Vintage DD turntables. Are we living dangerously?

Doron: I especially dislike the acrylic mat which sounds hard and lean to my ears and think that the groove isolator is a much better choice.

Totally agree. My first Delphi, Mk IV had that hard mat and with that stiff (clumsy to be honest) suspension it simply sounded awful (after a cheap Thorens !). So my first experience with Oracles was a disaster. Very well, thought I in frustration and bought a brand new GOLDMUND Studio. It was slightly better in sound quality but due to its floating and thus flimsy suspension it was just another disappointment, despite of its excellent direct drive and very heavy mass. But I wouldn´t give up with those extraordinarily designed Oracles and I changed the Studio to a beautiful looking heavier black acrylic based secondhand Delphi Mk III with gorgeous gold plated brass spring towers and with the original platter with the GROOVE ISOLATION mat. Unfortunately the adjustment stems for the spring towers were a bit out of place so the subchassis didn´t quite fit the stems so the suspension was impossible to finetune :/ Then I changed the Mk III to a secondhand Mk II... and bingo ! Along the way I lost a minor fortune but got a very nice sounding TT. Heh, young and foolish was I but it proved to a happy ending.
And I agree also in everything else you say about.

This is what I mean by a finetuned suspension:
https://www.youtube.com/watch?v=Ql9Gq6ir7hA

Sorry guys, this is totally off-topic but I just couldn´t resist (grin).

Fleib, I fear we are still on different pages. I am talking about how to mount an RS-A1. To do so, you aim it at the spindle and let the stylus fall about 21mm short of reaching the spindle. It is my belief that thus you will obtain tangency somewhere near the middle of the playing surface, or wherever you prefer by adjusting the stylus underhang (i.e., the stylus hits the label a little closer than 21mm from the spindle or a little farther away, whatever suits you). If you look again at the diagram in Hiho's reference, see the arc that is shown as a dotted line. See that achieving tangency at point B will require you to adjust underhang such that the stylus falls on that dotted line arc some distance from the spindle, which I take to be about 21mm, from my memory of the RS-A1 instruction manual.

Doren, For caps in the circuit, I would not stray from the original values given in the parts manual available on Vinyl Engine. Voltage rating can be higher than original but not lower. For caps in the PS, you may wish to use slightly higher values of capacitance, but there is no need for it. Yes, replace all. Any one of them can fail any time, after 30 years. Digikey and Mouser are good sources for Panasonic, Nichicon, and other top quality brands. For only a few bucks you can buy them all.

Lew, Right you are, different pages. I was talking alignment. Interesting thing about that Viv arm. They say you can mount it almost anywhere. No drilling, it's a surface mount.

What about replacing resistors? They are said to age also. Do them on an individual basis?
Regards,

Re-posting the diagram by the RS tonearm designer if it heps:

RS-A1 tonearm set up

Good luck!

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Fleib, RS-A1 is also surface mount with no fasteners to the TT plinth surface. Thus you can (all too easily) move it back and forth with respect to the spindle, if you want to fiddle with where on the LP surface you will achieve tangency. The saving grace is that alignment need not be at all exact, because the best you can do is to achieve a single point of tangency on the LP surface. Precise positioning only affects WHERE that single point will be located.

Resistors are ageless, except carbon composition ones (cylindrical in shape and brown in color, bearing circumferential colored rings that denote the value in ohms) which can indeed drift over time and due to temperature. I suppose it would not hurt to check carbon resistors to determine whether the value is within ~10% of the schematic value. If so, I would leave them alone. If not, replace.