I have no video, and no audio. but the red light in front of TV comes on, and you also hear the normal click sound. On the Power Supply Board all LED's come on, but there is one LED (D913) that only blinks twice, with less intensity the second time, after that initial blinking it never comes back on.
On one of the main boards (DPOX Deflection P.W.B.) there is another LED (DP37) that never comes on, and it is near the IC STR F6629B.
Someone mention to me it could be the convergence IC's, where are these at?
I have a power supply board mounted vertically on the side, and then 2 main boards mounted on the bottom flat.
Any suggestions as to whats wgong with this TV. Thanks
for diagnostic purposes there is a small black connecter (looks like a jumper from the middle board to the right hand board it is located closest to you looking from the back. if you flip that up then try to turn the tv on. if it comes on it is for sure the stk convergence ic's. If not it still can be the convergence ic's but it has taken out the power supply as well. (remove the connector only when the tv is unplugged then plug it in and try to turn it on, the picture will be out of convergence but it should come on)
zapdbf,
there are three jumpers, I disconnected the one closest to me looking from the back. I heard the static noise you get like from a tv channel that is not broadcasting. But no video what so ever.
I guess that means the power supply is out as well.
i think that model will blank the picture if there is no channel try hooking up an antinna, because if you heard static through the speakers that means the micro got past the 32 volt shutdown error. that is good !
Most likely you will need to replace the stk392-110 's on the right hand board. and you will in all likely hood have a resister burnt up that will have to be replaced as well. but i believe it was limited to the convergence board. that board is easy to take out and work on, just remove all the jumpers to the middle board and unplug the few wires connecting it and 3 screws and it will come out of there, that sounds like allot but realy it is very easy to get that board out.
zapdbf,
my big TV just became a big radio, lol lol lol lol lol...
with the jumper still removed between the boards, I connected the cable antenna, and I can hear all the channels, but still no picture.
I was able to remove the circuit board, however I have 2 "stk392-110" on the conver amp, as it is labeled.
I am assuming these are the convergence ic's.
should I replace them both?
thanks, I feel we are going somewhere, at least I got a radio lol lol lol...
yes replace both of them, and i use a version with higher wattage, stk392-150 this part will work fine, although mostlikely one of those resisters behind the stk stadning up off of the board are bad. you need to take a dvm and check for a resistance less than 5 ohms for each one of them, there are two sizes of resisters behind the ic, one is larger round than the other ones, it will most likley be the small round resisters, there are many of them all the way to the back edge of the board, be sure and check all of them.
be sure to put new heat sink compound behind the ic's most likley the compound had dried out, and will be somewhat chalky. and acts like a glue. you might even have to pry the ic's off the heat sink. don't do this untill you have the ic's de-soldered from the pc board and unscrewed from the heat sink. or you can dammage the pc board.
zapdbf,
I checked the resistors behind the stk's (the ones that stand off of the board) and they all seem to be ok as per the resistor color code. but some of them measure more, or less than 5 ohms, as per the color code.
I checked most of them, even the ones that are far from the convergence IC's, but could not find any bad resistors. they all seem to be ok.
these convergence IC's have about 18 pins each, and I am going to de-solder them so I can remove the IC's. what I notice is how close the pins are to each other. I'm going to be careful during the installation no to smear the solder accross. I haven't solder something like this in years.
the IC's should arrive some time this week.
soldering tip: keep a little extra liquid flux handy, it will remove the impurities that occur after repeated or prolonged heating of the solder. just a drop will shine it back up again. it also helps prevent solder bridges between the pins of the connector. Clean off with flux cleaner when done.
I replaced the convergence IC's, no help, I still have the same fault. I used stk392-110, by the time I read your advise to use a version with higher wattage (stk392-150) I had already ordered -110.
What else could it be?
It can be a fuse that the ic's have taken out, on the middle board. Check the glass fuses there. Also check the fuses on the board on the right side where the plug comes in, i am not sure where the voltage for the ic's come from without looking at the manual.
