FAQ
TL;DR: New TV connected → antenna PSU LED dies? Run a 3‑step short-to-test, then add a DC separator; there’s “minimal risk of burning the power supply.” [Elektroda, Artee, post #16937735]
Why it matters: This FAQ helps multi‑TV homes fix splitter/separator faults that kill signal when one set is plugged in.
Quick Facts
- Symptom profile: connecting one TV cut signal to 4 TVs and turned off the antenna PSU LED. [Elektroda, Krzychu_183, post #16937681]
- Root cause called out: bad splitter connection and no DC separator create a coax short. [Elektroda, Artee, post #16937691]
- Quick diagnosis: briefly short center pin to screen at the TV plug; LED off = missing separator. [Elektroda, Artee, post #16937735]
- Remedy: install an inline DC antenna voltage separator; “any cheap” unit works similarly. [Elektroda, Artee, post #16937758]
- Don’t hack it: insulating the braid may “work” but invites signal distortions later. [Elektroda, andpol 33, post #16942191]
Why does the antenna power LED turn off when I connect a TV?
A coax short is forming when that TV is connected. With a splitter and mast preamp, you need a DC separator so power reaches the amp without shorting at the TV input. Without it, the PSU trips and the LED goes dark. [Elektroda, Artee, post #16937735]
How do I test if a separator is missing?
Unplug the TV, access its antenna plug, and briefly short the center pin to the screen. If the antenna PSU LED switches off, your installation lacks a separator on that branch. Quote: “minimal risk of burning the power supply.” Do it briefly and only for diagnosis. [Elektroda, Artee, post #16937735]
What separator should I buy?
Use an inline DC antenna voltage separator. Any inexpensive model is fine because they perform the same basic function: pass RF, block DC to the TV. As one expert put it, “any cheap DC voltage antenna separator.” [Elektroda, Artee, post #16937758]
Can I reuse the plug from an antenna power supply as a separator?
Yes, in a pinch you can repurpose the plug from an antenna power supply as a makeshift separator. Treat this as a temporary workaround until you install a proper inline separator for reliability and safety. [Elektroda, andpol 33, post #16937893]
Is insulating the cable screen a safe fix?
No. Isolating the braid from the connector may appear to restore signal, but it violates proper coax practice and can cause distortions and instability later. Avoid hacks; install a separator instead for a durable repair. [Elektroda, andpol 33, post #16942191]
How should I connect a 4‑way splitter to avoid shorts?
Ensure the power‑injection path to the mast amplifier includes a separator so DC does not reach TV tuners. A poorly connected splitter or missing separator creates a short at a TV input and drops the PSU. Correct the wiring and add the separator. [Elektroda, Artee, post #16937691]
Could the new TV itself be faulty?
A defective TV with power leakage is possible but unlikely. The consistent trigger is a missing separator or short at the TV’s antenna input. Rule that out with the short-to-test before blaming the set. [Elektroda, Artee, post #16937735]
Why did everything work with the old TV but not the new one?
The old TV may have had a separate antenna socket or construction that didn’t expose the short. The new TV’s connector arrangement can reveal the missing separator, tripping the PSU when connected. Add the separator to fix it. [Elektroda, Artee, post #16937735]
Will the short-to-test damage my power supply?
The advisor notes a “minimal risk of burning the power supply,” but the brief test typically just turns the PSU LED off. Keep it momentary, and don’t repeat unnecessarily. Proceed only if you accept the risk. [Elektroda, Artee, post #16937735]
What does “screen” mean in this context?
“Screen” refers to the coaxial cable’s outer shield or braid. Shorting the center pin to the screen means touching the inner conductor to the shield to simulate a DC short for diagnosis. Do this briefly during the test only. [Elektroda, Artee, post #16937735]
How do I install a DC antenna separator?
- Disconnect power to the antenna PSU and unplug the TV’s coax.
- Insert the inline DC separator at the problem TV’s coax lead per arrow/label.
- Reconnect the coax, power the PSU, and verify the LED stays on and channels return.
“Any cheap” unit works. [Elektroda, Artee, post #16937758]
Stores don’t have separators—what then?
Some brick‑and‑mortar shops may lack stock. The OP couldn’t find one locally and resorted to a workaround. Order online or from a specialist electronics store to get the right part instead of improvising. [Elektroda, Krzychu_183, post #16954801]
Is insulating the braid a long‑term solution?
No. Community feedback warns that this tinkering leads to degraded performance. Expect distortions later, and it can mislead others into unsafe practices. Replace hacks with a proper DC separator. [Elektroda, andpol 33, post #16942191]
My setup has 4 TVs and only one causes the outage—is that normal?
Yes. In the case discussed, 1 of 4 TVs (25%) triggered the PSU shutdown. A single branch missing a separator can drop signal to the entire installation until fixed. [Elektroda, Krzychu_183, post #16937681]
