I found a solution to my first problem of 3 clicks when the set is turned on but never actually comes on. I replaced the flyback, also the resistor, and cap that came with new flyback. Now I get sound but no picture. I can feel the static on the front of the screen and the picture tube is coming on. Is there a setting I am missing or did something else get fried. Originally the set got real bright, then shut off. I could see an arc at the back of the flyback when you turn the set on, corresponding to the three clicks.
When you replaced the flyback the new flyback is shipped with the screen and focus controls set at minimum. These are the 2 controls on the flyback itself. Turn the set on and let it warm up a minute, then slowly turn up the screen (bottom) control with a small flat-head screwdriver. When the picture is around normal brightness, adjust the focus (top) control until the picture is nice and sharp. Then, turn the brightness and contrast all the way down and set the screen control until you can just see the picture, just above the point where the picture vanishes. Reset the brightness and contrast settings and your picture will be back to perfect.
Posted on Jul 03, 2007
The small disc capacitor you replaced has no polarity, so it does not matter which way you put it in. I have never seen any other resistors in that chassis that would cause low brightness when bad. On the early version of those sets there was a small surface-mount jumper between 2 of the flyback pins (2 of the pins on the tuner side of the flyback) and it was very easy to accidently unsolder that small jumper while unsoldering the flyback. Double check the board to see if there is a space between 2 of the pins for a surface mount jumper and if it is still there. A surface mount jumper looks exactly like a surface mount resistor but it is labeled "000". When you installed the new flyback, did you make sure that the screen (yellow), focus (thinner red) and high voltage (thicker red) wires were properly inserted into the correct flyback chimneys, or did you install a cheap generic replacement?
If you turn the screen control and the brightness does not change, and if you turn the focus control and the brightness changes a little then there is definately something still wrong with that circuit. Since the flyback is brand new I do not suspect it to be bad. Do not try realigning the RGB bias/drives until the flyback is working properly. Measure the screen voltage on the CRT socket using a voltmeter set to 1000 volts. It should vary from about 200 to 600 volts as you turn the screen control on the flyback. If that voltage is way too low then remove the screen wire from the CRT board and measure the voltage in the wire itself (unloaded). If the voltage in the screen wire is still low then remove the focus wire from the CRT socket and move it away from everything else, and then measure the screen wire. If you have good screen voltage when the wires are disconnected then you probably have a shorted spark gap in the CRT socket itself. I saw this symptom once when a flyback went bad and sent too much voltage through the screen and focus wires, causing arcing and burning in the CRT socket spark gaps. If this is the case then you will have to disassemble and clean the spark gaps inside the CRT socket or replace the socket.
If you disconnected the focus and screen wires, turned the screen control all the way up and you have 108 volts on the screen wire, then the flyback is defective and you should exchange it for another one. You should have around 600 volts.
I get original RCA flybacks from Union Elecronics in Beecher, IL (800-648-6657), Herman Electronics, AKA Panson (800-938-4376) or Fox International (800-321-6993), in that order.
Are you SURE you are turning the screen control up? Are you using a small flat-head screwdriver and are you sure the screwdriver is actually turning the control? I cannot think of any other reason that the screen voltage would be low. Your high voltage and your heater voltages must be right, or you wouldnt see anything on the screen, so the flyback must be working and therefore the screen voltage must be ok too.
×
147 views
Usually answered in minutes!
I went through the channels and managed to get one that came up but very dark. Adjusting the screen control had no effect. The screen is too dark to see the OSD for adjusting brightness.
I have one concern, relating to the disk capacitor I replaced. I know that electrolytic caps have a pos and neg, do disc caps as well. This cap wasn't marked and the pcb wasn't as well.
Could there be another resistor gone bad. I have replaced one in a computer monitor before to take care of a too bright screen.
I have been playing around and I seem to only be getting red, no blue or green. Also I have noticed when a very bright picture comes up on the screen, I don't have the osd for volume when I adjust the volume, and the menu doesn't show up either.
Is it time to right off this TV??
I got the original RCA flyback replacement (which set me back $75). The data sheet showed a picture of two different pcb types. The older one required the jumper, between pin 7 and 8, the new one did not. I double checked and had two other people look at the diagram and pcb to make sure I had the new one. I also gently tugged on the wires in the chimneys to make sure they were seated, but will check again. I will also check all my solder connections again.
Thank you very much for taking the time to respond to my post.
OK--upon flipping through more channels, I found that the blue and green guns are working, but I am not getting white. I need to realign the RGB and I can't see the on screen menu at all. Is there an adjustment somewhere inside. The focus control seems to add and subtract a little brightness but doesn't seem to affect the focus, the screen control still does nothing. Is there a possibility the flyback is bad.
With both wires removed and as far away as possible, I get a maximum of 108 volts. I am adding an image of what I get for a picture, maybe that will help.
By the way---the image is ShopNBC channel
Thank you for all the help. I hope the place where I bought the flyback will go good for it. If not, is there a place you could recommend that I could get another one.
OK---New flyback, all installed, same problem.
Low voltage at screen wire, even with focus wire removed. I checked spark gap, just to be sure, and it's clean.
Yes, I'm sure I'm turning the screen control.
I'm checking voltage through screen control at cold ground. should I be checking it some other way?
I have been researching and one cause of low voltage is a defective tripler. I can't seem to find anywhere that gives the output voltages of the tripler. I checked across snubber cap and I'm getting 157v dc with power off, manual says I need at least 140, so ok there.
Pin 3 of the flyback goes to 330v from the 157 at power up. I can't measure pin 1 and 2 of the flyback, my meter only goes to 1000v. Should pin three be higher.
P.S. I really appreciate all your help, once I get close like this, I have an obsession with finding a solution.
Well I trashed the TV. Thanks for all the help, I learned a lot about TV's during the experience.
×