I am in Indonesia and a tech guy here is helping me fix a circuit board that shorted out.

He says that we need a "transistor 1AN" and that he cannot locate one here in Indonesia.

Google is not providing any results for this. Can you give me any thoughts?

Thanks,
BCB

 

I dont have the data for "1AN" but I do know that "1AM" is MMBT3904L. Are there any other transistors on the same board with the "1AN" marking? May be you can confirm whether it is an NPN transistor using an ohmmeter.

Allen

 

Hi Allen,

Thanks for your reply.

The circuit board is with my Indonesian tech. He does not speak English and I don't speak Indonesian. Getting the answers to your questions is possible, but not easy.

If there are other transistors with the 1AN marking, what would be the benefit of knowing?

What benefit would there be in testing to see whether it is a NPN transistor?

I'll be happy to find those things out if knowing them will lead me to being able to replace this transistor.

Is there a supplier that knows pretty much all of this stuff that I could call directly?

Thanks,
BCB

 

If there are other 1AN transistor on the same PCB, he can at least confirm that "1AN" is an NPN transistor so he can use an educated guess on what to substitute it with something equivalent...

May be others have ideas on a suitable substitute for this transistor.

Allen

 

Thanks Allen,

Here's an attempt at uploading the image. I made it into a pdf because the board accepts larger files in that format. I think it is legible in this format.

I appreciate your thoughts,
BCB

 

I can see that U1 is TL555, a timer chip. The rest of the chips are filed off so no one was able to identify what they were.

I cant find any 1AN transistor on the PCB. Only a couple of components marked as "11AG". I am putting the link to the SMD data codes here for your reference....

http://www.marsport.org.uk/smd/mainframe.htm

Allen

 

Hi Allen,

The reason you don't see a 1AN transistor is because my tech guy removed it. That is the one that we are attempting to replace, so it is not currently on the board.

The second image on the PDF that I uploaded has a red arrow pointing to where that transistor should go.

I appreciate your link to the SMD data codes, but I have no reference point to even know what that means or how to use it.

Is there a supplier that I could contact that could help me figure this out?

Thanks,
BCB

 

Look through the attached image for some info on the possible codes for your transistor. The first column is the code that is on the transistor. The second column is the manufacturers actual part number. The other columns are just some descriptions of the part and package type.

 

Thank you, BSomer.

Unfortunately, I have no perspective from which to utilize that information.

I could be looking at the right code and I would never know it because I have no idea how any of this works.

Does anybody have any idea where I can go or who I can talk to who could provide this information?

The only other option I have is to send it back to the manufacturer in the USA. It's still under warranty, so they will fix it for free.

But the cost of shipping it to the USA and back would be substantial, so I'd really rather that my tech do it here...if at all possible. (The manufacturer refuses to give me the code...which is more than a little irritating.)

Surely somebody knows of a tech or a supplier who could provide this information.

Thanks to anyone who could be of assistance,
BCB

 

How about contacting the manufacturer and ask for a new part to be mailed to you; failing that, you could ask them to at least identify the part for you.

 

How about soldering wires to the pads, and test external transistor with 100 Ohms protection resistors?

And see the voltage levels (or waveform)?

Then maybe resistors can be removed. It could be NPN or PNP transistor.
Maybe it can be seen from the circuit what is base, emitter, etc.

 

Unfortunately, the manufacturer refuses to give me any information or assistance. They will replace it if I return it to the USA, but the cost of shipping is pretty expensive. I was hoping to repair it here to save both time and money.
bcb

 

How about soldering wires to the pads, and test external transistor with 100 Ohms protection resistors?

And see the voltage levels (or waveform)?

Then maybe resistors can be removed. It could be NPN or PNP transistor.
Maybe it can be seen from the circuit what is base, emitter, etc.

I very much appreciate your suggestions. This sounds like very helpful information.

I have no idea what it means, but I will attempt to translate it to my Indonesian tech and see what he can do.

Thank you!
bcb