Vintage DD turntables. 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.

Hi Lewm,

Yes, the platter is stationary where the constant hum is travelled up to the platter mat.

I'm in Canada where 117v is standard. I'm using an Elgar 600A power conditioner adjusted to the unit's minimal output voltage setting of 103VAC. 

There is a diagram on the TT-101 transformer depicting 100vac as primary and 2 x 16.5vac / 1.2a, and 10.0vac / 1.0a as secondaries. 

I've replaced all the capacitors (8 in total) on the PS board in hopes of curing the hum. No luck. However, the speed fluctuation that I was experiencing earlier seem to have disappeared with the new caps.  

Following other TOTL DD designs, I've decided to move the xfmr into an external chassis.  I'll post my results when this is done.