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Electronics => Repair => Topic started by: Johnny10 on August 10, 2018, 07:13:01 pm

Title: Snap-On Verus EEMS325 Blown Charger Input
Post by: Johnny10 on August 10, 2018, 07:13:01 pm
I did something really stupid today.
While repairing my Newmar Smart Battery Charger SMPS
I inadvertently connected my Verus oscilloscope to the SMPS with the charger connected.

I imagine I created a short to ground while doing this and after a loud bang.

And terrible smells I opened the unit to find a number of blown components.
Seems I even got the HD cable during the explosion, it passed over those two SMD parts.

What I need to know is... what are the blown components?
I can read the ON BG5100

But the 3 legged SMD parts with blown legs and pads??

I doubt if I can get any info from Snap-On.

The unit still powers on with battery and OS starts but I can no longer access the Verus software.

I have a feeling this is only the start of my problems with this device but hey !!!






Title: Re: Snap-On Verus EEMS325 Blown Charger Input
Post by: Johnny10 on August 10, 2018, 07:31:11 pm
Board 4 Channel Oscilloscope, Graphing Multimeter
Title: Re: Snap-On Verus EEMS325 Blown Charger Input
Post by: Johnny10 on August 11, 2018, 02:53:22 pm
So I think in the lower section.

Schottky Power Rectifier

And Varister
Title: Re: Snap-On Verus EEMS325 Blown Charger Input
Post by: Johnny10 on August 12, 2018, 01:40:35 am
Last two items are BAS40-4 Shottky Diodes 40V
Luckily, I found a youtube poster that was upgrading the OS, memory and HD on his unit and I asked if he could send pics of the board.
After seeing the numbers that were blown off my unit.

I can place an order tomorrow.

The adventure continues...



Title: Re: Snap-On Verus EEMS325 Blown Charger Input
Post by: Johnny10 on August 16, 2018, 12:04:19 am
Received all my diodes and also a TVS today.

After replacing the parts the charging circuit is working!
XP is working, oscilloscope working. Software all functional.
Charged battery completely, reset time (Got that call Customer Support Dialog box) and everything working again.

Thanks for the help  (I understand very few are having experience with these units)

Actually, I fix Tektronix scopes from the 60-90's as a hobby.
But I almost always have schematics.

This unit uses all SMD parts (those SOT-23)  WOW!! are they small, all soldering done through microscope on those blown diodes.
Title: Re: Snap-On Verus EEMS325 Blown Charger Input
Post by: Zucca on August 16, 2018, 07:42:00 am
Congrats,

if you want in the future to dance with SMD components you need hot air music.
Title: Re: Snap-On Verus EEMS325 Blown Charger Input
Post by: Johnny10 on August 16, 2018, 12:23:24 pm
I bought a Zephrytronics hot air station a while back but to tell you the truth I have never learned to use it.
Every time I practice on a board I end up burning the PCB !
Need more practice and better technique.

After working on this board  I realize you must use flux and add more solder to desolder parts.
That lead free solder is impossible to reflow !

The other day I picked up 3 Pace Sensa-therm handles: hot air tool, tweezers, and sx-70 desoldering handle.
Now I need to find a station for reasonable money.

Then last week I put together a Metcal DS-1, MX500, desoldering set-up to work on the double sided NewMar charging board.
Using the chemtronics braid was not getting all the solder in the through hole shafts.

My main tool is JBC ADC 4200 with various chisel tips.