WIZ110SR damaged by 12v power

Question

Hi, the first time we powered our WIZ110SR, accidentally was with 12v 0.5A. The power supply was in 12v mode instead 5v (I know, rookie error ). Now with 5v 0.5A the unit appears not to work. The RJ45 leds are off and the configuration tool can’t find the unit in our network. As this units are not sold in Spain we ordered it to USA. We think we can replace the damaged componets with another from here instead ordering a new unit from USA. Can anybody guide us to locate the damaged componets? Thanks.

jameskim · Answer

Ooops!!! I’m sorry to hear that. I don’t know whether voltage regulator was damaged or other parts like MCU or passive components were. Anyway, try to change voltage regulator first. In many cases, it makes good result. Location “U5” is LDO chip which drops 5V to 3.3V. You can check whether it is damaged with a multimeter. If its output voltage is not 3.3V, then change it with new one. Thank you. James.

colorines · Answer

javakys: Location “U5” is LDO chip which drops 5V to 3.3V. You can check whether it is damaged with a multimeter. If its output voltage is not 3.3V, then change it with new one. Thanks James. I checked the LDO values. In the upper pin marks 1.14v and on the lower pins marks 1.89v (left), 1.14v (center) and 0v (right). I’m going to look for a new LDO to make the change. I’ll keep you informed.

colorines · Answer

[quote=“colorines”] I checked the LDO values. In the upper pin marks 1.14v and on the lower pins marks 1.89v (left), 1.14v (center) and 0v (right).[/quote] I have changed the LDO and the voltage values are still the same… Any idea?

peter · Answer

There are two LDO. U5 and U7. U5 is 5V to 3.3V. U7 is 3.3V to 1.8V LDO Part name is LM1117MPX-x.x (x.x is 3.3 or 1.8) The upper-tab and center are output, Left-pin is GND. Right-pin is Input. is right-pin 0V? I don’t understand. Please, remove U5 and U7 and then check input voltage if 5V from DC-adaptor jack The 5V-net is only connected U5(LDO) from DC-adaptor jack. If 5V input is measured. You can assemble U5. And then, Please check LDO voltage, again.

colorines · Answer

[quote=“colorines”] I checked the LDO values. In the upper pin marks 1.14v and on the lower pins marks 1.89v (left), 1.14v (center) and 0v (right).[/quote] Hi and sorry, the values I gave yesterday were wrong. The right values with the old LDO were 1,85v at the input, 0,39v at the out and 0v in GND. The values with the new LDO are the same. It was inpossible to get the LM1117MPX-3.3. I use a LM1117T-3.3. It is a TO-220 type instead SOT-223 but it´s equivalent. As the TO has 3 pins and a tab I made a bridge from the TO’s tab to the contact were the SOT tab was solded. Today I unsolded the C19 capacitor and the new LDO. The values measured at the contact board without LDO and capacitor are: U5 LDO: 5v at the input, 0,39v at the out and 0v GND. C19 Capacitor: 5v upper pin, 0v lower pin. I solded the new LDO again and the values are: U5 LDO: 1,85v IN, 0,75v OUT and 0v GND. C19 Capacitor: 1,85v upper pin, 0v lower pin. U7 LDO: 0,74v IN, O,65v OUT and 0v GND I think there are something that makes the voltage supplied to the LDO be lower than usual. Thanks a lot.

abjq · Answer

Interesting I was looking at the datasheet for that LDO (U5) and it states it takes 15V max and 20V absolute max. As you don’t state an abolute max for the board in your datasheet can I use these figures? I am also a little perplexed why the OP’s PSU cooked the board, given these numbers.

colorines · Answer

Hi, I forgot telling that I solved the problem. I changed the two LDOs and the 5v power supply (the another one not worked very well). [quote=“abjq”]Interesting I was looking at the datasheet for that LDO (U5) and it states it takes 15V max and 20V absolute max. As you don’t state an abolute max for the board in your datasheet can I use these figures? I am also a little perplexed why the OP’s PSU cooked the board, given these numbers.[/quote] Hi Abdj. My english is not very well and I don´t understand what you are asking me. Can you try it again?