[morzh]

Just run sandard alignment.

First put IF through seeing if any freq close to it gets through, if not you need to troubleshoot.

[Ron Ramirez]

Do you have the service information for the 66?

IF frequency is 460 kc.

http://www.nostalgiaair.org/PagesByModel...013827.pdf

[ccomer1955]

Yes, but thank you. I have that CD with all the Rider's volumes in it.

[ccomer1955]

I think I need to let it sit for a bit while I think about things. New voltages are puzzling to me for several reasons:

80: Filaments=5v, plates=716v.
Heater voltages throughout are now running around 6.3v for all other tubes.
42: plate=265, screen=282, grid= -17, cathode=.7mV
6A7:plate=286, screen=76, anode grid=135, control grid=2.9 (positive voltage), grid cap was negative, but the voltage fluctuated up to -400mV and back down to like -5mV (kept cycling).
78: plate=283, screen=76, suppressor and cathode (pins 4 & 5 are connected)=2.9, grid=0, grid cap was much like the 6A7.
75: triode plate=193, diode plate=-4, cathode=.2mV, grid=.4mV, grid cap=-1.5

I'm not getting negative voltage on the control grid of the 6A7, the fluctuating voltage could be the Klein DMM being cheap, but it is worrisome. Plate voltages are too high now for the 78, 42, 75, and 6A7...not to mention the 80. The 80 and the 42 get pretty hot to touch just while I'm doing the voltages. The shielded tubes do not. I pulled the 80 and tested it on the Triplett 2314...it showed in the 70s for both tests. I might try a different 80 and a different 6A7 a bit later.

What would be the effect of a shorted trimmer (the 66 has plate/mica trimmers mounted along the back of the chassis)? Or perhaps a shorted tuning gang trimmer? They would all measure as open if they were shorted, right? Should I be hearing buzz/hum when touching grid pins on several tubes with the DMM probes? Also, getting a soft buzz touching the plates on the 80. Still no white noise, but the 42 and 75 seem to be operating OK, I get a loud buzz touching the ungrounded lug of the volume pot and a pop removing the 42. I looked at resistances for R44 and for R28 & 29, all are fine.

How much of the voltage is explained by the difference in equipment used to measure? This is why I like sets from the 20s.

[morzh]

Your voltages are a bit high due to you probaly having ditched the lamp in series and the Mains being 120V vs 110V. Which is Ok.
Your 80 and 42 should be hot. As long as they are not red.

Is your 6A7 grid cap having continuity to 78 grid cap and is the 38 resistor 2M?
If no continuity check the band switch.

[ccomer1955]

6A7 grid cap to 78 grid cap shows continuity. R38 is 2M. I guess I'm so used to things being wrong with this set, I'm gun-shy.

So, go ahead and start putting modulated signal into the grid caps and adjusting trimmers? I made a trimmer tool out of plumbing plastic pipe by heating the pipe up and jamming it onto a row of nuts the same size as the trimmer nuts. It works pretty well, but I have to remelt it every once in a while.

I want to adjust my signal generator tomorrow. It is an Eico 320, and is off by about 20KC or more. It has an adjustment, or trimmer (it looks like a small tuning cap), by the tuning capacitor. I can just connect to the antenna of the Philco 42-340 (my first restoration), tune to a known station in the area, and get closer to the markings on the generator dial, right? So we have a strong signal station at 680KC. Tune KKYX in on the 42-340 and then get the generator to push a tone at that frequency and adjust the generator until the generator dial reads 680KC and I get the tone at that point on the radio's dial. Bad idea? It might make more sense to use the generator like it is, knowing its faults and try to fix it after I get the Philco 66.

[morzh]

All these old generators are off by so much, more or less.
I use mine with a counter.
Even though A and B are practically accurate, but C band is off by almost 20kHz. And there are no separate band trimmers so it is not adjustable.

So using a station might work, better than nothing.

[ccomer1955]

Encouraging 15 minutes with the radio today. I first tried to find the IF on the 42-340 and found it (tone across the whole band?) around 420KC according to the markings on the Eico 320, so it is way off. I confused myself trying to locate frequencies using my Klein MM200 which shows the frequency markings on the Eico to be MUCH closer to the mark. The Philco 42-340 tunes across the band and pulls in all the local stations, so it can't be that far off even though the dial is off by about 40KC (680 comes in at 720). So quit using the Klein, right?
I ran both radios for a bit trying to see if the Philco 66 would oscillate, and the 66 screamed at me when I was at the extreme high end of the scale (around 1600-1700-barely engaged rotors). So, at that point, I was sending something like a signal through most of the radio to the speaker, right? I can't work on it much more today, but I have two other radios I can use to test the Eico before I commit to using it to align: a Zenith 8S436 that works reliably and a Radiola 18TRF, so not much use, but I love to listen to it). I haven't tried to zero in on 680, like I said, but since I know that one, maybe that is the way to go for a start.
I COULD also simply use the 42-340's IF as a starting point, and wobble around until I find 460KC on the 66? It should be near the 455KC for the 42-340, right? Start at the grid cap of the 6A7 with a low gain modulated signal, set the Eico a bit below the mark for the 42-340, and try to get tone by gently adjusting the primary trimmer for the 1st IF, then move to the others?
At any rate, I'm excited. That felt like progress.

[Warren]

A frequency counter helps alot when setting up you sg. Then you know it is at the right frequency. They arent very expensive on ebay.

