How to Spot Cracks in PCB

[Vacillator]

Hi,
I think I might have some cracks in the solder or pathways on
a printed circuit board in my car's wiper motor. I have looked at the
PCB from the side that is visible to me, and have not seen any obvious
cracks or gaps. Can I remove it safely from its holder, and if so,
how? It appears to be mounted on 3 small posts. Will the PCB pop off
the posts ? I could then turn it over to look further.

Thanks

 

[Wild_Bill]

I don't know how you can remove it, and you haven't mentioned what year/type
of car, or manufacturer of the wiper motor, so I doubt anyone else will know
either.

I've found that a high brightness LED on the back side of the board (pointed
straight at the board) is a fairly good way of detecting cracks in PCB
materials.

--
Cheers,
WB
..............


"Vacillator" <user132384@aol.com> wrote in message
news:24fbfbe3-ff71-4464-993c-d9c6110cbdad@u10g2000yqk.googlegroups.com...

Hi,
I think I might have some cracks in the solder or pathways on
a printed circuit board in my car's wiper motor. I have looked at the
PCB from the side that is visible to me, and have not seen any obvious
cracks or gaps. Can I remove it safely from its holder, and if so,
how? It appears to be mounted on 3 small posts. Will the PCB pop off
the posts ? I could then turn it over to look further.

Thanks

 

[Wild_Bill]

Even mentioning 1988 and GM car would've been helpful, something to ponder
for a future question post.

You might be able to find a wiring diagram of the wiper motor assembly
online. You may be able to find a manufacturer's mark on the assembly
(Delco, for example) that may be helpful in your quest.
There are possibly internal switches in the gearbox (maybe just one).

--
Cheers,
WB
..............


"Vacillator" <user132384@aol.com> wrote in message
news:54983f9e-78cb-4678-9d22-a50437179dae@h7g2000yqn.googlegroups.com...

Wild Bill,

Thanks for the tip about the LED. The car is a 1988 Pontiac
Firebird Trans Am GTA. But I think mounting of PCB's in auto wiper
motor applications is pretty standard : A plastic cover on the wiper
motor contains the pcb. I bet they are all ( 99 percent) attached to
the plastic cover the same way, with these little posts. But I could
be wrong.

BTW, I cleaned up the pcb a bit by gently scraping the metal contact
areas with a clean fingernail, reassembled it on the wiper motor, and
most of the functions have returned. But there is still one proble.
The off position does not work. May need to find a break somewhere on
the pcb.

 

[Vacillator]

Wild Bill,

Thanks for the tip about the LED. The car is a 1988 Pontiac
Firebird Trans Am GTA. But I think mounting of PCB's in auto wiper
motor applications is pretty standard : A plastic cover on the wiper
motor contains the pcb. I bet they are all ( 99 percent) attached to
the plastic cover the same way, with these little posts. But I could
be wrong.

BTW, I cleaned up the pcb a bit by gently scraping the metal contact
areas with a clean fingernail, reassembled it on the wiper motor, and
most of the functions have returned. But there is still one proble.
The off position does not work. May need to find a break somewhere on
the pcb.