If your tattoo power supply turns on but the machine does not run, cuts out or changes speed unexpectedly, stop the session and test one component at a time.
Do not keep increasing the voltage to force an unstable setup to work. If you notice a burning smell, sparks, damaged insulation, liquid ingress or abnormal heat, disconnect the equipment and have it inspected before using it again.
After more than ten years designing and building tattoo power supplies—and troubleshooting hundreds of customer setups—this is the diagnostic sequence we use, starting with the most likely causes.
The 60-second check
Before carrying out a longer diagnosis, check these seven points:
- Check the wall outlet and power adapter. Inspect both the AC lead and the cable running from the adapter to the power supply. Pay particular attention to the connectors, which are the weakest points in most cables.
- Confirm that you are using the correct adapter. Check its label against the input specifications of your power supply. Requirements are model-specific: the Machete MK-1 uses its approved 19 V grounded adapter, while the MK-2 Dual USB-C requires a 20 V USB PD source providing at least 45 W. Do not assume that the connector shape alone proves compatibility. For the MK-2, use the USB-C adapter and power-bank compatibility guide. We have encountered customers using a 12 V adapter, which may allow the unit to work only under certain conditions.
- Push every connector fully into the correct input or output.
- Make sure the machine is connected to the machine output, not the foot switch input.
- Check the RCA or clip cord. Cords rarely fail completely at first. They tend to cut out intermittently, making the problem look as though it comes from the machine or power supply.
- Check the operating voltage and mechanical load. Stay within the machine manufacturer's voltage range and inspect the cartridge, needle setup and machine adjustment for excessive resistance.
- Replace only one component at a time with a known-good alternative.
Run these tests away from a client and without making contact with skin.
Identify the symptom first
| Symptom | Most likely areas to check first |
|---|---|
| The power supply display is completely off | Wall outlet, power adapter, power connector, power supply |
| The display is on but the machine does not move | Operating mode, foot switch, machine cord, output connector, voltage, machine |
| The machine starts only at an unusually high voltage | Mechanical load, cartridge, motor startup torque, jumpstart setting, machine maintenance |
| Speed fluctuates while tattooing | RCA or clip cord, connectors, internal machine connection, mains stability, power delivery |
| The machine cuts out when the cable moves | Broken conductor near a connector, damaged RCA or clip cord, output socket |
| The power supply restarts or shuts down | Wrong adapter, short circuit, damaged cable, excessive load or protection response |
| A coil machine becomes progressively hotter | Setup, voltage, duty cycle, coil or capacitor condition, polarity and power quality |
The table gives you a starting point, not a final diagnosis. A fault can produce more than one symptom.
1. The power supply does not turn on
Begin before the power supply itself:
- Test the wall outlet with another device.
- Check that the adapter is connected firmly at both ends.
- If the adapter has a removable mains cable, reseat that connection too.
- Inspect both cables and their plugs for cuts, crushed areas, loose pins or heat damage.
- Confirm that the adapter's output voltage, power rating and polarity match the power supply's input specification.
Using the wrong adapter does not always produce a simple on/off failure. For example, a 12 V adapter connected to a power supply designed for a 19 V or 20 V input may allow the display or low-power functions to operate while failing at higher output voltages or under load.
For a model-by-model explanation of the power inputs, voltage memories and machine outputs, see our Machete MK-1 vs MK-2 comparison guide.
Do not open a mains adapter or power supply unless you are qualified to service electrical equipment. Internal components can remain hazardous after the unit is unplugged.
If a compatible, known-good adapter makes the unit work, the original adapter or its cable is the probable cause. If the display remains off, the power supply should be inspected by the manufacturer or a qualified technician.
2. The display is on, but the tattoo machine does not run
When the display works, separate the control path from the machine-output path:
- Disconnect the foot switch and test the power supply in continuous mode. This removes dirty foot-switch contacts and a damaged foot-switch cable from the equation.
- Confirm that the RCA or clip cord is connected to the machine output, not the foot switch input.
- Set a voltage that falls within the machine manufacturer's recommended range.
- Test a known-good machine cord.
- Test a known-good compatible machine.
