PSA to Ham Radio Operators!!! Astron Power Supply Malfunction & How To Avoid It!
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- Опубликовано: 10 сен 2024
- Yesterday I had my Astron Power Supply malfunction from a dead short between some terminals on the bottom of the unit I had no idea about. Smoke started pouring out of the unit as the secondary winding on the transformer started burning. This is something that can be avoided if you know about it which I didn't and so that's why I made this video.
Again, I have nothing against Astron or their products. This is a simple issue that was also a result of user error. Their products are very good and will work for many years under normal usage conditions.
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Bought my rs-35a in 1994. Still have it. I looked under it. It has insulated caps on each post, from the factory. At some ppoint yours were removed.
Interesting! You're the first person to mention that. Mine was used so that makes sense.
I have a RS-35A, “35 watt” model (more like 24 or 25 watts continuous current capability). It has the same arrangement with contacts that are above ground exposed on the bottom. The insulating caps are completely logical but my RS-35A was purchased new-and never had them.
Great idea to warn us that a short could happen to us. Thanks.
You mean amps not watts.
That is an absolutely unacceptable design flaw and Astron shout be ashamed of themselves for ever allowing a single unit like this out of their factory.
Those diodes could have easily and inexpensively been mounted to a piece of metal inside the case with no short hazard being exposed.
Those "posts" are your full wave diode rectifier. The circuit card is your voltage regulator circuitry with a basic current limiting (built in to the 726 regulator chip) . Not all Astron supplies use stud mount diodes (you called posts) some use half of a high current bridge which is fully insulated. Rather than a ground braid shorting out the diode (which has the low voltage AC) I would more suspect it touching a rear mounted pass transistor. If you measure with a VOM/DVM from a transistor case to the cabinet you will notice those have the full unregulated DC voltage maybe as high as 30 VDC. Those should really be insulated even more so than the studs.
Those "posts" are actually the diodes that convert the AC to pulsating DC.
thank you for yor fairnes....here 7n Germany it would have big big conequences for the Manufaktureed company !
so again thank you for beeing like you be! stay this way and the world will be a better place :)
73!
My VS-35m was bought second owner like yours, but mine has plastic caps over them? I don't know if original or 1st owner installed?
Good job on the video. My 10amp Astron don't appear to have those lugs on the bottom, but I have a 50amp that may, but I'm not going to look right now as it has other things on top and heavy of course. But glad I'm now aware of this! Thanks.
Thanks! It was really scary when it started smoking. Never seen anything like it before. I hope this video prevents a possible fire for someone.
also the two diodes can be removed and placed on small aluminum heat sing with insulation and thermal grease that be much better I think
good safety tip. tnx
The older ones had those lugs. They're blocking diodes for rectificating the voltage. My 1988 Rs-20a has a bridge rectifier mounted to the heatsink, and no lugs. I'm guessing they did away with that somewhere in the 80s. I had a scrap 1981 RS-20a with blocking diode lugs that were mounted to the heatsink instead of a rectifier. I'm guessing it was mainly the 35s and bigger that had them back then.
Forgot this existed. I'm part of the Shamrock News now
There should be rubber feet on the bottom of the chassis, to raise from the surface and allow ventilation, are yours missing? But,yes a good idea to insulate those posts 👍
Yes, I had them removed to take off the cover to find out what happened. The cable was still able to touch those terminals with the feet installed .
Yikes, thanks for the heads up
I have the same PSU and cannot for the life of me figure out how to ground it. How do you ground this one? Is it the little lug on the right towards the rear on the underneath?
Those posts are the rectifier diodes and it should have a blue plastic cap from the factory to insulate and protect from shorts. I have exactly the same version of RS-35A. I wonder if It I still available from Astron.
Good heads up !
wonder why they didn't have a fuse on the secondary winding. it shouldn't be too hard to add an in-line fuse to the lugs
I powered mine up.. smoke.... mine looks a little different on bottom
My needles buried....humming.... smoking... I got this in a state auction
Id just get a bus bar(held by insulators) for the inside, n remove those lugs, mount to insulators for busbar, n wire it as ya need it
n can do something similar for the diodes, so no exposure, no chance of short,
It would seem to me before doing a video on what hazard you caused, you should educate yourself on the subject manner.
Posts???? you kidding..
Some say tomato...
Some say . . . . posts...
No feet on a power supply. First people it’s the users fault for using that unit with no feet. If he had feet on it no problems would have happened.
The feet were installed when the incident happened. If you would have paid attention to the video, the unit was disassembled. The feet need to be removed in order to disassemble the chassis.
This RS-35A power supply has the rubber feet as the screws for the cover unlike the newer versions.
Not sure why everyone in the US seems to love these PSUs. The build quality is terrible.
They work. They are serviceable. They are affordable. They don't often malfunction and eat a radio.
A friend's Power Worx switching supply just ate his FT-710 as he watched the output voltage go to 20V after a power company brief 'blink' outage ...
The power supply is missing it's rubber feet #1 ✔ #2 loose ground straps or any other bare metal objects shouldn't be underneath or inside touching the components ✔ Remember Safety First ✔
The power supply was missing the rubber feet because I had it disassembled for the video.
Protection circuits? Try regulator circuits. Guessing you don't know much about how power supplies work. Your a ham? Really? Sad!
Lol, I work in the telecom industry. There are protection circuits to protect against direct shorts on the DC output. I also know that there are regulator and rectification circuits but that's not what I was referring to. Sad you couldn't catch on.