HughF
Member
- Messages
- 6,460
- Location
- Work: Dorchester, Workshop: Corfe Castle, Wife's place: Frome
As some of you may/may not know, day job for me is electronic engineering...
A member on here posted up that he acquired an air liquide citotig 200 which was in a non functioning state. I offered to look at and repair the board for him. I thought I'd start this thread to show how I go about surface mount repair/rework when a board is damaged, it's really not that difficult provided you have a steady hand and good eyesight.
I have received the board and done some preliminary cleanup with fluxclene and a sharp scalpel...
You can see that there's damage to the fr4 (glassfibre but made with epoxy instead of polyester) PCB laminate and we're missing a few pads/tracks. The PCB will be repaired with epoxy resin then we'll make a start replacing components and replacing track...
Luckily there are 4 gate drive circuits of identical construction on this board, they are laid out in pairs. We have an exact circuit to measure and copy, not that this is too difficult to reverse engineer by following the traces and studying the datasheet for the device, but it is nice to have confirmation.
The device is no longer available from the big 4 but aliexpress has this part available at sensible money, 4x new ones have been ordered but I'll only replace this one if it fails the bench test.
I'll update this as I work on the repair this week... any questions anyone has, just ask...
A member on here posted up that he acquired an air liquide citotig 200 which was in a non functioning state. I offered to look at and repair the board for him. I thought I'd start this thread to show how I go about surface mount repair/rework when a board is damaged, it's really not that difficult provided you have a steady hand and good eyesight.
I have received the board and done some preliminary cleanup with fluxclene and a sharp scalpel...
You can see that there's damage to the fr4 (glassfibre but made with epoxy instead of polyester) PCB laminate and we're missing a few pads/tracks. The PCB will be repaired with epoxy resin then we'll make a start replacing components and replacing track...
Luckily there are 4 gate drive circuits of identical construction on this board, they are laid out in pairs. We have an exact circuit to measure and copy, not that this is too difficult to reverse engineer by following the traces and studying the datasheet for the device, but it is nice to have confirmation.
The device is no longer available from the big 4 but aliexpress has this part available at sensible money, 4x new ones have been ordered but I'll only replace this one if it fails the bench test.
I'll update this as I work on the repair this week... any questions anyone has, just ask...