Mark;

I would agree with your assessment of the symptoms. You've had luck sofar and your key has survived your IGN switch (typically it's the other way around!). In your case, a Start Switch Upgrade would (cheaply and effectively) bypass what we both suspect to be a worn contact. There is no access to the electrical contacts, even after removing the lock cylinder. Everything has a limited life expectancy, but a Start Switch increases both the key's AND the STARt contact...the IGN ON contact in the switch is not switching that much inductive load current and so mostly endures mechanical wear...the START contact on the other hand is always making and breaking a heavy inductive load current which causes arcing and contact erosion...

I would totally dissagree with the Tom's statement that "most old Volvo's had to dump the armored cable..."...based on what does he make this statement?...has he taken a survey or is he making sweeping generalities from his own experience (how big is his sample?). Maybe we should do an impromptu survey here...I've NEVER had to replace an IGN switch*, nor has anyone that I can think of in my immediate group of acquintances (and we have/had a LOT of 544/122/1800 between us. Can those people who have installed a Start Switch be heard from please.... Futher, his statement that the armored cable needs to be removed when installing an electronic ign is also not correct.

* ...have had a number of key problems though, but that's a different issue...and since all my cars have Start Switches now, I've since NEVER had an issue...

Further info: http://www.intelab.com/swem/service%20notes.htm#Body

Cheers