Newbie.. I service machines which use 2 x 1980's Vintage Linear PSU's (one 15vdc & one 5vdc) by Lambda, Coutant, Power One, Int Power, Farnell. Eventually the electrolytic capacitors swell and the PSU packs in. I've refurbished all the above make 15v and ALL of the above make 5V PSU's WITH THE EXCEPTION OF the Lambda 5v. I've tried fixing up four of them by replacing the cap's but it only shoves out 2.5 volts. Adjusting the v-adj pot has no effect at all. Any ideas please??