I have a little problem, but I love fixing instead of constantly buying new ones. My mini Yx charger has broken down. I need help from someone who still has one and could do a small favor for me. Will there be at least one taker?

It might be better to say what the favour is........

I have an identical charger for the mini 2. There is a PCB inside for the mini 1 as per the description on the surface. Both types of batteries differ in the voltage, which is probably configured using a voltage divider on resistors. Unfortunately, the resistors are wrongly selected and instead of 8.8V I get 8.7V, which results in undercharging the battery to the end. Even in the advertising photo you can see 98%. The same is true for the mini 1 charger. I would like to raise this voltage by replacing the resistor in the voltage divider. It would be most convenient if I had a photo of both sides of the mini charger PCB and compared it with my charger. This way I will quickly find a resistor that has different values. I will choose the right one and thus set the correct voltage for both types of batteries. Could you make high resolution photos of pcb mini 1 charger for me? I will be very grateful.

That device (taking into account where it's made) can't possibly have a digital readout accuracy better than what you are already seeing on the digital meter? If it were at 100% and you're showing 98% you'd have a .02% accuracy? And the optimum performance of those batteries is not at 100%. I think you're nit picking in a direction that has no advantage? I'm also guilty of the same path on occasion. "Been there done that before."

PS: Manufacturers intentionally use light bars as level meters for a reason.

Any voice in the discussion is welcome. Most of all, however, I  need good quality photos of the PCB of this charger for the mini 1 version.

Not sure I follow, I think something got lost in translation. In any case, I do have the original YX charger for the Mini 1 (the model without the LCD) and I don't think it can be opened without breaking the plastic, so I'm sorry but I cannot send you photos of the PCB.
In any case, if memory serves me well, I think that even the charger I have doesn't really get to 100% charge... I noticed that when I first bought it, but since it gets close enough to 100% I don't pay attention anymore. A 2% difference is barely noticeable, unless you're really squeezing every milliamp from those batteries (which you should not do regularly, anyways).
Moreover, I'm a bit skeptical about your conclusion that all you need to do is to raise the voltage from 8.7V to 8.8V, to get 100% charge. I believe lithium-ions cells use a similar charging cycle than LiPos, which is constant current followed by constant voltage. For the Mini and its 2-cell batteries, that "constant voltage" should be 8.4V. I do not know where you're reading 8.7V, but I would be VERY careful messing with a lithium-ion charger unless you know 100% (pun intended) what you're doing.

I have a mini 2 drone and a Yx charger for this drone too. The final charging voltage of this charger is 8.7V, which results in charging up to 98%. The original DJI charger has an end voltage of 8.8V so charging reaches 100%. The battery for the mini 1 has an end-of-charge voltage of 8.4V. Probably your Yx charger does not charge to 8.4V, only to 8.3V which results in 98%. You should see four small screws on the bottom. When you unscrew them, the housing will open. Then you have to carefully remove the PCB and take pictures of what I care about. In this way, on the basis of visible differences, I will select a resistor that controls the voltage converter and raise the voltage to 8.8V and indicate the value of the resistor for your charger, which will allow you to raise the voltage to 8.4V

I see what you're saying... I looked better and it seems there are 4 tiny screws hidden under the sticker on the back of my YX charger, but I'm not sure I want to peel the sticker off to find out... sorry...
You seem to know what you're talking about... if you're sure the Mini 2 charger has an end voltage of 8.8V, then it means DJI must be using HV (High Voltage - 4.4V) cells. And I agree that if the charger stops at 8.7V, you will not see 100% charge. I have not measured the end voltage of my YX charger... it's very possible it's 8.3V instead of the nominal 8.4V.
I still do not understand why a photo of the Mini 1 YX charger (which it's 8.4V) will help you finding the right resistors for your Mini 2 YX charger (which is 8.8V)... but in any case, are you sure that this extra 2% of charge is worth the trouble? Unless you're always on the limit, 2% is a negligible difference...