I'm currently restoring a radio which I understand is a New Zealand built Philco, Model 816.
I've worked off a schematic for a 46-816 which seems almost identical, electrically. I am now chasing a full service manual or at least the full alignment process for the various bands.
Can anyone help?
I've recapped the radio and replaced various drifted resistors, it now receives on the broadcast band, just none of the shortwaves.
The 816 sch does not show the band switch which you then must have, due to the SW band.
1. have you tried aligning the radio? If yes, were you able to pass the signal through on the SW band?
2. Check the appropriate coils engaged in SW reception, both the RF and OSC.
Mike.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Thanks Mike.
I've attached the schematic ive been using which does show the band switch.
No alignment attempted yet, i wanted to see what additional info was available first.
I have to admit I am basically a novice in this field (perhaps "advanced novice). I have reasonable practical ability but no background in electronic theory.
How would I identify which coil is associated with which band? (other than tracing connections off the band switch, which I can do if need be)
You pretty much have to trace'em.
Let me switch too my tablet as the phone screen is small.
Ok, one way is, if measured with ohmmeter from C404 left sideto Gnd, in any switch position there should be some low resistance.
But there's also the oscillator coils. You might simply perform two radios test, having your set next to another on the band that is not working and see if the other radio will howl.
Best way is to trace and ohm out all of the coils.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
(This post was last modified: 09-27-2018, 09:06 PM by morzh.)
I've confirmed all SW bands do work, just by feeding in a signal in the general frequency range.
I don't think I have an adequate antenna to actually receive anything yet, just lots of noise from all the electronic junk in my house..
I've also aligned the IF and the BC band, the dial is now well calibrated on that band.
Do I align the SW bands in the same way as BC? (ie. Feed in 600/1500 and set the top and bottom of the dial)
If so, what frequencies would you recommend?
(This post was last modified: 09-28-2018, 05:14 AM by ashhhhh.)
Yes pretty much the same way. You could simply take an alignment procedure for any radio with SW band(s) similar to yours and see what they do, but simple feeding the frequencies and adjustings trimmer/padder will do.
If the generator is not capable of producing the frequency high enough, tuning to harmonics works too (say, using 7MHz for 14MHz/21MHz).
Transoceanic uses points in the middle of the scale. But the idea is the same.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
