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I got a 48-1263 some time back and yesterday I got around to recapping it. Someone had already been there and I only had to replace 4 paper/wax caps and both can caps and one 15K resistor that was reading 27K. Plugged it in and got nothing but dial lights glowing. I checked the tubes and 4 of the 8 showed bad or questionable. Is this likely or is my old Heathkit tester on the fritz? When I picked it up the owner had it turned on with the turntable running to show me "it works". I immediately unplugged it and took it home, but could she have done something then that wrecked those tubes? Yes, I am very new to restoring radios. Help!
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Bad or weak tubes on a tester don't always translate into non functioning tubes. I would start by doing voltage checks (assuming you have a DMM) on the tube pins to make sure they are within reason of what is provided on the schematic. What other testing tools (sig gen, tracer, etc...) so you have, if any?
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There are more to the radio than just tubes. RF coils that can get open, oxidized panels and switches, speaker, transformer.....so, start telling us what you have checked so far.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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It's also possible that the tester is not reading properly.
Which model Heathkit are you using??
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Also unclear about the radio as displayed to you in the shop: was it actually receiving radio stations?
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(07-13-2015, 12:04 PM)Nick3092 Wrote: Bad or weak tubes on a tester don't always translate into non functioning tubes. I would start by doing voltage checks (assuming you have a DMM) on the tube pins to make sure they are within reason of what is provided on the schematic. What other testing tools (sig gen, tracer, etc...) so you have, if any?
I have a multimeter and an old heathkit signal generator.
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(07-13-2015, 12:14 PM)morzh Wrote: There are more to the radio than just tubes. RF coils that can get open, oxidized panels and switches, speaker, transformer.....so, start telling us what you have checked so far.
I haven't checked anything else but tomorrow I am going to buy a magnifying lens so I can read the voltages on the schematic and we'll go from there.
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(07-13-2015, 12:41 PM)TA Forbes Wrote: Also unclear about the radio as displayed to you in the shop: was it actually receiving radio stations?
No. I bought it from a private individual who was moving; when I got to her house the radio was the only thing left, and she had the turntable running. I didn't hear any sound out of the speaker. The turntable will run very well right now so am I correct in assuming this means the power transformer is okay?
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The schematic in nostalgia air is tough to follow, BUT:
1. No, the power to the turntable is house current, switched.
2. If half the tubes are reading ? then that could be the problem.
PM me with what tubes are bad, I may be able to help.
Once you KNOW all tubes are good, then we can start troubleshooting.
If your sig gen has an audio output signal you can use separately or modulate with an RF signal, recommend this:
1. Inject an audio signal on the wiper of the vol control. If you hear it in the speaker and can control the volume by turning the vol control shaft, then trouble probably not in the audio section.
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Sorry for the long hiatus...but I want to tell everyone that the tubes WERE bad. New tubes and the 48-1263 is playing like a new radio! Got a new cartridge ordered from Ed Crockett of Vintage Electronics in Hattiesburg so the phonograph will soon be back to life also.
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Glad you got it going.
I've bought a couple of radios, where some unscrupulous seller had put all his old non working tubes in.
Both times it was through -bay. Maybe they were unhappy that the radio didn't sell for more, so they were trying to cut their losses.
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