Check this , then if you cannot find a problem let me know and i will look at the manual.
after replacing the ic's and with all the connectors back in there place does the tv have sound ?
I have not seen any glass fuses on the middle board.
the glass fuse on the right board where power plug comes in is good.
all the plugs are connected as they were originally.
after replacing the IC's the tv has the same fault, no audio, no video.
unless I remove the jumper on middle board, then I do get audio.
ok, the fact that you don't get audio when the jumper is down, leads me to believe that you might have a solder birdge on the ic's. take an exacto knive and run it between the solder pads of the ic's to make sure there is no solder ball or bridge. i do ths myself when i am unsure if there might be a bridged conneciton. I also believe on some models there is a green jumper wire on the bottom make sure it is connected backup and it is not touching any other solder connecions.
there is one more thing you can do to troubleshoot this, remove the jumper so the tv will come on , then turn up the screen untill you see retrace lines. if you can see this and you see a flat color (adjust any of the three colors) that is a good sign that your deflection circuits are working and your video is just muted. If not we may need to change stratigies here and look in another direction.
also look into the neck of the picture tubes and see if there is a soft yellow glow comming from them.
I checked with a magnifying lens and there was no solder bridge between the ic pins.
also, the green jumper is connected.
I noticed on the power supply board (the circuit board on the right) there is one troubleshooting LED that does not stay on. It blinks twice on initial power up, and then it never comes back on.
I wonder if this has anything to do with this.
for me this is an off brand television i don't service this brand often, i don't have a service manual, i thought i could get one from our sams photofact subscription but it is only in paper form. so that is out. It sounds like you have power supply issues, but without a manual it is difficult to proceed. It would be helpful to see if you can get the raster like i suggested, this will help you get closer to the problem, you can eliminate allot of circuits if the raster exists. As far as the led goes, it is just reacting to the problem and it is directing your attention to the power supply which i believe may have a problem. It is significant that when you pull the jumper the tv will come on. so i believe that the convergence circuit is involved in some way. At this point we need to trouble-shoot. this requires performing the tests i suggest. or if anybody here has seen this problem before and has a fix for it that would be great! but unless that happens troubleshooting is our only way out.
Service manual, troubleshooting section leads me to check voltage at pin 4 of IC STR F6629B (IP01), and it should be between 14V and 18V. I have less than 3 volts at pin 4 of IP01. So, with this scenario, then it leads me to check zener diode DP04, resistors RP02 and RP03, and capacitor CP05.
The resistors are good. I do not know about the capacitor or the zener diode. How do I check them?
The capacitor CP05 is no longer available, I can not get it any where. I hope it is good.
I also replaced the IC STR F6629B (IP01), but no help.
What type of cap is cp05? is it a round can (electrolytic) or another type, if it is a electrolytic just check the caps value in micro-farads, and its voltage, you can get these generically. The zinner diode is little trickier, you need to know what the zinner voltage is to test it correctly. but if you want to do a quick test put your dvm on diode check and check it both directions forward and reverse. in the forward direction you should get a forward voltage drop of about .4 to .7 at the most. In reverse it should be close to infinite depending on what the zinner voltage is. i am not sure how your meter will show this information to you. That quick test will only tell you if it is bad, it cannot verify that it is good. Because the zinner voltage could have changed.The cap is harder to test other then checking for a short, you need a special piece of test equipment that can test the reactance of a capacitor, sincore has a z-meter but it is very expensive. it would be easier to just replace the cap if you suspect it is bad.
Cap CP05 is a round can ( cap-electro 330 micro-Farads 35 v) , orininal part# 0800346R.
I just bought a capacitor from Mouser Electronics with the same specs.
Has anyone found a fix for this problem, I am experencing the same?
Has anyone found a fix for this problem, I am experencing the same?
I have the same problem. I have a similar model Hitachi 65swx20B. When you turn it on red indicator light in front stays on no blinking. I opened the back cover and there's one green led light towards the back of the power board that is not lit. Could this be convergence IC issue.
Can someone here share their success story fixing these models. Thanks