10. Troubleshooting
Most issues with the ΔStop fall into a few common categories, and most are resolved by checking connections, confirming settings, or cycling power. This section is organized by symptom. If you don't find your issue here, contact support using the information in Section 13.
Display Is Blank
Possible cause: The ΔStop is not receiving power.
Confirm the power supply is plugged into both the ΔStop and a working wall outlet. Test the wall outlet with another device if possible. Confirm the power supply cable is fully seated at both ends.
Possible cause: The power supply has failed.
If the wall outlet works and the cable is seated, the power supply itself may have failed. Contact support for a replacement. Do not substitute a different adapter, even one with matching voltage markings.
Display Is On But Shows Unexpected Values
Possible cause: A dial was turned inadvertently.
Check each dial position against what you expect. The Base Time dial is particularly easy to bump during a session. Turn each dial slightly to confirm the display responds, then return to the intended setting.
Possible cause: A stored configuration was recalled unintentionally.
If pressing a Program Memory button (1, 2, or 3) changed the display unexpectedly, a stored configuration is overriding the dial positions. Turn any dial to clear the recalled configuration and return to dial-controlled operation.
Enlarger Does Not Turn On
Possible cause: The enlarger cord is not connected to the relay unit outlet.
Confirm the enlarger's power cord is plugged into a Normally Off outlet on the rear of the relay unit, not a separate wall outlet.
Possible cause: The enlarger's own switches are not in the correct position.
Many enlargers have a lamp switch and a focus/timer switch in addition to their main power. Confirm the lamp switch is on and the focus/timer switch (if present) is set to the external or timer position as specified by your enlarger's manual.
Possible cause: The enlarger draws more current than the ΔStop is rated for.
Check your enlarger's specification plate against the ΔStop's load rating in Section 11. If your enlarger is within range and the issue persists, contact support.
Enlarger Is Plugged Into the Wrong Outlet
The relay unit provides four AC outlets on the rear panel: two normally-off outlets, one normally-on outlet, and one always-on outlet. These serve different purposes.
The normally-off outlets turn on when the relay activates during Focus mode or a timed exposure. Your enlarger should be plugged into a normally-off outlet so that the relay controls its lamp.
The normally-on outlet delivers power continuously but cuts off when the relay activates. The always-on outlet delivers power continuously regardless of relay state. A safelight belongs in the normally-on outlet so it turns off automatically during an exposure.
Symptoms of a wrong-outlet connection:
If a safelight is plugged into a normally-off outlet, it will turn on and off with the enlarger, which is not what you want during a printing session. If the enlarger is plugged into the normally-on or always-on outlet, the relay cannot control it.
Resolution:
Confirm your enlarger cord is plugged into a normally-off outlet (labeled on the rear panel). If using a safelight, plug it into the normally-on outlet. For accessories that should remain powered at all times, use the always-on outlet. Reconnect power and run through the First-Run Check in Section 6 to confirm correct operation.
Enlarger Stays On When It Should Be Off
Possible cause: The Mode selector is set to Focus.
Focus mode keeps the lamp on continuously. Turn the Mode selector to Test or Print. The lamp should turn off.
Possible cause: A timed exposure is running.
Check the display. If it shows a counting-down time, an exposure is in progress. Press Start/Stop to cancel, or Reset to return to the ready state.
Test Strip Sequence Does Not Run Correctly
Possible cause: The Mode selector is not set to Test.
Confirm the Mode selector is in the Test position before pressing Start. In Print mode, pressing Start produces a single exposure rather than a sequence.
Possible cause: The Test Interval dial is set incorrectly.
Confirm the Test Interval dial is at the desired fractional stop position (1/8, 1/4, 1/3, or 1/2). The current interval is reflected in the sequence timing.
Program Memory Does Not Store a Configuration
Possible cause: The Set button was not pressed before the memory bank button.
To store a configuration, press Set first, then press 1, 2, or 3. Pressing 1, 2, or 3 alone recalls the stored configuration rather than storing the current one.
Possible cause: The configuration is stored but the dials are overriding it.
After storing a configuration, turning any dial changes the current setting without affecting the stored value. To confirm the configuration is stored correctly, press Reset to clear any current dial overrides, then press the memory bank button to recall the stored configuration.
Program Memory Does Not Recall After a Power Cycle
Program Memory is persistent across power cycles. If a stored configuration is not available after cycling power, the memory may have been overwritten or the unit may have an internal issue. Try storing a test configuration, cycling power, and recalling it. If the issue persists, contact support.
Timer Feels Inaccurate
Possible cause: The perceived inaccuracy is a reading of cumulative darkroom variables rather than the timer itself.
The ΔStop's timing is accurate to a tenth of a second. Perceived inaccuracy almost always traces to something else: a warm-up delay on the enlarger lamp, chemistry temperature drift, safelight fog, or paper batch variation. Run a test strip with a known negative on fresh chemistry to confirm.
Possible cause: The enlarger lamp has significant warm-up behavior.
Tungsten enlarger lamps reach full brightness a fraction of a second after switching on, and very short exposures can be affected by this warm-up. For exposures under about 2 seconds, consider stopping down the aperture to lengthen the base time into a more stable range.
If the issue persists after these checks, contact support with as much detail as possible: the symptom, the conditions, and any patterns you've noticed.
Unit Behaves Erratically
Possible cause: Power supply interference or a brief outage.
Disconnect the power supply, wait ten seconds, and reconnect. The ΔStop should return to normal operation on power-up.
Possible cause: Environmental conditions outside the operating range.
Confirm the operating environment is within the temperature and humidity ranges specified in Section 11. Moving the unit from a cold space to a warm darkroom without allowing it to reach room temperature first can cause temporary condensation and erratic behavior.
If the issue persists, contact support.
When to Contact Support
Contact support if:
- The unit fails any check in the First-Run section and cannot be resolved by the steps above.
- The display, a control, or a connection shows physical damage.
- The unit behaves in a way not described in this section.
- You have questions about compatibility, accessories, or the workflow that are not answered by this manual.
- Support contact information is in Section 13. When reaching out, include your unit's serial number (located on the rear panel near the connections), a description of the symptom, and any steps you've already tried. This information makes diagnosis faster and gets you back to printing sooner.