UniMac Washer-Extractor Error Code Eio 38: Mosfet Enable Won’t Turn On
Eio 38 means the Mosfet enable on the input and output board will not turn on, so the board cannot power valves, the lock or other outputs. Turn the machine off, dry the floor, and call us with the code.
Medium: the cycle stops before any output is powered, with no stuck-on output reported.
- Code
- Eio 38
- Maker
- UniMac
- Equipment
- Industrial laundry
- Applies to
- CHM1792C family washer-extractor (QN models, 20-100 lb) front-end control
What does UniMac error code Eio 38 mean?
The input and output board on a UniMac QN washer-extractor has a Mosfet enable that must switch on before the board powers any output. When the control starts a cycle, it asks the board to turn this enable on. Eio 38 appears when the enable does not respond. Valves, the lock and other outputs cannot be powered, so the cycle stops and the control holds the code until the cause is found. This is the opposite of Eio 39, where the enable will not switch off. A washer that stops with Eio 38 usually does so at the very start of a cycle, before water enters the drum. The manual lists board supply and ground, connectors to the board, moisture on the board, and the I/O board itself. A missing or weak supply to the board is the first thing to check, ahead of replacing it. Record the point in the cycle, turn the machine off with the power control and wipe up any water you find.
Affected models and control systems
This applies to the CHM1792C family of UniMac QN washer-extractors, 20 to 100 lb, front-end control, for example the UCA020QN. Eio 38 is one of the I/O board enable codes.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- Eio 38 on the display, often right at the start
- No water entering the drum
- No door lock action
- Code that returns at each start
Possible causes
Listed in UniMac's documentation
- Board supply and ground
- Connectors to the board
- Moisture on the board
- The I/O board itself
Other likely causes — what usually sits behind error code Eio 38 on this control. A technician confirms which one it is before any part is replaced.
- A low-voltage supply to the board that fails to reach the level needed for the enable
- A ribbon or harness plug that has partly lifted from its socket
- Condensation or a drip inside the cabinet that has shorted the enable line
Safe checks before calling for service
- Record Eio 38 and the point in the cycle.
- Use the power control to turn the machine off.
- Check the floor for water and wipe up what you find.
- Call us with the code, keep the area dry and wait for us before using it again.
How a technician diagnoses error code Eio 38
- Read the code and note the exact cycle stage.
- With power locked out, inspect the connectors and harness at the I/O board.
- Measure the board supply voltage and ground path.
- Look for moisture, corrosion and heat marks on the board.
- Replace the I/O board after supply and connections are confirmed.
- Board supply measurements are taken with the control energized near mains-powered circuits.
- Moisture on a board points to a leak that has to be found before any part is fitted.
- A replacement board has to be set up for the machine's identity and options.
Technical reference
- Document
- Washer-Extractor Programming CHM1792C_SVG, Part No. F8641001ENR4, Error Codes Table 29 (pp. 100-107)
- Maker documentation
- UniMac owner support
- Edition
- Part No. F8641001ENR4, January 2020
- Models / control
- CHM1792C family washer-extractor (QN models, 20-100 lb) front-end control
- Section
- Error Codes, Table 29, pp. 100-108 (PDF pages equal printed pages)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related UniMac industrial laundry error codes
What does Mosfet enable mean?
It is the master switch for the board's outputs. If it will not turn on, nothing connected to the board can be powered.
Is Eio 38 the opposite of Eio 39?
Yes. Eio 38 will not turn on. Eio 39 will not turn off.
Can I try again?
You can switch off and on once, but if Eio 38 returns, leave the washer off.
Need help with UniMac error code Eio 38?
A technician confirms the cause on site and gives you the price in writing before any work starts.