If one machine works and another does not with the same power supply and cable, the fault is probably in the machine or its setup. If neither machine works, continue isolating the cable, foot switch and power source.
If known-good replacements are unavailable, a qualified technician can check the no-load output with a multimeter and test the cord for continuity while gently flexing it near the connectors. A no-load voltage reading confirms that some voltage is present, but it does not prove that the output will remain stable under working load.
Do not deliberately short-circuit the output with a pencil or another improvised conductor. Smoke is not a reliable measurement, and the test can damage connectors, contaminate the work area or trigger the power supply's protection.
3. The machine starts only at high voltage
This does not necessarily indicate a fault in your equipment. Startup behaviour often depends on the complete mechanical and electrical configuration, and there may not be a universal solution for every setup.
A rotary motor needs enough initial torque to overcome cartridge resistance and the inertia of the drive system. A hard cartridge, unsuitable needle setup, dry or poorly maintained mechanism, or very low starting voltage can stop the motor from starting cleanly.
A configurable jumpstart function can apply a brief starting pulse and then return to the selected working voltage. It is designed to help the motor start; it should not be used to hide a damaged cord, bad connector or internal machine fault. Read Is jumpstart good or bad for a tattoo machine? for the detailed explanation.
Never exceed the voltage range stated by the machine manufacturer.
For a coil machine, use only the minimum rubber-band tension needed to stabilise the needle bar. Excessive tension creates unnecessary friction and makes the machine work harder.
If a coil machine struggles to start, inspect and clean the clip-cord contact surfaces and the contact point between the contact screw and front spring. Carbon builds up at this point over time, increasing electrical resistance and making startup less reliable. Follow the machine builder's maintenance procedure so that you do not alter the spring geometry or contact gap.
4. The machine speed fluctuates under load
Based on our troubleshooting experience, speed fluctuations most often come from these areas, in this order:
- A damaged RCA or clip cord: the cable is repeatedly bent, pulled and vibrated, especially near its connectors.
- An internal machine fault: a loose connection or short can appear only in certain hand positions or under vibration.
- Unstable mains power: this is more likely at conventions or in locations with poor electrical infrastructure.
- Inconsistent power delivery: a damaged adapter or degraded power supply can become unstable when the machine demands more current.
There is also a non-fault explanation worth considering. If the sound or speed changed after switching cartridge brand or model, the new membrane may create more or less resistance. The machine may be responding normally to a different load, so establish the new baseline before assuming that a component is defective.
The cord is one of the easiest components to eliminate. Replace it with a known-good cable and repeat the test. MUSOTOKU's Cheating Pedal technique can also detect many intermittent cord failures using a compatible power supply with a foot-switch input and visible activation indicator.
5. The machine cuts out when the cable moves
This symptom strongly suggests an intermittent cable or connector fault. With the equipment disconnected, inspect the cable near both connectors for sharp bends, loose strain reliefs or crushed sections.
During a controlled test away from a client, gently move the cable near each connector. If the machine or activation indicator cuts in and out, stop using that cable. A conductor that reconnects only in a particular position is still damaged and can fail completely without warning.
Replacing the cord is normally safer and more reliable than continuing to work around the failing position. The output socket on the power supply can also be damaged, although this is less common than cord failure. If several known-good cords fail in the same way at the power-supply connection, have the socket inspected.
6. The power supply restarts or shuts down
A restart or shutdown can be a protection response rather than a software problem. Disconnect the machine, foot switch and output cable, then turn the power supply on with only its approved adapter connected.
MUSOTOKU power supplies stop the output when they detect a dangerous power demand. The most likely causes are a short circuit or a mechanical obstruction that is forcing the machine to draw excessive power. Without protection, that condition could overheat and permanently damage the motor.
To isolate the problem:
- Make sure the machine is connected to the machine output, not the foot switch input.
- If the power supply stays on with nothing connected to its output, reconnect one component at a time.
- If connecting a particular cable or machine causes the shutdown, remove that item from service.
- If the power supply restarts with nothing connected to its output, test the approved adapter and contact technical support.
- If the power supply restarts or stops working only above a certain output voltage—for example, above 12 V—check the adapter. An incorrect or underpowered adapter is a likely cause.
