[Collins] HP-410B calibration problem

[Ray V.]

Since this meter will (hopefully) be used eventually to work on my 
Collins gear, figured I'd asked here:

I just received an HP-410B yesterday, did a quick test and of course it 
needs a little work. I've done no troubleshooting myself yet, just 
thought I'd ask if anyone had encountered these problems themselves, or 
had any comments before I dig into it myself.

1. DC Calibration: I'm unable to get the DC voltages to read accurately. 
I've gone through a quick calibration from the manual using a 
battery/dropping resistor and two Fluke DMM's for comparison to set up 
for a 1 volt standard and am unable to get the HP-410B to read better 
than .8 volts full scale. The calibration adjustment of the 410 is at 
maximum attempting to get a full scale reading. Changing the battery 
voltage input shows about 1.2 volts on the Flukes needed to get a full 
scale 1 volt reading on the 410B. Double checked these readings with my 
Oscilloscope Standard Calibrator (provides a 1, 10 and 100vdc standard), 
verified the voltages were correct with both Flukes and the HP reads .8, 
8 and 80 vs 1, 10 and 100. Any suggestions before I start checking the 
HP-410B?

  2. Ohmmeter Calibration: I am unable to get a full scale (infinity) 
swing on the HP-410B except in the RX1 position. In RX1, I can use the 
Ohms adjust to get to the Infinty mark (and further), but in any other 
position (rX10 etc) I can't bring the needle any higher than the about 
midway between the 100 and 500 mark just below Infinity, can't get the 
needle to Infinity. Again, anyone else had this or anybody got some 
suggestions?

3. Haven't test AC calibration yet.

Tonight I'll start making my own measurements of the 410, swapping ubes 
etc but thought I'd see if anyone else had experienced and resolved 
these symptoms before.

I also checked volatges reported by the Flukes with my TS-505 that I 
have been using and the TS-505 agrees with the Flukes. I'm sure it is 
the HP-410B that is not reading correctly.

Thanks, Ray  W2EC