sleep by itself, tries by itself to go back on but it does not and then to sleep and sometimes if i try so many times it does not even show the red led anymore unless i unplug and plug again, after the first try if i try again to turn it on it never show anything on the screen anymore, just goes to sleep
what could be it?... -
Now i am at the original problem the customer was complaining from, which is the tv works sometimes and then goto standby , then might work again by itself and so on randomly,
what do you think specially that i did not find any blown nor a swollen capLeave a comment:
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The TV worked again directly after a correct trace reconstructions based on your suggestion, will let you know if there are any problems, so far so good, thank you very muchLeave a comment:
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yes indeed i agree with your assumption
i have shared a pic showing where is the opticoupler
now i need first to check that STR, see if it might be still good or bad, i know it is impossible to know for sure on cold testing but at least pass it
can you tell me how to test it for that?
thanks a lot for your help and time [ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3654578}[/ATTACH]...Leave a comment:
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21SF8XEL 21" CRT TV ripped pads, PCB (kd -331 (v1.0) sh12144)
Hello
someone forced the STR (FSCQ1265RT) out and ripped the pads off
now I need to reconstruct the tracks but I dont know how it will go (no prior pics before the damage)
Attached the affected area pic, pic 2 is the best i could found online for the same area [ATTACH=JSON]{"data-align":"none","data-size":"full","data-attachmentid":3654435}[/ATTACH]
the pins from 1 to 5 are for the STR
any help is appreciated
ThanksHello
someone forced the STR (FSCQ1265RT) out and ripped the pads off
now I... -
it turned out that the cause of the noise is from the pc and not the amplifier...Leave a comment:
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Pioneer A-205 faint noise/hiss issue
as the title says, i noticed a faint noise/hiss when there is nothing playing that i dont think i have had with this unit before ever, i have not changed its location
what makes it more weird, this noise is gone almost completely if my hand gets within 5cm or less close to it (close to the panel)!!
out of curiosity what does that mean?
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hmm i found the problem
it is from the "good" end of the same cable i fixed its other end, the connector looks so intact but i discovered the problem when it twist, so aparently it needs to be cut and remade, i know i have not done anything wrong in the assembly it is just that cable is so evil, it never failed the dmm tests also
but the unit is working great now
thank you very much...Leave a comment:
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I have checked also that cable and the connectivity is correct
this is the large cable from the back pcb to the top one
could the problem be from a tiny transistor on the main board? i have seen a video with a channel not working and a transistor was the issue
i am stuck here now, plz help...Leave a comment:
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ok i am back to a good middle point
i found a bad connector! which made all the late issues
i fixed it properly and now i am back to:
just no left channel, headphones are very good, no relay issues, overall sound quality and volume really good, no noises from the pot at all
i have blobbed the direct switch pins so i am testing now with much less possible issues
where the problem could be?
i tried to move the other larger cable which looks good but nothing at all at that channel, i think if the input was the problem i would never get signals from both channels...Leave a comment:
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I also removed the headphone jack, just to get it out of the equation (however it is good)Leave a comment:
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plz dont forget to tell me about these 2 pins specifically coz i did something, i desoldered both using the copper wick (completely clean) and i did test the switch (both pins isolated from the pcb), and it works perfectly it does d/c and connect them so the short is not from the switch, however when i test the pads continuity they are always connected, so i want to know if that is ok or they should not be connected all the time at any state
the other pin does d/c / connect, the other B switch is perfect also, it is important coz it could mean something, however like i said keeping A on...Leave a comment:
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this is the best i could find with my limited knowledge in schematic drawings for the direct switch pins
but here it is rotated compared to the pcb pic i shared, is the small + means connected together? and on which state is that? off by default
just trying to learn something new
thanks...Leave a comment:
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in addition:
also here is a pic for the front panel, showing the 12 pins
i would like to first solder them to the "direct switch" OFF state without using the switch, just to make sure and make it easy to diagnose
plz let me know how should i blob / wire them without the switch, just mark for me the connected pins and i will do it
thanks...Leave a comment:
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ok finally some good news
i re soldered again and add a re flowing /soldering to the relay pins and some other pins that looks they have little solder (close to the connector)
there is sound on both channels , but for few seconds and when i tried to press on the direct switch there was noises (which is not news, i know it have issues) but the news is that the relay started to go on/off quickly, so i decided to power off the unit immediately to check
now i removed the direct switch
and disassembled it, it is complex and have 12 pins!
for that i need to know what is...Leave a comment:
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i am assuming that "x" issue (connected all the time) should not be the problem coz whether A switch is on or off the output is not affected as far as B switch is good and ON and that by itself is worrying me...Leave a comment:
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i thought to test the connectivity of these switches
B is perfect which is the one i am using all the time
A connect / disconnect only the one marked right, X is always ON no matter what
is that right or wrong? can this cause all that issues including the very faint sound on the phones?
i really dont want to pull these out unless i am sure it is the issue coz it is a lot of work
the 2 switches are both crimped to a single steel plate, for that i will have to desolder the 12 pins at the same time in order to be able to pull it out!
thanks...Leave a comment:
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