Tonomac TV with cushion effect
Hello, check the state of the coils of the horizontal sector if you see any with overheating it is possible that this is the cause.
Good morning, these chassis have no published diagrams, at least with that serial, to which I mean that there are license plates between them (Las Chinas) that are identical plates. So if you know of another license plate to look for diagrams, such as PX20172, you can find a more or less reliable diagram, that is, what you will find there is not the absolute truth, there will be variants on your plate that you will not find in the diagram found on the WEB.
Now, this device with this chassis that says, personally, I think it is one of the best in the market, that is, those that could be bought before the explosion of sales of televisions that are currently. They have complicated failures like everyone else, but from the roll of these TVs so SLIM this chassis is more friendly to repair
These chassis have many repeated variants, in reality the minimum differences are as additional arrangements of the chassis design to be able to use such a tube and such a yoke, so depending on these components some more stages in the chassis will be used to correct or adjust the TV. .. For me to say all this, to take this data into account, and to see how complex the horizontal stage is, identify the corrective stage I / O (East / West) you can start by looking for the power transistor of this stage V486 Remove it carefully and measure it outside to see what results it throws.
And it is as indicated by the reheated horizontal stage coils is evidence of failure, they are not commercial, all of them have their values indicated at the top, the most faulty in this chassis is the L464. If you use a tester, for example, you will measure continuity just to find out if it is in poor condition, you will need another measuring device ...
The lining can be removed and if it is with short turns it can be wound with the same turns and the same wire gauge, then a heat shrinkable is put on top and sealed again.
Hi Carlos, thank you very much for your contribution! L464 was totally destroyed when I started to unwind the wire I found it cut in several parts, I proceeded to put another coil of another chassis that had recycling but unfortunately not the same chassis, I only made measurement with the tester and it gave me continuity so place but the fault remains the same as before (cushion effect with dark screen on the sides.
Is the same inductance ?, because it has to be the same, 500uH and the same wire gauge.
also check the transistor in position v 485 (2sc 1815) whose collector goes to the base of v486 (A940). All this is if by doing the "cushion effect" on both sides of the parabola you have left the outer parts in black. Now if it does the "cushion effect" and also has excess width, the inductance L485 (600 uH) is probably wrong; in this case also check the r465 (10k)
Hi José, thanks for the input!
Check the a940 and the c1815 and apparently they are in good condition as well as the r497 (470ohm) also check the electrolytic c487 I measured it and it has (6.5 if) it is not so undervalued it seems (for me it is fine) what does not I know if the voltage is ok since in the datasheet that I have it is not indicated what voltage there should be in that line, well the voltage that is there is 39 volts at the base and emitter of the v486 (a940), as well as the same collector voltage v485 (c1815) that voltage line comes from l485
José forgot to mention that the l464 coil was bad, when I unwound the wire I found it cut in several parts, so I changed to another coil that had recycling, (not the same chassis unfortunately) I measured it with the multimeter and it gave me continuity so I placed it on the TV but the fault remains the same with the straight cushion with black screen sideways.
Friend José there is something that catches my attention and that is that at the base of v485 (c1815) there is no voltage, and I think there should be a voltage there, at the base there is no voltage, in collector there are 39 volts and the emitter is earth ...
Yes, in the base of v 485 there must be o, 5v or o, 6v in its collector (as in B of v486) there must be about 25v, you have 39v because there is no consumption when there is no voltage at the base of v 485. In the collector of v486 about 26v or 27v. Due to the lack of voltage on the basis of v 485, check on this line the r that comes out of said base and then another that connects with this one that is r489 (4k7) and the + 5v-2 that comes from the source secondary must arrive through the 5v regulator N556. check the input filters to this one c572 (1.000uf 16v) and the output filters in leg 3 c556 / 470uf 16v). In leg 1 see tr.v571.
The L464 must be measured with a multimeter that has to measure inductances and should be around 500 uH. The transistor v486 works when it is well polarized and as it is a PNP it must be the positive emitter with respect to the base, that is the tension in E must be somewhat greater than in the base. The tr v485 is an NPN and to be well polarized the base t must be positive with respect to the emitter.
Friend José Fernan and the others thank you all for helping me in this repair, I really had no idea how to solve and which area of the TV to work on, I was able to solve the fault thanks to everyone, say hello