38-10T chassis Restoration begins - Printable Version
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RE: 38-10T chassis Restoration begins - radiorich - 04-08-2024
Hello Chas,
Yes , I was giving this link by a friend https://www.dairiki.org/hammond/cable-lacing-howto/?fbclid=IwAR10G_QG0VN0yKJW9Ry0cQRcvRQUJ-eveMrLohQqjsCsw75efIfVnDVKnVI_aem_ARJBxVwaPUwq7nXJUl7FItAq1l1zkxXcko1f81CqUhpzpXRwitAc03p5wnpJuw9xd_MSI-Hd76K1eG9Hbrv0qsxQ
Anyway I will just do the two ends like the original now I need to figure out what color wire I do have Green and Red and white I bought my wire from radio daze !
Well Bob thank you after this wire my next item is to reproduce some old style resistors .
Sincerely Richard
RE: 38-10T chassis Restoration begins - Chas - 04-09-2024
Richard,
Yes, the WIKI tells you why but the Navy document tells you how. That, I have taken note as all the conventions in the document I learned at Raytheon. I re-processed the html into a pdf. Easier to send and read without a browser...
Just a note, harnessing is not for a radio that has been functional. Altering wire positions and bundling certain connections can cause oscillation. In "boatanchor" radios harnessing is designed in.
You might do some online searching as there is a four-wire textile covered cable used for lighting that would save the aggravation of finding the specific wires and wrestling with a braided casing. There is also cotton braided casing that can be dyed brown. That type of braid, as long as it is near to size can be hand worked to tighten around the wire bundle.
I had a dream, that when I retired I would set-up a specialty braiding mill. Capital was available so long as I did not have more than two or three employees. I HAD all the machinery in storage. But, it was the necessary bookkeeping and the mill SPACE that became the issue. Along with all the other requirements an industry has. My dream became a nightmare that fortunately I awakened too before it came a reality. What was the realty, I did however, set up one braider and one bobbin winder. What I can say from that trial run is that any custom braider WILL have a minimum time and materials costs. Especially if the yarn is not in stock. Winding 16 bobbins for a run takes at least 90 minutes, trial runs for tension and braid angle another 1/2 hour before even the first inch of cable is produces. Today's labor costs, I estimate that is roughly $500 in time and material before the start button is pressed. My dream from textiles hobbyist to mill manufacture simply vanished. My total expense during the "learning curve" was around $7,000.. It would have cost me some $150,000 for four years in a textile manufacturing college, but I would not have had any fun, I think I got a bargain...
Chas
RE: 38-10T chassis Restoration begins - radiorich - 04-10-2024
Hello Chas,
Yes, and far as this wiring harness goes it is just from the radio chassis to the speaker !
Sincerely Richard
RE: 38-10T chassis Restoration begins - morzh - 04-11-2024
Chas
I applaud your entrepreneurial spirit for at least having tried, as myself, I would've not even try. Just the mental picture of me running a business scares the bejesus out of me. I am an eternal employee type.
RE: 38-10T chassis Restoration begins - radiorich - 04-26-2024
Hello Guys,
I have a question about the wiring colors for the Philco speaker wires is there a chart or does anyone know what factory colors are used.
Here is the schematic
Sincerely Richard
RE: 38-10T chassis Restoration begins - Chas - 04-26-2024
Rich,
The schematic "seems" to suggest it is green, white and blue...
RE: 38-10T chassis Restoration begins - radiorich - 04-26-2024
Chas,
Thank you I seen Green and white but I did not see the blue I will also look what color is still atached to the speaker I always leave like 1/4 inch .
Sincerely Richard
RE: 38-10T chassis Restoration begins - Chas - 04-27-2024
The blue label is at the filament of the rectifier which is common to the field coil. Though the wire itself may be another color as it is routed to the speaker. At this point it would seem blue would be consistent with an identical circuit connection to the "hi" B+...
Chas
RE: 38-10T chassis Restoration begins - radiorich - 04-27-2024
Chas,
Yes, I agree that would be the most logical!
