I have a Crosley 56TX (AA5)that I recapped and checked all tubes to be good. It still has a low hum and a loud squeal when the volume is turned up. It's worse on lower freqs. Can anyone give me a clue? Thanks

:I have a Crosley 56TX (AA5)that I recapped and checked all tubes to be good. It still has a low hum and a loud squeal when the volume is turned up. It's worse on lower freqs. Can anyone give me a clue? The adjustments in the IF cans are extremely sensitive.

Initially, any chance that the 'Sa7 and Sk7 slots are not now using metal tubes ?
As for the unit breaking into oscillation down towards the 550 kc end of the AM band, how about a taking of a VERY short leaded .1ufd 500v disc ceramic capacitor and try a tube pin bypassing..... right to ground...of the screen grids of the two aforementioned tubes and see if the osc stops or markedly subsides. Also the, next point to try would be the like shunting of the cathode bypass cap of the 'Sk7. Also, if their is any question of the quality of the replaced electrolytics in the power supply...specifically as to their ESR factors and equally appropriate RF bypassing capabilities, try bypassing them also.
Next step would be to confirm that the osc was not occuring within the AF loop of the receiver...but...
ZUJ'ing...standing by for feedback :^) )

73's de Edd

:Initially, any chance that the 'Sa7 and Sk7 slots are not now using metal tubes ?
:As for the unit breaking into oscillation down towards the 550 kc end of the AM band, how about a taking of a VERY short leaded .1ufd 500v disc ceramic capacitor and try a tube pin bypassing..... right to ground...of the screen grids of the two aforementioned tubes and see if the osc stops or markedly subsides. Also the, next point to try would be the like shunting of the cathode bypass cap of the 'Sk7. Also, if their is any question of the quality of the replaced electrolytics in the power supply...specifically as to their ESR factors and equally appropriate RF bypassing capabilities, try bypassing them also.
:Next step would be to confirm that the osc was not occuring within the AF loop of the receiver...but...
:ZUJ'ing...standing by for feedback :^) )
:
:73's de Edd
:I do have metal tubes in it. The bypassing didn't help,so I undone it. Anything else I could try?

OK..well I guess that the next thing might be to zero on in as to whether the quirk is in the RF section, the AF circuitry or the improper bypassing action within the power supply or inadequate filtering.

Back to the onset of the "noise"...... could it be categorized as a squeal, that will change in freq a bit as the vol control level is changed ?
1..

Also as I understand your verbiage,if the radio was tuned to the high end of the band to a station..say 1400.. there would be no squeal at any level of the volume controls setting..even at its max?
2...

Whereas,upon tuning down band there would be a point of the onset of that "noise" and its continuing presence on down to the low freq end of the dial. Right?
3...

At the point where the "noise" is the worst, would the volume control have the capability to gradually diminish this "noise" as the volume is incrementally run down, or is there a particular higher volume threshold whereupon the " noise" just disappears ?
4...

Can we assume that in the radio that line item 22, which is an .022ufd AVC line decoupling capacitor, did get replaced ?
5..

On the adjunct condition of the presence of a HUMMMMMM from the speaker ..is it controllable ?.. in the respect, that if you run down the volume, will it have gradually diminished in level and disappeared also, OR is the hum level still present after the volune control is at its min vol position ?
6..

If you will go back and research the above info and then come back and fill in the blanks between the lines, further steps in analysis can then be made.

73 de Edd