• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Early 2270 distorted equally in both channels

Davidmac5

Davidmac5

AK Subscriber
Subscriber
Hi all,

Just acquired a nice engraved 2270 S/N 3024 and it has some issues. The problem is the output is equally distorted in both channels, low volume its somewhat clear but as you increase the volume it gets distorted, the more you increase the volume the more distorted it gets. I pulled the jumpers and tested the amps separate from the pre and both amps are crystal clear at all volumes, so the problem is in the preamp section. I cleaned and deoxed all the switches and pots but the problem remains.

So my question is where would I start looking for the distortion issue that is feeding both channels at the same time? P400? Any advice would be appreciated.

Second issue is FM doesn't work at all, all I get is hissing through the hole spectrum. AM works fine but as with the other modes it too is distorted. I can deal with the FM issue another time, for now I just want to get the distortion issue solved. I would have used the search engine to find other threads on this issue if it was working. Thanks for any help.
 
Register to hide this ad
If you turn it on without a source playing, is it quiet? Does it stay quiet as you ramp up the volume? Can you hear any artifacts/quiet sounds/odd noises if you leave it like that for a half hour or so?
 
Without a source its dead quiet at all volume levels, I have had it on for several hours letting it play the same CD over and over and it's pretty clear until you volume it up to about the 10 o'clock position then it starts to distort, by the 12 o'clock position its very distorted. Also the gain level is not where it should be for this receiver, at the 12 o'clock position it should be just about running me out of the room but it's not.
 
Well problem solved kinda, I rebuilt P800 first thing when I got it and forgot check the voltage, when I did check it, it was at 14VDC, I increased it to the required 35VDC but the voltage is not stable and R809 is super touchy it will jump from 22VCD to 39VDC with the slightest touch and if I get it close to 35VDC the voltage will start creeping upward and I have to keep readjusting it. Bad R809?

After moving the voltage to 35VDC the distortion disappeared and the receiver plays fine except FM which isn't working at all.
 
Davidmac5 said:
Well problem solved kinda, I rebuilt P800 first thing when I got it and forgot check the voltage, when I did check it, it was at 14VDC, I increased it to the required 35VDC but the voltage is not stable and R809 is super touchy it will jump from 22VCD to 39VDC with the slightest touch and if I get it close to 35VDC the voltage will start creeping upward and I have to keep readjusting it. Bad R809?

After moving the voltage to 35VDC the distortion disappeared and the receiver plays fine except FM which isn't working at all.
Click to expand...
What all did you replace?
Check all voltages it’s outputting.
 
I replaced all the electrolytics and that's it. The only voltage I tested was for the 35VDC at J802 and J803. Like I said earlier R809 is super touchy and can jump from 22VDC to 40VDC by barely touching it and it won't settle or stabilize on 35VDC, I can get it close but then the voltage starts slowly creeping upward and after 30 minutes or so the voltage has drifted up from 33VDC to 37VDC and slowly continues to climb.
 
Davidmac5 said:
I replaced all the electrolytics and that's it. The only voltage I tested was for the 35VDC at J802 and J803. Like I said earlier R809 is super touchy and can jump from 22VDC to 40VDC by barely touching it and it won't settle or stabilize on 35VDC, I can get it close but then the voltage starts slowly creeping upward and after 30 minutes or so the voltage has drifted up from 33VDC to 37VDC and slowly continues to climb.
Click to expand...
Well test the 13.5 too.
That's your issue. P800's always have carbon comp resistors that are way off, corrosive glue, and leaky transistors. Replace them all, and the zeners. Adjustment trimmer is 3386F-1-502LF.
 
I tested the 13.5vdc and it's at 12.74vdc and very stable but the 35vdc is not stable at all, it continues to drift. Replacement components are on the way from Digi-Key.
 
Voltage problem solved, R809 was the problem component, replaced it and now P800 is set on 35VDC and steady. Next and final problem is getting the FM to work, all I get is a hiss throughout the whole tuning band. I would use the search engine to find earlier posts on the subject if it was working but it's not. If anyone would care to weigh in on where I can start looking for the problem would be greatly appreciated or should I just start a new thread on the subject?
 
Davidmac5 said:
Voltage problem solved, R809 was the problem component, replaced it and now P800 is set on 35VDC and steady. Next and final problem is getting the FM to work, all I get is a hiss throughout the whole tuning band. I would use the search engine to find earlier posts on the subject if it was working but it's not. If anyone would care to weigh in on where I can start looking for the problem would be greatly appreciated or should I just start a new thread on the subject?
Click to expand...

Here's what I found on the Marantz 2270 FM from AK using a Google search:

https://www.google.com/search?q=mar...-wQrQIoBHoECBUQBQ&biw=1366&bih=635&dpr=1#ip=1
 
You must log in or register to reply here.
Back
Top Bottom