Aldi £59 petrol generator and television

I repair hundreds of the things, and irrespective of the topology of any individual design, most work by the skin of their teeth. Left alone, in general, today's generation are fairly reliable, but in my experience, subject them to the slightest abuse, and they fail - often catastrophically

Arfa

Arfa Daily wrote

But clearly don't understand the basics with well designed switch mode power supplys.

That's just plain wrong.

Switch mode power supplys, particularly the ones designed to work on a voltage range of 80-260V don't, and they don't give a damn about the frequency of the mains from a generator, because they rectify the mains.

Oh, how silly of me not to know that ...

Where did I ever dispute that such designs don't care about frequency or input voltage ? I merely stated that if you abuse them, they have a predisposition towards catastrophic failure - and I base that on many years of repairing the things every week for a living. Even if they do have a PFC front end, that in itself is just another SMPS, and the control IC and switching FET are just as prone to failure as in any other design.

Arfa

Switchers fail gracefully. The output voltage goes to zero. Analog power supplies are not so graceful when they fail. The output usually goes to the maximum of whatever the unregulated part of the power supply will deliver, which destroys everything connected to it. I like switchers.

"Jeff Liebermann"

If that is on a 5V rail, it destroys most of the ICs.

Very few have a "crowbar" to stop it .

.... Phil

Arfa Daily wrote

But clearly can't work out for yourself that they will work fine on that generator.

And using one of those on that generator doesn't qualify.

But clearly can't work out for yourself that they will work fine on that generator.

Wrong when the only downside of that generator is that it may well not control the voltage and frequency of what it generates very accurately. The SMPS won't give a damn.

Jeff Liebermann wrote

Not always.

Yes.

Not necessarily.

Me too, particularly when used on that sort of cheap generator.

No.

Both of these are an extraordinarily rare ocurrence in the real world.

Gareth.

You don't know that. For all you know, the output might be covered in crap like ignition noise. In which case, a lot of switchers will fail sooner or later. I don't know what your background is - I've never seen you on S.E.R. before so I guess you're here as a result of the cross-posting. For all I know, you might be the best SMPS designer in the world, and your efforts might be bomb-proof. But for every one of you, there are a thousand Chinese sticking their s*it-street designs in everything from light bulbs to vacuum cleaners. I see this crap every day (as well as some good ones) and many of the designs do, as I said, work by the skin of their teeth. If you throw mains at them that's covered in spikes and other garbage, they *will* fail. It's not at all rare to see items such as TV sets that have been used on the end of cheap inverters and generators, with either blown power supplies, or corrupted EEPROMs.

I would also point out that many cheap Chinese designs without a PFC front end rated to 260 volts AC, have a single main filter cap rated at 400 v. Even with mains at the high end of 'normal', that doesn't allow a lot of overhead. If the output of this generator is poorly regulated, the input voltage to the power supply could easily take this cap close to its limits. In which case such a supply may well 'give a damn'.

So to the O.P., if you want to believe this guy and ignore Aldi's warning, go right ahead. You might get away with it if if the TV or whatever has one of Rod's designs of PSU in it. Otherwise you may well not ...

Arfa

Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:

in today's digital ATSC TV world(USA),reception may not be possible out in the boonies. better to buy a portable DVD player with LCD screen.

Not likely. See

Yeah sorta. I could probably contrive a design that would do that. However, I haven't seen any like that since the days of the original Compaq portable, which did have such a PS. I've seen a fair number of computah power supplies in the last 30+ years. Very few that I've seen fails to full output voltage.

However, there are exceptions:

I think this one failed to full output voltage. It was in a no name PC. No evidence of lighting or power mains problems. It simply blew up. Proof positive that it is possible to design a lousy switcher.

Yep. Oddly, I haven't seen many such motherboards with all the IC's blown. Plenty of other failure modes, but no volcanic eruptions in the middle of chips. That's what full power over-voltage does. It blows out a small piece of the epoxy-B package.

None of the schematics that I've seen have such a feature. Most of them rely on a "power good" circuit inside the regulator chip to provide the necessary protection. That's not as good as an external crowbar, but then, I don't think any PC power supply manufacturers are going to add 30Amp SCR's for protection.

ATX power supply specification.

See Section 3.4 for the multitude of output protection circuitry required. Output faults are suppose to shutdown and latch.

True, but nobody runs unregulated power supplies these days. By analog, I meant linear power supplies with analog (non-switching mode) regulators.

