Audio Fix / setup help
Anthem MRX 540 8K: replace an unwanted fixed startup source with Last Used
Anthem MRX 540 8K — replace an unwanted fixed startup source with Last Used. Confirm the actual setup and observed response before reporting an outcome.
Manufacturer-documented Reviewed 2026-11-09 · Revision 1
Follow these checks in Audio Fix →When this guide applies
Known fixed Power-On Input; preserve intentional installer startup behaviour.
Connection scope: Device controls / power only. Symptom: Switching between devices isn’t working.
This is a documented check, not a diagnosis of your equipment. The model name does not confirm the selected input, mode, software or connected partner.
If your exact model or a required setting is unknown, use the “I don’t know” branch below. Do not apply a similarly named model’s instructions.
Checks and possible outcomes
Start at step-0. Follow the link that matches what you actually observe. Alternative branches are not a single sequence of actions.
step-0
Does the wrong source appear only at normal startup, matching a fixed Power-On Input?
A live CEC or streaming takeover is a different trigger.
Look for: Confirm the stated setup or observation. Unknown stops safely.
- If Yes / confirmed → Is that fixed startup choice unwanted rather than installer-required?
- If No / cannot confirm → Stop and retain the actual observations
- If I do not know / cannot check → A required fact is unknown
- Manufacturer-documented Anthem 8K Operating Manual mapping ↗Public support download metadata: Operating Manual, MRX 1140 8K / 740 8K / 540 8K — The explicit three-model 8K Operating Manual links to manuals.anthemav.com/mrx-avm/en#. The actual web application Download PDF uses /media/manuals/{manualSlug}_{language}.pdf; mrx-avm/en therefore yields the exact English PDF cited below.Exact MRX 540 / 740 / 1140 8K shared operating instructions, not an inferred US/EU variant substitution. · Source checked 2026-11-09
- Manufacturer-documented Anthem MRX 540 8K official manual ↗PDF pages 50 — Power-On Input selects a specified available input or Last Used. This is separate from Power-On Volume and streaming-zone preferences.Startup source selection rather than unexpected switching during playback. · Source checked 2026-11-09
step-1
Is that fixed startup choice unwanted rather than installer-required?
Retain the existing input name before changing it.
Look for: Confirm the stated setup or observation. Unknown stops safely.
- If Yes / confirmed → Do you want the last selected input to be restored at the next normal startup?
- If No / cannot confirm → Stop and retain the actual observations
- If I do not know / cannot check → A required fact is unknown
- Manufacturer-documented Anthem 8K Operating Manual mapping ↗Public support download metadata: Operating Manual, MRX 1140 8K / 740 8K / 540 8K — The explicit three-model 8K Operating Manual links to manuals.anthemav.com/mrx-avm/en#. The actual web application Download PDF uses /media/manuals/{manualSlug}_{language}.pdf; mrx-avm/en therefore yields the exact English PDF cited below.Exact MRX 540 / 740 / 1140 8K shared operating instructions, not an inferred US/EU variant substitution. · Source checked 2026-11-09
- Manufacturer-documented Anthem MRX 540 8K official manual ↗PDF pages 50 — Power-On Input selects a specified available input or Last Used. This is separate from Power-On Volume and streaming-zone preferences.Startup source selection rather than unexpected switching during playback. · Source checked 2026-11-09
step-2
Do you want the last selected input to be restored at the next normal startup?
Ensure future listening levels are safe; this does not change Power-On Volume.
Look for: Confirm the stated setup or observation. Unknown stops safely.
- If Yes / confirmed → Set Preferences > Power-On Input to Last Used
- If No / cannot confirm → Stop and retain the actual observations
- If I do not know / cannot check → A required fact is unknown
- Manufacturer-documented Anthem 8K Operating Manual mapping ↗Public support download metadata: Operating Manual, MRX 1140 8K / 740 8K / 540 8K — The explicit three-model 8K Operating Manual links to manuals.anthemav.com/mrx-avm/en#. The actual web application Download PDF uses /media/manuals/{manualSlug}_{language}.pdf; mrx-avm/en therefore yields the exact English PDF cited below.Exact MRX 540 / 740 / 1140 8K shared operating instructions, not an inferred US/EU variant substitution. · Source checked 2026-11-09
- Manufacturer-documented Anthem MRX 540 8K official manual ↗PDF pages 50 — Power-On Input selects a specified available input or Last Used. This is separate from Power-On Volume and streaming-zone preferences.Startup source selection rather than unexpected switching during playback. · Source checked 2026-11-09
step-3
Set Preferences > Power-On Input to Last Used
Leave volume limits, CEC and Default Streaming Zone unchanged.
Look for: Perform only the stated operation and confirm whether it was possible.
- If Yes / confirmed → At the next normal startup, is the expected last-used input selected?
- If No / cannot confirm → Stop and retain the actual observations
- If I do not know / cannot check → A required fact is unknown
- Manufacturer-documented Anthem 8K Operating Manual mapping ↗Public support download metadata: Operating Manual, MRX 1140 8K / 740 8K / 540 8K — The explicit three-model 8K Operating Manual links to manuals.anthemav.com/mrx-avm/en#. The actual web application Download PDF uses /media/manuals/{manualSlug}_{language}.pdf; mrx-avm/en therefore yields the exact English PDF cited below.Exact MRX 540 / 740 / 1140 8K shared operating instructions, not an inferred US/EU variant substitution. · Source checked 2026-11-09
- Manufacturer-documented Anthem MRX 540 8K official manual ↗PDF pages 50 — Power-On Input selects a specified available input or Last Used. This is separate from Power-On Volume and streaming-zone preferences.Startup source selection rather than unexpected switching during playback. · Source checked 2026-11-09
step-4
At the next normal startup, is the expected last-used input selected?
No forced power cycle is needed; choose Unknown if a later observation is not yet possible.
Look for: Confirm the stated setup or observation. Unknown stops safely.
- If Yes / confirmed → Checks completed — report what happened
- If No / cannot confirm → Stop and retain the actual observations
- If I do not know / cannot check → A required fact is unknown
- Manufacturer-documented Anthem 8K Operating Manual mapping ↗Public support download metadata: Operating Manual, MRX 1140 8K / 740 8K / 540 8K — The explicit three-model 8K Operating Manual links to manuals.anthemav.com/mrx-avm/en#. The actual web application Download PDF uses /media/manuals/{manualSlug}_{language}.pdf; mrx-avm/en therefore yields the exact English PDF cited below.Exact MRX 540 / 740 / 1140 8K shared operating instructions, not an inferred US/EU variant substitution. · Source checked 2026-11-09
- Manufacturer-documented Anthem MRX 540 8K official manual ↗PDF pages 50 — Power-On Input selects a specified available input or Last Used. This is separate from Power-On Volume and streaming-zone preferences.Startup source selection rather than unexpected switching during playback. · Source checked 2026-11-09
Possible result
Checks completed — report what happened
Completion is not an automatic solved result. Report your actual outcome; no Audio Review physical test or measured repair is claimed.
steps completed
Reaching this result does not mean the issue is solved. Only your own feedback can report improvement.
Possible result
Stop and retain the actual observations
A required fact or response was not confirmed. Consult the exact product/partner documentation or official support. Do not escalate to a reset, update installation, internal repair or unsafe wiring change.
next support
Reaching this result does not mean the issue is solved. Only your own feedback can report improvement.
Possible result
A required fact is unknown
Confirm the actual model, source, partner capability and current state before continuing. Do not guess a menu or interrupt a live session/update.
insufficient data
Reaching this result does not mean the issue is solved. Only your own feedback can report improvement.