Marantz 2600 (2500?) AM tuner not working

[jeffsplat88]

I have a 2600 that I'm finishing up a restoration on. The FM and quartz lock is working flawlessly - In fact it's picking up stations way better than my two other 2500. However, the AM on this 2600 is not working. Dead silence. No static. Nothing. I'm not sure if the AM sections of a 2600 is identical to 2500 or others. I'm not experienced at tuner restorations and alignments and don't have the RF generators to do signal injections. So I was hoping maybe someone has some pointers on quick easy things to look at first before I go on the learning journey (or take it to an expert). Any pointers appreciated

 

[dr*audio]

Check the power supply voltages in the AM circuit.

 

[jeffsplat88]

Hi Folks, So I did some poking around with my DMM on IC Q151 The HA1197 AM tuner IC. What I saw were out of spec voltages on pins 14 (0 vs 1.5v spec), Pin 13 (2.7 vs 0.7 spec), and 12 (0 vs 1.5v spec). What appears to be most suspect to me is that R155 which is in series with IFT L154 has about 4VDC across it. Since that L154 has a capacitor in series with the inductor, would expect zero volts DC across that resistor (no DC current flow). This leads me to believe that capacitor inside the L154 inductor is shorted? Is this possible? I seem to recall reading somewhere that it's not uncommon for the caps inside these inductors to short out. it would be great if someone experienced in tuner repairs could confirm that this is indeed a common problem and could be the source of the AM tuner malfunction.

And if confirmed, how difficult is it to find a replacement L154 (Marantz part number LI10015060 IFT)?

 

[catrafter]

Some Marantz 2265B's use that transformer. I haven't done a detailed search (you could go through all the manuals here in the AK data base) but my WAG (wild a$$ guess) is that most any Marantz receiver that has an HA1197 AM IC uses that part.

Tom