2220 No FM reception

[clk1981]

I have a 2220 not a model B, that has no FM reception at all. I am thinking the problem is in the FM front end, but the board has no bottom access and I am not very good at rewinding tuner strings. Does anyone have any ideas where to look or what might be the cause? With an antenna hooked up, moving the dial, the signal meter does not move and I get no sound output. All other functions of the receiver work fine.

 

[bktheking]

Check your voltages for power to the fm section for starters.

 

[Beamer302]

Check the voltages on the transistors near and including the ones of the front end . They can get wacked from static or lightning surges coming through the antenna . If you have to flip the board over then tape up the dial string every where and remove the big dial pulley and tape it to the side of the chassis. I also tape up the string so it stays on the dial pulley . I use blue painters tape . Make sure you don't turn the tuning capacitor while the pulley is disconnected . You can tune down so that the tuning capacitor is fully closed . Good luck .

 

[clk1981]

I didn't see the voltages stated in the service manual but I do remember seeing roughly 10VDC on a few pins.

 

[clk1981]

Ok, I checked the transistor voltages on the FM front end (100 board) and they seemed to all be there, although about 10% or so lower than the service manual.

Here are some other voltages I measured.

J205 - 1.4V

J207 - 10.9V
J210 - 10.9V

J302 - 10.8V
J304 - 38V
J308 - 14.88V

It looks like none of the transistors on the 200 board have their proper voltages. However, I do have 10.8V going to the 200 board.

Any help is greatly appreciated. Thanks!

 

[Beamer302]

You might want to check out the voltages on the 800 board (power supply) . J809 shows 12 volts on the schematic . It goes to J109 (on the 100 board) . If you are using a DBT when taking voltage readings they will be different than the schematic.

 

[clk1981]

You might want to check out the voltages on the 800 board (power supply) . J809 shows 12 volts on the schematic . It goes to J109 (on the 100 board) . If you are using a DBT when taking voltage readings they will be different than the schematic.

J809 read 10.8V. No DBT tester being used now.

 

[bktheking]

Two things could be happening but i'll take a stab at one. Something is dragging your voltage down, could be a capacitor on one of the FM boards that has gone bad. To narrow it down start disconnecting boards fed by the 12V until it comes back to normal voltage.