I inherited this and the meter works when testing the line voltage. I set it up for a tube and the voltages are all there on the various pins. When I press P-4 nothing, no "test". The P-4 switch is good. The 5Y3 is good and I got a SS replacement for the 816. The schematic is a little hard to follow due to its size and that it all won't fit on screen at once. Plus I'm no good at something I haven't worked on before. I'm hoping this is a problem others have encountered and someone can point me in some direction. Thanks in advance. The lamps and fuse and such are good.


ET

I tested a few 6H6 on my 538, and thought they were bad. Also, noticed any of my diode tests did not work. I was told to clean that one, and it worked.

Right, some of the test circuitry runs through switches that are rarely used, and those contacts could use cleaning. Worth a try.

Agree with the above.....

Time to flip the board on it's back (use the case as a stand) and go through all the switches with a burnishing tool. It would also be a good time to check all connections (Lord, there are a ton of 'em so take your time!) My 533A has given me excellent service for nearly 20 years but I still can't train it to do any sort of self-diagnostics! (shucks!)

Here's a good site for reference....
http://www.saegerradio.com/downloads.html

...Jim

My working 533DM has a type 83 tube along with the type 5Y3 tube. The 816 is quite different. Hickok may have made changes in the circuit over time or someone may have modified the tube tester at some time but that tube is where I would start. First check the filament voltage where the 816 tube is inserted. If it is 2.5-volts, then the 816 may be correct. If it is 5-volts, it most likely should be a type 83 tube (if circuit changes were made to accommodate the 816 tube, they will need to be reversed). Second check for plate voltage. The 83 tube has two plates both of which should have high AC voltage on them when the P4 button is pressed (possibly also when not pressed). The 816 only has one plate which should have high AC voltage on it when the P4 button is pressed. An open filament on either type rectifier tube will also cause the problem being experienced.

I encountered the same symptom and found it to be a broken transformer winding at the lug for the plate of the 83 tube.

Norman

Oops, yes it was an 83 not an 816. Sorry and thanks all for your input.


ET

So have any of our comments been of help? Have you been able to get the tube tester to function?

Norman

They have helped. I haven't tackled it yet but will soon.


ET