Guest pyrodork Posted December 2, 2011 Share Posted December 2, 2011 (edited) i've restored a couple old radios in the past, but i've never come across this problem before. anyway, i got a radio for my 37. a philco 1450; which is correct for the year. i've done the standard replacing of wiring, caps, a few tubes, etc. i got it powering up and tuning in stations, but i can barely hear anything. i have to have the room absolutely quiet in order to hear that i've got a station tuned in. not many stations do come up, but that could be due to the amplification issue or that the antenna is indoors. i've had the project on hold for a few months as i do other things and see if a new idea comes to mind. i recently thought the speaker may be bad, so i got a spare 2-wire car speaker hooked up, but all i got was a loud buzz. the speaker wire harness for the radio is 4-prong, but only 3 have wires on them. i also discovered a port on the side of the radio that appears to have been for an external speaker, but it's got a jumper across two of the prong plugs (i suppose to complete the otherwise open circuit). essentially, i'm looking at finding out what may be my amplification issue, how to test what i have, and maybe a resource of where i may come across a replacement part. i'd also like to know about that alleged "external speaker" port and how common they were, where the speaker was placed in the car, and the cost of that additional option. i know the radio itself was a $60-some option by itself. there's also the switch for an under-car antenna... which i'd like to know more about, too. i have no literature aside from the diagrams inside the radio itself. Edited December 2, 2011 by pyrodork (see edit history) Link to comment Share on other sites More sharing options...
Guest pyrodork Posted December 3, 2011 Share Posted December 3, 2011 sadly, a lot of that just flew by my head. i'm fairly certain the volume control is fine, and it's the final amplification that is the problem. i was wondering if maybe the transformer unit that the speaker wires run to may be an issue. anyway, considering the volume control is ok, could you give me a step-by-step on how to do the remaining tests you suggested? i'm not certain what to use for testing equipment, either. if posting pictures of my radio would help, i can do that.most of my electronic background is from trial and error, and not measuring this and reading up on that. although i have done it a few times, it's not my standard routine. i do have a cheap multimeter, but i have no idea how to use it aside from checking batteries.on a side note, i heard there's a way to test a capacitor with a multimeter to see if it's causing a problem. i have a 3mfd, 330v (massive) cap from an old pedestal fan and i'm trying to figure out if that's my problem or if the motor burned out.i know, i know... i should study up on this kind of thing before poking around in stuff. Link to comment Share on other sites More sharing options...
Guest pyrodork Posted December 8, 2011 Share Posted December 8, 2011 (edited) yes, i bought new/never used parts.which tube/tubes are for amplification? (or is that a stupid question?) Edited December 8, 2011 by pyrodork (see edit history) Link to comment Share on other sites More sharing options...
Guest DodgeKCL Posted December 8, 2011 Share Posted December 8, 2011 Give me the line up of tube numbers. Link to comment Share on other sites More sharing options...
Guest pyrodork Posted December 9, 2011 Share Posted December 9, 2011 417578 (x2)846A7 Link to comment Share on other sites More sharing options...
Guest pyrodork Posted December 10, 2011 Share Posted December 10, 2011 (edited) thanks! i appreciate your help!i just did some backtracking and noticed that i bought two 78's and a bunch of 75's. i think i only replaced the RH 78 (i remember the metal cap broke off) and the 75. every tube glows now, but i know that's not always a sign that they work. i think it's safe to assume i only replaced those two tubes. the capacitor can underneath 84 i did replace with regular caps, but put the can back in because i think it's fine (and apparently the can itself has its own rating). i'm suspecting 84 is the amplifier tube; as it's near where all that bundle of stuff is. here's a pic of the radio and the diagram posted inside the box. unfortunately, i have no other paperwork for this radio. the bracket on the RH side above the black fabric screen is the plug for the speaker; which i removed for clarity. Edited December 10, 2011 by pyrodork (see edit history) Link to comment Share on other sites More sharing options...
Guest pyrodork Posted December 13, 2011 Share Posted December 13, 2011 more pics Link to comment Share on other sites More sharing options...
Guest DodgeKCL Posted December 13, 2011 Share Posted December 13, 2011 Interesting what the internet brings. I've never troubleshot a radio in this way,of course, so I'll have to chew on the photos every once in a while over the next few days and see what I come up with. I'll then post everything at once. I have the photos on my desk top. Link to comment Share on other sites More sharing options...
Guest pyrodork Posted December 14, 2011 Share Posted December 14, 2011 thanks! take your time. i sold my studebaker recently and threw in the 6v battery i was using to power the radio, so i've gotta grab my other one from the garage on the other side of town at some point. Link to comment Share on other sites More sharing options...
oldmopar Posted December 16, 2011 Share Posted December 16, 2011 At the link plug in your tube #'s and you will get information on what they are. Nostalgia Air Tube Substitution & Characteristics Guide Link to comment Share on other sites More sharing options...
Guest pyrodork Posted December 18, 2011 Share Posted December 18, 2011 great!however, i had a knowledgeable guy over tonight. didn't power it up, but he's pretty sure the speaker is frozen. ...coil wires bubbled and locked the speaker cone in place (or something like that). that actually makes a little bit of sense. i never really investigated a bad speaker. Link to comment Share on other sites More sharing options...
Guest pyrodork Posted December 24, 2011 Share Posted December 24, 2011 okay! new update! i removed the speaker from the cover plate to find that the speaker surround is completely unglued and has deteriorated some. i found new foam surrounds on ebay: PRO GRADE 8" SPEAKER FOAM SURROUND REPAIR KIT !!!! | eBay and the measurements appear to be correct. i think this is the first step. the voice coil seems fine in itself, as well as the cone. slap a new surround on it and i may be in business! Link to comment Share on other sites More sharing options...
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