I have two HL 553 Impulse Distributor's which took a surge of electricity and got fried. (Don't ask, long story) Obviously they don't work. I took them apart and found a couple of the IC's burnt pretty badly and one of them actually exploded.
Tag does not have replacement circuit boards for these and I had to buy two new ones. However, since it appears that the most expensive part of these boxes is the case and the bannana plug assemblies, I was wondering if anyone out there who has sufficient knowledge of electronics would be interested in trying to repair them. I don't know enough about what makes them tick to take a stab at it. My guess is that someone out there might be qualified. If you're interested, send me an e-mail at dirkgouwens@gmail.com

Dirk:

http://www.thetimingguys.com/products/blinkybox.html

If you need to replace any more 553s, take a look at The Blinky Box instead. The design is 20 years more current, and in this case you could have bought replacement boards for it - you do not have to replace the entire unit.

We use The Blinky Box for alpine World Cups like Lake Louise and Kitzbuehel. It has a lot of features not available on the 553.