1958 Zenith Deluxe 500 Radio Issues - Videokarma.org TV - Video

vortalexfan · #1 05-30-2020, 05:17 PM

Hello everyone, a couple of years ago I bought at a local antique mall a 1958 Zenith Royal Deluxe 500 Radio that when I got it one of the battery terminals inside was corroded so badly that it broke off from the battery compartment but it still worked if I set the terminal up against where it was originally set and hold it in place with the battery.

Anyways I was trying to do an alignment of the radio and I was trying to adjust the IF Transformers (it has 3 IF stages) and the 1st IF stage has two IF Transformers a Primary and a Secondary.
When I was trying to adjust the secondary transformer I accidentally broke the slug (or at least I think its broken as it refuses to turn using a smaller sized screwdriver), how do I go about repairing one of those broken IF Transformers?

And also I've tried using this radio at work to listen to some of my faivorite stations on the AM Band and for some reason or another the AM Band is completely dead on the radio all I hear is static and various noises that sound like a signal generator test tone at various spots on the dial, I can even hear the music that is being played on the sound system at my work over my radio at around the 900 kHz mark on the dial, which is weird because as far as I know their sound system is of the hardwired variety complete with wall panels for controlling the sound system in the various sections of the restaurant.

So my question is, how on earth would a hardwired sound system be able to transmit sound onto a radio without some sort of low power radio transmitter?
Also What would the restauarant I work at have electronics wise that would more or less jam the entire AM Band on a battery powered AM Radio?
I know security systems interfere with FM Signals and so do Florescent lighs with electronic ballasts, but I've never heard of any of those things interfering with the AM Band to the point of completely disabling the AM Band.

Any Ideas as to what might be going on with my radio or at my work that would make it so that a radio of any sort is basically useless there?

Thanks for your help.

Electronic M · #2 06-01-2020, 12:39 PM

Buildings with metal roof and metal or masonry facades are basically Faraday cages so there wouldn't be signal to begin with. Some florescent lights do jam the AM band . Asside from the 2-3 strongest AM stations in the area the florescent lights in the garage either add a frustrating amount of buzz or outright jam most AM stations. Many newer florescent lights have switch mode supplies that jam everything... many switch mode supplies jam everything (I can't use power inverters to demonstrate radios at swapmeets because they jam the whole AM band).

McDonald's is so bad a number of AM and FM stations die when I get my car radio within 20' of their building.

vortalexfan · #3 06-03-2020, 03:55 PM

Quote:

Originally Posted by Electronic M

Buildings with metal roof and metal or masonry facades are basically Faraday cages so there wouldn't be signal to begin with. Some florescent lights do jam the AM band . Asside from the 2-3 strongest AM stations in the area the florescent lights in the garage either add a frustrating amount of buzz or outright jam most AM stations. Many newer florescent lights have switch mode supplies that jam everything... many switch mode supplies jam everything (I can't use power inverters to demonstrate radios at swapmeets because they jam the whole AM band).

McDonald's is so bad a number of AM and FM stations die when I get my car radio within 20' of their building.

Well the place where I work isn't metal or brick, its a regular old stick built building that part of it dates back to the 1920s (that part is cement block) but then the rest of it is a timber frame building that was built in the style of an Amish Barn.

There are Florescent Lights throughout the building but as far as I know none of them are new enough to have electronic ballasts in them (the newest florescent lights in the building dates to the mid 1990s).

They do have a security system but like I said it only affects the FM Band, and not the AM Band because when I drive up to the building it knocks out my FM Band on my car radio but the AM Band on my car Radio isn't affected.

As for trying to repair the broken 1st IF Secondary Transformer, how does one go about doing that? Can one use a modern IF Transformer from a more modern transistor radio on this radio?

zeno · #4 06-06-2020, 05:41 PM

Take your radio for a nice picnic way out in the country. Get away
from your car and any electronic crap you have. If its working OK
you will not believe the difference. Almost EVERYTHING that plugs
in or runs on batteries causes interference to the AM band.
Our shop like most used florecents. We got one AM station & if it
came in the radio worked. The only radio that worked good was a late
30's Zenith console. That had a big loop antenna ( Wavemagnet ).
built in. That radio could show how GOOD AM could sound. I miss
that radio. A customer just had to have it & payed $400 for it.

