The SP-404SX has three built-in test modes that can help debug noisy output or a flaky pads. Function Test includes battery & LED checks. Line Test has a factory MIDI & preset loading test. Service Test is the one Roland documents for repairs.

Getting to Test Mode

Start with a spare SD card formatted in the SP-404SX. The device check writes a file called MEM_TEST.BIN for the memory tests, and the factory preset steps can overwrite your samples and patterns. Turn the MIC LEVEL down before you start.

With the SP-404SX off, hold the three controls in the table below and turn it on. You can also start a test by putting its text file at the top level of the SD card and then powering on with no buttons held. The file should contain Roland SP-404SX in plain text, starting at the very first byte. Put only one of these startup files on the SD card.

Mode Held While Powering On Startup File
Function VOICE TRANS + DJFX LOOPER + pad 1 FuncTest_SP-404SX.txt
Line VOICE TRANS + DJFX LOOPER + pad 3 LineTest_SP-404SX.txt
Service VOICE TRANS + DJFX LOOPER + HOLD ServTest_SP-404SX.txt

All three start on the version screen. Hold down TAP TEMPO and press a numbered pad to jump to the corresponding check below. In Function & Service, MIC advances through many of the screens. In Line, use the pad shortcuts to navigate from the version, device and audio screens. When you are done, power off. If you used a startup file, remove it or swap cards before switching on again.

Check Function Line Service
Version, Device, PHONES, LINE IN/OUT 1–4 1–4 1–4
External Mic 5 5
Internal Mic, Buttons & Lights, CTRL Knobs 5–7 6–8 6–8
Battery, then the separate LED Test 8–9
Mute & SD Card Removal 10 9 9
Factory MIDI & Preset Loading 10
Output Noise & Factory Destination Setting 10
Completion Screen After mute 11 11

What the Checks Tell Us

Version. 107 is application version 1.07, the most recent offical firmware. In Line & Service, A/F shows the application version and B/G shows the boot version. Function & Line compare both against tje file version_SP-404SX.txt on the card. A missing file can give the same mismatch as a wrong version. If there is a mismatch, Function alternates the version with an e display and Line lights a pad. The number 1 means application and 2 means boot. Service shows the versions and lets you continue without the comparison.

For a unit with boot 1.00 and application 1.07, put these two lines in version_SP-404SX.txt at the top level of the card. Use the versions you actually expect on your unit.

BOOT_VER=1.00
APLI_VER=1.07

Device. Go to TAP TEMPO + pad 2 and let the scan finish. Function shows the failing numbers one at a time on the display. Line & Service light the corresponding pads. The numbers mean the same thing in each mode.

Number What Failed
1 Flash Memory Check
2, 3 Main Memory Checks
4, 5 Audio Processor Memory & Processor Checks
6 SD Card Write & Readback
7 MIDI Input
8 Internal Stereo Audio Check

If 7 comes up with nothing plugged into MIDI IN, that's expected. You would use a MIDI device sending Active Sensing (FE) for this check. If 6 comes up, try a known good writable card. An 8 directs us to the internal audio check. Use the PHONES and LINE pages to check the actual jacks.

Audio. Start with the listening level low. Supply a signal into LINE IN one side at a time and listen for it on the matching side of PHONES or LINE OUT. Speak into the mic on the relevant mic page and listen for it on both output channels. On the external mic page, the signal should get louder as you turn up MIC LEVEL. Unplug the external mic to check the built-in one. If you are measuring levels, we would use a 1 kHz tone at −10 dBu. The target is −3 dBu at PHONES with the SP's VOLUME at max, and −13 dBu at LINE OUT, both within 3 dB.

Controls & Mute. Press each lit button to bring up the next one. Watch the display for missing segments. On the knob page, turn each of CTRL 1–3 fully both ways so the test can register both ends. If the sequence stalls, note which button or knob it is waiting for. At MUt, use MIC to mute and bring back the tone. Eject the test card at rMV and reinsert it if prompted with Sd.

How the Modes Differ

Function. The battery check waits for a low reading followed by a high one. 000 means it sees the high reading. If it starts there and stays there, the low-to-high check is still pending. For a quick panel check, jump to pad 9 and watch the separate LED sequence for missing lights.

Line. Mdi on pad 10 waits for a factory MIDI SysEx message that selects which preset data to use. This step needs the factory MIDI setup and the matching data on your test card. Fct offers a factory-data load with MIC, Lod means loading, and Err means the load or verification failed. For a hardware check with no factory MIDI setup, jump straight to pad 11 after the shared checks.

Service. At PrE on pad 10, the flashing pad shows the stored factory destination. Pad 1 is the 117 V group, pad 2 is the 220–240 V group, and pad 3 is the 100 V group. If you're just checking it, read the flashing pad and leave the selection alone. Picking a pad and pressing MIC starts the factory-data procedure. For the noise check, Roland calls for −66 dBu or lower on both line outputs and PHONES with a noise meter set to DIN AUDIO.

CPL is the completion screen. If you get ErP there, press MIC to shut down and then flip the power switch off. Keep track of the results on each page as you go. You can jump to the end even if you skipped a check.