UnLinked Technologies

30/05/2026

Roland SH-101 – Structural restoration, CPU recovery, and high-precision calibration

This SH-101 arrived in the lab in critical condition, with clear signs of past non-standard repairs and evidence consistent with an old liquid-related event. Several ICs had already been replaced, suggesting a historical failure that affected the power and logic sections, including key voice circuitry around the Roland IR3R03 area and the CEM3340.

A major issue was the internal harness. The original mainboard-to-CPU wiring had been rebuilt with unsuitable wire and adhesive, and multiple solder points near connectors were compromised. Several IC sockets appeared to be donor parts, with stressed pads and unreliable contact. Before any calibration could be trusted, the platform had to be rebuilt for mechanical and electrical stability.

We rebuilt all critical inter-board connections using new, stable wiring designed to avoid movement-related intermittency. The power section was returned to correct configuration by removing adapted parts and replacing non-compliant components, restoring a stable +5 V reference rail required by the CPU and logic functions. The CPU pins showed oxidation; the pins were cleaned and the CPU was reinstalled using a new gold-contact socket. Damaged traces and heat-stressed areas were reconstructed and reinforced, applying the same method to the Roland and CEM sections to ensure continuity and stable voice behavior. The ON/OFF switch assembly and pitch bend board were also restored to eliminate intermittent behavior.

Because this is an early-series unit, calibration required rebuilding the correct CEM3340 reference network. A non-matching reference configuration was preventing stable scaling. Once restored, calibration became consistent and repeatable.

Final scale check shows excellent accuracy: the two-octave ratio test (F3 to F5) reached 99.957% ratio accuracy, equivalent to about -0.74 cents over two octaves. Less than 1 cent error over two octaves is a rare result on an analog SH-101 and approaches the consistency typically associated with more rigid digital-referenced systems.

19/05/2026

This Technics SL-1200MK2, produced in March 1988, came into our lab with issues affecting both tonearm performance and speed stability.

The tonearm bearings were still intact, but the pivot was partially seized and lightly oxidized, so the assembly was cleaned, lubricated and carefully lapped to restore proper movement.

The pitch fader had also been previously tampered with, but it was still recoverable. After cleaning, restoration and lubrication, it was brought back to the best possible operating condition, with the Pitch Lock LED replaced at the same time.

Work then moved to the main board, where the critical solder joints around the drive and speed control sections were reworked, selected capacitors were replaced, and known stress points such as D301 and R307 were renewed as part of the restoration process.

The Start/Stop and 33/45 RPM control sections were serviced, the pop-up light assembly was restored, new signal cables and ground wire were installed, and the entire unit underwent full internal and external cleaning before final reassembly.

As the final stage, Quartz Lock and pitch gain were calibrated according to the Technics service manual, restoring proper speed reference and pitch response.

turntablerepair vintagetechnics vintageaudio audiorepair restoration electronicrepair analogaudio djgear djturntable pitchfader quartzlock vinylculture unlinkedtechnologies

19/04/2026

Vestax PMC-CX – Cue/PGM/Master Selector Service and Calibration

This Vestax PMC-CX returned to our lab after a previous intervention where we restored and upgraded the power supply section. This time, the issue involved intermittent behavior on the Cue, PGM, and Master selectors, causing unstable monitoring and inconsistent routing.

We were able to replace and restore the affected selector circuitry despite the complexity of this model’s double-layer PCB design, which requires careful desoldering and controlled heat to avoid damaging internal vias and pads.

During the same service, we refurbished the Master Isolator potentiometers and carried out a full verification of the mixer’s performance, including frequency response checks and gain calibration across the relevant channels. The VU meter was also calibrated to ensure consistent level indication after the electrical work.

The unit is now stable and fully operational again, with reliable routing, clean control response, and properly aligned levels.

IsolatorService VUCalibration GainCalibration FrequencyResponseTest AnalogMixer ProAudioRepair PhonoLab UnLinkedTechnologies

19/04/2026

Vestax PMC-250R – Isolator EQ Repair After Impact Damage

This Vestax PMC-250R returned to our lab after a few years. During its previous service we restored the two master volume potentiometers, bringing the unit back to stable operation.

This time the mixer came in after a fall. The impact compromised the three potentiometers in the isolator EQ section, and also damaged the gain control on one channel, causing unstable response and inconsistent control behavior.

We restored the unit by replacing the damaged channel gain pot and fully recovering the three isolator EQ potentiometers. These isolator pots are a critical point on this model because they are no longer available on the market, so restoring them correctly is essential to preserve both functionality and the original control feel.

The PMC-250R is now back to stable operation, with the gain stage and isolator section fully restored and ready for professional use.

VintageMixer DJGearFix AnalogMixer ProAudioRepair PhonoLab UnLinkedTechnologies NapoliAudioLab RareParts VintageGearService

17/02/2026

Sequential Circuits Pro-One – Power Rail Restore and Grounding Correction

This Pro-One came into the lab with power stability concerns and a grounding configuration that had been modified in the past, creating potential noise and reliability issues. The objective was to restore the original electrical architecture and secure the instrument for stable long-term operation.

