This looks like a good place for some advice on this strange multi tap multi coil transformer, this RS lump of a 40-0-40 @ 1A transformer came to me after an earlier eBay purchase was delivered damaged and the seller sent uninsured, he replaced it with this as I told him I needed 40V 500mA for a filament feed on an old TV PL519 sweep tube I was experimenting with. "I have a great one just what you need" was the answer and this arrived.
After looking at the available voltages I thought yes this will do the job and I began testing all the separate coils and all test good, they are in two identical rails and are 0-1V 0-3V 0-9V 0-27V which I thought would just link in series to 40V per rail with the 0-1V linked on 0V but it seems not? Here are the secondary tags.
Can anybody advise me the best way to achieve the rated 40-0-40V as I cannot find the datasheet on the internet and I have never seen or used a transformer like this before.