In ham radio, the RF noise produced by switchers makes weak signal work rather difficult. Most ham radio power supplies use fairly simple linear power supply designs. The leading company is Astron:

Schematics can be found at:

Note that *ALL* of the linear power supplies have an SCR crowbar across the output. The slightest hint of overvoltage, and it will shut down and latch the regulator. This is rather irritating when the power supply is located at a mountain top radio site. Various reset circuits have been contrived. For example:

I don't know which flavor will best survive a crappy generator. I've seen switchers run on a much wider range of voltages and fequencies than linear power supplies. However, during ham radio Field Day, it seems that the switchers are the ones that are most susceptible to protective shutdown from generator spikes and transcients. Most of the power supplies running during last months Field Day were linear, to keep the RFI down, except for the switchers used to charge the laptop batteries.

Repeating again, I don't see any evidence of an overvoltage problem in the multitude of switchers that cross my bench.

Of course. But I'm still right.

You're behind the times a little. These daze, campers have satellite receivers and dishes. OTA TV reception in the middle of nowhere tends to be lousy.

The main purpose of the generator is not to run the TV. It's to keep the 12V fridge alive. The generator usually has a 12v charger output, which keeps the battery up, which runs the 12v fridge. For those with really cheap generators, add an external battery charger. Few campers have 12v chargers for their laptops, so there's another reason to run the generator. Solar panels as chargers are also common, but are rarely large enough to replace a generator.

It's been a very long time since I've gone tent camping. When I last did that, we went past a "wilderness" trailer camp, which is distinguished from a regular trailer camp site by the lack of hookups. We could hear the multiple generators running for miles away. As we approached the trailer camp site, we could hear a cacophany of full blast television audio from some campers. We begged some supplies, loaded up with drinkable water, and got as far away from that nightmare as possible, which was not a trivial exercise in the dark.

Leave the generator and TV at home.

Or to Vin.

So do boost regulators, not that it's necessarily a bad thing.

I have no preference. There is rarely a choice (I guess if there is it's an automatic "choice" for the linear - so no real choice).

The last time I slept in a 'tent' was in the early '70s in Alaska. Cold weather survival training. You were issued a 'tent half' (basicly, a small canvas tarp) , sleeping bag & folding shovel. You had to find a suitable spot to anchor the 'tent half' where the wild wouldn't blow in the opening, then bury all butthe entrance in snow for insulation. The temperature was below -20F during the day, and we were there for three days. Have you ever built a fire with frozen wood, or cut down small, ice covered trees without an axe?

Camping these days for me is done in 2-3 star hotels (i.e. Motel 6). I can't afford 5 star.

I did something like that, except in the desert. I wasn't paying attention, forgot to do a few things, and ended up dehydrated, with a major sunburn, and infested with sand fleas.

Not frozen, but certainly wet wood. I've been heating my house during the winter with firewood for 39 years. At one point, I was cursed with some soaking wet green firewood. Even mixed with dry wood it didn't burn very well. It was better than freezing, so I eventually learned how to start a fire with the stuff with a propane torch. I also used an axe, hatchet, chain saw, bow saw, and table saw to prepare the logs and kindling.

I've converted small trees into kindling by driving over them with a bulldozer, but I suspect that's not what you were doing. How did you prepare firewood from iced over trees? Cable saw? Swiss army knife? Explosives? I would have just scrounged for dead fall branches on the ground and left the wet live trees alone.

Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:

yeah,I've seen RVs with satellite dishes...

will an 800 WATT generator keep a fridge going? an 800 watt generator might not run the TV and the satellite receiver[humor]....considering that 800 watts is maximum output(surge?),and you can realistically expect only 400 watts from it,continuous.

I agree that TV,stereo,etc,is inappropriate for camping. Camping is about ESCAPING all that stuff,enjoying nature,bugs and all. Laptops on a camping trip? sheesh,why not just pitch a tent in your backyard? then you can run an extension cord from your house to run all your stuff.

Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:

the TEK 1710,20,30 professional TV waveform monitors SMPS would commonly fail high,and burn a hole in the PCB under the HV OSC xstr in the process. they regulate off the +5,but the +5 main filter cap would go high in ESR,the PS would drive harder to keep up,the +40unreg for the HV osc would go to >60v,and the osc xstr would overdissipate and char the PCB. Eventually,the PS would go into current limit,or fail to start.the PCB was usually conductive under the osc xstr.

TEK had bunches of problems with caps in their TV products,I'd replace them by the handfuls. I finally got myself a Dick Smith ESR meter...on my own dime.

Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:

When I was a kid,I read an old Argosy magazine(outdoorsman stuff) about how the author would camp in wintertime in his shirtsleeves,no special cold weather gear. He'd make a bed out of pine branches stripped from trees and lay on that,it insulated him from the cold ground. So after Xmas,I got a couple of discarded Xmas trees,stripped them,made a bed several inches thick,and camped out in the backyard. It worked. All I had was a thin sleeping bag,and a canvas leanto for cover. Wasn't cold at all,despite a foot of snow in the yard.

BTW,pine cones light pretty easily,they're full of resins and turps,good for starting fires. They burn hot.