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All American Five radio receivers

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Re: All American Five radio receivers

#41

Post by gumboza »

buescher wrote: post #23

The hot chassis design is mind-blowingly dangerous by contemporary standards. These things weren't designed to modern creepage distances either. I would worry about creepage to controls on these things. THe article mentions screws potentially being hot as well as other shock hazards finger-accessible through vent hols so no joke be careful to unplug a radio before moving it or otherwise handling it in a way beyond tu…

Yes they are terrible. Should be consigned to museums and never celebrated.

My grandmother had a tube TV with a hot chassis. The Bakelite controls were on chassis connected metal shafts. The only protection you had from being killed was beeswax you had to rely on the TV repair guy to apply to the grub screw holes on the shafts.

Re: All American Five radio receivers

#42

Post by gumboza »

Aloha wrote: post #40
gumboza wrote: post #32

Earlier quoted context omitted.

Famous last words. Leave that scope probe ground clipped on something and every earth is floating live on your bench. Source: ex EE.

And at 110v, thats a risk I'm willing to take. I wanna note, I worked as an FSE for a telecom, I've been 'bit' more than once by 130v, and by 160v B+ in shit, the sparks from crossed neutral are fine. Anyone who is deeply concerned can buy an isolation transformer.

110v can fuck you up. Don’t take your own advice please. At least no one else should. Isolation transformer will only stop you getting killed one of three ways.

Worth backing my experience up as well. Ex EE covering RF and power in defence sector.

There is no room for arrogance or assumptions in dealing with safety.

Re: All American Five radio receivers

#43

Post by gumboza »

dekhn wrote: post #16
123pie123 wrote: post #12

Earlier quoted context omitted.

"but quite safe unplugged" a CRT monitor is typically (I would not gamble on it - again!) not safe when unplugged

yes, you two are in agreement. it's the radio receiver that's safe when unplugged.

Not necessarily. The main filter caps can retain a high voltage depending on how it’s wired and if the designers installed a bleeder resistor and if the production guys didn’t remove it to save a few cents.

Re: All American Five radio receivers

#44

Post by 1970-01-01 »

pyinstallwoes wrote: post #6
floren wrote: post #3

Earlier quoted context omitted.

Dangerous to poke around inside when plugged in, but quite safe unplugged (unlike say an old TV).

Why is an old tv unsafe?

CRTs hold a deadly charge for minutes to hours after being unplugged. CRTs can also emit x-rays if you bypass safety circuits. And touching a live flyback would be shaking hands with death. They were also manufactured before RoHS, so don't lick the PCBs or throw them in the ocean. Other than that, they're perfectly safe.

Re: All American Five radio receivers

#45

Post by daedrdev »

123pie123 wrote: post #8
floren wrote: post #3

Earlier quoted context omitted.

Dangerous to poke around inside when plugged in, but quite safe unplugged (unlike say an old TV).

DO NOT ASSUME a CRT MONITOR or 'old' TV IS SAFE to poke around when unplugged!!!!!! https://www.instructables.com/How-to-take-apart-TV/

Thanks, I did not know they were still dangerous when unplugged, but it kind of makes sense that they act as some kind of capacitor.

Re: All American Five radio receivers

#46

Post by RjQoLCOSwiIKfpm »

gumboza wrote: post #37
jhallenworld wrote: post #22

Earlier quoted context omitted.

Yeah, they are dangerous, but their safety can be improved: add polarized cord (probably have to move the power switch to the hot side for this) and replace the chassis ground capacitor. Table top FM radios and TVs also tend to be hot chassis.. (that mains transformer is just too expensive). Even today you can find capacitor dropper powered devices which are hot. AA5s are nice in that you can almost always get them t…

Polarised cord only works if your house sockets are wired correctly which is not necessarily the case and your earth bond might not be as good as you think it is. Always assume that the lowest competence is applied when it comes to safety evaluation. At this point I wouldn’t run one of these things at all. If you drop dead you have no idea if some relative is going to plug it in and kill themselves with it. They were…

Please do not willy-nilly dispose of beautiful pieces of interior design which likely won't ever be produced again with similar aesthetics. [1]

People constantly throwing away cultural heritage without any second thoughts is the reason why we barely have any left from only even more than 100 or 200 years ago - thousands of years of furniture, decoration, etc. are gone.

If you don't want them to be dangerous, make them safe.

If thats too complex for you, remove the cable and clearly label the backside with "DANGER! [...]" to explain that this shouldn't be used as is, and ideally put a letter inside which explains the technical details.

[1] Yes, I know there are things which are newly produced to "look" old. But they only do to people who aren't into that taste. If you are, all of the modern reproductions look like cheap, insufferable garbage.

Re: All American Five radio receivers

#47

Post by mikewarot »

buescher wrote: post #23

The hot chassis design is mind-blowingly dangerous by contemporary standards. These things weren't designed to modern creepage distances either. I would worry about creepage to controls on these things. THe article mentions screws potentially being hot as well as other shock hazards finger-accessible through vent hols so no joke be careful to unplug a radio before moving it or otherwise handling it in a way beyond tu…

I avoid anything over 12 volts or 15 amps, but I wouldn't call this mind-blowingly dangerous.

Working on Kilowatt amplifiers with 3KV at 1 amp ready to burn you to a crisp, that's dangerous.

In Europe, with 220+ volt lines, I'd have a different opinion.

Re: All American Five radio receivers

#48

Post by wglb »

mikewarot wrote: post #47
buescher wrote: post #23

The hot chassis design is mind-blowingly dangerous by contemporary standards. These things weren't designed to modern creepage distances either. I would worry about creepage to controls on these things. THe article mentions screws potentially being hot as well as other shock hazards finger-accessible through vent hols so no joke be careful to unplug a radio before moving it or otherwise handling it in a way beyond tu…

I avoid anything over 12 volts or 15 amps, but I wouldn't call this mind-blowingly dangerous. Working on Kilowatt amplifiers with 3KV at 1 amp ready to burn you to a crisp, that's dangerous. In Europe, with 220+ volt lines, I'd have a different opinion.

110 is seriously dangerous enough.

Re: All American Five radio receivers

#49

Post by agiacalone »

I had one of these when I was a teen! Granted, it wasn't originally mine, but I found it in my grandfather's shed in the early 1990's and I kept it on my nightstand for years. It worked too (I might have replaced the vacuum tubes originally...I don't remember now) and the thing got uncomfortably hot.

It had an "alarm clock" feature which would turn on the radio at the time the connection for the alarm would happen. But I was always too nervous to use it because I was afraid the house would burn down if I left it unattended.

Edit: Also, I don't know if it was the tubes or the internal speaker, but the damn thing was LOUD.

https://www.radiomuseum.org/r/motorola_56ce1_56_ce_1_chhs_49...

Re: All American Five radio receivers

#50

Post by 13of40 »

neilv wrote: post #34

Even when the local department store was selling home computers based on microprocessors, they still devoted a chunk of retail floor space to a self-service vacuum tube tester. https://www.ebay.com/itm/195497221166 https://www.ebay.com/itm/324762243586 https://www.ebay.com/itm/403979880899 I wonder when these finally disppeared from stores, and what the market is like for vacuum tubes for antique TVs and radios?

I remember them, and it would have been the late 80s or early 90s. I had to ask my dad what it was, but I remember thinking maybe I would need to use that service someday.

If you want to go down a rabbit hole, here's a classic video where a guy makes a brand new tube by hand: https://youtu.be/EzyXMEpq4qw

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