Vintage Hallicrafters SX-99 Issue

[macnmoons6]

Hello folks. I recently purchased a Hallicrafters SX-99. It was re-capped by the previous owner. I changed some out of tolerance resistors. The radio cleaned up well and looks great. My issue is that it only works with the selectivity control in the broad or sharp position--it doesn't work in "normal" position. For the life of me I cant figure it out. Does this sound familiar to anyone? The schematic of the circuit is attached. I believe the switch is in the normal position.

 

[k7ng]

Hello folks. I recently purchased a Hallicrafters SX-99. It was re-capped by the previous owner. I changed some out of tolerance resistors. The radio cleaned up well and looks great. My issue is that it only works with the selectivity control in the broad or sharp position--it doesn't work in "normal" position. For the life of me I cant figure it out. Does this sound familiar to anyone? The schematic of the circuit is attached. I believe the switch is in the normal position.

I don't have a SX-99, but I do restore 'vintage' radios once in a while. Right offhand I might guess that the switch at the 'normal' position is not making contact. Try some contact cleaner carefully applied to the contact and wiper using blotter paper, don't just hose down the whole wafer or you'll be sorry. See if that works. If not, maybe the switch contact is simply worn thru. A little effort with a small probe might allow the contact to be adjusted enough that it makes contact again. That would be a temporary fix.

 

[macnmoons6]

Thanks, but continuity is the first thing i checked--all good. Need to dig a bit deeper.

 

[RufusDawes]

Have you aligned the crystal filter?