Saga of the capacitors or "Another failure of covers"

Sometimes I read Habr, mostly DIY. Sometimes it is rare, because it’s work, you know ... And now, not so long ago, I came across a habrapopek with surprise (I won’t poke a finger) with a description, so to speak, of an LCD monitor repair. Quickly overlooked, he felt at first the desire to cry, and then - to laugh. Why?

I have about 8 hours a day working in just one fun organization, one of the activities of which is the repair of various equipment, including LCD monitors. I wanted to express everything that can only be expressed in the comments, but I could not. I decided to write at least in the Sandbox, because there are no forces to be silent.
A cursory investigation revealed that the author of the very topic dedicated to the "repair" of the LCD monitor, managed to publish one more, this time about the repair of the TV. I must say that these topics generated not a very long thread in the closed section of one well-known technical forum. The general mood of this thread can be characterized by the following quote taken there:

We are waiting for the author of the new opus on the topic:
“How to remove hemorrhoids using curves of hands, a mirror and scissors”
"Drill and reduction of intracranial pressure"

Often it is necessary to repair the equipment after other masters who could not identify the malfunction, or did not have the opportunity to eliminate it. And very often - after amateurs who tried to “repair” the device with the help of another “instruction”, in a multitude of generously scattered around the Internet. And, to be honest, I was very surprised to find 2 such “instructions” on Habré at once.
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So, let's start with the notorious "repair" of the TV, since this is the first to appear. First I would like to indicate the presence of such a parameter as ESR. Anyone who wants to elementary will start this term and get the entire theoretical base. Therefore, we will not consider it closely. We are only interested in the fact that electrolytic capacitor troubleshooting is performed not only upon the swelling of the aluminum jacket, but also on this very ESR parameter. In fact, this is quite important, since the condenser swells due to excessive heating, which leads to an increase in pressure inside its case due to evaporation of the electrolyte. And the higher the ESR, the higher the condenser heating. Thus, after thinking for a couple of minutes, we will understand that there may well be quite a large number of capacitors in the power supply unit, not yet swollen, but already with an overestimated ESR. Those. in fact already faulty, but to a simple look still not visible. The simplest instruments available to any child are used to measure the ESR, however many masters use them quite rarely, since the simplest solution to the problem is to replace all electrolytes with a so-called "Cold" part of the power supply, also called the "secondary". It is impossible to change only swollen capacitors without checking the others, not swollen. As it is fraught with not profit, but repeated repair after a short period of time. Moreover, given the circuitry of modern digital technology - it is quite possible that the repair is not only BP.

Another mistake of the author is the soldering technique. Have mercy, why to trick the capacitors? Which after installation still have to be cut?
And the use of acid in the installation work? Highly active soldering fluxes of the “Soldering acid” type are generally not designed for electrical work! These are fluxes for soldering ferrous metals. And acid are not called casual. "Soldering acid" is capable of in a couple of months to erode the soldering of this condenser itself, even if it is applied in insignificant quantities. That is why after applying such fluxes, soldered surfaces must be washed with water, solvents, and preferably with special liquids. And you can never use them in radio installation work.

Very often in the price lists of service organizations it is indicated that an increase factor is applied to the cost of repairing equipment with traces of non-qualified repairs and this is not casual! As an example - the described TV is quite capable of delivering an hour or two of fun entertainment to any service after an indefinite period of time. From a week to a year.

The second habratopic dedicated to the "repair" of the monitor is also very fun. Any specialist knows that repairs begin with measurements. The author of the topic also carries out measurements of such parameters as “the flammability of a light bulb” - the measurement result is “off”, and “monitor performance” - the measurement result is “dead”. The repair technique is also thoughtlessly replacing the visually swollen electrolytes with tears from the “ancient power supply unit”, and even with less voltage. Of course, the LG designers are fools - for some reason they put 16-volt capacitors, if 10-volt ones are working ... And another miracle - the flammability of the light bulb has risen to "lit", we urgently post in Habr ...

Believe me, all this is written not for the reason that I am afraid to remain without work. On the contrary, such “obstetricians of pregnant litas” just provide normal masters with work. Unfortunately, often, when after replacing a condenser, the monitor still does not work or does not work satisfactorily, the monitor begins to "dig" cruelly, spoiling the tracks on the board, dispensing parts, etc. And repairing such a copy is quite another matter. We, for example, apply a multiplying factor of 1.3 to the price for such devices.
Here the problem is different. Most recently, I was forced to give the client a “dug-out” monitor, due to the modest fact that the “digger” “dug” the BP-inverter board to death, before a hole in the PCB under one of the transistor assemblies. He also did not know that a wide negative track under the assembly was laid for a reason. And the number of such examples is multiplying, precisely because of the wide distribution of various "instructions" written by various "experts" ...