Yamaha RX-V1800 acting strangely

[atunguyd]

Hi Wonder if anyone can help me debug this strange issue.

I have an old Yamaha RX-V1800 which has started to act up - no real reason to replace it so hoping to try fix it.

About 2 years ago it did have the no power on issue and I fixed that by replacing the C4 22nF 630V capacitor on the power board. Been working just fine since.

Last couple of days I have noticed that the power button on the front panel will not switch it on or off (not the master switch but the soft touch power button) although it switches on and off just fine from the remote.

I can live with that but tonight it started acting really strange - we were watching TV and suddenly the relays on the speaker boards started clicking madly. I switched it off and back on and it was working again but after a couple minutes the relays started to go nuts again.

I thought it might be related to the C issue again so I removed and replaced that cap but still the same - switched on and off via remote just fine and relays start clicking. I also noticed that on some power on cycles there was no click from the relays and there was no sound coming from the speakers, just sound coming from the active sub woofer. On these occasions I needed to power it off (master switch or at the wall) and back on and it occasionally came right, but then started the mad clicking again.

I confirmed that it is the speaker relay board that is clicking as placing my fingers on the relays I can feel them activating. It is also not just one of them, but sound slike all of them clicking on ad off. This makes me think it is not a faulty relay on that board (they would not all go together surely).

Not sure where to look now so would appreciate any advice.

Thanks
Anthony

[mzacharias]

Lots of problems with the tact switches on the front panel. Since they're in resistive ladder arrangements they can and do cause all sorts of issues.

Pretty sure that takes care of your first problem (the power ON tact switch), maybe even the relay issue.