Hi I have been a member on this forum for some time and the amount of information and help is tremendous. Using this I have given a new lease of life to a number of monitors a tower pc power supply & two lcd tvs, without actually asking for help.
I recently bought a small philips lcd tv for 99p described as "the tv light does show on the television however doesnt seem to turn on" I hoped it would be simple recap job as I only have a very basic multimeter and soldering iron but being retired - time.
Imagine my disappointment when I opened it up to find it stuffed with Rubycon Caps. No bulging or discolouration and no burn marks anywhere. There was even very little dust and the only visible "problem" I could see was that some of the insulation was cracking off one of the wires in the connector cable from the main board to the panel (at the main board end).
The 12v 5amp power supply is OK - tested on another set and this set tested with a known working PS produced the same problem.
I am writing this as I go along as I have many interruptions to contend with.I am also rebuilding a laptop so have used that as an input.(Having first tested it with external monitor & earphones)
On initial switch on with no inputs the standby led changes from red to green then back to red- nothing on screen- not even a flash.
No clicks or hum from speakers(that I could hear). Pressing Volume+ on remote causes red light to flash. Listening to it later I found that there is a "tick" in the region of 7910 34063AP1. I have not been able to pin it down to a particular component. It ticks nine times when the green light is on then stops.
With the laptop as input the green light stays lit and the ticking is continuous (at the same rate)
I have tried connecting Audio in but it makes no difference and have tried earphones - there is a very quiet background hiss and it picks up the "tick"
I have tried inputs via the scart socket - set top box and dvd but selecting them had no effect. Red turned green 9 ticks and back to red.
I have tested the main fuse (1002) and it is ok. I think I knew that would be the case as the leds work and also components on both main boards get warm.
I have downloaded the schematics,
not that they mean much to me! and am going to look for other fuses.
Only 2 fuses and one on the inverter board all ok.
Aha! Whilst I initially thought (oh dear) ALL the caps were rubycon the two 25v220 s on the inverter are Teapo. As these are/were not highly regarded I dashed out bought and fitted 2 Rubycons thinking great this will fix it. Alas it did not - same problems persist.
I am now posting this as I could do with a bit of help as unassisted poking around with my meter is likely to do more harm than good. I am thinking of working down the voltage tests on p25 of the schematic but need a bit of advice even before I can do that.(dont laugh - oh well - you might as well!!)
1. Does 3V3 mean 3.3 volts 2V9 mean 2.9 volts etc.
2. When it says measure voltage on pin x does that mean I put the
positive lead of my meter on the pin and the negative on the
chassis?
I am sorry this is a bit of a read but as I see it I may as well say what I have tried in the hope that someone has come across a similar problem and to put you in no doubt as the limitations of my knowledge.Also as it is only a 15" tv I dont really want to be spending a lot of money trying to fix it.
On second thoughts I am going to delay posting until I have tried to rig something so I can test the back lights - even a flash would be encouraging.
Have tested each ccfl using an old laptop inverter all lit well, only a short test but enough to know they work.
Just preparing this and getting the pictures together and decided to google the inverter board as I was only getting 12v and had recently read that LCD Tv inverters need 24v.
I now know that some smaller tvs (including this one) are 12v. Anyway one site which came up had someone with the 17 inch version f his tv with the same symptoms as mine and they appear to have fixed it replacing some of the 25v 470 caps on the main board, so now I am going to try that, even though they are Rubycons!
Hurrah! partial success - fitted new caps to the main board( justleft them on long legs in case it never gets fixed) and voila - the back lights came on. Checked and rechecked the vga cable to the laptop source then decided to press on with replacing the caps on the Tuner board.
When I took it off I spotted that I had not re connected the cable to the panel - while I was plugging and unplugging the panel to see what happened having read "Acer V193W No display/Light, odd ticking from boards..."post by InixPc.
