I recall from a while back (years) it used to be said that device that had been left unpowered for a long time needed to run a while to have the capacitors re-formed".
The explanation I recall was old electrolytics (stored uncharged) would exhibit low capacitance and high leakage until they had been provided a DC voltage across then for a while.
1) Is this true?
2) If so, and you have a device (Happened to be a 12Vdc to 120Vac inverter) that will not start after sitting for several years, is this likely the cause?
3) Since it shuts down, there is no easy way to let it build up some "re-forming" time. In this case is it best just to replace the capacitors with new parts?

A little background;
The inverter is dated 2003 and sat unused till about a year or so ago.
When first tried it would produce power (lit a 100W bulb) for a fraction of a second then shut off.
I tried several times.
It did not blow fuses, it does not get hot and it does not draw excessive current.
It went back on the shelf.
I now have another project for it.

Thoughts?

 

Harbor Freight has a 750 watt inverter for about $50 the schematic is posted in AAC.
Been using them for about 6 years now 12 hours a day.
No Problems except for me blowing them up doing dumb things with them.
The 2000w inverter $124,
$100 with 20% off will run a 6000 btu Air Conditioner, several been in use 6 years now.
https://forum.allaboutcircuits.com/threads/harbor-freight-inverter-schematic-diagrams.118260/

 

This is a nice industrial 1000 Watt inverter, so probably worth a little investment.
Guessing equivalent to a 1500 to 2000 watt unit from HF.

 

This is a nice industrial 1000 Watt inverter, so probably worth a little investment.
Guessing equivalent to a 1500 to 2000 watt unit from HF.

Make sure the battery is large enough to run a 100w bulb (12amps aprox.) most inverters turn off when the battery voltage drops below 10.7 volts to protect the battery from reverse charging a cell.
watch the voltage to the input of the inverter make sure its not going below that voltage.
if the wire your using to power the inverter is not large enough the voltage will drop below 10.7 also.

 

I monitored the input voltage. Used heavy short wire.
Tried it with no load and a small (100Watt load).
I got the same results. Assuming it was not DOA in the package, I am guessing it is related to the 10+ year shelf time and maybe bad capacitors from the early 2000's

 

So, I started replacing caps. It was a PITA, as the board was multilayer with very small plated through holes.
My solder-sucker would not get the holds open to easily insert the new caps.
I started on ones I though would be easy, and checked each one I pulled.
I put in new caps as I went and when I got to the first one that was bad, I checked the board for more of the same value (figuring they would be from the same batch) and replaced a second one.
By that point my patience was a bit worn, so I put carefully applied power and it worked.
I looked over the board to see if there was any capacitors that looked suspicious (Since it was a shelf failure, I did not expect, nor did I see any).
Not seeing any I put it back together and gave it a couple of hundred way test. All seem good!

 

My solder-sucker would not get the holds open

Buy a kit of stainless steel dental picks or use something else that solder won't stick to, like a sewing needle or a very tiny steel drill bit. Just poke. Do not make any attempt to drill out the hole!!!

 

Thanks for the memory jog!
It is amazing how much you forget when you haven't done something for about 20 years.
Now if I can just find my dental picks (As I am sure my son borrowed them in his model building days, and am just as sure they never made their way back to my tool box)