Another aspect to consider is the risk involved by not using an insured repair tech. I'm a DIY guy myself and hate spending money on anything that I don't have to, but if you repair your own equipment and there is a problem, think malfunctioning timer or electrocution, you are going to be liable. You aren't just fixing something that you will use, you are responsible for your clients while they use your equipment.
You may have some protection from your
insurance policy, but about any policy is going to exclude you working on your own equipment unless you are an electrician. The policy may cover you, but I'm betting you would have to fight your carrier and adjuster all the way. It's very sketchy either way.
Basically, the point I want to get across is that there is a financial risk you take when you repair your own equipment.