Fluke 179 Broken On Fused Positive Test Leads

[jerdobi]

I fried my Fluke 179 by attaching to a power source that blew the fuses.   .  After replacing fuses the 400Ma and 10A  side shows an open circuit with COM although the V (red) lead will work COM lead.  Even with replacing the fuses it will not work so something on the fused side of the circuit is fried past the fuses.  So, I'm going to start researching the DF06S I see just down stream from the fuses, etc..   That said, I'm sure some experts know what may have failed and can give me a recommendation?

[retiredcaps]

I'm confused with your description.  Let's start with the following.

Q1. What were you measuring that blew BOTH the 400mA and 10A fuse?  What did you have rotary switch set on?

Q2. Does measuring a 1.5 AA cell work?  Do you get 1.5V DC?

Q3. Does measuring a 1k ohm resistor work?  Do you get 1k?

Q4. If you measure low level DC mA current, like a flashlight, does it work?

Your picture is too small for us to see any details.

[jerdobi]

Sorry about picture.  It shows no damaged or burned components.  I was measuring parasite drain on a 12v car battery and shorted it across both pos and neg on the battery.  Seems working fine on unfused but not on fused side.  I checked the rectifier DF06S and it checked out.

[retiredcaps]

Is the big 1 ohm Dale resistor open?

[retiredcaps]

Is R10 smd resistor, marked 1004, (1M ohm) on the pcb open?  R10 is by U1. See attached pic, circled in red.  Pic from

https://www.eevblog.com/forum/testgear/fluke-77iv-and-179-differences-with-teardown-photos/

Any burn marks underneath the white plastic rotary shield?

[jerdobi]

Doesn't show open nor any burnt components or traces seen on board.  Interesting that unfused works with in my testing with diode test and ohm testing.  Just the fused side is dead.

[AG6QR]

Are you absolutely sure that the replacement fuses are good?  Have you tested them with another meter?  If you don't have another meter, can you take them out and test them each with the Fluke 179 in ohms mode?


When you put the meter in the ohms mode, and connect a probe directly from the red V+ socket to the 400mA current socket, what does the display read?  How about when you connect the probe directly from the red V+ socket to the 10A current socket?  (If the meter and fuses are good, readings in the neighborhood of 1.8 ohm for the 400mA socket and 0.1 ohm for the 10A socket are typical.)

[jerdobi]

Fuses check out and your guidance checks out.  Fuses are good and I have another Radio Shack multimeter.