If you want to download your Saab's software from your Saab's computer (ECU) or flash new software on your ECU you can do this trough a CAN/USB interface or trough a BDM interface. When you use this robust BDM interface you will need to make a connection directly to the circuit board of your ECU.
This guide will show you the most effective way to do this with a trionic 5 / trionic 7 ECU.
First you will need to open up your ECU, on a trionic 5 ECU you can do this by unscrewing the 6 torx screws on connector side of your ECU. A trionic 7 ECU has 6 torx screws on the connector side and a additional 2 on the back side of the ECU.
If the screws are put aside you can gently pull on the black connector and pull the casing off.
Heat up your pointy tipped soldering iron to 300 degrees.
Put a blowing nozzle on your compressor and set it to aprox. 3 bar (or use a spray can with compressed air for cleaning use).
A trionic 7 ECU is coated with a rubbery protection, this will shield the board from solder tin, a trionic 5 ECU does not have this protective coating so you need masking tape to protect the circuit board. If you do not protect the circuit board the soldering tin spray can make unwanted connections rendering your ECU useless.
When handling a circuit board you should take care not to touch it where you don't need to. Static electricity could damage your ECU and render it useless. Pro's use a anti static cord connecting your wrist to the circuit board, we have learnt that if we just take care not to wear nylon or rubber shoes and take care touching the circuit board only on the edges they will survive the operation.
Mask your trionic 5 ECU carefully, use wide tape and mask 1 mm away from the 8 holes we are going to blow clean. Do this on the front and backside of the ECU. Only pressing the edge of the tape next to the 8 holes. We don't want the tape to stick to the rest of the ECU.
Place the ECU in front of you with the holes on the far side and the connector side near you (this way you will blow most of the tin off the board).
Heat the soldering tin in the hole with your iron, when the tip goes in leave it there for a second, pull it out just a fraction and blow out the hole with the compressor nozzle.
Repeat this procedure 7 times for a trionic 5 ECU and 9 times for a trionic 7 ECU.
When you are done you will find that not all the holes are perfectly clean. Turn over the ECU and repeat the procedure on the other side of the ECU.
Now we have a ECU with nice clean holes, in the following steps we will solder the connector pins on the circuit board.
Gently put the strip in the clean holes, the high side of the pins should be on the circuit board side where all the connectors / chips are located (otherwise the ECU will not fit back in the casing).
Turn over the ECU and push back the pins so they are aprox. 0,5 mm under the print plate. This wat you have a tiny hole you can fill with soldering tin.
Fill all the holes with soldering tin and so making a conducting connection from your pins to the circuit board.
Turn over the ECU and slide the black plate against the circuit board securing the pins.
You are now all done and can attach your BDM interface to the ECU.
