07-27-2015, 04:05 PM
Hey Sean,
That's a nice set!!! I've had a few Hallicrafters sets over the years. I think I sill have a few of the AC/DC jobs S-41W and G, Echophone EC-1 and such. Did have a SX-25 and a SX-11. They are pretty hard to find in good cosmetic shape. They seem to rust pretty easily. As always enjoy replacing resistors and caps!
After the IF strip was working what the heck let's go for broke connected the signal generator to the ant post and see if the RF and mixer are working. Sure enough they where kinda. Had the chassis up on end to measure and connect the tracer and such. Lay it down flat and it would quit. Grrrrr. Turned out to be a loose tube the 1st RF amp tube.
So now it's picking stations but has some major issues. Audio is wicked distorted and low. Someone replaced the RF gain control but wired it backwards full is ccw and all the way down is cw. The volume doesn't work properly raises the tone a bit along with the volume.
At first I thought the distortion maybe an AVC problem so I measured the control grid voltage on all the RF/IF tubes. Looked ok. then I used the tracer and listen to the signal at each stage. Ahah!! All sounded nice and clean till I got to the last IF amp. Grid was good. Plate was awful! Very distorted. Measured the cathode voltage and it was way high. Methinks the 300 ohm cathode has gone open. Soldered a replacement across the old one and now the plate signal is nice and clean too.
Onward to the volume issues. Still low and the distortion is better but not gone. Started thinking that the volume control was open. Flipped it back over and took the nut off of the control and there it was. The lead connecting the detector to the control was broken at the solder joint. The pot came off the chassis and took it apart to clean it.
Cleaned it up made a small splice for the broken connect and got it all back together.
Power it up and was rewarded with a mostly working set. Lots of volume distortion is gone. So now there are a few minor issues. Backwards RF gain control, crystal filter doesn't work( probably need the crystal cleaned) need the IF alignment again ( with the last IF amp working properly it needs to be dead on the crystal frequency) New cloth covered power cord and some cabinet stuff.
A very happy
Terry
That's a nice set!!! I've had a few Hallicrafters sets over the years. I think I sill have a few of the AC/DC jobs S-41W and G, Echophone EC-1 and such. Did have a SX-25 and a SX-11. They are pretty hard to find in good cosmetic shape. They seem to rust pretty easily. As always enjoy replacing resistors and caps!
After the IF strip was working what the heck let's go for broke connected the signal generator to the ant post and see if the RF and mixer are working. Sure enough they where kinda. Had the chassis up on end to measure and connect the tracer and such. Lay it down flat and it would quit. Grrrrr. Turned out to be a loose tube the 1st RF amp tube.
So now it's picking stations but has some major issues. Audio is wicked distorted and low. Someone replaced the RF gain control but wired it backwards full is ccw and all the way down is cw. The volume doesn't work properly raises the tone a bit along with the volume.
At first I thought the distortion maybe an AVC problem so I measured the control grid voltage on all the RF/IF tubes. Looked ok. then I used the tracer and listen to the signal at each stage. Ahah!! All sounded nice and clean till I got to the last IF amp. Grid was good. Plate was awful! Very distorted. Measured the cathode voltage and it was way high. Methinks the 300 ohm cathode has gone open. Soldered a replacement across the old one and now the plate signal is nice and clean too.
Onward to the volume issues. Still low and the distortion is better but not gone. Started thinking that the volume control was open. Flipped it back over and took the nut off of the control and there it was. The lead connecting the detector to the control was broken at the solder joint. The pot came off the chassis and took it apart to clean it.
Cleaned it up made a small splice for the broken connect and got it all back together.
Power it up and was rewarded with a mostly working set. Lots of volume distortion is gone. So now there are a few minor issues. Backwards RF gain control, crystal filter doesn't work( probably need the crystal cleaned) need the IF alignment again ( with the last IF amp working properly it needs to be dead on the crystal frequency) New cloth covered power cord and some cabinet stuff.
A very happy
Terry
