[Dekatron]

At what temperature did you measure those values?

Did you check the inductance too?

It's not that far from the values that AVO stated in their documentation, so my guess is that it is just fine:

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Amplifier Transformer:

Use Universal Bridge TF 1313, Marconi, for the following measurements.

PRIMARY:

Resistance: 0,2 Ohm +/-20% at 20°C, Inductance at 10KHz 99.5uH, Q-factor: 2.4 +/-10%

SECONDARY:

Resistance: 45 Ohm +/-10% at 20°C, Inductance at 10 kc/s 99.5mH +/-2%, Q-factor: 14 +/-10%
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I don't know of anyone who can supply another transformer, of any kind, for an AVO nor anyone who can supply the two NTC-resistors on the oscillator board.