A piece of industrial electronics I designed for a previous employer has failed after 15 years, possibly caused by a nearby lightening strike. There's no one at my previous employer who has any clue about this system, and worse yet, they destroyed any records of the project during a recent move. Their response to the customer after some very rudimentary troubleshooting was a suggestion to buy a new measurement system, which was really not an answer at all as a new system doesn't duplicate any of the required functions.
They asked me for some help and then left it up to me to make whatever arrangements I like with the customer.
I have contacted the EE who designed the main circuit board and probable culprit of this system. Fortunately, he still has schematics for some version of the board. It may not be exactly the same but the changes if any will be minor, so troubleshooting to the component level is possible. My former employer happens to have 2 assembled boards (of some version) that are of no use to them that they are willing to give me. If the boards are in fact the same version, some parts may need to be changed for this application (low and high-pass filtering).
The system (a permanently installed monitoring system) is bolted to a plant wall not far from the middle of nowhere. A trip there would be expensive, so I hope not to have to go there. Troubleshooting of the system may find some other faults than the board - a power supply or something easily replaced. Their technicians are capable of doing this under my guidance. If it is a problem with the circuit board, it can be removed pretty easily and sent to me for repair or replacement. Replacement requires the 2 boards side-by-side to identify any differences in component values. Somewhere between minutes and hours could be involved, particularly if the available boards aren't the same version.
The major functions of the system can be duplicated with modules from another vendor. This requires system integration, rewiring and changes to the operating procedure. Not all of the functions would be duplicated but this approach provides the critical function. This is an expensive option.
So here's my quandary. How would you charge for something like this? If my former employer could provide support, they would charge a high rate to do so. I could charge nothing, particularly since the replacement boards were given to me at no charge. I could charge time & materials and either give them the circuit board or put some value on it. Or I could hold them hostage and charge some significant fraction of what change to a different system would cost. It's unlikely that I'll have any other dealings with this customer.
I'm leaning towards time and materials plus some charge for the board but I'm curious what others would do in this situation. I expect that a fair amount of time is going to be required because some documentation will have to be re-created for the on-site troubleshooting, board swap-out and adjustments. The customer may feel that even this is a rip-off, but he may be used to paying yearly warranty and support charges on other data collectors from my previous employer. On the other hand, they may be relieved that an expensive upgrade isn't required.
when designing products, do you think about what will happen down the road? What happens if they break and nobody is left with the company who knows anything about it? I never considered this 15 years ago...
Thanks for any comments.