Services
What I Work On
Each of these has its own page with the common faults and the documented work: tube amps, synths, Hammond, Leslie and Rhodes, and pro audio.
Tube Amplifiers
Retube, bias, recap, hum diagnosis, tone issues, and full troubleshooting. Fender, Marshall, Vox, Mesa, and all major brands.
Synthesizers & Keyboards
Vintage and modern synthesizer repair, key contact cleaning, component replacement, and general troubleshooting.
Pedals & Effects
Troubleshooting, jack and switch replacement, component repair, and modifications. All brands and formats.
Professional Audio
As a working backline technician at Jonas Productions I service professional audio equipment across all major brands.
Documented Repairs
Every repair is logged with diagnosis, fix, and parts used. You get a clear picture of what was done and why.
Pricing
Service Rates
All repairs begin with a $75 bench fee - applied to your repair total if you proceed.
Tube Amplifiers
| Retube + bias - combo | $105 + parts |
| Retube + bias - head | $135 + parts |
| Bias only (your tubes) | $75 |
| Power supply recap | $175–275 + parts |
| Speaker replacement | $75 + parts |
| Troubleshooting & repair | $105/hr + parts |
Synths & Pedals
| Synth troubleshooting | $125/hr + parts |
| Key contact cleaning | $95 |
| Pedal troubleshooting | $85/hr + parts |
| Jack / switch replacement | $55 + parts |
| Modifications | Quoted per job |
Policies
| Bench / diagnostic fee | $75 · $50 pedals |
| Minimum charge | 1 hour |
| Parts markup | Cost + 15% |
| Standard turnaround | 3–7 days |
| Rush service (48hr) | + $75 |
| Labor warranty | 30 days |
Documentation
Repair Log
Selected repairs documented from intake to completion.
Marshall JCM2000 DSL100 — HF Oscillation Traced to the FX Loop Jack Contacts
2026-09-02 • Fixed - pending soak test
Device: Marshall JCM2000 DSL100 (Superlead Standard)
Symptom: In as "buzzy." High-frequency oscillation, visible on the scope when the amp was driven hard and absent at low volume. The original complaint - not something introduced on the bench, and unrelated to the thermal bias drift this same amp also had.
Marshall JCM2000 DSL100 — Thermal Bias Drift (Conductive Trace, Bias Supply Hand-Wired)
2026-09-02 • Fixed
Device: Marshall JCM2000 DSL100 (Superlead Standard)
Symptom: Bias would not hold as the amp came up to temperature. Set correctly cold, the idle current climbed as the chassis heated and kept climbing - reaching the high 100s of milliamps per tube, several times what an EL34 should be idling at.
That is not a tone complaint. At that current the output tubes are being destroyed while the amp sits there doing nothing, and the output transformer is next.
Roland Juno-106 — Full Voice Chip Set & Factory Calibration (Plus Three Pedals)
2026-08-29 • Fixed
Device: Roland Juno-106 Polyphonic Synthesizer; Keeley Loomer; Ross Chorus; Cooper FX Gen Loss
Symptom: A Juno-106 in for a complete voice chip replacement, plus three pedals on the same visit: a Keeley Loomer with a footswitch dented in and broken, a Ross Chorus that buzzed on external power, and a Cooper FX Gen Loss whose buttons kept sticking.
Roland Juno-106 — Dead Noise Source & Noisy Chorus (R115 Drift, BBD Replacement)
2026-08-29 • Fixed
Device: Roland Juno-106 Polyphonic Synthesizer
Symptom: Two complaints. The DCO white noise source was effectively dead — barely audible regardless of where the noise slider sat. Separately, a persistent oceanic swishing sat in the background of the chorus even with no notes playing.
Fender '65 Deluxe Reverb Reissue — Full Recap + Robinette Main Filter Mod
2026-07-19 • Fixed
Device: Fender '65 Deluxe Reverb Reissue (combo, rental fleet unit)
Symptom: Came in with a farting, blubbery tone on the low notes — classic sign of an amp that can't hold its supply voltage when you dig in. Then it got worse: after sitting on the shelf a week waiting for parts, it powered up into a loud hum at full volume with nothing plugged in. The noise only appeared with the amp driving a load, which meant it was coming through the output stage — the amp was amplifying something, and that something was its own power supply ripple.