73 Zeno

LFOD !

Titan1a · #5 06-06-2020, 08:27 PM

My favorite radios are the Philco 116 (still malfunctioning) and my Zenith 11S474. While technically not "HiFi" they both have a great "bottom" and solid vocals. My QRM has lowered but is still noticeable. It seems to sound like facsimile. Oh how I long to go to central Wyoming where there's no people or interference! I could string up a monster Beverage antenna!

JohnCT · #6 06-13-2020, 06:01 AM

My house is one big AM jammer. I used to use my Radiola 62 regularly to listen to NY ballgames in CT, then it no longer worked. I used it for local broadcasts and even that got noisy. I assumed the Radiola needed to be rebuilt as it was running on 100% of it's original parts except for four of the 8 tubes.

One day I was doing brakes on my car and brought my trusty Zenith Royal 500 to listen to the ballgame, and it was all noise. Huh?

After the brakes were done, I threw the main breaker on the house and the noise all went away, and the Zenith performed perfectly. I shut off all the breakers in the panel, turned on the main, and started turning breakers back on. I found several sources of AM noise in my house: the wireless router was the biggest offender, but also my outdoor motion light fixtures were making a big racket. There were a few other sources that weren't as bad but still existed.

I'm going to try an extension cord from my basement to the Radiola with all the breakers off (maybe Sunday) and see how the old girl does with no interference.

As for your IF coil, you're probably going to need a donor.

If the ferrite slug cracked cleanly and in one piece, some cyanoacrylate glue (tiny amount!) can glue it together.

If the slug piece is crumbled, you can try filling the crack with a *tiny* amount of *slow* set epoxy (the 24 hour kind). Use the tip of a needle under an eye loop and work a bit into where the ferrite top cracked to rebuild the slot.

In either case, the proper size adjustment tool is critical. If the tool is too small, it will put a point load into the gap and crack it.

John

Electronic M · #7 06-13-2020, 03:40 PM

Quote:

Originally Posted by JohnCT

My house is one big AM jammer. I used to use my Radiola 62 regularly to listen to NY ballgames in CT, then it no longer worked. I used it for local broadcasts and even that got noisy. I assumed the Radiola needed to be rebuilt as it was running on 100% of it's original parts except for four of the 8 tubes.

One day I was doing brakes on my car and brought my trusty Zenith Royal 500 to listen to the ballgame, and it was all noise. Huh?

After the brakes were done, I threw the main breaker on the house and the noise all went away, and the Zenith performed perfectly. I shut off all the breakers in the panel, turned on the main, and started turning breakers back on. I found several sources of AM noise in my house: the wireless router was the biggest offender, but also my outdoor motion light fixtures were making a big racket. There were a few other sources that weren't as bad but still existed.

I'm going to try an extension cord from my basement to the Radiola with all the breakers off (maybe Sunday) and see how the old girl does with no interference.

As for your IF coil, you're probably going to need a donor.

If the ferrite slug cracked cleanly and in one piece, some cyanoacrylate glue (tiny amount!) can glue it together.

If the slug piece is crumbled, you can try filling the crack with a *tiny* amount of *slow* set epoxy (the 24 hour kind). Use the tip of a needle under an eye loop and work a bit into where the ferrite top cracked to rebuild the slot.

In either case, the proper size adjustment tool is critical. If the tool is too small, it will put a point load into the gap and crack it.

John

I'd start dealing with that by replacing the power brick on the router and those motion sensor lamps with different brands.

JohnCT · #8 06-13-2020, 05:26 PM

Quote:

Originally Posted by Electronic M

I'd start dealing with that by replacing the power brick on the router and those motion sensor lamps with different brands.

The router has been replaced since, but I misspoke. It was the modem that was making most of the racket. It belongs to the cable company but there's no security screws, so I took it apart and changed the bridge bypass cap, and that took about half the noise from that contraption.

Yes, the motion sensor fixtures are a big contributor and I should replace those soon. I notice that when I pull into my driveway, the AM is fine until I pull up closer to the garage where the lights are, and the noise totally wipes out anything except the local station one town over.

My alarm system is also a significant noise maker. I was going to try putting some ferrite loops on the keypad wiring and see if that helps quiet the alarm system down.

It's always something I plan to tackle but somehow never get around to it!

John