Philco 48-482 - AM dial aligns ok, FM dial way off? - Printable Version
+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Philco 48-482 - AM dial aligns ok, FM dial way off? (/showthread.php?tid=21734)
+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Philco 48-482 - AM dial aligns ok, FM dial way off? (/showthread.php?tid=21734)
Philco 48-482 - AM dial aligns ok, FM dial way off? - redwing57 - 10-23-2020
Hi. I'm doing a light restoration of a Philco 48-482 I inherited from my grandfather. It's a radio I fondly remember from my childhood, and it's exciting to get it working.
It receives AM ok, and the frequencies line up pretty well on the dial plate (after indexing the indicator.
However, while it's receiving FM pretty well also, the frequencies are way off. The actual frequency is around 1-2 MHz below the indicated frequency. I can't tune a station below about 90 MHz, as the tuning cap runs out of travel. It seems like it's some sort of zero offset problem, since the whole scale is similarly off.
For stations with a decent signal, the volume output is quite acceptable.
Is there a way to shift the alignment of the FM frequency response? I've seen the service manual's guidance for "FM alignment", but it is primarily talking about how loud, or clear, the signals are.
Any suggestions? Thanks in advance!
Jerry
RE: Philco 48-482 - AM dial aligns ok, FM dial way off? - Radioroslyn - 10-23-2020
Hi Jerry and welcome,
Here is the service manual for your set: https://worldradiohistory.com/Archive-Rider/48/Rider-1948-PQR.pdf Scroll down to pg 95. I would take a crack at C-501C and use it to set the high end of the FM band. Didn't see an adjustment for the low end.
RE: Philco 48-482 - AM dial aligns ok, FM dial way off? - falcon123 - 10-25-2020
nostalgia air has the philco service sheet.its a complicated radio to align from what i read.
RE: Philco 48-482 - AM dial aligns ok, FM dial way off? - redwing57 - 10-26-2020
Ok, thanks. Yeah, I've read the FM alignment procedure and it is rather complicated. It seemed "alignment" was mostly for the sensitivity, or volume level, at both ends of the band. Though perhaps it includes getting the frequencies to align properly too. It just wasn't evident that was the intent of the process.
I'll study that some more, and see if I can possibly figure out that process!
Thanks for the suggestions.
Jerry
RE: Philco 48-482 - AM dial aligns ok, FM dial way off? - falcon123 - 10-31-2020
i hope you get it perfected so if i get stuck i can ask you about it. i have one of those being shipped to me!!!