Hi my brothers in electronics, I have a big problem with a multimeter JM70A model which is the following: I had the battery discharged uses two batteries of 1.5v each I was measuring some resistance, and the test went out for lack of battery I have a small adjustable power source which is connected to the multimeter to place the three volts already on some occasions I had done it to solve while I got the batteries (eye) for laziness but that day I neglected and placed 9v accustomed to the other multimeters that use 9v batteries was an oversight of mine. Okay the same when placing the 9v turned on and quickly the screen distorted and turned off, disassemble it completely and I realized that one of the fuses was open because it uses two, take out the display and take advantage of cleaning it with isopropyl alcohol as they do in some in youtube videos. Once the fuse has been replaced, the display turns on very well, so that I can see the screen, I have to put it in front of it, you can't see anything, check component by component and everything is fine, I think that the bad is the elastic belt that does not let the screen does not show the numbers in black, if you could help me please this way I appreciate it, although the tester does all its functions but the problem is the screen is blue auto ram excellent multimeter that would like to repair it or take it somewhere Where you can put your hand, I am again Sparta uses a black integrated round as a chip will be that of the problem ...... I already have time as an electronics technician but as I said I would like to save him from that problem .... .

These that carry the integrated round black are not repairable. It probably broke down without repair, the 9V were excessive for its 3V power supply.