Plugged it in -put the Tuner Board back reconnected everything switched on and my windows desktop is there. Even got sound when I eventually spotted Audio in and Audio in (Pc) are not interchangable.
Great ran upstairs with it to test with DVD and Digital STB and..... failed ! picture is green!!! I know that this is sometimes down to the scart cable but this was separate inputs with separate cables. I am now googling like mad and will retry tomorrow -on the table -not wobbling about on the bed.
Still green - tried scart, video in, s-video- still green but as a pc monitor it is spot on.
Changed the 25v470 caps and tried again - still green.
Changed a 16v 1000 and 16v470 and its gone back to black and ticking - wished Id quit whilst ahead - who needs tv. Going to back track 1 cap at a time. Done a few but no luck.
Its been a bit chilly here so having read somewhere cold caps = high esr thought Id give it a blast with a hot air gun. Hah, it came on and more importantly, in my mind, wouldnt come back on when cooled. I now just need to narrow it down a bit - it seems its the tuner board perhaps caps near the TV tuner box. Cant find any that size so its back to the shop.
Got replacements and fitted them and... its on but the tv section is still green but on PC it works fine???.
I am now under pressure as its all got to be cleared away for Christmas. Just happened to wonder if there is a separate video chip for the pc and one for the tv- no doubt someone would have spotted this if id put it on the forum. When I press on the larger chip the picture is fine - whoops -if I press almost anywhere on the board it is fine - I guess it must be a cold joint somewhere.
Cant just see where so I have resorted to putting it back together with a plastic post between the circuit board and the metal cover and some more packing between the metal cover and the set back.Measured it all so its not too much pressure just enough to get it
working. Will try it again in the morning and post this as some of it may be of help to others.
Well it works- pictures attached to prove it.
After the new year I might have another go at getting it to be not green. If anyone has any good ideas on which area I should look in for poor joints which might directly affect the screen colours that would be a help. If the chips need reseating/reballing? that's something I wont be trying. In any case I have another small tv project that I can get started on as well as the hundreds of other things I am leaving till next year.
Best wishes to you all.
Selldoor
I recently bought a small philips lcd tv for 99p described as "the tv light does show on the television however doesnt seem to turn on" I hoped it would be simple recap job as I only have a very basic multimeter and soldering iron but being retired - time.
Imagine my disappointment when I opened it up to find it stuffed with Rubycon Caps. No bulging or discolouration and no burn marks anywhere. There was even very little dust and the only visible "problem" I could see was that some of the insulation was cracking off one of the wires in the connector cable from the main board to the panel (at the main board end).
The 12v 5amp power supply is OK - tested on another set and this set tested with a known working PS produced the same problem.
I am writing this as I go along as I have many interruptions to contend with.I am also rebuilding a laptop so have used that as an input.(Having first tested it with external monitor & earphones)
On initial switch on with no inputs the standby led changes from red to green then back to red- nothing on screen- not even a flash.
No clicks or hum from speakers(that I could hear). Pressing Volume+ on remote causes red light to flash. Listening to it later I found that there is a "tick" in the region of 7910 34063AP1. I have not been able to pin it down to a particular component. It ticks nine times when the green light is on then stops.
With the laptop as input the green light stays lit and the ticking is continuous (at the same rate)
I have tried connecting Audio in but it makes no difference and have tried earphones - there is a very quiet background hiss and it picks up the "tick"
I have tried inputs via the scart socket - set top box and dvd but selecting them had no effect. Red turned green 9 ticks and back to red.
I have tested the main fuse (1002) and it is ok. I think I knew that would be the case as the leds work and also components on both main boards get warm.
I have downloaded the schematics,
not that they mean much to me! and am going to look for other fuses.
Only 2 fuses and one on the inverter board all ok.
Aha! Whilst I initially thought (oh dear) ALL the caps were rubycon the two 25v220 s on the inverter are Teapo. As these are/were not highly regarded I dashed out bought and fitted 2 Rubycons thinking great this will fix it. Alas it did not - same problems persist.
