Fluke 179 won't tun on

[tibimakai]

Re: Fluke 179 won't tun on

You guys, are really awesome and I'm not.
I have some visitors(family) for a couple of weeks and I'm not able to work on this, the way I should.
Sorry about this.
I try to measure some voltages on the fly, when I have a couple of minutes.
I have other devices that require my attention, 55" Samsung LED TV, Kenwood DNN990HD nav unit, etc.

[tibimakai]

Re: Fluke 179 won't tun on

Measuring, from pin #98 to pin #100 or from pin #99 to pin #1 I'm getting 0V.

[tibimakai]

Re: Fluke 179 won't tun on

It seems like, none of the ICs getting anything. At the top half part, I don't see traces through the board, it's all black.

[tibimakai]

Re: Fluke 179 won't tun on

Found this trace, which to me it doesn't look good.
It seems like it's going to the negative of the battery.

[keeney123]

Re: Fluke 179 won't tun on

Found this trace, which to me it doesn't look good.
It seems like it's going to the negative of the battery.

You could ohm that trace to find out if it is good. I would stick with what retiredcaps suggested as he knows the sequence of how the meter's circuits function. So if that trace checks out you will want to find the LDO circuit. You would trace the 9 volt supply line until you come to some regulator that lowers the voltage to the 3.6 volts. I do not know if they would do this with a IC or discrete components or a combination of the two. What ever it appears to be, it will have the 9 volts that are input-ed into it. The idea is to lower the voltage and regulate it so when the battery starts to decrease it maintains the same 3.6 volts DC

[retiredcaps]

Re: Fluke 179 won't tun on

This is the best I can touch up of the picture for you retiredcaps.

Good effort, but this is what I expect. From the eevblog 179 teardown thread, this photo shows what is needed in terms of focus, clarity and readability. My only wish is that it is a bit higher resolution to make it easier to read some of the smaller print and that it is shot directly over top.

https://lh4.googleusercontent.com/-3...h572-no/15.JPG

Here I can clearly see that PCYI is a 5V LDO made by Texas Instruments. A few more searches, I found this application report entitled "Interfacing the 3-V MSP430 to 5-V Circuits". It gives a number of suggestions on how to convert 5V down to the 3V needed by the MSP430.

https://cdn.badcaps-static.com/pdfs/...26c30b52eb.pdf

Just to the left of PCYI pin 1, is a via hole. Just to the left of the PCYI pin 5 is another via hole. Assuming both are pins are connected to their respecitve via hole, if you turn the pcb around these vias will have tracks. Tracing these tracks will show where they go.

There are also 5 other major ICs on the same side as PCYI. Get the datasheet for each IC and check to see if VCC/VDD exists. Note the min and max for each IC wrt to VCC/VDD. Some might require 5V which is why the PCYI is used and not some other LDO that drops it directly to 3V? This will also help track down possible broken traces and vias. Continuity, with a reading of less than 1 ohm, is your friend when checking the vias and tracks.

As I mentioned there are at least 3 revisions of the 179 that I know of. The earliest ones didn't even use the MSP430!

[tibimakai]

Re: Fluke 179 won't tun on

That trace is broken. Via is filled with oxidation as well.

[keeney123]

Re: Fluke 179 won't tun on

Good effort, but this is what I expect. From the eevblog 179 teardown thread, this photo shows what is needed in terms of focus, clarity and readability. My only wish is that it is a bit higher resolution to make it easier to read some of the smaller print and that it is shot directly over top.

https://lh4.googleusercontent.com/-3...h572-no/15.JPG

So is that the IC in the Lower left corner?

[stj]

Re: Fluke 179 won't tun on

he ltpz is a regulator

[tibimakai]

Re: Fluke 179 won't tun on

That was made, with a USB microscope to show the broken trace inside the PCB.
The rest won't show, because if I look through the board is all black.
Only around the selector switch, is "see through".

[keeney123]

Re: Fluke 179 won't tun on

even If you used a high intensity light in the back and then you your USB microscope.