MFJ-886 Frequency Counter - Burnt Resistor

spongella

SatelliteGuys Pro

Original poster

May 12, 2012

1,625

1,236

Central NJ

• Sep 23, 2015

• #1

Need some help from anyone owning an MJF-886 frequency counter. I inadvertantly burnt one of the resistors (located at the bottom of the PCB) when I bought a replacement battery. The new battery had the wrong polarity on the plug it seems. Below is a picture of the burnt resistor, and if anyone can send a pic of theirs, or let me know the colors of the resistor rings that would be nice. Unfortunately MFJ does not include the schematic with their manual. Thanks.

 

M

Magic Static

SatelliteGuys Master

Lifetime Supporter

Oct 12, 2010

7,498

4,853

Montana

• Sep 23, 2015

• #2

The blackened color of the burnt resistor may not go "to the bone". Take a razor blade/xacto and scrape across the blackened part and you may reveal the true colors of the bands at the edges of your scraping. Magnifying glass needed here.

 

• 

Reactions: spongella and KE4EST

KE4EST

SatelliteGuys Is My Second Home

Staff member

HERE TO HELP YOU!

Lifetime Supporter

Aug 9, 2004

26,903

7,264

EM75xb

• Sep 23, 2015

• #3

Also, you have to remove it to replace anyway, sometimes on parts are burnt. You may be able to look at the back and get something off of it.
This with what Magic Static said about a razor you may be able to recover it.

 

• 

Reactions: spongella

jayn_j

Press On Regardless

Supporting Founder

Sep 29, 2003

10,990

3,995

Sheboygan, WI

• Sep 23, 2015

• #4

Why not call and ask tech support?
Technical Support
662-323-0549

Is the counter less than 12 months old?
http://www.mfjenterprises.com/warranty.php

 

• 

Reactions: spongella

spongella

SatelliteGuys Pro

Original poster

May 12, 2012

1,625

1,236

Central NJ

• Sep 23, 2015

• #5

Thanks for all the suggestions guys. Will try all of them.

 

spongella

SatelliteGuys Pro

Original poster

May 12, 2012

1,625

1,236

Central NJ

• Sep 24, 2015

• #6

Removed the resistor, burnt to a crisp, checked it on an Ohmmeter, open circuit. Tried the scraping technique, the thing just broke with slight stress. I like that idea though. Waiting for MFJ to get back to me. Thanks guys.

 

waylew

SatelliteGuys Pro

Aug 23, 2010

2,911

1,213

northern WEST new york

• Sep 24, 2015

• #7

Metal film resisters,when they fry,THEY FRY

 

spongella

SatelliteGuys Pro

Original poster

May 12, 2012

1,625

1,236

Central NJ

• Nov 3, 2015

• #8

Update if anyone can use this info for future use - the resistor is a 56 Ohm, got that info from a ham who was kind enough to open his counter up.

After a few emails and a phone call to MFJ, they said to mail it in for repair. I just substituted a 50 Ohm and the counter works great. Thanks for the suggestions.

 

• 

Reactions: Titanium