Electronics > Repair

My first serious multimeter (Fluke true RMS) and I messed it up. Help

(1/3) > >>

highcap:
Hey friends, got this nice Fluke 8060A and I was eager to place a new battery and start using it.

Since the 9V battery connector was corroded along with the battery, it broke when I pulled it out, so I was left with the raw red and black wires.

Hold a 9V battery onto the wires just to see if it powers on, and it kind of did but very shortly and digits seemed to not be complete, then it faded out.

Since I didn't had a good grip on the the small wires onto the battery tips, I have mistakenly reversed the polarity and the battery started to heat.

Now the multimeter does not power up at all and kind of puts short on the battery (measured about 2,3 Ohm on the batt wires).

Did I messed it up completely or there's some hope in repairing it? I have attached some pictures.

Thank you everyone for any inputs!

stevopedia:
There's a good chance this is an easy repair! Do you have access to a soldering iron and another multimeter?

If you look on page 139 the manual PDF (https://assets.fluke.com/manuals/8060a___imeng0300.pdf) you'll see the schematic for the main board of the meter. The part we're interested in, the power switch and such, is tucked away in the bottom-left corner. VR3 is a 12 V Zener meant to protect the meter from reverse voltage such as accidentally reversing the battery. In this case VR3 probably failed short, which means it did its job perfectly!

Turn on the 8060's power switch, and then with the other multimeter measure the resistance across the battery wires in both directions. If VR3 failed short, you should see a very low resistance in both directions. Page 135 of the PDF shows where VR3 is on the board: placed vertically and tucked under the display, right next to the battery eliminator jack. If you cut or unsolder the wire coming out of VR3 and the short on the battery input goes away, then you've found the cause. Remove the original VR3 from the board and replace it with a new 12 V Zener diode to restore the 8060's reverse polarity protection. The meter will work without VR3, but if you accidentally reverse the battery again and VR3 is missing you will cause irreparable damage to the meter.

coromonadalix:
yep  vr3  could have shorted out to protect the main section

highcap:
Thank you that's great news!

I will first replace that diode before doing anything else, considering how I messed up with the polarity.

I will post an update as soon as I have it solved.

Best.

lowimpedance:
 And while your in there, check the miniature electrolytic caps for electrolyte leakage as this will damage the PCB.
Its a common issue with these vintage meters, search the forum for details of 'others' repairs and possible suggested replacement parts.
I would actually change them anyway as a preventative measure.

Navigation

[0] Message Index

[#] Next page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod