Artificial Intelligence Response
Direct answer to the question
Yes — this symptom usually means the receiver is not completing its startup sequence, not merely that the front display is bad.
The most likely causes are:
- Intermittent standby or low-voltage power supply failure
- Protection circuit tripping during startup
- Cracked solder joints / poor connector contact
- A weak relay or relay-drive path
- Less likely, a display board problem, but only if the receiver otherwise works normally with audio
A very important distinction is this:
- If you hear the relay click, the unit does not respond, no audio, no front-panel activity, no display → suspect power supply / protection / control logic
- If you hear the relay click and the receiver actually works but only the display stays dark → suspect display board or its supply
Detailed problem analysis
Your symptom is classic for an intermittent transition from standby to full power-on.
In a receiver like the RX-V373, startup usually happens in stages:
- Standby supply is already alive
- It powers the microcontroller and IR/power button logic.
- You press power
- The controller commands a relay or power-enable sequence.
- Main rails come up
- Audio, display, DSP, and control sections receive normal operating voltages.
- Protection checks pass
- If DC offset, overcurrent, abnormal supply levels, or thermal faults are detected, the unit aborts startup.
When you hear only a relay click and then nothing else, it strongly suggests one of these failure modes:
1. Standby supply is marginal
This is one of the most plausible causes.
A standby supply can become unstable due to:
- aging electrolytic capacitors
- high-ESR capacitors
- cracked solder joints around hot components
- a weakening regulator
- poor relay-drive voltage
- in some designs, a degraded mains-rated film capacitor in the standby supply path
What happens electrically:
- the receiver tries to start
- current demand suddenly increases
- a weak supply rail sags
- the microcontroller resets or protection logic aborts
- relay clicks, but the unit never fully boots
That exactly matches an intermittent “sometimes yes, sometimes just click” behavior.
2. Protection circuit is stopping startup
If the amplifier or power section detects an abnormal condition, Yamaha receivers will often refuse to complete startup.
Common triggers:
- shorted or partially shorted speaker wiring
- failing output transistor or driver stage
- abnormal DC on the speaker outputs
- incorrect secondary rail voltage
- thermal/protection sense faults
This is why the first field test is always:
- disconnect all speakers
- disconnect HDMI and all other inputs
- leave only AC power connected
- test power-up again
If the behavior improves, the issue may be external or load-related.
3. Relay contacts or relay control issue
The click tells you the coil is energizing, but it does not prove the relay contacts are passing power correctly.
Possible faults:
- oxidized or pitted relay contacts
- weak coil drive transistor
- intermittent solder on relay terminals
- cracked PCB trace near the relay
In that case, you hear the click, but the downstream circuits never receive stable power.
4. Connector or solder-joint intermittency
This is very common in equipment that has seen years of thermal cycling.
Likely locations:
- PSU board connectors
- display board connector
- regulators mounted to heat sinks
- relay terminals
- transformer pins
- larger resistors and diodes
- front-panel/display board header
An intermittent solder joint can behave exactly like this:
- cold start works
- warm start fails
- tapping or flexing changes the symptom
- the unit may work for days and then fail again
5. Display board fault
This is possible, but only under a narrower condition.
If, when the display is dark:
- audio still works
- input switching still works
- remote still works
- volume changes still affect the sound
then the receiver may actually be running normally, and the fault may be isolated to:
- display board supply
- display driver circuit
- connector to the front board
- front-board electrolytic capacitors
- display bias/filament supply
- oxidized adjustment trimmer, if present on that board revision
But if the unit is otherwise dead, then do not start with the display board. Start with power/protection.
Current information and trends
Based on the current sample information you provided, the most credible recurring pattern is:
- intermittent startup in the RX-V373 is usually associated with power-delivery instability or protection behavior
- technicians and users commonly focus on:
- the power supply board
- standby/startup rail integrity
- relay operation
- protection-state diagnostics
A useful engineering takeaway is that for this symptom, “relay click” is not the fault itself. It is evidence that the startup sequence begins, but something prevents successful latching into full operation.
Current repair trends for AV receivers of this age are also consistent:
- inspect and replace aging electrolytic capacitors
- reflow cracked solder joints on power components
- verify standby 5 V / 3.3 V rails
- confirm whether the unit is entering protect mode
- replace suspect relays if coil operation is present but contact conduction is unreliable
Supporting explanations and details
Why the display matters diagnostically
The front display is useful because it tells you how far the startup sequence got.
-
Display comes on normally
Main logic and front-panel supply are alive.
-
Relay clicks but no display at all
The unit likely fails before the logic/display rails stabilize.
-
Display flashes briefly then dies
Often indicates brownout or protect shutdown.
