38-1 code 121A - Printable Version
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RE: 38-1 code 121A - Electrothaumaturgist - 11-28-2017
UMMM, yeaaah. I will have to revisit my "before" photos to make sure I didn't make a wiring mistake, (or followed a wiring mistake) as one lead of cap #67 (.1uf), one lead of r#60 (32,000 ohm) and one lead of r#62 (99,000 ohm) plus the wire from the "mystery box" are all tied to that non-grounded lug. Right next to it is another non-grounded lug only having a single wire on it coming from the outer negative pin of the 6r7 socket. NOT right! I shall review this. I guess I've been staring at this thing for too long and am seeing spots before my eyes... I thank you Terry. I will review this section!!!
RE: 38-1 code 121A - Electrothaumaturgist - 11-29-2017
After a thorough check of photos, sketches, schematics, and with soldering iron at the ready, I have concluded and made an executive decision that the mystery box is an add on repair, and it will be decommissioned, as my new 3k (3.3k) resistor and restuffed .25 will go to the 2 leads at the choke, and the wire going to the 3 lug area will be removed. (I misspoke when I said the wire from 6r7 was incorrect. it IS correctly going to the center chassis lug). I was fully prepared to unsolder the whole mess and start over. Happy to report I don't have to do a thing, except to remove the wire for the mystery box!
I have been up close and personal with all the components and have accounted for each piece and matched it with the schematics and am confident that this does not belong. That old box does look like it has universal mounting holes on the bracket. It does, however, have very nice flexible cloth covered wires on it. I may take my electrolytics apart again and replace the modern wires with those!
RE: 38-1 code 121A - Electrothaumaturgist - 12-03-2017
I was able to appropriate the wires from the mystery box (which were still in great shape and quite flexible) and use them to re-wire the double AND single electrolytic cans (which I had already cut the cans open and re-stuffed, but used modern wire for that, as my supply of ancient components are almost gone). The results were nice, in my book. The chassis is looking great and original, save for the blue resistors in the midst. (had to do this radio on less than a shoestring budget, and was not able to get the nice carbon composites as I've done in all my other repairs). No matter. Progress has come to a screeching halt as my soldering iron has decided that I may be getting far to close to completing the electronics on this unit, (about 97% done) and therefore will not fulfill its' contractual obligations with me. I have attempted to repair it, as per a section on this Phorum, but don't have the correct gauge wire, I guess. The best it would do was to melt the solder and little else. Have to order a few "extra" caps and resistors anyway, some rottenstone for the cabinet, RF chassis mounts, and a few odds and ends. That lousy van wiped me out mentally, physically and financially, so I expect this thing to be up and running by January... 2021.
Jim
RE: 38-1 code 121A - Electrothaumaturgist - 12-04-2017
Okay. I need to install an auxiliary input into this radio, as it has none. Where is the best place to cut that in on this chassis? Thanks.
Jim
RE: 38-1 code 121A - Radioroslyn - 12-04-2017
Do you mean circuit or chassis??
RE: 38-1 code 121A - Electrothaumaturgist - 12-04-2017
So sorry. I meant circuit- sometimes my fingers tap out things before it is verified by the brain-Should be an easy task, I suspect, I just haven't delved too much into it yet.
RE: 38-1 code 121A - Radioroslyn - 12-04-2017
Break the connection between #39 and 42. Signal connects to 42 and gnd.
RE: 38-1 code 121A - Electrothaumaturgist - 12-04-2017
Thanks again, Terry!!! Figured it was just a snap of the fingers.That just made my day!!!
