Marantz 2252 sound scratchy and weak in the morning

[SimonWang]

Hi everyone, I got the Marantz 2252 recently and all functions works well. However I found the sound is scratchy and weak in the morning when I first time truned it on, and all source have that issue. But after several minutes, it is back to normal and after that the sound is pretty normal and good for the rest of the day (I keep it rinning for most of the time although there may be turning off for 1 or 2 hours) but almost every morning when first turning on the receiver it will be weak and scratchy.

I have done the pot and switch cleaning and it seems all switches should be pretty clean. What shall i do to diagnose further or any possible reason?

The relay clicks quickly and sound clear every time turning on.

Thanks.

 

[punchback]

I wonder if the relay contacts are a little oxidized?

 

[AZBiker]

Sounds like you have some thermal sensitivity issues going on. Could be anything from some small signal transistors to a hairline fracture in PCB trace to a cold solder joint. The only way to troubleshoot that is open it up and start poking around, (carefully, with a non-metallic probe). Many times a can of freeze spray will come in handy if you suspect a specific area/device.

 

[tarior]

Scratchy and weak in the morning? Hmmm...I resemble that remark.

 

[blhagstrom]

Had a 2240 driving me crazier trying to use it in the office. Cleaned the pots, checked the relay.

Kept getting scratchy and dropping a channel.
Twiddling the controls would sort of sort it out a while.

Finally had time and got it to the bench.
Checked adjustments on power supply and amp.
All good.

Recapped the power supply and the amps.
Seems fine now.

Will probably finish a recap job when I find time.

Just another example of old caps being trouble.

I’m finding more and more units where the only problem is old caps.

10 years ago we could argue about recapping merits. Now it’s getting to be less of an argument.

There are plenty of things that can go wrong, but old caps are losing my faith quickly.