Practical fault separation test
This is the fastest diagnostic split:
Case A: dark display, but receiver still functions
- audio output present
- remote/front buttons still work
→ likely display/front-board issue
Case B: dark display and receiver nonfunctional
- no sound
- no control response
- only relay click
→ likely power / protection / startup logic issue
Why capacitors are common suspects
Electrolytic capacitors age by:
- losing capacitance
- increasing ESR
- becoming temperature-sensitive
That causes intermittent startup because startup is the moment of highest stress on the low-voltage rails.
Typical symptom pattern:
- fails more when cold, or sometimes more when warm
- works after repeated attempts
- may recover briefly after being unplugged
Why external speaker wiring must be checked first
A single stray copper strand at a speaker terminal can create a partial short. The receiver then protects itself immediately.
This test is simple and noninvasive, so it should be done before opening the unit.
Ethical and legal aspects
Because this involves mains-powered equipment, the main issue is electrical safety, not ethics in the usual sense.
Relevant safety points:
- AV receivers contain hazardous mains voltage
- large capacitors can retain charge after unplugging
- probing live power-supply circuits can cause shock, burns, or further board damage
- substituting incorrect components, especially mains-rated safety capacitors or relays, can create fire risk
From a compliance standpoint:
- use the same safety class for any mains-connected capacitor
- use the same or better relay contact rating
- preserve insulation barriers and creepage distances
- do not bypass protection circuits
If you are not comfortable making live measurements, this should go to a qualified service technician.
Practical guidelines
Step 1: Determine whether it is only the display
Next time it fails, check:
- Do you get any sound?
- Does volume change?
- Can inputs switch?
- Does the remote work?
- Do speaker relays engage later?
If yes, suspect the display/front board.
If no, suspect power/protection.
Step 2: Eliminate external causes
Disconnect:
- all speaker wires
- HDMI cables
- RCA/optical/coax cables
- antenna leads
Leave only AC power connected, then test multiple startups.
If the fault disappears, reconnect one thing at a time.
Step 3: Try a full power reset
- unplug from the wall
- leave it unplugged for 15–30 minutes
- reconnect and retry
This will not fix a hardware fault, but it may clear a controller latch-up.
Step 4: Watch for pattern dependence
Note whether failure is related to:
- cold start vs warm start
- being moved or tapped
- humidity
- time since last use
- repeated power-button attempts
This helps distinguish:
- thermal solder fault
- marginal capacitor
- mechanical connector issue
Step 5: Internal inspection if you are qualified
With power removed:
Inspect for:
- bulging or leaking electrolytic capacitors
- darkened PCB areas
- cracked solder joints
- overheated resistors
- loose board connectors
- relay solder fractures
Most important areas:
- standby PSU section
- regulators
- relay pins
- transformer pins
- connector headers
- front-panel/display board connector
Step 6: Electrical measurements
If you have electronics repair experience, measure:
- standby rail voltage
- logic rails during startup
- whether they sag when the relay clicks
- relay coil voltage
- continuity/conduction across relay contacts when energized
A rail that collapses at startup strongly indicates a marginal power supply.
Step 7: Consider protection diagnostics
If the RX-V373 service mode/diagnostic mode is accessible on your unit, it can help identify:
- DC protection
- power-supply protection
- thermal/protection flags
If you are unsure of the exact key sequence, verify it from the proper service documentation before trying.
Possible disclaimers or additional notes
- I would not start by assuming the display module itself is defective unless the receiver still works when the display is blank.
- I would also not assume one specific capacitor or one specific Yamaha bulletin without board-level confirmation.
- The offline sample mentioning a display-board trimmer may be relevant only if the receiver functions normally except for the display.
- The stronger engineering probability, based on your symptom as stated, is still startup power/protection instability.
A corrected prioritization would be:
- external short / protect trigger
- standby or startup PSU weakness
- cracked solder / connector issue
- relay/contact problem
- front display board fault
Suggestions for further research
If you want to continue diagnosis properly, the next useful data would be:
- Does it produce sound when the display stays off?
- Does it click once, or click on and then off again?
- Does it fail more when cold or when warm?
- Have you tried with all speakers disconnected?
- Can it enter Yamaha diagnostic mode consistently?
- Do any supply rails dip when the fault occurs?
For deeper technical work, the best next resources are:
- RX-V373 service documentation
- board layout / power tree
- standby PSU schematic
- protection-line logic
- front-panel/display board interconnect details
Brief summary
Your Yamaha RX-V373 most likely has an intermittent startup fault, not simply a bad display.
Most probable causes:
- standby/startup power supply instability
- protection circuit shutdown
- relay/contact issue
- cracked solder joints or connector faults
Only suspect the display board itself if the receiver is otherwise operating normally when the display is dark.
If you want, I can give you a step-by-step troubleshooting flow for:
- non-invasive checks only, or
- multimeter-based board diagnostics.
