Just an update on this. I checked the PSU voltages at the test points and all, except the 130V line, are high by about 10% which is pre-regulator voltage. I did a swap of equipment with another member of this group and obtained a R7844 as a spare, so did a quick swap of power supplies and everything is now OK bar calibration. I'll repair the damaged PSU at a later date when time permits and post a report on here.
Thanks for the replies.
