EH Scott Philharmonic AM/FM - Printable Version
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RE: EH Scott Philharmonic AM/FM - rfeenstra - 01-28-2021
What a mess!!!! I tried to lay out components as they were originally. A lot of capacitors had been changed with Solar's, MicaMould, "Black beauties", Sprague, and who knows what else. A boatload of .05's had been changed. I had a good supply of Philco .05's, so this Scott has been Philcoized. I did turn the Philco brand capacitors so that you could not see the "philco" though! All resistors have been replaced. Now on to the next section.
RE: EH Scott Philharmonic AM/FM - morzh - 01-28-2021
Scott and Philco is a marriage made in heaven
RE: EH Scott Philharmonic AM/FM - Phlogiston - 01-28-2021
As I had mentioned in the blog post on the many Crosleys that I had to work on -
https://www.russoldradios.com/blog/thalia-melpomene
Many if not all of the original caps had been thrown away. Even with my large stash of originals, I was out of most of the Crosley numbered W-XXXXX caps. My second choice is to use the same caps- CDE, Sprague, Solar, Micamold that the manufacture used, less the correct part #. With Crosley, it was most of these manufactures. With other manuf. they often used only one brand for the paper caps maybe another for the electrolytics. I have seen factory caps that were a mix of branded and unbranded. So with most manuf. - not Zenith - this sub is almost as good as original.
Your radio looks good, in any case.
Russ
P.S. I wish there were some way to encourage people to save the old original caps that they throw away (clink). I have even offered to pay for factory originals from the 1920s & 1930s. I just posted a WTB on ARF, so let's see.
RE: EH Scott Philharmonic AM/FM - Arran - 01-28-2021
Russ;
I was already in that habit before I started restuffing paper caps, other then Philco ones most are brands like Aerovox, Sprague, Etc. I think the solution is to find a source of cardboard tubing, I found a source for the larger sizes, and sort of did for the smaller, some wire coat hangers have cardboard tubes on them but not often.
Regards
Arran
RE: EH Scott Philharmonic AM/FM - rfeenstra - 01-28-2021
You will see one radial lead, brown cap in there. I couldn't fit anything in the original cardboard tube! So, for now, one modern cap in a forest of re-stuffed ones. But then, all of the resistors have been changed and they do not look like the original ceramic style. I just can't bring myself to trying to make all of those look original. Quite frankly, I'm getting tired of re-stuffing all of those caps! Starting to think that the brown Panasonics are looking pretty good.
RE: EH Scott Philharmonic AM/FM - morzh - 01-29-2021
I did not notice it, until you told us., The one on the right.
BTW I have, on a few occasions, stuffed radials in the tubes. As long as they fitted inside. If teh leads were not enough I simply wrappped them around buss wire and made lead extensions which then were potted.
RE: EH Scott Philharmonic AM/FM - Phlogiston - 01-29-2021
I have run into issues stuffing 630V yellow caps into some of the original tubes. Much smaller (yellow) caps, rated for 400V are available through Mouser at reasonable prices.
RE: EH Scott Philharmonic AM/FM - morzh - 01-29-2021
Russ
So far I had few if any issues stuffing yellow 630V axials into the original tubes.
One that I had, I think, was the larger type, 0.15uF and the tube was not much longer than the cap itself. That is, to do what I typiclaly do, spiralling a paper strip, putting it on top of the yellow cap and potting with plastic, I had no space left.
What I then did was, instead of cutting a strip and making a spiral, I cut a disk size of the internal diameter of the tube, slid it down the lead and then potted. This gave me enough space and still protected the yellow cap from the hot plastic damage.
And you are right, 400V will do in most cases.
RE: EH Scott Philharmonic AM/FM - rfeenstra - 02-08-2021
Ready for final assembly. All of the electronic work is finished. Next up is to mount the dial assembly. I need to install the tuner cap cover and all of the coil shields. The candohm was completely disabled internally (I wish I had a black resistor instead of the green!) Then, I'll try to keep the smoke in when I power it up and find out how many wiring errors I made! Because of the component density and so much stuff on top of the tube sockets beneath, finding and repairing errors and future service will be a b**ch. This is definitely the most complex radio I've worked on. FUN!!!
