Video & projection
Hollyland Cosmo C1 troubleshooting
The Hollyland Cosmo C1 problems live-event techs bring to Ask Roadie most (also called Cosmo C1 transmission). Pick your symptom, or describe your own in plain words, and get the likeliest fix first, with the manual page when there is one.
Common Cosmo C1 errors & problems
What techs run into most, and what's usually behind it. The step-by-step fix for your exact unit is in Ask Roadie.
- Step-by-step fixGet the fix →
"No Video" — transmitter shows no incoming signal from the camera
Likely cause: The TX only accepts clean 1080p/1080i; on-screen info overlays and HDMI-CEC control signaling on the camera output corrupt or block the feed the TX can lock onto.
- Step-by-step fixGet the fix →
Abnormal display when feeding an Atomos Ninja V over HDMI
Likely cause: ProRes RAW changes the HDMI signal characteristics in a way the C1 cannot pass cleanly; standard ProRes outputs a normal HDMI signal.
- Step-by-step fixGet the fix →
Black screen when feeding 1080p60 into a Blackmagic (BMD) switcher via SDI
Likely cause: A true 60.00 Hz SDI signal exceeds BMD's 59.94 ceiling and is rejected; 50 Hz / 59.94 is within spec.
- Step-by-step fixGet the fix →
Camera's own screen goes black while recording (through the TX)
Likely cause: The camera's single video pipeline can only feed one destination at 4K; dropping to 1080 or inserting a recorder that duplicates the output restores simultaneous monitoring.
- Step-by-step fixGet the fix →
Color blocks / artifacts appear on the monitor after turning on a LUT
Likely cause: The monitor's 3D-LUT processing conflicts with the C1's output signal and produces block artifacts; turning the LUT off removes the conflicting processing.
- Step-by-step fixGet the fix →
Displayed frame rate differs from the camera's set frame rate (e.g. 59.94 shows as 60)
Likely cause: The receiver's HDMI scaler outputs integer frame rates only, so NTSC-fractional rates are rounded on output.
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Firmware upgrade procedure and matching the right file to the unit
Likely cause: The bootloader reads firmware only from a FAT32 drive ≤32 GB, and H000 vs H100 use different images — loading the wrong image or interrupting power can brick the unit.
- Step-by-step fixGet the fix →
Image turns green when connected to an ATEM Mini
Likely cause: Port 1's RGB-only handling misreads the C1's YUV color data as a green cast; the other ports handle YUV correctly.
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Measured latency is higher than the advertised 40 ms
Likely cause: The 40 ms spec is the encoder core figure; real glass-to-glass adds camera, transport, and display processing, and the SDI path adds conversion overhead over HDMI.
- Step-by-step fixGet the fix →
Signal bar shows "×" on the transmitter screen
Likely cause: The signal-bar icon reflects link state between TX and RX; without a paired RX on a matching channel there is no RF link to display.
- Step-by-step fixGet the fix →
Sony mirrorless camera gives a black screen through the C1
Likely cause: Sony's HDMI info overlay and CEC control, plus a recording-format (4K/fractional) output, prevent the TX from locking; a clean 1080p/i output resolves it.
- Step-by-step fixGet the fix →
Video freeze, blur, or mosaic / macro-blocking on the received image
Likely cause: Freeze/mosaic is almost always 5 GHz co-channel interference or a marginal link; moving to a clean channel and raising the RX above ground clears the RF path and restores a solid bitstream.
Not on the list? Describe it your way, or paste the error code off the display. Ask Roadie works the problem with you until it's fixed or you have a clear next move.
How Ask Roadie helps with the Cosmo C1
- 1. Pick the Hollyland Cosmo C1. It's already in the list.
- 2. Describe what you're seeing. In your own words, or the error code off the screen.
- 3. Get the likeliest fix first. Steps in order, the manual page when there is one, and a note when other techs have confirmed it.
- 4. Still broken? Tap 👎 and it keeps going from where you left off.