B&k 747 tube tester died

[mike685s]

My B&K 747 Tube tester just died in the middle of a restoration. I was testing a 12SN7. The first section tested perfectly and I had just changed the settings to the second section when the tester gave no result. Moving back to the first section I also got no result. Replacing the tube under test with a good 6K6 I also got no result. Checking tube voltages, I found Fil B+ and screen voltages on the 6K6 were correct but there was a negative 54 volts on the grid even with the test switch no pushed. Pushing the switch resulted in a negative 60 volts on the switch. Clearly a component on the PC board attached to the meter died. My question is ..Should I get the replacement board being offered or should I simply troubleshoot the old board. I was planning to replace the board at some time in the future because the new board looks great. Comments?????