Do not repeatedly reconnect a component that may be short-circuited. Protection can reduce damage, but it should not be treated as a test that can be repeated indefinitely.
7. The tattoo machine is getting unusually hot
Some heat is normal because motors and coils convert part of their electrical input into heat. Temperature rises with load, speed and operating time. Excessive heat, a rapid change from the machine's usual behaviour, loss of performance or a burning smell is not normal.
We have encountered machines whose internal mechanisms shifted after being dropped from a workstation. The resulting friction or misalignment forced the motor to work harder and caused abnormal heat. Bear in mind that a machine may have been knocked or dropped during cleaning or while other people were clearing the area, even if you did not see it happen.
For coil machines, setup, capacitor condition, polarity and power quality can all affect temperature. As the coils heat up, performance can fall, tempting the artist to increase voltage and creating a cycle of still more heat. See Why does my tattoo coil machine get hot? for the full technical explanation.
Stop using any machine that becomes abnormally hot and allow it to cool before diagnosis. Follow the machine manufacturer's maintenance and polarity instructions.
A reliable isolation sequence
Use a known-good reference setup and change only one variable at a time:
- Approved power adapter and wall outlet.
- Power supply with nothing connected to its output.
- Known-good machine cord.
- Known-good compatible tattoo machine.
- Foot switch, if required.
- Original cord and original machine, reintroduced separately.
Record the combination that reproduces the fault. If changing two components at once makes the problem disappear, you will not know which one was responsible.
When to stop troubleshooting
Disconnect the equipment and request qualified service if you find:
- Burning smell, smoke or sparks.
- Melted, discoloured or loose connectors.
- Exposed conductors or damaged insulation.
- Liquid inside the power supply or adapter.
- Repeated shutdowns with no output device connected.
- Abnormal heat that returns after the setup has cooled.
- A fault that cannot be reproduced safely away from a client.
For a MUSOTOKU power supply, consult the MACHETE MK-1 product information and manual before changing settings or accessories.
If the problem appears only when the same machine is powered by a wireless pack, use the tattoo battery troubleshooting guide to test the charging chain, battery and machine independently.
Frequently asked questions
Why does my tattoo power supply turn on but not run the machine?
The most common areas to check are the operating mode, foot switch, machine-output connection, RCA or clip cord, selected voltage, power adapter and machine itself. Test one component at a time with a known-good alternative.
Can a bad clip cord make the tattoo machine lose power?
Yes. A broken conductor or loose connector can create intermittent contact, causing speed changes or complete cut-outs. Failure often appears when the cable bends near either connector.
Why does my tattoo machine run only when I increase the voltage?
This is not necessarily a fault. The motor may be struggling against cartridge or mechanical resistance, or it may need more startup torque. Check the cartridge and machine condition before using jumpstart, and stay within the manufacturer's voltage range.
Is jumpstart bad for a tattoo machine?
No, when it is implemented correctly and used according to the manufacturer's instructions. It is a brief starting pulse intended to help the motor overcome initial resistance; it is not a repair for a damaged cable or machine.
MUSOTOKU power supplies limit the jumpstart peak to 12 V. This is compatible with rotary machines rated to operate at up to 12 V, including Cheyenne models with internal overvoltage protection. Always follow the voltage limits specified by the machine manufacturer.
Why does the power supply shut down when I connect the machine?
The cable or machine may be creating an excessive load or short circuit, causing the power supply's protection to react. Confirm that the machine is connected to the correct output, disconnect the suspected component and do not repeatedly reconnect it until it has been checked.
Should I test a faulty setup while tattooing?
No. Diagnose the equipment away from a client and without contact with skin. Use a controlled bench test and known-good components.
Can unstable wall power affect tattoo-machine speed?
Yes. Mains dips or an unstable adapter can affect the energy delivered to the setup, particularly under load. This is more likely at conventions or in locations with poor electrical infrastructure.
When should I send the power supply for service?
Request service if it remains off with an approved working adapter, restarts with nothing connected to the output, shows physical or heat damage, has been exposed to liquid, or cannot be tested safely.