to the brain trust

[B52sRule]

I have a Parallax 7400 series, Model 7445 charger converter I pulled out
of my coach and use as a bench test unit.  It just stopped working, not
even the fan is turning.  I pulled the cover off expecting to fine
something burnt, fried, blown, smoking and again nothing.  The internal
fuse and bot external fuses are fine.

Any suggestions before I consign it to the recycle bin?

Thanks,

Len Novak

--
Len and Pat Novak 1978 GMC Kingsley The Beast II with dash lights that
work and labels you can see! Las Vegas, NV new email: B52srule
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/

 

[johnny]

Your friendly VOM is Your Friend. A/C at the transformer input? If not, trace back to theA/C input and find where it stops. A/C into the
transformer, A/C out? If not, toast. If so, trace the A/C output to the rectifiers, control sitcuit if any, etc. They're fairly simple.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell

 

[B52sRule]

Kinda figured that. Project for the weekend.

Thanks, Len Novak

On Thu, Apr 14, 2022 at 14:06 Johnny Bridges via Gmclist <

> Your friendly VOM is Your Friend. A/C at the transformer input? If not,
> trace back to theA/C input and find where it stops. A/C into the
> transformer, A/C out? If not, toast. If so, trace the A/C output to the
> rectifiers, control sitcuit if any, etc. They're fairly simple.
>
> --johnny
> --
> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> I forgive them all, save those who hurt the dogs. They must answer to me
> in hell
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--

*Len and Pat Novak*

*1978 GMC Kingsley*

*The Beast II with dash lights that work and labels you can see!*

*Las Vegas, NV* new email: B52sRule

http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

 

[RF_Burns]

A google search of the make/model number shows it to be a switching power-supply/charger. My 40yrs experience doing board level electronic repairs is
its not worth the time to repair a switching power supply.

Troubleshooting you will find the first faulty parts and replace them... then power up and then more smoke comes out! When you finally get it working
it will fail again a short time later. If you are in the business of repairing electronics, you will be married to this equipment for free repairs
forever!

Just replace it, move on and enjoy life!

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[B52sRule]

It is a bench unit, pulled out of my GMC years ago. I’ll play with it for
a bit as nothing was self evident, no smoke, smell, burnt anything,
discoloration, fuses….nothing. I’ll trace as far as I can and then find a
suitable replacement. My son has the old buzz box in his coach so there is
hope. Giant step backwards!

Len Novak

> A google search of the make/model number shows it to be a switching
> power-supply/charger. My 40yrs experience doing board level electronic
> repairs is
> its not worth the time to repair a switching power supply.
>
> Troubleshooting you will find the first faulty parts and replace them...
> then power up and then more smoke comes out! When you finally get it
> working
> it will fail again a short time later. If you are in the business of
> repairing electronics, you will be married to this equipment for free
> repairs
> forever!
>
> Just replace it, move on and enjoy life!
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--

*Len and Pat Novak*

*1978 GMC Kingsley*

*The Beast II with dash lights that work and labels you can see!*

*Las Vegas, NV* new email: B52sRule

http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

 

[B52sRule]

After playing with a VOM for a min or so....no ac power on one of the
input terminals. R&R, bit of dielectric grease......it works.........for
now.

Len Novak

> Your friendly VOM is Your Friend. A/C at the transformer input? If not, trace back to theA/C input and find where it stops. A/C into the
> transformer, A/C out? If not, toast. If so, trace the A/C output to the rectifiers, control sitcuit if any, etc. They're fairly simple.
>
> --johnny
--
Len and Pat Novak 1978 GMC Kingsley The Beast II with dash lights that
work and labels you can see! Las Vegas, NV new email: B52srule
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/

 

[johnny]

Cool. Being as it's a switcher according to someone above, no step down transformer.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell