David, your videos are golden....you should get paid to do this. You appear to really enjoy your craft and I am gratefull you are on UA-cam to share your knowledge. Keep up the good work.
@dukestt Pretty cool find. I have never seen a TV start working just by blowing out the dust. Sometimes temperature variations can effect the way electronics work. Especially with capacitors.
@daltonsbadboy Thanks for the comment. It's satisfying to see these videos are helping people. Electronic repair is much like playing a board game but far better since we get paid when we fix something. It can be extremely frustrating when things don't go right but most of the time it's fun.
@CanyonLakeTX If you replaced the main board and power supply there isn't much left other than the inverter board. Are you guessing at what might be wrong rather than doing tests?
Have fixed many CRT tv's...many times if listen carefully when you plug the tv in you'll hear a little squeaking sound from the power supply, that means it's working.
@GrantsPassTVRepairs I had it on bench test all yesterday and its working fine now and i didnt do anything to it other than suck all the dust out with a hoover and turn it upside down. I got it from the local tip (dump) so i have got a working 32" JVC flat screen for nothing. Cant complain happy days.
@GrantsPassTVRepairs Unfortunatly I am mostly a componant level replacment skill, I wish I was more. Will the inverter board cause the system to try to start then power off? THanks JQ
@dukestt Sounds like a strange problem. The only things I have ever seen cause a TV to automatically turn on is when one of the tactile switches goes bad. Sometimes you can't even tell the switch is bad when you test it. In a case like this I disconnect the switch panel and use the remote control to see if the problem continues. Dave
nice sniffers you got there... one thing about using a DMM is.. you need to watch out for the AC B/W. Most of cheap DMMs have only 400Hz bw. they are only good for you know what.
@GrantsPassTVRepairs I replaced the entire main board and the power supply and it did not change anything. There is another long skinny board next to the screen that I have not yet replaced, however I don't know if it will help/
David I have a LCD that starts up about 2 minutes after you turn it on and then it flashes white and shuts off. If that is the LCD back light it it tost??
I have a JVC flat screen and it does rather a strange thing. It started by turning itself off after around two hours and then switching back on. Nothing strange in that could be a few things. No, the strange thing is , if you have the TV upside down nothing happens it stays on but if you turn it right side up it switches off after two or three minutes. I'm not sure what is causing it but there you go. Any thoughts?
Your pickup coil at 1:31 is quite (physically) large, if you ever need a smaller one, you could try say 50 turns of thin enamelled wire on a short thin length of ferrite rod, like that used for AM radio "loopstick" antennas internal to very small radio handheld portable radio sets. you need less turns due to the ferrite magnifying the inductance. Bigger rods are used in larger sets, but you need a thinner one, though you can score and cut the rod shorter (they are quite fragile so a tap with a hammer after scoring it around with a junior hacksaw will usually result in a clean break) In some newer tiny sets they are made like rectangular slabs like a bar of iron, but they work the same way. The ferrite increase the inductance per turn and therefore the pickup of the coil, but hopefully reduce the size of it and make it more accurate, especially if there's a lot of noise going on in the chassis. For long-rod ferrite coils, they have nulls (dead-spots) off their ends, in line with the centre of the rod and maximum pickup broadsides to it, but for short rods (maybe an inch long) this is less pronounced. [In fact, radio hams doing direction finding actually use the end-on null of the long-rod loopstick response to take bearing on a transmitter, not the maximums, because the nulls are sharper than the maximums so are more accurate] Another thing to use (and much more compact than a ferrite rod coil) is a high-value inductor component, one with PCB legs and maybe a quarter-inch in size at most, shaped like a tiny bobbin with 2 legs out the bottom. Look for values in the high hundreds of microHenries up to about a couple of milliHenries for pickup of most switchers. You can sometimes find these small bobbin inductors on junked boards. Like the ferrite rod coil I describe above, the ferrite inside increases the inductance but makes the coil more compact, so makes it more accurate. This may reduce the pickup (simply due to reduced pickup area) but makes it a lot easier to attack to a plastic rods and poke into hard-to-get places - I've even mounted on on a drinking straw end with fine wires and poked it through the vent holes to diagnose a open switcher without even taking the case off (shining a torch through the slots to see where the general location of the PSU was) Make sure you use a non-metallic rod though, both for safety and not to interfere with the inductance and pickup pattern.
David, your videos are golden....you should get paid to do this. You appear to really enjoy your craft and I am gratefull you are on UA-cam to share your knowledge. Keep up the good work.
ty for all the links
thanks you so much for this keep up the good work
@dukestt Pretty cool find.
I have never seen a TV start working just by blowing out the dust.
Sometimes temperature variations can effect the way electronics work. Especially with capacitors.
@daltonsbadboy
Thanks for the comment. It's satisfying to see these videos are helping people. Electronic repair is much like playing a board game but far better since we get paid when we fix something. It can be extremely frustrating when things don't go right but most of the time it's fun.
Nice to see a new video! It's been a long time.
@CanyonLakeTX I would start by testing the caps in the power supply.
Dave
@CanyonLakeTX If you replaced the main board and power supply there isn't much left other than the inverter board. Are you guessing at what might be wrong rather than doing tests?
@CanyonLakeTX Yes. I have often seen the inverter board cause the TV to shut off right after it starts.
Hi I am from mexico and I am very happy for find your awesome videos thanks for all the tips thanks alot
Have fixed many CRT tv's...many times if listen carefully when you plug the tv in you'll hear a little squeaking sound from the power supply, that means it's working.
@GrantsPassTVRepairs I had it on bench test all yesterday and its working fine now and i didnt do anything to it other than suck all the dust out with a hoover and turn it upside down. I got it from the local tip (dump) so i have got a working 32" JVC flat screen for nothing. Cant complain happy days.
@GrantsPassTVRepairs Unfortunatly I am mostly a componant level replacment skill, I wish I was more. Will the inverter board cause the system to try to start then power off?
THanks
JQ
@dukestt Sounds like a strange problem. The only things I have ever seen cause a TV to automatically turn on is when one of the tactile switches goes bad. Sometimes you can't even tell the switch is bad when you test it. In a case like this I disconnect the switch panel and use the remote control to see if the problem continues.
Dave
nice sniffers you got there...
one thing about using a DMM is.. you need to watch out for the AC B/W. Most of cheap DMMs have only 400Hz bw. they are only good for you know what.
@GrantsPassTVRepairs I replaced the entire main board and the power supply and it did not change anything. There is another long skinny board next to the screen that I have not yet replaced, however I don't know if it will help/
David
I have a LCD that starts up about 2 minutes after you turn it on and then it flashes white and shuts off. If that is the LCD back light it it tost??
clearly observe power section for any dry solder & change power card
I have a JVC flat screen and it does rather a strange thing. It started by turning itself off after around two hours and then switching back on. Nothing strange in that could be a few things. No, the strange thing is , if you have the TV upside down nothing happens it stays on but if you turn it right side up it switches off after two or three minutes. I'm not sure what is causing it but there you go. Any thoughts?
Your pickup coil at 1:31 is quite (physically) large, if you ever need a smaller one, you could try say 50 turns of thin enamelled wire on a short thin length of ferrite rod, like that used for AM radio "loopstick" antennas internal to very small radio handheld portable radio sets. you need less turns due to the ferrite magnifying the inductance.
Bigger rods are used in larger sets, but you need a thinner one, though you can score and cut the rod shorter (they are quite fragile so a tap with a hammer after scoring it around with a junior hacksaw will usually result in a clean break) In some newer tiny sets they are made like rectangular slabs like a bar of iron, but they work the same way.
The ferrite increase the inductance per turn and therefore the pickup of the coil, but hopefully reduce the size of it and make it more accurate, especially if there's a lot of noise going on in the chassis. For long-rod ferrite coils, they have nulls (dead-spots) off their ends, in line with the centre of the rod and maximum pickup broadsides to it, but for short rods (maybe an inch long) this is less pronounced. [In fact, radio hams doing direction finding actually use the end-on null of the long-rod loopstick response to take bearing on a transmitter, not the maximums, because the nulls are sharper than the maximums so are more accurate]
Another thing to use (and much more compact than a ferrite rod coil) is a high-value inductor component, one with PCB legs and maybe a quarter-inch in size at most, shaped like a tiny bobbin with 2 legs out the bottom. Look for values in the high hundreds of microHenries up to about a couple of milliHenries for pickup of most switchers. You can sometimes find these small bobbin inductors on junked boards.
Like the ferrite rod coil I describe above, the ferrite inside increases the inductance but makes the coil more compact, so makes it more accurate. This may reduce the pickup (simply due to reduced pickup area) but makes it a lot easier to attack to a plastic rods and poke into hard-to-get places - I've even mounted on on a drinking straw end with fine wires and poked it through the vent holes to diagnose a open switcher without even taking the case off (shining a torch through the slots to see where the general location of the PSU was) Make sure you use a non-metallic rod though, both for safety and not to interfere with the inductance and pickup pattern.
@GrantsPassTVRepairsyOU CAN SAY THAT AGAIN