I am now posting this as I could do with a bit of help as unassisted poking around with my meter is likely to do more harm than good. I am thinking of working down the voltage tests on p25 of the schematic but need a bit of advice even before I can do that.(dont laugh - oh well - you might as well!!)
1. Does 3V3 mean 3.3 volts 2V9 mean 2.9 volts etc.
2. When it says measure voltage on pin x does that mean I put the
positive lead of my meter on the pin and the negative on the
chassis?
I am sorry this is a bit of a read but as I see it I may as well say what I have tried in the hope that someone has come across a similar problem and to put you in no doubt as the limitations of my knowledge.Also as it is only a 15" tv I dont really want to be spending a lot of money trying to fix it.
On second thoughts I am going to delay posting until I have tried to rig something so I can test the back lights - even a flash would be encouraging.
Have tested each ccfl using an old laptop inverter all lit well, only a short test but enough to know they work.
Just preparing this and getting the pictures together and decided to google the inverter board as I was only getting 12v and had recently read that LCD Tv inverters need 24v.
I now know that some smaller tvs (including this one) are 12v. Anyway one site which came up had someone with the 17 inch version f his tv with the same symptoms as mine and they appear to have fixed it replacing some of the 25v 470 caps on the main board, so now I am going to try that, even though they are Rubycons!
Hurrah! partial success - fitted new caps to the main board( justleft them on long legs in case it never gets fixed) and voila - the back lights came on. Checked and rechecked the vga cable to the laptop source then decided to press on with replacing the caps on the Tuner board.
When I took it off I spotted that I had not re connected the cable to the panel - while I was plugging and unplugging the panel to see what happened having read "Acer V193W No display/Light, odd ticking from boards..."post by InixPc.
Plugged it in -put the Tuner Board back reconnected everything switched on and my windows desktop is there. Even got sound when I eventually spotted Audio in and Audio in (Pc) are not interchangable.
Great ran upstairs with it to test with DVD and Digital STB and..... failed ! picture is green!!! I know that this is sometimes down to the scart cable but this was separate inputs with separate cables. I am now googling like mad and will retry tomorrow -on the table -not wobbling about on the bed.
Still green - tried scart, video in, s-video- still green but as a pc monitor it is spot on.
Changed the 25v470 caps and tried again - still green.
Changed a 16v 1000 and 16v470 and its gone back to black and ticking - wished Id quit whilst ahead - who needs tv. Going to back track 1 cap at a time. Done a few but no luck.
Its been a bit chilly here so having read somewhere cold caps = high esr thought Id give it a blast with a hot air gun. Hah, it came on and more importantly, in my mind, wouldnt come back on when cooled. I now just need to narrow it down a bit - it seems its the tuner board perhaps caps near the TV tuner box. Cant find any that size so its back to the shop.
Got replacements and fitted them and... its on but the tv section is still green but on PC it works fine???.
I am now under pressure as its all got to be cleared away for Christmas. Just happened to wonder if there is a separate video chip for the pc and one for the tv- no doubt someone would have spotted this if id put it on the forum. When I press on the larger chip the picture is fine - whoops -if I press almost anywhere on the board it is fine - I guess it must be a cold joint somewhere.
Cant just see where so I have resorted to putting it back together with a plastic post between the circuit board and the metal cover and some more packing between the metal cover and the set back.Measured it all so its not too much pressure just enough to get it
working. Will try it again in the morning and post this as some of it may be of help to others.
Well it works- pictures attached to prove it.
After the new year I might have another go at getting it to be not green. If anyone has any good ideas on which area I should look in for poor joints which might directly affect the screen colours that would be a help. If the chips need reseating/reballing? that's something I wont be trying. In any case I have another small tv project that I can get started on as well as the hundreds of other things I am leaving till next year.
Best wishes to you all.
Selldoor
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