G203V's and blown(?) power supply

[jhowelb]

So the gremlins are testing my sanity. My system has been up and running for some time now, happily turning out my projects.

Now today when I power up there is no response from the steppers. Closer inspection shows the BOB getting it's 5 volts from the little wall wart connected to the same AC source but the lights are out on the G203V's.

My multimeter shows 1 volt dc where there should be 40. I can't buy that so I switched to AC on the multimeter and find that it is indicating 86 volts on the down stream side of the rectifier.

The only smoke is coming from my ears! Has the rectifier dumped? More importantly, what has happened to my Geckos?

[Al_The_Man]

I would remove all load from the DC supply, leave the cap in place, and check the DC again.
If you get voltage on the AC side and no DC then it virtually points to the rectifiers or bridge.
BTW, 86VAC will give you 120v DC, is this what you need?
Also, a quirk of the Fluke meters is that before you get a low battery alarm, the AC voltage reads about x2 that it should.
Al.

[jhowelb]

Not a chance that I'm trying to put that much juice into a Gecko! There has always been about 40 vdc at the cap. That's where I'm getting 86 vac! (unless my meter has ALSO gone nuts!)

[Crevice Reamer]

Easy enough to check the meter--stick the leads into your AC socket and see if it reads normal AC Voltage. Geckos should be fine--Worst case blown internal fuse.

CR.

[jhowelb]

I may have uncovered a part of the problem. A wire terminal, one of those that you crimp in place, released the positive wire at the point of connection with the cap.

After the system bleeds down I will reconnect and remeasure everything.

(GRRRR......)

(Meter reads 119 vac at input to the xformer)

[Crevice Reamer]

Originally Posted by jhowelb I may have uncovered a part of the problem. A wire terminal, one of those that you crimp in place, released the positive wire at the point of connection with the cap. After the system bleeds down I will reconnect and remeasure everything. (GRRRR......) (Meter reads 119 vac at input to the xformer)

Sounds like you know what it feels like to handle a live cap!

You may have found entire problem. I hope so!

CR.

[jhowelb]

LOL, I have NO desire to experience an instantaneous discharge! (Especially into one of my digits!)

For any newbies reading, please pay attention !! A live (charged) capacitor will zap you like a lightening stroke!

[Al_The_Man]

Originally Posted by jhowelb I may have uncovered a part of the problem. A wire terminal, one of those that you crimp in place, released the positive wire at the point of connection with the cap.

I found out a long time ago that the ordinary single lever hand crimper was very unreliable after experiencing many bad connections, I now use the pre-tension type, these automatically amplify the normal single leverage type and only release when the correct compression is met.
Al.

[jhowelb]

At about the time that I think I'm really getting the "hang" of the electronics end the gremlins throw me another curve ball. Actually, this one is a screwball!

Al, thanks to your suggestion about removing the load I found the errant terminal. Else I'd still be pulling my hair out by the handful. (Don't HAVE that much!)

The little Geckos are happy, I can see their little green eyes shining back at me. (Best investment I ever made!) The meter shows me 42 vdc at the cap but still insists that there is a presence of 86 vac!

So I've lost a day of production (I'm retired!) and sprouted several dozen gray hair while learning a hard won lesson about connectors.

All is well that ends well.

Thanks for the response, guys and a big kiss to Mariss for the G203V!

[Crevice Reamer]

Glad to hear all is well! Tomorrow starts a fresh new day!

CR.

[Al_The_Man]

Originally Posted by jhowelb The meter shows me 42 vdc at the cap but still insists that there is a presence of 86 vac!

Its not unusual to find that Electronic Multimeters give strange results when used on the wrong Range Setting.
On AC, your meter is looking for and AC signal, pure DC confuses it.
Al.

[acondit]

Originally Posted by jhowelb LOL, I have NO desire to experience an instantaneous discharge! (Especially into one of my digits!) For any newbies reading, please pay attention !! A live (charged) capacitor will zap you like a lightening stroke!

Many years ago I was playing with an electronic flash for my camera. I had something like a jewelers screwdriver and I shorted (accidentally) across the leads of the flash capacitor and it ate the shank on my screwdriver.

So yes, do not touch live caps.

Alan