Tuner Alignment for 2240 & 2238

N

nballin

New Member
Hello all,

First, I wanted to thank everyone for tons of great info on this forum.

Now, I have questions regarding tuner section of two marantz models, 2240 and 2238.

Everything works great on 2240, except when FM is in tune(i.e. I get good signal with Stereo light on), the 'center meter' is not in center.

It is to the right.

What can I tweak on tuner section of this receiver to correct this problem?

On 2238, also everything else is great, but I get virtually no AM reception.

Is there simple alignment that I can do to improve AM reception?

Thank you in advance for many help.
 
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Welcome nballin.
You need the service manual along with the proper FM alignment gear. Just turning the coils won't help. In fact it will cause more harm than good.

The meter will drift as the set warms up. That's to be expected. It may also indicate that the front end has drifted. You need to determine where the problem is before touching any adjustment points.

Ron
 
One needs know-how ( and experience )and test tools to perform a good tuner alignment, service manual is helpful sometimes but not essential.
 
Basically, the ratio detector should (if aligned) produce a centering of the center-tune meter on interstation noise. (I often use the very top of the band.)

One core of the detector transformer can be slightly adjusted for meter centering on interstation noise. The other core requires a distortion analyzer and an FM generator to align. I will introduce a mono signal at 80-100%modulation, and adjust the core for minimum distortion on the analyzer.

NOTE: You MUST use plastic tools to do this alignment.

Fred Longworth
 
Regarding the plastic adjusting tools, I have a plastic pot trimmer that I've used for the secondary on the top core (secondary) which works just fine, but this tool doesn't seem to bite into anything on the bottom. What kind of plastic tool is needed for adjusting the primary? Is it just a flat screw driver?

Thanks,
Ken
 
I have a special tool that has a 'neck' behind that hexagonal part that fits the secondary core, you just push it throu the 2nd core until the hex part engages the primary core...Its an old Bernstein tool, I wonder if one still can buy them today?

Helmut
 
hi. you can go to hi fi engine and download owner and service manuals free and easy. they also list service updates
 
I have a 2238B factory service manual that describes the procedure quite nicely. As I recall, I think the procedure called for the use of some equipment which you may or may not have. Let me know if you want me to copy the procedure for you and I'll do so when I get home.
 
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