We replaced the main power supply capacitors to restore proper filtering and rail stability. The grounding was then brought back to the original single-point layout by removing and correcting previous modifications that had altered the intended ground path. Finally, the rear ON/OFF switch was replaced to ensure safe, consistent power control.

After the work was completed, the unit was tested for correct supply voltages, rail stability, and general functionality, confirming clean operation without grounding-related anomalies.

PowerSupplyService Grounding ElectronicsRestoration UnLinkedTechnologies NapoliAudioLab ProAudioRepair VintageGearService SynthTech StudioHardware

17/02/2026

Roland SH-101 – Full Control Restore, Power Service and Calibration

This SH-101 arrived with multiple control issues caused by aging, oxidation, and previous non-ideal interventions. The goal was to restore reliable operation across the entire control surface, stabilize the power and logic sections, and bring the instrument back into proper tuning spec.

We started by refurbishing key potentiometers, including Tune (previously compromised), Volume, Portamento, and Bender, restoring smooth travel and consistent electrical response. Several critical selectors were then serviced and rebuilt, including LFO/MAN/ENV, Sub Oscillator Octave, Gate/Env, Transpose, and Portamento, along with corrective work on the ON/OFF switch assembly.

On the electronic side, we replaced selected capacitors on the power rail, the Bender board (which interfaces control functions with the output stage), and the main logic/CPU supply section to improve stability and reduce the risk of intermittent behavior.

Both audio output connections were restored by replacing the Output and Phones jacks, ensuring solid mechanical fit and clean signal transfer.

The final step was a complete calibration following service procedure, restoring tuning stability and accurate scaling, followed by full functional testing of controls, selectors, outputs, and overall behavior under operating conditions.

Calibration PowerRailService CapacitorReplacement JackReplacement ControlRefurb UnLinkedTechnologies NapoliAudioLab ProAudioRepair VintageGearRestoration

17/02/2026

Roland TB-303 – Control Path Restore and CV MOD Safety Service

This TB-303 arrived with unstable response on the main controls and a front panel that had become unreliable after years of use. We focused on restoring consistent operation and securing every critical point before moving forward with any deeper refurbishment.

Work performed included refurbishment of the Cutoff and Resonance potentiometers to recover smooth, stable response, and a complete replacement of all 24 tactile switches using original ALPS parts. We also serviced the power section by replacing a key capacitor to improve filtering and long-term stability. Critical solder joints were reworked and reinforced, especially around the connector area where mechanical stress often damages pads and intermittently breaks continuity.

A dedicated step was reserved for the existing CV MOD. The wiring was checked for continuity, reorganized for proper strain relief, and all exposed points were insulated using an electronics-grade compound to prevent shorts and intermittent behavior. The Waveform selector was also refurbished and brought back to reliable operation.

Final testing included full functional verification of all controls, switches, PSU stability, and CV MOD continuity.

TactSwitchReplacement ALPS PowerSupplyService SolderingRepair CVMOD UnLinkedTechnologies NapoliAudioLab ProAudioRepair VintageGearService

29/01/2026

Roland TB-303 – Filter Section Repair and Power Rail Service

This TB-303 came into the lab after many years of use, showing a common but critical fault in the filter control path. The Cutoff and Resonance potentiometers were compromised, causing intermittent response and unstable behavior during performance. Issues like this are often the result of oxidation, contamination, and long-term inactivity, and they can make the instrument unpredictable even when the rest of the circuit is still working.

We approached the repair in a structured way, focusing first on restoring control stability and then on securing the power section that supports it.

Work performed:
• Full inspection of the filter control path, confirming intermittent behavior at the potentiometers
• Refurbishment of both Cutoff and Resonance pots to restore smooth travel and consistent electrical response
• Replacement of selected power rail capacitors to improve supply stability and reduce the risk of recurring intermittent issues
• Final functional verification to confirm stable filter sweep, repeatable resonance behavior, and reliable response under continuous use

This is the first stage of a broader restoration process. Once the unit is electrically stable, we’ll move on to the next steps of the full refurbishment to bring the machine back to consistent long-term reliability.

FilterRepair CutoffResonance PowerRailService ElectronicsRestoration ProAudioRepair UnLinkedTechnologies NapoliAudioLab StudioHardware AnalogCulture

29/01/2026

19/11/2025

E-MU E6400 Ultra – Front Panel Refurb

This E-MU E6400 Ultra sampler came into the lab after being out of service for many years. As a result, the entire front panel was unresponsive — buttons were unreliable, and the main encoder suffered from inconsistent behavior.

We carried out a full front-panel restoration:
• Replaced all tactile switches with new high-quality units.
• Refurbished the rotary encoder, restoring precise parameter control.

Now fully functional and responsive, this Ultra-class sampler is back in action — ready to return to studio use with restored precision.