12-16-2021, 07:29 PM
Put a 260kc signal and scope on the i.f. transformers in the 70. The first i.f. input transformer peaked out at 260kc spot on, the second i.f. peaked out around 175kc - could not peak at 260kc, so I checked another output i.f. transformer coil out of another early 70 - it too peaked out NOT at 260kc, but around 225kc, could not get to peak right even with adding the trimmer cap. I read this in and old Radio Service Shortcuts:
'PHILCO 90 (With one -17 output) Weak, stations do not track with dial settings . . . although the i.f. peak is given as 260 kc. by the manufacturer some were built to align at 175 kc'.
Has anyone else ever run in to this? Was this a factory coil error or service error? Shouldn't it peak at 260 also?
'PHILCO 90 (With one -17 output) Weak, stations do not track with dial settings . . . although the i.f. peak is given as 260 kc. by the manufacturer some were built to align at 175 kc'.
Has anyone else ever run in to this? Was this a factory coil error or service error? Shouldn't it peak at 260 also?
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