I happen to have those 3 colors too.
One thing I need to do is to order some more colors. I have been using 20 gauge for most of my wiring. I currently don’t have any 18 gauge cloth wire except power cords .
. Do you think 20 gauge is heavy enough for the blue wire?
Anyway I am starting to get more work doing old car radios too.
Sincerely Richard
P.S. Who do you buy your cloth wire from ?
RE: 38-10T chassis Restoration begins - Chas - 04-27-2024
Richard,
It's great when one has stock on hand. I have been collecting/sorting new/used radio parts for more than 60 years. unfortunately, that takes up a lot of room and one actually does waste a lot of time sorting and even spending money for storage materials...
The 20ga is fine for hookup. Only when there is a number of filament connections does the wire size become important. I am also a fan of solid wire as it stays in place.
I have not bought single conductor replica textile covered wire as yet. I really do not know of a vendor either.
I have heard stories of the replica wire many years ago offered by a vendor of which the textile braid was not sealed to the PVC, it would unravel when stripped.
I missed an ARF classified sale last week from a member who had some surplus textile covered wire. This looked like new manufacture and by appearance alone it looked like good quality.
https://www.antiqueradios.com/forums/viewtopic.php?t=437177
Might inquire with Jim Dutridge as to quality...
Some 20 ya when I was still working, I specified reels of Alpha hookup wire. All 100' spools, all EIA color, 20ga and 22ga both solid & stranded for company projects. I got 600 volt in the solid it was the same O.D. as the old rubber covered wire. It was awfully expensive, averaging some $30/spool. The order was in excess of $1200... Yes, I took some lengths home to re-wire both a Zenith and an RCA for a friend, nice stuff to work with and I kept to the color scheme too.
Quality wire will, strip cleanly, tin and solder no problem, no retraction of the PVC core on tight bends from solder heat.
Let us know what happens...
Chas
RE: 38-10T chassis Restoration begins - radiorich - 05-05-2024
Hello guys,
I worked on my Philco 38-10t again this weekend Installing the newly made speaker wire harness and replaced the Pilot light bulb along with new wire and rebuilt the socket .
my next step was to take the IF can apart to replace grid cap wire .
Here are few photos showing my progress .
Sincerely Richard
P.S. here is a Photo of the Chassis stand I added a brace to make it a little stronger !
RE: 38-10T chassis Restoration begins - radiorich - 05-13-2024
Hello guys,
I started cleaning some rust spots on the top of the chassis and replaced one IF cans Grid Lead .
Then I will be pulling the tuning capacitor off to clean and re-lube plus new rubber mounts .
Here is one those dog Bone resistors that I want to make it is a 3watt at 10K .
I know someone on the forum made some of these before I was looking for the post on it to see what they used .
Sincerely Richard
RE: 38-10T chassis Restoration begins - GregD - 06-01-2024
Richard, I am also just finishing up the restoration of a 38-10T and have a question for you. What voltage are you seeing at the plate of the 6Q7? The philco spec is for 120 volts. I’m getting about 214V. There is a 330K resistor in line from the b+, which can’t drop it enough. I’m interested in your experience. Incidentally, all of the other voltages are close to within spec on my set. I’m wondering if it is a typo.
The work you’ve done looks great, and I was happy to see this at the same time I have been working on mine.
Greg
RE: 38-10T chassis Restoration begins - RodB - 06-02-2024
Hi Greg,
Typically when you see a voltage close to B+ on the plate of a tube there is little or no current flowing in the tube. When no current flows through the tube no voltage drop occurs across the plate load resistor. Voltage drop across the load resistor should be in the 100 - 150 volt range for your tube. If this is the case then either the tube is bad or the grid is biased so high it cuts off current flow.
GregD - GregD - 06-03-2024
Thanks for the reply, RodB. I was most hoping that Richard may have measured his to see if it is a typo on the schematic. My set is working very well subject to further alignment so if the bias is very far off, I don’t think that would be the case.