RE: EH Scott Philharmonic AM/FM - mikethedruid - 02-08-2021
OH MY GOD ! Rat's nest hardly describes that MESS !... Better you than me. You have my sincere sympathy I realize now that there is a definite advantage to the military nature of the SLRM. I look forward to hearing more about your continuing adventure. (Personally, seeing that, I have less respect for the engineers who designed that radio. Serviceability should ALWAYS be a concern, and, seeing that, it CLEARLY WASN'T for the designers of that chassis.)
RE: EH Scott Philharmonic AM/FM - rfeenstra - 02-08-2021
No it wasn't!! The standard Philharmonic is a little less congested. Yet, at some point in this radio's history, a lot of capacitors and a few resistors had been changed, some of them under the upper layers. Someone took the time to dig deep. Scott crammed the FM section in the same chassis as the AM Philharmonics by removing the "expander" and added far more tubes, circuitry and coils than they removed, thus increasing the component density. I just hope like crazy that everything works when I power it up! NO SMOKE PLEASE. The SLRM is a dream in layout. I suppose it was designed to be easily serviceable by minimally trained military service techs. I love the performance of mine! I hooked it up to the phono input of my EH Scott "Beam of Light" Philharmonic that is sitting right next to the SLRM in the shop. The SLRM sounds great through a full range audio system. In the HF switch position, the frequency response is very good for an AM radio. You are going to love it!
RE: EH Scott Philharmonic AM/FM - rfeenstra - 02-09-2021
OK. Ready for smoke test! I'll upend both chassis so I can monitor voltages as I turn up the variac.
RE: EH Scott Philharmonic AM/FM - mikethedruid - 02-09-2021
Shure is pretty, RF... I'm anxious to see what happens now, and wishing you luck !
RE: EH Scott Philharmonic AM/FM - rfeenstra - 02-09-2021
Well, it didn't blow up! I get stations on 2 of the short wave bands, nothing on the broadcast band, long wave, or the highest band. They are totally silent so I suspect an oscillator problem. I get a lot of noise on the FM band until it picks something up (there are no FM stations at these frequencies - 42 to 50 MHz. When it does tune something in, the FM eye closes and the set goes silent like the limiters are kicking in, killing AM noise. Or so I theorize. On the bands that do work, changing the selectivity control will shut them down. They only work in a very narrow range on the selectivity. This would suggest that the IF alignment is way off. I knew it would be as I cleaned the connections on the trimmer air caps, swinging them through their range and trying to reset them where they were. The first thing I have to do is align the IF as it might bring in the other bands.
Actually, the first thing I need to do is to bring the B- into line. It is supposed to be at -27 volts but is actually at -39 volts, upsetting the bias on the whole system. RF and IF AGC depend on the B- voltages. B+ voltages are just a tiny bit high, but not too bad and will probably come into line when the biases are correct. AF system seems to be working fine. A lot of power available with a radio signal or my finger on the phono input.
The dial lighting system is LED with a control to vary the brightness. That is working. I tried to make some LED bayonet lamps for the "Beam of Light" pointer system. I let a little smoke out on those! I'm going to have to order some of the LED lamps that Ron is using.
One always hopes that everything works first shot out of the box, but that is not to be. I'm very please, however, with where I'm at. Considering the complexity of this radio, I did expect a few problems!! It will be fun to sort everything out and get the radio properly aligned - a fairly major project. I'm anticipating a great preforming radio when I'm finished.
Ron, your radio is coming alive! You'll have to make a trip up to Michigan to hear it in action. I'll leave the light on for you.
Rob
RE: EH Scott Philharmonic AM/FM - rfeenstra - 02-10-2021
Adjusting the bias voltage brought a couple of bands back. I found a solder connection in the oscillator section for the BC band that was the problem there so all bands are now working! Now to do some alignment.
Almost 2 AM. Time for bed.