One guy who might help (semi-retired electronics technician who has worked for major UK companies) is:
Brian Chapman
211 Chart Downs
Dorking
Surrey RH5 4DD
Tel. 01306 888382
He has done a good job on my elderly studio flashheads, I assume he can fix timers as well! A strong point of his is that he is willing and able to work on older gear.
I needed help with the conversion of a Colourstar 3000 analyser to allow it to run on a Durst enlarger as opposed to a Devere which is what it had been set up for and Nova Darkroom put me onto a company called Lightwave which it has used for a number of electrical jobs.
The guy there is very helpful and gave me advice on how I could do the conversion myself so he wasn't looking to capitalise on my ignorance and isn't looking for a "quick buck". Companies like that deserve our business.
I can't say he can handle your job but he's worth a try.
Thanks. Shame it's in the States. They weigh about 12kg, so I hate to think what the shipping would cost. I haven't heard if my unit is repairable so I may have to plum for this one anyway!