Hi,

I am trying to troubleshoot Fluke 8842A DMM. If anyone has knowledge of this particular unit please share your thoughts.

No blown fuses both front and back and inside the unit.
AC power supply to VFD ( Vacuum Florescent Display) reads 4.1 Volt at Transformer pins 14, 16. ( 4.5 v nominal )
Power supply to Display IC voltages all have power (DC Power supply voltages )
VFD physically not damaged.

 

Service manual, see page 185 for psu..

https://www.manualslib.com/manual/1325733/Fluke-8842a.html?page=185#manual

 

Page 185 checked for the following. See attached picture. Thank you.
Table 6-23 Power Supply Voltages

+ 5 Vdc read + 4.88 Vdc
+7.5 Vdc read + 7,25 Vdc
+15 Vdc read +14.76 Vdc
+30 Vdc read + 29.4 Vdc
-8.2 Vdc read - 7.64 Vdc
-15 Vdc read - 15.05 Vdc
-30 Vdc read - 29.8 Vdc

- 6.2 Vdc read - 6.1 Vdc

No leaky or bulged capacitors.