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Trouble with FM on 2220 Marantz

mlannoo

mlannoo

New Member
I picked up a 2220 on Craigslist a while back and began my first recap job. The unit was working except the FM part (stations would not come in, volume was very low and signal strength was poor).

I purchased a recap kit online (caps, trim pots, bulbs, key transistors etc.) and after overhauling the P500 pre board, P700 main board, P800 power board, P900 phono board and the large cap can filter caps I find the FM problem persists - still the volume on the FM is very quiet compared to the AM, Phono and Aux channels. The signal strength meter is all the way left indicating poor signal also.

I took it to a local tech who opened it up and had a quick look and he suggested I try recapping the P200 FM IF board and the P300 MPX stereo board. So I gave that a try and also replaced all of the transistors on both those boards and once again, the problem persists.

Any ideas on where to look next? This is the "shotgun" approach I know but it's a fun learning experience and hopefully when I get this figured out It will help me (and others on here) down the road.
 
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Steven Tate said:
If you are getting a signal, but it is weak, I would carefully follow the steps in this thread about cleaning a tuner cap.

https://audiokarma.org/forums/index.php?threads/how-to-clean-a-tuner-analog.144163/
Click to expand...
Appreciate the tip. I ordered some non-residue contact cleaner and will give it a try.

Take a look at the "before" picture of this 2220. It had a HUGE layer of dust on the top side. I'm hoping that giving the tuner cap a thorough cleaning will solve my problem.

https://drive.google.com/file/d/1jq1j1B-SibfgpDXlRcTl9PFnS7qZkVL8/view
view
 
Yep, that’s pretty dirty. Hopefully, a careful cleaning will solve the problem. If not, there are some tuner experts on here that can likely point you in a direction for the next step. In the tuner cleaning instructions, don’t skip #4 with the Faderlube. If you have a spray can, spray it into a small dish and use a micro dropper to put a small drop everywhere the main shaft passes through a bushing. Good electrical connections at those points are important, but you don’t want excess lubricant to attract dust or affect the metal fins.
 
Good tips thank you.

I gave the tuner cap a cleaning tonight. I can definitely tell that the grounding bars have corrosion. I blew everything out with compressed air. then used CRC QD Contact Cleaner (no residue) on the contact points and fins. I also used a Q-tip with contact cleaner and it was black by the time i had finished (see attached "before" picture). Worked the dial back and forth 20 or so times then repeated the process. Let it sit for an hour then blew it out with compressed air again. I have a can of Fader Lube arriving tomorrow and will carefully drop some on the ground contact points (avoiding the fins!) and give it a try - fingers crossed.

Only thing I notice now is that the fins appear to have some sort of pale yellow build up possibly as a result of the cleaning? or are the fins possibly brass? See photo.

Before cleaning pic:
https://drive.google.com/open?id=19-6r_PovLHv_jvuVlPR-LqOlP3zH0LdQ

After cleaning pic of fins:
https://drive.google.com/open?id=1jCstNmYAzQ_9T0pFcQPUXLH6z4v8P2mi
 
OK I fired up the FM tonight after a thorough cleaning and applying the fader lube. There was a definite improvement. I still don't think i'm at full volume and only stations at the far left and right of the band seem to be coming in with any real strength. There's a lot of static between stations too. Also nothing comes in with the Stereo light on either. Any thoughts on what to do next? Give it another cleaning? Should I move this topic over to the Tuner section?
 
It sounds like it needs an alignment but I'm just as suspicious that the first FET in the front end is blown.
 
I took the 2220 into a tech and a week or so later I got a call back. It was a $70 bench fee to start. They said they need to repair the FM oscillator and the RF output stage - and that involves about 4 hours of work including the removal and reinstalling the tuning cord mechanism - for $350 (minus the $70 bench fee). On the plus side, they said whomever recapped the receiver (ME!) did an excellent job!

What do you guys think? Outside of having the tools and know-how to do an FM alignment, is it worth paying them to repair those things mentioned above? I feel like if it's just a matter of replacing components, I can do that!
 
I'd try to find a used front end and swap it in. Heck, maybe even just buy a whole 2220! Then part out the rest but as a low power model you'd likely have a hard time moving boards and such.
 
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