Hammond B-3 — Recapping the AO-28 Power Supply (120 Hz Hum)
2026-06-27 • Fixed
Device: Hammond B-3 Organ — AO-28 Preamp/Output Amplifier
Symptom: Steady low 120 Hz tone sitting under everything coming out of the organ — not a buzz, more of a hum riding right into the output. The tell was that it didn't move with the volume. Pull the expression pedal all the way down and the tone was still there, which placed it after the volume control — down in the output stage or its supply, not up in the signal path.
Ampeg SVT Classic — Screen Resistor Failure & Full Retube
2026-03-30 • Fixed
Device: Ampeg SVT Classic Bass Head
Symptom: Screen resistor failures — likely triggered by a shorted or failing output tube. Burnt smell, possible loss of output. Some resistors visually burned or cracked, others stressed but not yet failed.
Avalon U5 — Total Positive Rail Failure (Transformer Winding Open)
2026-03-30 • Fixed
Device: Avalon Design U5 Pure Class A DI / Preamp — PCB ASSY 5600-9520
Symptom: Unit presented with suspected power supply fault. No audio. Voltage measurements on intake confirmed severely abnormal supply rails — positive side completely dead, negative side partially degraded.
Fender Twin Reverb — No Reverb (Dead Recovery Tube)
2026-03-30 • Fixed
Device: Fender Twin Reverb Guitar Amplifier
Symptom: Reverb completely absent. Not weak — fully gone. Reverb knob from 1 to 10 produced no change in the dry signal whatsoever. Amplifier otherwise sounded normal: loud, clean, full output.
Leslie Speaker — Motor Service (Dry Bearings & Glazed Drive Wheel)
2026-03-30 • Fixed
Device: Leslie Rotary Speaker Cabinet
Symptom: Scraping, chirping, or rattling noise from the cabinet during operation, especially at slow rotor speed. Noise worsened over time. Rotor spin sounded rough when turned by hand with power off.
Minimoog Model D — Oscillator Tuning & Calibration
2026-03-30 • Fixed
Device: Moog Minimoog Model D Synthesizer
Symptom: Oscillators drifting off pitch during play. Notes sliding flat shortly after power-on. Tuning unstable — chords sour, oscillators not tracking each other correctly across the keyboard range.
Rhodes Electric Piano — Full Tuning & Pickup Setup
2026-03-30 • Fixed
Device: Rhodes Electric Piano (Stage)
Symptom: Multiple notes out of tune across the keyboard. Some notes flat, some sharp, some with slow wobbling beat frequency against adjacent keys. Uneven output volume across registers. Tone lacking characteristic Rhodes bark on hard keystrikes.
Korg Triton — Factory Reset & Sound Reload
2026-03-30 • Fixed
Device: Korg Triton Music Workstation
Symptom: Unit needed full factory reset. Sounds corrupted or missing. Required return to factory default state with all original programs, combinations, and samples restored.
Not Local?
Mail-In Repair
Most of the write-ups on this page describe a specific fault, not a specific city. If you found one because your gear is doing the same thing, you do not have to be in Indiana for me to fix it.
Email Before You Ship
Tell me the make, model, and what it is doing. I will tell you whether it is worth shipping, roughly what to expect, and how to pack it. Do not send anything before this step.
Pack It Properly
Tubes and reverb tanks travel separately - they are what break in transit. Double-box with two inches of padding on every side and insure it for its real value. You pay shipping both ways.
Same Bench, Same Process
It goes on the same bench as everything else here. You get the diagnosis, photos where they help, and a written estimate before any repair happens. Nothing proceeds without your approval.
Back To You
Repaired, tested, documented, and packed the way it should have arrived. Same 30-day labor warranty as a local job.
Smaller items - pedals, modules, voice boards, synth chip sets - ship cheaply and I take those from anywhere in the world. For heavy amps from overseas, freight usually costs more than the repair; email me and I will tell you honestly whether it is worth it.
Book a Repair
Submit a Repair Inquiry
Fill this out and I'll get back to you within 24 hours to confirm dropoff.