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  1. V

    EMMC replacement

    Hello everybody. I am repairing boat chartplotter. So i need some advice. Let's say we have same manufacturer, only different sizes of screen. 7" screens have the same hadware board as 12" chartplotter. This one i received is 12", i found out that EMMC is gone. I have spare EMMC, but from 7"...
  2. V

    Replacement for MOSFET

    I didn't study the board layout so much, but as I saw theese mosfets are going directly to outputs (3 outputs for 3 different batterie banks). They dont have heatsinks, they are through hole mounted on the board. So my logic says that there cant be any voltage higher then 14.5 on source/drain of...
  3. V

    Replacement for MOSFET

    I am repairing battery charger. It has 6 STP180N55F3 mosfets, 3 are gone. Can I replace it with IRFB7440PBF? In datasheet they seem similar, except power discipation. STP180N55F3 says 300W, IRFB7440PBF says 208 but it has countinous dran current 208A while STP180N55F3 has 120A? I have some other...
  4. V

    Low voltage buzzer alarm

    Great idea. I will put a switch to it so that it can be turned off when leaving the boat. The boat is for rental purposes, so alarm is for guests actually when they are abusing the batteries...
  5. V

    Low voltage buzzer alarm

    Hello. I am building low battery buzzer alarm. I have done this guided by schematics and it works great. My question is is it reliable to leave it just like this in boat with few components? I see in the datasheet of lm339 that it can hande much bigger voltage then 12V (around 30) so I would put...
  6. V

    Is this possible to repair? (flash memory chip)

    I found some usefull info regarding the extraction and programming of flash memory chips. The tool that electronic repair shops mostly use is RT809-H programmer with adater for 153/169 BGA chips. It is for eMMC, can it be used in this case if this chip is MLC as Zasto wrote?
  7. V

    What is this circuit

    Thanks for great explanation. Do you maybe know what is this small 8 pins component that is connected to the gate of mosfet? It says MTRP S148 on it, but I can't find anything with thoose marks?
  8. V

    What is this circuit

    I got this board for repair and i am not sure am I crazy or am I missing something here? The component that is missing is FDS6680 mosfet.. I removed it because it was in short circuit. But when i tried to figure out what that mosfets does I was scratching my head... So I marked 12V coming from...
  9. V

    What is this component?

    Omg theese are really diodes. But this whole board is covered by coating... And it looks like how much i tried that i couldn't make a good contact with leads when I was measuring in diode mode. When I took them off and scraped really good I can get a voltage drop of a diode in one direction...
  10. V

    What is this component?

    Hello everybody. Does anybody know what is this red component with black stripe on one end? I found that some of theese are faulty. They are giving me reading all around from 10-60 k ohms, but only in one diretion. In diode mode - nothing. I know that they are problem because i changed them with...
  11. V

    Is this possible to repair? (flash memory chip)

    This one on the picture is fried. But I have a same device that is working ok, i could teoretically take off the same chip. So i would extract data from that one and copy it to a new one (blank). I don't need to know what is in there, i am interested only in "copy paste" I can handle hardware...
  12. V

    Is this possible to repair? (flash memory chip)

    Omg, i have read about extracting the data and it looks like a science fiction to me...
  13. V

    Is this possible to repair? (flash memory chip)

    Hello. I have got a device which didnt wan't to turn on, and i found a problem. When I took this chip out of board it turns on, but only on start screen. And then restarts after some time. This looks like some kind of memory chip, maybe flash? But i can not find anything on the internet about...
  14. V

    Bootstrap doesn't work

    Hello, i wanted to say that bootstrap won't work if the low side mosfets are not turning on... Maybe I am mistaken but aren't low side mosfets TR2 and tr3 thoose which should connect grounds to bootstrap capacitors? The problem is that TR2 and TR3 are not oscillating although they are receiving...
  15. V

    Bootstrap doesn't work

    I contiued... I took of R6 and R9, and now on the pins 7 I don't get any pwm, it just stands on 12V althought the signals on inputs seems ok... Anybody got some idea? Edit: i'm still a noob, but if i figured out right, there shouldn't be any output on pins 7 with low side mosfets turned off...
  16. V

    Bootstrap doesn't work

    Here goes. First picture is on pins 1&2, second is 1 & 7 and third and forth are 2 & 4. Don't let forth picture confuse you, it is in mode when reverse direction is applied. All other pictures are when trying forward direction. On pin 3 I have 0V, on pin 4 11.2 when in reverse direction, and 8.5...
  17. V

    Bootstrap doesn't work

    I didn't design this, this is autopilot computer from manufacturer raymarine. HD_pwr voltage is around 12V 1599051285 I dont doubt in your knowledge friend, but mistakes that are made in production won't help me because there are large number of theese computers on the boats and they are working...
  18. V

    Bootstrap doesn't work

    Hello. I am struggling with this for whole day and i just can't figure out what is wrong. I had similar problems, but nothing like this. So i have 2 IR2183 which are used for h- bridge. As I can see on the scope the logic side before IR2183 is fine. I am receiving good signals on pins 1 and 2...
  19. V

    Important circuits to learn

    Hello. My hobby is electronics repairs, and when i watch other people repairing electronics on youtube i can see that they can a lot of time read from components and their connections excatly what is the purpose of that part in pcb. I am mostly repairing marine electronics, but to be honest I...

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