Taylor 45D2. DOA.

[dfriedman]

I've received the Taylor 45D2 as DOA & have invested lots of time for a reasonable working condition!

In spite of the DOA, the pilot indicator was on(flickering @ 120vac) - it was connected to the o/p of the power sw, but no power! A wire from the voltage changing panel to the 250v on the x'former was torn. The same for a .01 cap. 1 side the indicator should have been connected to the 240v on the x'former - 2nd to 0. The A pot is hard to adjust & its ccw is not @ 0 ohms, which're a must for some tubes. The test pb doesn't always make real 0 ohms. I tried w/ different pots of lower resistances, but I rally need 2k. Both these components are on order from the far east. Some of the B9A contacts are a bit lose - tightened them. Some of the rolling sw's have oxidized or don't make good contact, so I sprayed cleaned them - OK.

Now we come to the -Vg. THE AVO calculated procedure for Gm of of my Bogey 6SN7(~= 12AU7 / 6680 / CV...) was almost equal to my AVO VCM Mk.3(2550 uMho vs 2650), but not on this Taylor - too far off. My 6L6 Bogey(gleaned from the AVO @ 4800, Va 350v, Vs 250v, -Vg 18v)) shows on the Taylor as 3950(100, 100, -6, very strange!). Even @ 250, 250, -14, the result is not too close)I found the -Vg pot positioned @ .5v. Positioning.
So, is there some kind of calibration available?

Thank you, Dany, Toronto, Canada

[dfriedman]

To add more about my new Taylor 45D2. Someone has worked on it with deplorable results, besides the Pilot Light (it sure doesn't flicker when it's connected to the 240v tap of the x'fprmer).
The previous bridge & the 2 parallel diodes have been changed with something like 1N914/4148 (!) & they look as a horrible mess. Also 2 parallel resistors & 2 in series, instead the 2 proper resistors - all installed in a mess. Besides restoring these to their proper values, I'll test the other original resistors & change accordingly. I also "made" a 2A fuse (1A for 240v, 2A for 120v)) from a proper length fuse of 1/4A of mine that blew up @ 1 time switching on (it was only a matter of time...) - pity the fuse holder doesn't accommodate the longer miniature fuses.
Old resistors prove to be very much off, especially in Hickok TV-2's, where there's no calibration because the tube tester depends on the 21x 1% resistors (4 are ww - don't change value) & the rest of the 50.
Regards, Dany, Toronto

[Dekatron]

Before starting to refurbish the 45D2 you should make sure that the meter has the correct FSD current and internal resistance, they are prone to loosing magnetic flux over the years as most moving coil meters and it might be out of tolerance. If it is out of tolerance you need to address that before trying to fix the rest of the tester as all measurements rely on the instrument being correct.

I can recommend that you at least save the two power resistors as they are very seldom out of tolerance, likewise with the two wire wound shunt resistors. There are a few resistors on the rotary switch which sometimes are burnt so check those too.

The two resistors R15 & R16 are single resistors in the 45D but a pair in parallel in the 45D2 and sometimes that pair has one or two extra resistors in series to make up the proper resistance needed.

You can also quite easily replace the older fuse holders with modern ones.