Hello Everybody.
I do not know what to do!
After extensive troubleshooting on my modified Vanrock ATOM101, I’ve identified the root cause of persistent sibilance/whistling during cutting:
- A plastic part of the weight/Lock-Free mechanism was damaged during shipping, making it impossible to adjust tracking force or engage the LOCK/FREE function.
- The tonearm is now stuck at ~62g with no way to reduce pressure.
- Additionally, the stylus (sapphire or diamond) consistently tilts inward (toward the ATOM label), causing lateral scraping instead of clean groove penetration — even with a new stylus and heated polycarbonate blanks.
- Attempts to shim under the cartridge mount or adjust the pivot screw have not resolved the azimuth misalignment.
Despite multiple tests (different springs, shims, heating protocols, silent cuts), I cannot achieve a clean, quiet groove.
--> The mechanical integrity of the current tonearm assembly is compromised.
I’m now seeking a complete, functional tonearm assembly (the original block with all 9 adjustment screws) to restore proper azimuth, VTF control, and LOCK/FREE operation.
If anyone has a spare ATOM101 tonearm block — or knows where to find one — I’d be very grateful!
Thanks Everybody
Marc from France
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Actions what i did:
- Action 1
Removed SERATO/STOP-FORWARD module
Free the arm for access
LOCK/FREE and fine weight adjustment disabled; plastic part broken in transit
- Action 2
Installed thin spacer (guitar pick) under V-block
Allow minimal stylus contact
Stylus touches disc, but tracking force remains stuck at ~62g
- Action 3
Tested various springs (0.8×7×25, 0.9×8×35, 0.7×6×25, 0.6×5×25 mm)
Reduce effective weight via spring tension
No reduction below 54–60g — arm appears mechanically limited
- Action 4
Tested with new sapphire + heated (42°C) polycarbonate
Rule out stylus wear or cold disc
Immediate high-pitched whistling on contact → mechanical issue confirmed
- Action 5
Visual inspection: stylus tilts inward (toward ATOM label)
Identify cause of sibilance
Confirmed: stylus attacks disc at an angle → lateral scraping
- Action 6
Shimmed under V-block with rolled tape
Attempt to realign stylus angle
Uneven results: some areas cut, others whistle — suggests warped platter + misalignment
- Action 7
Used bubble level on arm (on disc vs. in air)
Measure vertical/lateral alignment
Arm is level when on disc, but tilted laterally when suspended → torsion in cartridge mount
- Action 8
Attempted azimuth adjustment via cartridge screws
Correct stylus angle
Impossible — shank is seized (likely glued or over-tightened); screws also carry heater wiring
- Action 9
Final diagnosis
Understand system limits
--> Conclusion: Modified/damaged tonearm assembly prevents proper setup. A full replacement is needed.