Marantz 2270 Static when turned on

Rean

New Member
Hi all. Was looking for opinions/suggestion on a 2270 that I would like to rebuild. When powered on, regardless of any knob setting, there is a very loud static/popping. So loud that I can't turn it on with speakers hooked up. I wound up plugging in headphones and I get the same thing. I can faintly hear audio behind the static. Pre amp outs yield the same static. A member here suggested, on another post, to plug the headphones into dubbing out and see what happens. Doing this, it works perfectly. Every function is normal. I would greatly appreciate your suggestions. Could this be solved with a recap of the unit? Parts are already on order. Thanks very much.
 
Pull the jumpers on the back and do you still get static?
If so it's in the amp modules or relay,possibly speaker switches.
If you have another amp/receiver then go from preamp outs on the 2270 into the aux or tape inputs on that unit to determine if it's the 2270 preamp or amp.
You also ought to be able to determine if its both channels or one of them.
I believe the dubbing jacks are ahead of the preamp.
A thorough cleaning of controls and switches would also be a good idea.
Report back.

Bob
 
Pull the jumpers on the back and do you still get static?
If so it's in the amp modules or relay,possibly speaker switches.
If you have another amp/receiver then go from preamp outs on the 2270 into the aux or tape inputs on that unit to determine if it's the 2270 preamp or amp.
You also ought to be able to determine if its both channels or one of them.
I believe the dubbing jacks are ahead of the preamp.
A thorough cleaning of controls and switches would also be a good idea.
Report back.

Bob
Hi Bob and thank you. I did exactly as you wrote. 2270 preamp out to aux in on a different receiver and got the same noises on both channels. I already did a good cleaning. Just to be clear, I'm not talking about minor static. It's so loud I can't turn it on unless I plug in headphones. Greatly appreciate the response!!!
 
It appears to be in preamp then.Noisy transistors?
Freeze spray sometimes isolates noisy transistors but it's hit and miss.
Possibly in regulated power supply board but that usually gives you a hum from failing caps.
I think I would double check all ground wires to the chassis and go ahead and recap the power supply and preamp boards.
The preamp board is easy to access so do a total recap,check operation and if static persists then noisy transistors are next.
The 2270 doesn't have the BA312 chips that the 2275 and 2325 have so no availability issues there.

Others will chime in with their suggestions so be patient.

Bob
 
It appears to be in preamp then.Noisy transistors?
Freeze spray sometimes isolates noisy transistors but it's hit and miss.
Possibly in regulated power supply board but that usually gives you a hum from failing caps.
I think I would double check all ground wires to the chassis and go ahead and recap the power supply and preamp boards.
The preamp board is easy to access so do a total recap,check operation and if static persists then noisy transistors are next.
The 2270 doesn't have the BA312 chips that the 2275 and 2325 have so no availability issues there.

Others will chime in with their suggestions so be patient.

Bob
Thanks again Bob! Love the Penny and her new friend picture.

I agree so far. I'll receive everything to recap it tomorrow so I may just start with that and see where I wind up. The unit has been in storage for probably 20 years but I know it worked when it got put away.

Looking forward to any comments. Once again, thank you sir. Greatly appreciated.
 
So its loud even with the volume off?, Like an after volume pot (Between) to rca jack ???? Did you check the pre amp voltage for AC ripple getting past the power supply 800 board??
The main amps use a different supply voltage.
My vote is on bad caps on the pre amp, passing garbage through. Like bob said, definitely check for a ground or" no ground" issue coming out of the pre amp., That will be noisy as hell going into the mains
 
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Just wanted to throw in an update. First of all thank you for your input. While recapping I decided to take a break so I replaced the transistors on P400. Taaaa Daaa! No more horrible noise when powered up. Now I can listen to FM, CD,.... but the volume in the left channel is there but lower than the right channel. Also, Balance full left, no sound in right channel. Balance full right, I can still hear the left channel slightly. Great progress so far. Any additional suggestions would be greatly appreciated!!!! Thanks.
 
