Whats the best way to connect to the tiny drill holes on the pcb ? I need to connect to certain points / pcb drill holes just to test circuit. I tried inserting solid wire into the hole but wire just bends. Tried to solder wire to it but the holes metal are so tiny the solder doesn’t stick.

 

 

Hi,
Try to soldered on the top of hole (start wire )and extent the other end of the wire to be soldered on the top of your choice hole.
Use a thin wire and careful of soldering it.

 

The gloss of all the parts and board make me think the board was sprayed or dipped into a clear polymer to preserve the board. You’ll have to scrape or dissolve the polymer before trying to solder.

 

The gloss of all the parts and board make me think the board was sprayed or dipped into a clear polymer to preserve the board. You’ll have to scrape or dissolve the polymer before trying to solder.

Bingo... Sure looks like its got some conformal coating on it.. As such you need to get through that first before you can access the connection properly..
A sharp lead of a test probe may be all you need.. Make sure to repair that void in the coating after testing..

 

I also agree the board looks to be coated so any coating must be removed by scraping it or using a chemical stripper and the latter is messy so try scrapping and cleaning with some isopropanol alcohol.

Ron

 

Yea it's definitely coated, I scrape off alittle with exacto knife than burn remains with the soldering iron. is that good practice to do ? Than I try soldering to the holes, but my solder is non-lead so it doesn't wanna stick to the holes and there's so little surface area to heat the metal of the holes.
Just ordered lead solder, will try with that when it arrives.

 

Curious why you need to solder to the vias if this is just for testing?

 

need to read and reprogram memory chip

 

I did a search for this: spring test probes
Here is the result:
https://www.google.com/search?q=spring+test+probes&ie=utf-8&oe=utf-8

Maybe one of these will have sharp enough points to penetrate the conformal coating. Then, no soldering is needed.

 

need to read and reprogram memory chip

Was the circuit designed to allow in-circuit reprogramming?

 

Was the circuit designed to allow in-circuit reprogramming?

Yes, and a programmer too.
this is immobilizer unit from a car, need to write new vin number into replacement one.