Update on the
hp 5216A with toasted mains transformer.
Last weekend I had set it up for 110V operation, as half of the primary required for 230V is open-circuit, testing with a lamp limiter up to 100W and I only had about +60V on the +155V PSU output. Not much point in continuing, as I would need dig out the larger step-down transformer and the 5216A is only rated for 20W, the faulty transformer would probably go up in smoke.
Yesterday I pulled the PSU board & set it up with external PSUs for each required supply. The 6237B was set for +5V on the main output for the logic, +6V/-6V for the analog supplies and the 711A was set for about +150V for the display supply.
Everything was double checked before applying power and to my surprize the 5216A powered up OK and seemed to be counting.
An oscillator was used to check the counting functions & the display drivers were 100% working.
Only thing not working seemed to be the gate light, this was verified to be a dead lamp, by adding a new one in parallel, an easy fix compared with replacing the transformer.
David