Push in the mono switch,sound in both channels?
Yes- preamp issue
No- amp,speaker switch or protection relay issue.

Bob
 
Hi Bob......mono switches in I have sound in both channels. I'll keep digging and thanks for the assist!
 
Greetings haven't looked at service manual but imbalance on stereo and full equal channels on mono with mono/stereo switch. After 'major' repairs or even a transistor I'll check rails but also recheck my soldering. Not saying your soldering skills are poor but even I've missed one or two so I recheck with magnifier glass and I have a good station. Just sometimes these old solder pads and traces are subject to tear or not full contact on the pcb. trace or missed a cold solder joint. (very common) and checking continuity between new solder traces may reveal a broken trace at any solder joint /pad.

I actually didn't learn proper soldering until I started using a magnifier with my solder station and found many 'dribbles' or solder tears that 'slightly' touched another trace and found that other traces from factory I hadn't even touched were cold.
hope it helps.
bink
 
Thank you Binkman. I may have explained incorrectly. In mono I have the same as in stereo. Low left channel. I did go over the preamp board with a magnifier after I recapped and replaced transistors. Just to be safe I wetted every solder joint and looked again. I don't see anything suspicious. That doesn't mean that I didn't miss something. Has happened to me in the past. I happen to have another 2270 sitting next to this one on the bench but sadly it is displaying the EXACT same problem. Go figure. Thank you for the suggestions! You folks have far more experience with these receivers than I do. Actually, I have close to none but I am learning fast. Thanks again.
 
Update.....I found that the balance pot is bad. Does anyone know of a replacement? Thank you all for your help. Tough to find apparently.

Update.......I found one on ebay for a different model but the service manuals list them as the same part number so I'm taking the chance. Wish me luck and I'll let you know how it goes.
 
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As long as the resistance is the same and it's a "stand alone"(not board mounted) balance pot then you should be good.
Always tip the pots "back" when you deox/clean them so you don't inadvertently wash the grease from the shaft which kills that "silky resistance" feeling when turning the knobs.

Bob
 
Thanks Bob. I wasn't aware of the tip it back tip. Good one. Another question though......The balance pot is linear taper? Correct?

Apparently very difficult to find. Has anyone out there sourced one?
 
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The balance pot was the problem and the 2270 is working great! I do however have a question on FM tuning. On AM the dial pointer is accurate. On FM it reads lower than the tuned station. I found a post here with following information:

There are two things the 2270 normally needs by way of a "basic alignment." The first has to do with detector symmetry. This shows up as a tendency of the center-channel tuning meter to skew off to one side (usually to the right) when no signal is applied. The detector alignment cores are accessible through topside holes in the IF module about 1/3 from the left edge of the set. The core farthest to the right is for center channel symmetry. To do a basic tweek, disconnect the antenna and tune to interstation noise. Adjust the rightmost core to center the pointer.

NOTE: Go to an electronics store and pick up a kit of plastic alignment tools before attempting these adjustments.

The second tweak involves adjusting the oscillator coil in the RF module. The oscillator coil is marked, and is accessible through a topside hole. It's located in the right-rear corner of the RF module. You will usually find that on AM stations correspond to dial pointer position, but on FM they don't. Adjust the oscillator so that the dial pointer lines up with stations.

On about one 2270 in ten, the dial cord is stretched and you may need to move the dial pointer. Be VERY careful.

I'm concerned about proceeding with trying this procedure. Not because of the information provided, simply because I know that these adjustments can be very tricky and require test equipment that most don't have. Thoughts please?
 
I too have a 2270 although recently acquired that has pretty much the same symptoms you described. After sifting through the many posts here I decided not to attempt making any adjustments myself, rather trust a local tech experienced and equipped to perform a complete alignment for me. I'm taking it in next week and feel it will be money well spent. From what I understand it will not be a costly service.
 
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