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I have a transformer from a 1953 jukebox that seems to be increasing in voltage over time. When I first got it, it was outputting 32V. A week later it seemed steady at 38V, then 45V. Now I just measured it and it's at 50V.

I see no visible signs of burning or excessive heat and I've not seen or smelled any smoke.

It is supposed to be a 115V => 32V (approx) transformer.

What is going on? Do I need to throw this thing out?

enter image description here

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    \$\begingroup\$ I guess that could happen if the primary windings were shorting out one-by-one. I don't know how likely that is. Are you testing the transformer by itself or is there a circuit connected to it? \$\endgroup\$ – user253751 Jul 23 '20 at 23:00
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    \$\begingroup\$ Check the battery in your multimeter. Seems like it might be going flat. \$\endgroup\$ – brhans Jul 23 '20 at 23:05
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    \$\begingroup\$ Could it be old/weakening battery in the DMM causing incorrect measurements? As a test, if you measure a AA battery and instead of 1.5V it reads 2.3V, that's the problem. \$\endgroup\$ – MarkU Jul 23 '20 at 23:05
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    \$\begingroup\$ Welcome. Are you tracking the AC input voltage as well? This can and will vary with time. \$\endgroup\$ – user105652 Jul 23 '20 at 23:05
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    \$\begingroup\$ What kind of DMM are you using to make these measurements? Some very low quality DMMs are not rated for measuring 110VACrms line voltage safely. Peak 110VAC voltage is more like 170V peak. And 48V DC is considered the highest "safe" DC voltage. \$\endgroup\$ – MarkU Jul 23 '20 at 23:08
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@brhans was correct above - once I replaced my batteries I started getting stable readings out of this transformer. Thanks everyone

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