[ccomer1955]

I got back in with the radio and signal generator for a few minutes. Put signal generator on the 6A7 grid cap with red on the cap and black on the ground clip. I get a loud tone at where 460 should be based on where 455 was for the 42-340. I wobbled the signal generator dial a bit and the signal faded and peaked as I moved the knob. I dialed the Philco 66, and heard the tone across the dial with a minor variation in loudness. I peaked both IF trimmer sets by ear, I got adjustment to volume from both trimmers on both sets, and I switched the signal generator red clip to the antenna.
One final update: I had static for a bit (very faint) static went away, but I am able to peak nicely at good volume with the signal generator on the ground and antenna posts for both IFs. What I can't seem to do is get any sort of signal except the IF of 460KC. Like all the other trimmers, the antenna and oscillator trimmers (C7 & 11) were screwed down all the way. The antenna trimmer's mica looks a bit ragged, but the trimmer turns and moves in adjustment. I turned each about a quarter turn from tight to loosen them, applied signal around at three different HF points (1700, 1400, 1200) three different times, and wobbled slowly on both tuning knobs (the generator and the radio) in turn giving both dials about 10KC on either side of the target. I tried a different 6A7, but no luck. I don't seem to be getting oscillation. No effect on the 42-340 when I turn the tuning knob across the dial of the 66. Seems like I'm pretty close, but not there. The AVC works...don't ask how I know.
Also tried broadcast and SW for static, neither worked. Put the antenna wire directly on the 6A7 cap, and also no luck. By the way, it's a stupid question, I know, but I should be using modulated signal on all these adjustments, right?

[Mondial]

Have you checked the oscillator coil for open windings?

It definitely seems like the oscillator section of the 6A7 is not working. Without the oscillator operating, you will have no reception at all on the broadcast or police bands.

It does seem like the IF and audio sections are working properly, so you need to concentrate your efforts on the components in the oscillator circuit.

[ccomer1955]

Yeah, that was my first thought. I measured lug to lug across the primary and the secondary, and it seems to be intact. I measured all the resistors connected to the 6A7, and they were all within 10-20% of correct. I changed out C46 & R45 because they looked a bit sketchy. R10 is spot on, and R15 is a 30K instead of 32K. R47 is 39K instead of 37K. C12 is tubular instead of mica, but the value is correct.
I'm starting to wonder more about the trimmers. I've never had a set with bad trimmers before, so I don't really know what to look for there. They measure some resistance in each of the IF trimmers (17, 19, 22, and 24), but they could be dirty, or intermittent. I can see some of the mica looks a bit ragged, and I have a memory of seeing some mica flakes when I first got the set over a year ago, and the wave trap was a dead short, so I by-passed it. The antenna now connects directly to the band switch. I have some mica sheets that are about the right thickness and cut quite easily. I wonder if it is possible to rebuild this type trimmer (they are riveted at the bottom and have metal leaves separated by mica sheets).

The ones on the tuning cap: one looks in good shape (11) and the other (7) looks a bit ragged and loose in its frame.

The other thing I wonder about is the band switch. It moves like it should, and has a solid click to it, but could be cleaner, I suppose. Also, I am a bit muddled on reading the schematic there. I read six different switches (one has three contacts), and I'm sure about which is which on the set, but I'm less sure about the switch where the antenna connects to the band switch and R3. The antenna coil has a lug on its top and 6 around the bottom including the grounded lug. The way I read it, the lug up top is lug one and the lug to the right of the grounded lug (looking from under the chassis) is lug two. If that is right, then I have the band switch connected correctly. The antenna coil measures out good, too.

[ccomer1955]

I had some time to pull the o/c coil and I get continuity/ohms across each of the three windings (individually and from start to finish). I took the opportunity to do some re-tracing, replacing, and cleaning up. I replaced R15 and C14 (R15 is a 30K resistor, now). IF trimmers peak as before although it seems to me C19 has less of an impact on peaking ( this is the one with the mica cap across it), but the tone is clear and loud. I am able to hear a VERY weak tone at 1500KC and the tone responds to tweaking at C7 and C11 (the antenna trimmers). The tone also is specific to that part of the band (I only hear it right there. The radio also hums now at the extreme high end of the tuning scale (around 1200-1700) with and without the signal generator. I assume that when I hear the weak tone, I am using the signal generator as an oscillator?
Someone who has an abundance of free time might want to check my reading of the schematic for o/c. coil connections:

If I arbitrarily number the lugs on the o/c. coil starting with the lug to the right of the coil as viewed from under the chassis as #1, I have made the following connections:
lug #1: the lead that goes to pin 5 of the 6A7 and from there to C11.
lug #2: C14 connected to pin 3 of the 6A7 and one end of a 70 ohm resistor (the other end of the resistor is on lug #4).
lug #3: R10 connected to pin 6 of the 6A7 and a lead connected to C13.
lug #4: the 70 ohm resistor.
lug #5: a red lead connected to the band switch.

[ccomer1955]

I'm trying to see if the o/c. coil is viable or not, and took the following measurements from the following locations (three times to be sure). Did I measure in the right places and do the numbers I got rule out the coil?

6A7 pin 5 to the bandswitch= 0 ohms (not open, just zero ohms)
from that same spot on the bandswitch to C13= 3.3 ohms
from C13 to C14=72.6 ohms

I had similar numbers when I pulled the coil to look at the windings.

[morzh]

Ok,

you have to pay attention to what you measure and from what pin to what pin.
You cannot measure part to part, you measure pin to pin.

For that matter, it makes no sense when you measure via GND. GND is solid wire.
Unless you specifically measure to make sure the GND is OK.

Now, when you say 6A7 pin 5, it is helpful when you add that it is the Control, or First, Grid and then C13 should not have any continuity to it, unless, again, you measure via GND which makes no sense as it serves no purpose.

Otherwise 6A7 Grid 1 to the Bandswitch (one pin of it) should indeed be a short and c13 (ungrounded pin going to one half of coil 16) to C14 should show continuity.