I need help identifying a component.

pmd34

Joined Feb 22, 2014
499
Thank you. I was able to find that but I wasn't sure about the part number being right.
For reverse engineering things like this you have to go to the data sheet, check what the manufacturer says the markings on the device should be, how their logo should look if its there, and the device package size. It can normally take some doing if many manufacturers produce the same device and it is too small to put many characters on it.
In this case though its pretty simple!
 

Thread Starter

OG Style

Joined Aug 18, 2017
15
I got the part replaced but it's still not working. It might be a wiring issue but I did notice that one of the SMD caps looks like it might be bad. Is there anyway to to tell the value of a SMD cap? There is no writing on it.
 

narkeleptk

Joined Mar 11, 2019
383
You can use something like a LCR or dmm with capacitance tester on it to see what the value is reading as. Then use an educated guess to determine if its about right, but there is really no way to know for sure the correct value with out schematics or maybe comparing it to a working unit. Those small ceramic caps are usually pretty sturdy. I'd probably look elsewhere unless its showing a short.
 
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MisterBill2

Joined Jan 23, 2018
4,564
If the part failed there must be a reason, some other part failed and caused the part to fail. So of course, replacing that part did not solve the problem. What was the indication that made you think it was failed? So you will need to trace out a bit of the circuit to see what other parts are connected to this diode. And if the part is an IC, you may be out of luck, since most auto companies have the parts numbered with their own part numbers to thwart any outside repair attempts. And the replacement parts are not available.
What are the symptoms? If it is part of a switch-mode power supply then finding the failed part may be a challenge.
 

MrSoftware

Joined Oct 29, 2013
1,615
Diodes do fail on occasion, but test the part that you removed to be sure it's bad. Most multi-meters have a diode test function. If it is still good then the real problem is something else.
 

MisterBill2

Joined Jan 23, 2018
4,564
Diodes do fail on occasion, but test the part that you removed to be sure it's bad. Most multi-meters have a diode test function. If it is still good then the real problem is something else.
Yes, diodes do fail, but very seldom for no reason. Excess current is often the cause, excess reverse voltage can also break down a diode. AND I am still wondering what are the symptoms as a result. Does the GPS system share a screen with other parts of the car? On mine the radio, CD player, and GPS all use the same screen. Do other parts of the system function???
 

Thread Starter

OG Style

Joined Aug 18, 2017
15
The car belongs to a friend and he bought it with with this problem. I did notice that someone replaced the 10 amp fuse with a 25 amp. It's hard to tell what the previous owners did to it.
 

MisterBill2

Joined Jan 23, 2018
4,564
The car belongs to a friend and he bought it with with this problem. I did notice that someone replaced the 10 amp fuse with a 25 amp. It's hard to tell what the previous owners did to it.
The diode does not look like it had a 25 amp failure, which usually results in melting and cracking. So presently the GPS does not function. Does everything else function? Radio and other entertainment things?
 

narkeleptk

Joined Mar 11, 2019
383
If the part failed there must be a reason, some other part failed and caused the part to fail. So of course, replacing that part did not solve the problem.
Yes, diodes do fail, but very seldom for no reason.
The diode does not look like it had a 25 amp failure, which usually results in melting and cracking.
Not trying to start an argument with you or anything just something you can think about. In automotive modules (which this is) its actually fairly common for certain diodes to fail from external sources and not effect anything else in the module. Many cases it will not have any visible damage to them. Might not be the case in this users situation but its worth keeping in mind for future topics on automotive electronics.
 
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