Thank you for your answer and forgive my poor English. It is a hard labor to express my thought in English
. Sometimes I feel embarrassed as much as my counterpart whom I talked to when I realized that my attitude made them confused and embarrassed. If I was rude, please undestand that it wasn't what I meant.
That is right,,there is no R82...I mistyped. It is R80.
And it was R35 not 37. I checked again and he told me turntable is R35 and tonearm is marked R36 and catridge R37. (I hope I heard right this time ^^)
Now I have to explain again what I did to solve frequency problem.
I solved the problem using Hz converter.
Yes, I have solved the 50Hz frequency problem by using frequency converter which makes 60Hz electricity to 50Hz.
I wrote " The converter output is 100 V and 117 V only and I had to rewire to make the turntable for 100V".
That is also right. I had to rewire the green cable from 220 to 110 to make the turntable work with 110 voltage. Please see the picture attached. (yes,,,right, a picture tells more than my terrible English)
The center spindle which is shown in your web site is very different from what I have on mine (you wrote that "the original one is quite 'thin', 5 mm to allow for a precise centering of the vynil grooves: see a similar item fitted on a 927F at http://www.stefanopasini.it/EMT_index_927.htm
and this can be fitted on any 927, as the glass platter"). But it doesn't mean the 5mm thin "record pin" of your 927F is "original" and mine is not original.
The center spindle what you have on 927F is not 927D spindle. The spindle of the D type 927 is not straight with 5mm diameter. It is conical shaped variable spindle which has diameter of 6.5mm (top of the spindle) and the bottom 7.5mm with 2.5°inclination so any LPs which is supposed(recommended) to have 7.24 to 7.33mm center hole but actually has 7.0 to 7.35mm , because of the tolerance of each LP manufacturer, can stop in the middle of the 927D's variable spindle. So the LP will be in the air little bit up on the platter and the spindle will be pushed lower with the help of the weight of the LP itself and another auxiliary weight to make LP contact the platter completely.
It is possible because the spindle has a spring which pushes up the spindle when there is no weight that presses down the spindle. You wrote that "My EMT 927F has a special 5mm record pin instead of the 7,5 mm standard to allow a perfect centering of the records, like the fabled 'laboratory' version 927D". But it is not right in two ways. First the D version doesn't have the 5mm thin 'Record pin". Second, If the standard spindle diameter is 7.5mm, there will not be many LPs which will fit to the "standard" spindle if not you expand the record hole by yourself.
And the "original" D version ("fabled 'laboratory' version 927D") used 'glassmat' instead of acrylic mat. This glass mat has the weight of 2.5kg and 4.9 mm thickness. As Jean said " The "D" means that it has a glass auxiliary platter (Glassmat ) , a special glass-rubber mat that replaced the standard acrylic mat . The "st" means that the power supply is made for the 139 stereo phono equalizer. The lighter acrylic mat ( 927 A ) has a felt brake to allow instant start/stop for broadcast use. With the glass auxiliary platter the clutch system can't be used but it is not a problem in domestic use." He is right when 'D' means that it is a special (fabled 'laboratory') version which has a glass mat. But may be wrong because glassmat was specially designed for professional use of checking original records.
(Anyway no 927 was designed for home use
This glass mat has butyl rubber on the surface ( 1mm thickness under the glassmat and 2mm up of the mat) and it is extremely flat because the D version was specially made for checking for the first LPs by engineers - I don't know if I can call this as a LP - which is cut by cutting machine. The horizontality deflection of this super flat glass mat is far 'less than +- 0.05mm' which is decided? for a turntable for professional usage and 927 D version's horizontality deflection is almost not measurable. (for reference, horizontality deflection for consumer usage is less than 1mm)
The spindle , which you called " 5mm record pin" is also designed to make the LP location in the center of the platter (" for perfect centering of the records"), same idea as D version. This idea was originated with and used for old version (low serial No) of 927 and Lyrec AG40-2. Because the spindle ( 5mm record pin) is thinner than the record center hole it needs the Center weight which you have explained in your web site. The end of the Center weight will fill the space between 5mm spindle (record pin) and center hole of the LP . Without the help of the Center weight the LP on the paltter will not be correctly center located because the 5mm is too thin compare to the diameter of the hole of LP.
The motor is different too ( If I was informed right. But there were no way for me to check this) . I was told that the 927D motor has stronger torque that makes for the turntable to reach its proper speed in a second. With the felt brake, usual 927 is designed to reach proper speed in 0.5 second. As D version having no brake, EMT made its motor to have stronger torque. And this strong torque was needed for the original LP checking purpose.
And this D version has a different Optical locator. This Optical locator with scale indicates the lateral movement of the tonearm so it can check revolutionary eccentricity. The D version Optical locator moves two times faster than usual 927 locator.
I started this thead because I was confused with marks. My turntable is engraved as 927ST and name plate as 927D. It might not mean anything. But with the information I got from various sources and several 'EMT speciallist' I could believe that my 927 is a D version.
Nobody can sure what has happened when EMT had special orders from various customers. So it become fabled.
I might have wrong information. It will be good that somebody with correct information can correct me and I can grow my knowledge on this turntable.
Thank you again for your advice.