Need help for R/C receiver

[stefan_mkd]

Hey guys,

I have an r/c receiver for helicopter but unfortunately one part broke. It works, the motors and servos move, but i don't want to fly it like that because there might be a chance to damage it. Can you help me what to do? Here is a picture of the broken part. The numbers on that part are 5819.
**broken link removed** **broken link removed**

 

[cr0sh]

Probably a 1n5819 diode...

I am surprised, though, whatever it is, that it is still working without it! How'd it break, anyhow?



See this:

https://www.electro-tech-online.com/custompdfs/2010/08/1n5817-1n5819.pdf

Dot probably points to cathode...

 

[stefan_mkd]

Hey,
I was flying the helli and lost control. When i picked it up one motor was not working properly and i heard that there was something banging inside the receiver. When i opened it one part (the black square) was out. So i welded it:S, and the only part left to fix is this one.

btw the link is science fiction to me .

Another question, Is there a similar substitute for this part?

 

[cr0sh]

Hmm - sounds like the part overheated and the solder joints melted (while the part cracked from overheat and stress); you soldered it back in place, but I doubt it will work long in the condition it is in. What I linked to was the datasheet for the SMD (surface mount device) version of the 1n5819 diode; you just need to look that up on Mouser or Digikey, and purchase one or more (I would actually buy a few - it won't matter shipping-wise, and you might want to replace that other one and have a few on-hand for future needs - they probably don't cost much):

Digi-Key - 1N5819HW-FDICT-ND (Manufacturer - 1N5819HW-7-F)

48 cents each, or 10 for three dollars and some change - get the ten...

As far as a substitute, you would have to look at the datasheet and see if you can use something similar from a place like Radio Shack or Frys Electronics - you may be able to find something similar. But why, I just gave you the link above; put in the quantity, click "add to order", and check out...

On your part, there is a line - this represents the cathode side of the diode (it is polarity dependent!); some parts have a dot or an indentation to represent this side; you won't know until you have the new part in-hand. On the PCB, the silkscreen should show something similar to indicate which side is the cathode and which is a anode; you need to install it properly in order for it to work. Now, I don't know if you re-installed the one that fell off properly, or if it is no longer acting like a diode - you may have got lucky (50/50 chance), or it is just acting as a piece of wire or solder bridge (because it overheated and failed). Note that you shouldn't try to just bridge the pads with a piece of wire or something; that diode is there for a purpose - if the designer had wanted to not use a diode, believe me, they would've (it would have saved them a lot of money over 10 thousand units, say) - so don't do it; replace it with the proper part.

Note - I am assuming this part is a diode; its the closest thing I could find that matches your pics, sizes, and number on the part...

 

[stefan_mkd]

Thanks a lot. Btw i did not sold the other part by my own, i went to an electric shop and they sold it. Before purchase sth from the internet i will go again to some electric shops here and see if i can get any help. And i had some issues with the shipping. I cannot get the shipping price to Macedonia, Skopje zip 1000. I would be very thankful if you could help me out with the price. Thanks a lot Stefan

EDIT: I found the same diode in my local electronics shop and i just tried it at home but one motor does not work. Probably the part that overheated is broken. Here is a picture of that part

**broken link removed**

this is written on that part "apm4412 xk6fn"

can you please help me

 

[cr0sh]

Yes - that part is most likely this:

APM4412K pdf, APM4412K description, APM4412K datasheets, APM4412K view ::: ALLDATASHEET :::

An "N-Channel Enhancement Mode MOSFET" manufactured by this company: Anpec Electronics Corporation

Unfortunately, they aren't stocked by either Digikey or Mouser; maybe Farnell or RS can source it? You might have to get in contact with Anpec to see if they can recommend a distributor of there products in or near your country (sometimes these companies have their own independent distributor network, rather than selling it to the "big boys", because they can't make a profit otherwise or something). Its a good sign that it is at least a part that has a datasheet for it publicly available - that means its a part that was or is available to the "open market", and not a custom device or anything made just for the company that made the RC module. So you have at least a snowball's chance in hell of getting it.

I can't help you any further, though; you might find it easier simply replacing the entire unit, instead of going part-by-part and hoping to get lucky; not really worth the time or effort, IMHO...

 

[stefan_mkd]

Replacing the whole unit will cost around 70$, i will try this one as the last option. If it does not work i will defiantly replace it. Thanks a lot again