Repair of a 1959 Philco AM FM Model F-974 Tube Radio

Picked up this radio. Lets see what it will take to get it working reliably again.

[@radiotvphononut]

As far as getting the old solder to melt on these PC boards, I've found that adding a bit of new solder to the old solder connection will help melt the old solder, and then you can use desoldering braid and/or a solder sucker to remove the molten solder. As far as the old capacitors reading higher than their rated value, these modern capacitor meters use a time constant to determine the capacitance value. In other words, the meter measures the amount of time that it takes the capacitor to charge to determine the measured value. When a capacitor is leaky, it takes an excessive amount of time for it to charge, which fakes the meter into showing you that the capacitor has a larger value than it actually does. If you were to test those capacitors with an "old school" capacitor tester that will allow testing at rated working voltage, those things would be leaking like crazy. As far as the resistor in the power supply, a flameproof film or wirewound type in the 3W to 5W range should work and if something shorts (such as the diode or filter capacitor), the resistor will open. I really don't care for those "flexohm" resistors and I've seen a good many that were open.

[@mohinderkaur6671]

very insightful ! Wisdom!

[@brianfletcher9774]

Pretty cool to have FM in 1959. Here in South Dakota, I understand FM didn’t come around until the mid to late 60’s.

[@BrumAdam]

A nice radio and a bargain too! Another great video - thank you

[@45AMT]

To all those who will question why I bypassed the fuseable resister and didn't add a fuse. I didn't have a power resistor that was 120 ohm. I had a 100 Ohm and a 150. Furthermore there were 1000's of AA5 (line driven sets) made without a fuse. So what do you think was the fuse in these circuits? Answer the tube filaments. On this set I would much rather blow a tube than that fuseable resistor. They're impossible to get and cheaper than a replacement resistor.

[@garyk.8674]

I like the retro look to this radio

[@melvinlewallen7796]

Love your videos keep up great job been watching a few years 😎

[@m.mustapha794]

👍 from ALGERIA.

[@hestheMaster]

Sometimes manufactures of radios put different chassis in same cabinets which that's why you may find holes in the bottom or front of the cabinets put there for no apparent reason. General Electric often did that even into the solid state era with cabinets. This was an excellent repair video and enjoyed this far better than your "show and tell " shorter videos.

[@howardoller443]

I really appreciate you sharing your knowledge and experience about old radios. I also appreciate you don't dress in drag in your videos. Just sayin'......

[@lurkersmith810]

You had me at "bumble-bomb"!

[@MowerJunkie]

Nice work, another old radio rescued.

[@LouinVB]

You need a heavier solder pencil tip for enough thermal inertia to heat the joint up quickly. Skinny tips cool to quickly. The big solder gun is overkill unless you're soldering to the chassis. Superglue for lifted traces.

[@edmccormick8024]

In 1962 Ford motor company bought the Philco company they called it Philco-Ford

[@a587g]

Most likely this cabinet also used an AM only chassis as well, hence the extra holes. Zenith did this with a few models too. Philco loved their circuit boards and couplets in this era... Made things harder to fix but definitely cheaper to assemble. Most of these early FM sets sounded nice since they were aimed more at classical music aficionados.

[@edmccormick8024]

1959 Philco was a struggling company and the Philco Predicta line of Tvs was the last nail in the coffin for them sadly they had made great radios and televisions for years The Predictas has many many issues Now they are like an Edsel folks are looking for them

[@showbizsam4440]

Is AM still used in North America? In the UK, during the day, I can only pick up about three or four stations on an AM radio. The local station has a "classics" second option, playing a mix of disco and 80s chart music. It's as if punk never happened! There's also a BBC local station that uses it for soccer commentary, and when there's no sport it just provides the FM/Digital version of the station. Final one I can think of is a music station. Don't know how it survives, as AM doesn't really lend itself to music. I can recall US MW radio being 'famous' for Conservative talk radio in the 90s, but it's a long time since I've heard anyone speak of this.

[@abcsd1254]

I am convinced this was the beginning of disposable electronics because that was not well engineered for ease of repair. You certainly made the best of it however

[@dougmcartin3881]

I only really worry about adding fuses on transformer sets. Old transformers can short at any time without warning and cause quite a bit of smoke so a fuse is cheap enough protection. This one is going to work just fine without a fuse. After all these radios are not going to be used as daily drivers

[@45AMT]

My exact train of thought on fuses.

[@jamesmdeluca]

Greetings: Instead of the 120 ohm series dropping resistor, use an electrolytic dropping capacitor between the silicon diode and the first filter cap. The capacitor value uses the formula c=1/(2 pi f Xc) where Xc is the same as the dropping resistor. In this case a 22 mfd 200 wvdc is used. (No wasted power, no extra heat.) +side to the diode cathode. Easy test to try! Can you tell whether the FM tuner has/uses AFC?

[@mohinderkaur6671]

Try it! wont work! dropping capacitors work for series filament string. value is that needed by the vector sum of impedances.

[@zbaby82]

It didn't need an alignment?

[@poormanselectronicsbench2021]

I realize this is your radio, and you can do with it as you wish, but since you removed and bypassed that fusible link, wouldn't it be a good idea to add some sort of fuse to the AC line feed or the B+?

[@45AMT]

Tube filaments act as a fuse.

[@poormanselectronicsbench2021]

@@45AMT @ 26.26 , the schematic shows the rectifier circuit to be a parallel circuit to the tube filaments, so, there is no current limiting or protection done by the filament string ( which was done by that "L11" fusible link). Granted, you replaced most of the parts that may fail with age and cause an overcurrent in the B+, but the filament string is offering no protection to that situation. I guess the good news is, that 120 ohm resistor you put in, would become a sacrificial part if a low resistance short ever occurred on the B+, as the power load could go up to 120 Watts on it. It would get a bit smoky if that happened though.

[@45AMT]

@@poormanselectronicsbench2021 This was just a temporary fix until I get a 120ohm power resistor. When I get that I'll just reinstall the fuseable resistor or add a fuse.

[@greggaieck4808]

Radio rescue your philco 1959 module f. 974 am fm radio Receiver is cool am band goog for DXing at night. My hobbys are painting pictures and lisining to shortwave and ssb iam thinking about getting my ham license I have 4 shortwave receivers iam thinking about getting Tecsun Pl 660 mw lw fm air SW ssb 6 bands receiver

[@45AMT]

Good luck on your ham ticket if you choose to get it.