[klondike98]

OK with the 100pF cap in place and signal injected on pin 6 of 1LC6 I do hear faint tone. I'm pretty sure its due to the signal since it disappears when I switch off modulation. Guess that means that the 2nd IF transformer 47k resistor is kaput or there's something else wrong in it. If that's the case, I'll have to study it a bit to see how best to get that off, opened and repaired.

[Radioroslyn]

I'd pop the IF can off and have a look inside. If your really lucky the 47k resistor will be open. Or may have a broken wire from the coil. Feeling lucky????? Basically we are just looking at the coil and resistor the internal caps aren't going to be a problem.

Terry

[klondike98]

As I started to look at the 2nd IF transformer to take it out of the chassis I realized that it had 5 wire connections and the one I had taken as Green was actually the one labelled SL ( for slate I think).  Yea, I know, I should have looked where the wire was attached but I figured green was green ... right... nope.

OK so now I can say that the correct Green (which is actually a white with green trace wire) to Brown reading is 65k ohms ( rather than 450k I reported earlier).  That's still 38% too high.  So the previous 450k ohm reading was for the SL to Brown.  That might be reasonable since there are multiple current paths, I'll have to recheck when I get the can out of the chassis.  Here's the diagram with the SL lead highlighted in grey.

[Image: https://www.dropbox.com/s/iwp813pdl6txno....jpg?raw=1]

[klondike98]

I have the 2nd IF transformer out.  

[Image: https://www.dropbox.com/s/dsz760vupeswiq....jpg?raw=1]

That 47k resistor is going to be tough to get to I think.  The coils both have 15 ohms as they should and there is infinite resistance on the slate lead to all other leads (that's just a low voltage ohms test not a cap tester).  Some of the rubber coated wire needs recovering or replacing so I'll do that.

[klondike98]

Well that was an exercise in frustration.  Replaced the off spec 47k resistor, checked all the coils, got it all back in the can, checked all the coils again, soldered it all back in place and realized I did not replace the fish paper that was around the coils inside the can     That can is not coming out again unless it really needs to.  

Anyway, after all that, still no tone coming through.  I rechecked that I could still get tone by by-passing the transformers  with a 100pF cap and do hear tone faintly.  I also still heard tone when I disconnected the by-pass lead with the 100pF cap from the diode plate (pin 4 of 1LD5) but still had the lead connected to the IF 1LN5 pin 2 plate.  Is that telling me something?

[Radioroslyn]

> Is that telling me something?
It's saying that the primary is not open but that is about it.
If you apply a 455kc 400cy modulated signal to pin 2 of the1LN5 do you hear any tone in the spkr? If not crank up the output of the generator to full blast and tune it around a bit say from 400-500kc. It may be way out of alignment.

Terry

[klondike98]

hmmmm.....I do not get any tone when on pin 2 of IF 1LN5 at full generator and any radio dial setting. I am now however getting tone on pin 6 of 1LC6. That seems strange to me??? Its difficult for me to hear a difference in volume as I try the alignment. Where is the best place for the AC voltmeter to monitor the alignment? Maybe as you suggested its just way out of alignment. Thanks for all this help!!!

[Radioroslyn]

Good. Try turning the generator output down till you can just barely hear it from the spkr with the volume full up. Then see (hear) if you can get a peak from the 4 adjustments (slugs). To answer the question use an ac voltmeter set to it's lowest voltage scale across the spkr terminals. Since we are dealing with the IF stages the dial position (frequency) should have little to no affect on this adjustment. If it does something else is going on. Most of the time alignment instructions will say to set the tuning cap at max capacity (closed) for the IF alignment.

Terry

[klondike98]

OK here's a pic of the speaker terminals I'm monitoring...I only get about 33 mv that goes up to 49 mv when generator is on full blast and volume all the way up, that seems too small.  adjusting L24 on 1st IF I can see some peaking and hear tone disappear and reappear as I go through the peak but I don't get much peaking on L25 of 1st IF and no peaking on L26 and L27 of the 2nd IF.

[Image: https://www.dropbox.com/s/8mlrwz5hb2j1th....jpg?raw=1]

[Radioroslyn]

Got another 1LN5???? Did you also say that your 9v filament line was low even w/the variac turned up?? How much dc voltage do you have across pins 1 and 8 of the 1LD5 tube?

Terry

[klondike98]

Its on order.... so I'll have to wait to see if that's it....

[Radioroslyn]

Check the filament voltage and see if you've got 1.5vdc between pins 1&8.
You could swap it with the rf amp tube.
Terry

[klondike98]

I get 1.6v DC between pin 1 & 8.  I swapped the 1LN5 tubes.  I was able to peak both the upper and lower caps on 1st IF.  2nd IF doesn't seem to do much.  I went ahead and did next step in alignment @ 1600kc then steps 3 and 4 at 1400kc.  I do now get a local am broadcast station but have to have the set volume all the way up to hear it so things are looking up but not quite there yet....

[Phlogiston]

Bob, do you have a signal tracer/sniffer? We had a very similar problem on a recapped SX-99 the other day. Tracing the signal found a cap taking the signal to ground on one of the IF transformers. Not saying that is what is wrong with yours, but it can sure narrow the problem down to a particular part.

Have you moved yet?

Russ

[klondike98]

No, don't have a signal tracer. I would have replaced the caps in the 2nd IF transformer when I had it out but the values are not on the schematic.

No, have not moved but the PA house will be listed for sale next week so hopefully soon.