I bought a De Vere timer, from a UK supplier, not Odyssey,and it didn't work, at first, only after a spray with electric contact cleaner did it give me timed exposures, However It stops working , and I have to spray it again, obviously not an ideal situation, however i am going to replace the switch with a generic push for on switch from Maplins for a £ or 2, as it's cheaper than sending it back.
I had a reply to an email I sent to Odyssey asking about the 504 dichromat, and they told me that particular model does need a timer to work.
I agree with you Luis,, I've worked with and owned a few De Veres, and, once properly aligned, which is what i did today, they are unbeatable! I've packed my little Durst away for a while to get used to the Dichromat head. I'm using white light, and below the lens filters to get the grades, as I cant be bothered with the uncertainty of using the enlarger dichroics.