Just looking for some insight into the 'repair' sector of electronics.

occasionally send out PLC components (IO Cards, SBC's, etc) for testing and repair and was wondering what methodology they use for repairing these devices.

do they have documents from the manufacturers?

do they go component by component?

is it magic?

 

Hello,

There are certain criteria for repairing a board.
One of them is " is it worth to repair or is replacement cheaper ".
An other can be the parts are easy to exchange because of holders for the parts.
(relais are often placed on holders).

Greetings,
Bertus

 

here are a couple senarios we've been up against.

one was a single board computer, 386 that ran a LCD panel and user interface. It was made by an italian company that would not offer support. It was replaced for the cost of 1250 euros.

In a basic attempt to repair the board blindly, i had replaced any socketed chips (rs232 drivers, and some logic components). This attempt failed.

Second example was a Siemens PLC transducer card. We actually had two of these go in the past few months.

first card was repaired, but they did not specify exactly what was wrong with it - mentioned water damage.

second card, they found something bad with a power supply circuit.

for whatever reason (supply & demand) these components are $2000+ to buy, and often 1000 to repair.

Being an electrical engineer, i was wondering what type of systematic approach they take to repair. Without some background knowledge, or ways to test the boards it must be next to impossible? impossible, meaning it would take too long.

 

Hello,

A great resource for repair questions is the site of repairfaq:
http://www.repairfaq.org/

Here is its link on troubleshooting:
http://www.repairfaq.org/REPAIR/F_tshoot.html

It is basicaly on consumer stuff but the way the things are done can be used at other stuff.

Greetings,
Bertus