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Philco 42-380X SW Band problem
#1

Hi:

This radio has three bands, an AM and 2 SW. I recently recapped the radio and did a rough tuning by ear that worked out ok. I replaced the two 41 tubes in that they were weak and generally cleaned the chassis. The upper SW band never really worked that well in that though it tuned alot of stations in the sound on this band is terrible. The voices/music are garbled, or distorted indicating something is very wrong. The entire upper SW band is like this, where the lower SW band is fine. Please help me find out what is wrong and how to correct it. Thanks in advance for your help, both here and on previous occasions. Icon_rolleyes

God bless,

Dave

Joh 3:7 Marvel not that I said unto thee, Ye must be born again
#2

.... check all orig factory solder connections point-to-point. A cold solder joint could cause this, especially in a band-switch, tube socket-pin connection(s), or the chassis' antenna-coils solder connections. While the set is in operation, wiggle and tap on the tubes also. If you find any intermittent-prob there, and reception improves, bingo. Also, double-check your antenna connections. If your set has the dreaded- loctal type tubes also,(most probably?) most likely you have a dirty pin-connection somewhere on tube pins. These type tubes& sockets pins are infamous for bad connections also. Scrape the loctals tubes pins connections "shiny-clean" with a exacto knife. Just quick-guessing here, tryin to help. If it has pushbuttons tuning, check for clean contacts there also.
#3

Tex:

Thank you for you insight, the push buttons have nothing to do with the SW bands, so it eliminates that. Should I clean the terminals on all the tubes or just some? Further, why is only the upper SW band affected and not the other SW band?
Would the 42 tubes have any affect on it, they are new? Again, thanks. Icon_rolleyes
God bless,

Dave B.

Joh 3:7 Marvel not that I said unto thee, Ye must be born again
#4

David B Wrote:...the push buttons have nothing to do with the SW bands...

Actually, they do. This radio uses pushbuttons to not only select your five preset AM stations, but also to select the band you want to listen to (AM, low SW or "police", high SW).

Remove each tube, one at a time, and carefully scrape each pin until they are shiny and bright. Then, take a can of contact cleaner and spray into each tiny hole of the tube socket. Then reinsert the tube. It is best if you can remove and reinsert the tube a few times. Repeat this for every loctal tube in the set. Just be careful when wiggling each tube; the design of 1942 Philco sockets are poor, as the thin wafer insulator on the top of the loctal tube socket is easily broken.

Now as to the pushbuttons. Liberally spray contact cleaner on every contact of the band switch/pushbutton assembly, going over the contacts carefully with a stiff toothbrush as you spray (before the cleaner evaporates). Then push every button, up and down the line. Repeat this once or twice.

Pushbutton assemblies can go bad. I restored a 42-380 for a client a couple years ago. It was returned to me a month later with a complaint of no reception on one or two of the bands. Cleaning did not help. I ended up having to lift an entire pushbutton assembly from a parts chassis and install it in the customer's set. That was major surgery, and a real headache. But the thing worked afterward, so it was worth it.

I hope yours responds to a good cleaning, and does not require a replacement of its pushbutton assembly.

It is crappy design like this that makes me prefer the older Philcos; chiefly those made in the 1936 model year and before.

--
Ron Ramirez
Ferdinand IN
#5

..."high 5" on that Ron!! The pushbutton assemblies sure had many more probs than the rotary-type switches in my past experiences. I just restored a old 38-39 mod RCA 95T5 with pushbutton select-coil adj tuning, and the contact-points were very well worn previous!! I almost just jump-wired the manual-tuning button instead. After careful tweeking all the contact individual preset connections, it worked again, but just how-long Im not sure! I told my customers not to depend on the preset tuning anymores. It did work when the set left my bench, but no one can guarantee those mechanical difficulties of days past cheap designed push-switches! My hats-off to you for repairing those mechanical probs with other-rare sub mechanical parts indeed! Ive done a few on auto-radios before, no picnic indeed!! Icon_wink
#6

Gentlemen:

Many thanks, and I stand corrected as to the SW bands and that they are push button dependant. Upon restoring the radio I sprayed all the tube holders with a contact cleaner, its a combined cleaner lubricant from Radio Shack, and it leaves a greasy deposit behind that I don't care for. I will pull the tubes again and clean their pins as you directed, and clean the sliding contacts again as well. I did not know what loctals were and looked it up, are all the tubes in this set loctals? I really hope to get that upper SW band to work correctly, it's a nice radio. Presently I am refinishing the cabinet and hope to complete all in the next week or two. Again thanks.


God bless,

Dave B.

Joh 3:7 Marvel not that I said unto thee, Ye must be born again




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