Question Onkyo 646 breaking freeview?!?


Active Member
Hi all, and thanks in advance...

OK, long story so here goes.

Have an older non wifi sky box with an RF output, so using that to send the sky channel to all 8(!) TV's in the house via a wall plate that takes the signal to a distribution thingy in the loft and then to all TV's, this distributor also has the freeview aerial input direct from the aerial so each TV also gets the free-view signal.

Had an Onkyo 606 AV receiver, which I've since discovered affected the signal as the freeview TV's kept dropping out of signal or showed weak signal, we always presumed that it was a problem with the aerial as it's inside the loft. Onkyo was to blame as when it went pop I replaced it with the Sony 860 AVR, and all the TV's worked a treat. Then Sony 860 broke after 3 weeks (lost all ability to connect to a network wired or wireless), so took it back to RS and exchanged it for the Onkyo 646.

You can probably guess what happens next... Yup, lost all freeview signal as soon as I turn the main TV/Sky/Onkyo setup on. As soon as I turn it all off again, the signal comes back.

Any ideas on how to get around this, or do I cut my losses and take the Onkyo back to RS and get the Denon AVRX2200W which has been very well reviewed and is on offer at £379, and hope that it doesn't have the same effect?

No other issues with the Onkyo, and think in general it's a great piece of kit, also when initially buying the Sony 860, RS reduced the price by £100 a week after I bought it, so went back in to get £100 back, then returned that receiver for the 646, so don't want RS to think that I'm taking the mick, by changing the AVR every month.

Again, thanks in advance for any suggestions.
Last edited:


Distinguished Member
Sounds like interference...

Move amp and Sky box/modulator apart.

Swap UHF TV aerial fly-leads with alternatives, ideally double-screened cable. Check any hand-made plugs are done properly How to wire a Belling-Lee connector

Keep hdmi leads as far away from aerial cables as possible. Signals in hdmi cables are known to cause problems with UHF TV frequencies, sometimes even if devices are in standby). Swap hdmi leads with alternatives (pound store ones are sometimes better at shielding interference in them than over-priced branded ones!) You may be able to prove which hdmi cable is the problem by disconnecting both ends of a hdmi cable from the two devices and seeing things come good?


Active Member
Rodders, many thanks for the reply, much appreciated.

I'll try unplugging all the HDMI's tomorrow sometime and see how I get on, shouldn't be an issue with the cables being of too good a quality, as I usually buy Maplins standard cables (not the extra cheap ones...).

All the COAX cables are hand made by me, not soldering and primarily twist on F types, never had much luck soldering anything other than copper pipes, solder keeps dropping off whatever it is I'm trying to solder. I did re-plumb the entire house so understand the process etc.

The bit about the cables causing the interference is confusing me as it worked a treat with the Sony AVR with all the same cables?


Distinguished Member
Coax cables are not all the same quality... Satellite, Television, FM, DAB, Aerial, Coaxial Cable, Plugs, Sockets, Connectors & Leads

HDMI cables are not all the same quality for screening, either.

Screw on F-plugs come in different sizes to match the cable diameter... too small or too big might, perhaps, mean a poor screen contact is made?

F- to TV plug adapters may not all be the same, either if you have used them.

I moved all my kit into a new AV cabinet and suffered Freeview interference issues... Tracked down to one hand-made TV plug that had suffered 'cable tug' and the screen braid wasn't firmly made off... a quick re-make of the lead and all was well. So it is possible/probable that you have something similar happen in your re-install of the kit with the new amp?

Possible differences between the Sony and Onkyo that may affect interference generated by the amps and so conducted into the UHF aerial system:
- Case and earthing of case... (my Onkyo 515 is metal cased but uses a 2-pin double-insulated mains supply so only a 'virtual' earth on the metalwork until connected to other kit.) Don't know about the Sony? {EDIT It may be worth trying: open up the UK 13A adapter plug and turn the 2-pin euro plug through 180 degrees so Live-> neutral and N-> L. This 'polarity' thing shouldn't matter but if it helps your problem... }
- Different hdmi board and video circuitry / scaler engine.
- Different front panel display circuit / drive circuits.
- Possibly different AV output / scaling settings chosen on the Onkyo cf the Sony?


Active Member
Rodders, thanks once again. Got the motivation to have a look, so wheeled the TV out of the slot with all the boxes and cables still attached, Freeview started working, wheeled it back in, Freeview still working! I did then unplug all the HDMI's but no change (still worked), obviously tricky to find the fault as if it ain't broke etc...

So must be a cable issue, but as it's working I'll leave everything as it is until next time!

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