pcb & multi pin plugs

spiff

spiff

Executive Member
Joined
Oct 17, 2007
Messages
6,949
Reaction score
2,722
Location
/\/¯¯¯¯¯\/\________ MOTHER OF ALL CITIES
On one of my 2015 cnc wire cutting machines, there is a large pcb that has many multi-pin plugs "pressed" into the board and not soldered to the board. these multi-pin plugs are for the driver cards etc. (see pic below)

saw teeth.JPG

now this machine has been giving me endless trouble, like not booting up properly / losing voltage / not reading the driver cards / drives not working / not edge finding / running extremley slow etc. The machine supplier has no idea what the probem is and they have been swapping out driver cards for over a year now trying to "fault find" to no avail.

My concern is with all the movement of removing & re-installing cards into these unsoldered "pressed in" multi-plugs, surley this will cause more poor connections and worsen the problem?

anyone can advise me on why it was done this way?

is this just a cheap way to assemble the multi plugs to the pcb?

what can I do?

My gut feeling is to solder all the pins?

any advice will be appreciated
 
When the pressfit connectors are installed properly they make an airtight seal between the inside of the plated through hole and the corners of the connector pins. VME / CompactPCI / VPX motherboards are all built like this. However, if your tolerances are off it's a problem.

Those pins don't look like pressfit to me though, dunno.
 
spiff said:
can't say 4sure - my guess is pressed in?
Click to expand...

I am not sure either; hence, I asked. It didn't look pressed, and pins are intriguing, and it looks like it has teeth? Not knowing what you have there, I would think it has to be socketed. Don't quote me on this. Just an observation.

spiff said:
either way IMO its a crap way of doing electronics?
Click to expand...

It depends on the application. You don't want something soldered that is interchangeable. One could argue maintenance, but a system in production will be soldered, but then you could also have sockets (as per my above remark).
 
Those do look dodgy. There is no way that makes a reliable connection especially with all the vibrations.

If a part needs to be interchangeable you will use a edge connector, or a IDC connector.
 
gregmcc said:
Those do look dodgy. There is no way that makes a reliable connection especially with all the vibrations.

If a part needs to be interchangeable you will use a edge connector, or a IDC connector.
Click to expand...
my thoughts exactly. :unsure:

this is not an interchangeable board - it's fixed to the frame and all other driver boards plug into this board.
 
ok found a blown cap on one of the boards I extracted from the controller frame.

grok says - "electromagnetic interference (EMI) suppression and connection to AC mains"

anyone know where I can get a replacement locally?

cap3.JPG
 
Ahh the good old RIFA caps. These are notorious for drying up in old retro computers. You power the computer back on and bang. They stink like hell!

BTW that photo is for a 150nF. You need a 470n

I would replace it with a polypropylene Class X2 470n and not another rubbish RIFA paper cap.
Something like this: https://za.rs-online.com/web/p/film-capacitors/7398648?gb=s
 
Last edited:
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X