Vintage DD turntables. Are we living dangerously?

To all Victor TT-101 owners:

I’m hearing a “hum” when I press my ear up to the platter mat. Sounds like a transformer hum.  Doubt very much this is normal. Would other JVC DD table owners please chime in and comment on this?

All the electronics are original. Will replacing the caps in the PS board eliminate this hum? Or is it something more seriously wrong? Like a bad/noisy transformer? The wall voltage measures between 102-103VAC.

Plans to replace all the electrolytic caps are in the works.

I’ve also noticed on several occasions the speed briefly jumps from “33.33” to “33.32 or 33.34” during lp playing. Is this normal? Playing one side of an lp, this may occur once or twice, or no at all.  

Halcro, is this what you mean by “Are we living Dangerously”?

Hi Norm,

Neither is normal.  The hum could be high load on the PT due to bad filter caps in the PSU.  The speed issue may be a consequence, or there could be other causes. 

A recap isn't a fix-all though - it will need calibration afterwards, and that's a smidge tricky on these. 

Halcro, is this what you mean by “Are we living Dangerously”?

Kinda....😩
The TT-101 is just more complex electronically than any other deck I know of.
I've never heard a 'hum' with mine however.
Apart from replacing the electrolytic capacitors....the most critical thing I found with my TT-101 are all the 35 year-old solder joints. There can be micro cracks which are invisible to the naked eye.
The best 'fix' is to flush them all out and re-do the lot.
The most critical ones (especially if the speed indicator changes)  are the joints under the control panel.
I would strongly recommend that you send your deck to jpjones (if he is willing) who is somewhat of a 'guru' electronically and was able to fix Lewm's intransigent Victor where others had failed.

Once fixed....I believe you can look forward to years of NOT living dangerously..👀
Good luck...

Lucky enough to procure not one but TWO Denon DN 308 Direct Drive tables from Mexico.  Now there is a DD table, had one some years ago which I restored, its now spinning Records at kftool s place on the east coast.

These two will be "GrooveMastered" too, somewhat of a challenge as the motor is the size of a gallon paint can but I'm sure I can figure out something aesthetically pleasing.

Good Listening 


Peter

http://pbnaudio.com/audio-components/audio-turntables/groovemaster/groovemaster-vintage-direct

Norm, A few questions:
When you press your ear to the platter mat, I presume that the platter is not rotating. Correct? (It would be quite a trick to put your ear down on the mat with the platter up to speed.)
The hum: is it a constant or intermittent?
You say the "wall voltage" measures 102-103 VAC.  I presume you mean this is at the output side of a 120 to 100V step-down transformer, if you live in the US or any other country with 120V standard.  If not, what?  
And in connection with the last question, are you sure your TT101 is set up to receive 100V? Most are, but at least a few (mine included) were sold with selectable taps on the power transformer primary such that one can feed the motor with 240, 120, or 100V.  Check that the wall voltage and the transformer voltages are copacetic.