Jim
RE: 38-1 code 121A - Electrothaumaturgist - 12-16-2017
Well, tomorrow I should be getting final electrical components in the mail. Just tying up loose ends on this unit before final assembly. Something that I've been putting off are the speaker connections... The plug connection from the chassis has only one wire connected to it, and is going to candohm #3320 (this set has 3 separate candohm units), as the other three wires were pulled out of their socket holes at the speaker when I got the radio. I've poured over the schematics, and every time I think I have it, I get an overwhelming feeling of doubt. On the speaker socket, (4 pin connector, 5 wires), with the 2 wide spaced pins on the bottom and the 2 narrow spaced on top, the one wire that is connected from candohm goes to the top left of speaker connection (Narrow section- this has 2 wires at the pin- one to the output transformer, the other to the voice coil). The other wires: one goes to 6f6, another to the next 6f6, and the last goes to #3282 candohm. How shall I attach these wires correctly. Should be a piece of cake, I know, (and I've got a good idea how they should go), but I need verification. THANKS
Jim
RE: 38-1 code 121A - Electrothaumaturgist - 12-16-2017
86 that last post... I think I got it... Was looking at the thing too long or something, as I went away from it for awhile, and when I came back, the solution was quite clear, and is a simple circuit on the schematics. The resistance values given matched (fortunately) with the readings from the voice coil and output transformer with a good tight tolerance
I'm getting kind of stoked now!!! I looked high and low on various sites for front rf mounting cushions (to no avail), rear rf washer and chassis feet. It appears no one makes the special front hook mounts, so I re-fabricated some from soft rubber slotted pieces I made when I worked at an injection mold company some time ago and had the foresight to keep a few for just such an occasion. Renovated radios has a nice exact dimension rear rf grommet type mount, and the chassis feet, but have to wait till January to order when he gets back from the holidays. I can live with that, as I hope to tackle the cabinet soon anyway. Jim
RE: 38-1 code 121A - Electrothaumaturgist - 12-25-2017
Tuesday afternoon at 3:16 saw power being applied to the 38-1 for the first time in over 40+ years using the ole dimbulb checker (I think it may have detected me, but was keeping mum about it)
attached the three speaker wires to where I thought they'd go on the pin connectors (as per the schematics hopefully and before initial power up) and threw the dice. Apparently I attached the wires correctly because to my surprise, nothing snapped, crackled or popped!!! left it running with the dimbulb (was quite dim, indeed) for about 20 minutes, checking for any anomalies and smoke.. Power transformer was cool as ice, though all tubes lit up and were hot. Took the bulb off and plugged 'er in. It was receiving a frequency noise up and down the scale, but no reception. Played with the antenna wire and and attached it to the grid of the 6A5 (or so I thought) and got a weak but solid signal- she played "My Sweet Lord" by George Harrison, then I was called away till later. Tried again with the wire at different locales, with one station coming in weak. Next morning, pulled the 6A5, and luck would have it, there was only tube on the whole chassis that you couldn't make the lettering out on, which actually was the 6U7 (with the chassis still on the cradle on the floor, it was slightly difficult to access the tubes or anything else on the flip side. I rebuilt the entire chassis on the floor, sitting Indian style- no easy task) aside from going through the entire tube lineup, I stuck the mystery tube in the freezer for a few and found it was the 6U7!!! I had that one and the 6A5 swithched!!! Installed the tubes into their respective sockets and BAM! Pulled stations in across the board down to about 740, then there was a big gap of nothing but noise in the lower spectrum, but played the stations it did receive from 740 up LOUD AND CLEAR!!!!! The tone control works wonderfully and does a very nice job of tempering the bass and treble at all volume levels. The volume and bass controls work fantastically and really produces a dynamic type of sound the louder the volume goes, (there is no end to the volume control. the louder it gets, the better the sound. I don't dare to open it up and blow my speaker cone out into the next room) even with that disintegrated speaker cone which I had to fix gaping holes and cracks on! The transformer runs so cool, only gets tepid after an hour of running, the input transformer is almost cold after an hour, as well as the field coil and voice coil. The only things that run a little warm are the choke (was running hot at first, but now just very warm after an hour) and the 3 candohm strips- those DO run a tad hot for my taste, but I guess that is their nature. How hot is too hot for them? The side of the chassis gets toasty. Coincidently, that warm running choke is directly above the candohms, and had its wax melted out at some point in the past, but I checked it just now, and it doesn't seem to be anywhere near as warm as it has been previously. Had a problem installing the lower RF cover- everytime I put it on, reception would go out. Checked for pinched wires (none), re-routing a couple of them in vain, and checked everything under the sun to no avail. Decided to just put the cover on and take it off the cradle, and address the topside. A poor solder connection (ancient joint) pulled from the bottom lug of the tuning condenser. Soldered it up and it's back to life! Replaced a couple wires on top, and opened up the frequency range to get stations below 740, and straightened a maligned tuner plate. I am so happy with this... I removed antiquated repairs (MANY) and put everything back to schematic specs. Apparently I miswired nothing 
Now to put the dialscale back on and do a quick alignment (doesn't need much) Even get a few shortwave stations in on both bands... the mag tuning even works to some extent on the upper frequencies, and the dial lights all work! Thanks again for everyones help in bringing another Philco to life!!!!!!!! MERRY CHRISTMAS TO ALL MY PHILCO PHRIENDS
RE: 38-1 code 121A - EdHolland - 12-26-2017
Congratulations Sir!
I can only hope I have a similar experience with the 16X.
RE: 38-1 code 121A - Electrothaumaturgist - 12-27-2017
Thank you Ed! I hope you get that 16X up and running, as that is a gorgeous set and worthy of your efforts!!! In all of the radios I've brought back to life, miraculously, I've never had half the problems some members on this site have had to deal with, which is very odd, considering these radios mostly seem to seek me out at random and are in all manner of disrepair. This project has been an odyssey it seems, and I am incredibly happy with the results. Got my dialface on and did a crude alignment (Oh, what I wouldn't do for a signal generator!!!) Yesterday morning I pulled about a dozen shortwave stations in on SW1, and about 6 on SW2. That was the proverbial "cherry on top".
Jim