Well - I was about to use two pairs of 8uF 500V electrolytics in series to replace the 4uF HT caps in my Mullard Valve Tester, but I'm not so sure now!!!!
I'm having difficulty obtaining 4uF 500V eelctrolytics - but I see that they are readily available for dishwasher motors!! Look:
http://cgi.ebay.co.uk/UNIVERSAL-DISH...item48352a0f15
Can I use those
Bryan