Fluke 187 teardown photos

[bigsky]

Hi,

I've just got myself a used 187. Nice meter (apart from the battery life). A few questions:

• The continuity bleeper is a pulsed tone - is that normal?
• Is there any way of displaying the number of calibrations it's had? (like you can on an 87V)
• Is there any way of displaying the firmware revision? (like you can on an 87V)
• The calibration manual references some service software - can this do anything interesting or useful?

Would people be interested in some internal pics? I can take a few more than free_electron did here: https://www.eevblog.com/forum/repair/fluke-189-teardown-repair/ (that's not a criticism)

Would people be interested in seeing it connected to my chinese voltage reference?

[retiredcaps]

1) Use Eneloops.
2) Yes, beeper is a pulsed tone and normal.
3) Calibration is closed case and I don't/haven't found a way to display the number of calibrations.
4) To see firmware, I think you need FlukeView Form??  I don't think there is any keypress to display firmware.
5) Pictures are always welcome.
6) Yes, show pics of the 187 with your Chinese voltage reference just like your 87V post.

[Muttley Snickers]

In addition to retiredcaps great advice,

I have both a 187 & 189 and never worried about firmware versions, the speculation about these chewing batteries in my case is a load of bullshit, turn it on, find the fault, turn it off. Others may need a meter running all day on the bench, I don't, for me they are or field service work.

You probably should check the current draw of the unit as other people did have issue's with the super cap.

Remove the batteries for long term storage.

Here are my values for reference:
Model                                    187             189
Power Off                            70.00ua       75.70ua
Power On Ohms Open         12.10ma      12.10ma
Back Light Low                   37.00ma      36.50ma
Back Light High                  73.50ma      71.00ma

Current draw tests were done with an Agilent U1272A

Fantastic meter, good choice, well done.

Muttley     

 

[Svuppe]

No need to check the current draw. The 187 doesn't have a supercap, only 189.
I've had my 187 for over a decade, and I've changed the batteries once or maybe twice in all that time.

[biot]

Some pictures of my 187 here: http://sigrok.org/wiki/Fluke_187/189

Got it cheap, but it was a little broken: the probe socket assembly (last picture in free_electron's teardown) is sort of badly designed, and a part had snapped off. Be gentle inserting probes, I guess.

[bigsky]

Here are some photos of my 187. The quality isn't wonderful as I only have an old Canon Powershot A560,  and took them using natural light.  If anyone needs more or better pics, let me know and I'll try to oblige.

I am not going to repeat much of what free_electron said here - https://www.eevblog.com/forum/repair/fluke-189-teardown-repair/ - so read this in conjunction that.

I hope the way I've done this is OK - it's my first - notes are under the pictures. I don't have the meter with me and have written the comments based on the pics, but hopefully I haven't missed anything.



PCB underside - this is what you see when you open the case. It's fixed to the front with two screws, one through the hole in the shielding cover, and the other to the left of the smaller fuse. The larger fuse has been replaced with an incorrect 15A one. Note the battery contact pads at top centre.



Close up of fuse contacts - the red dots are adhesive. Note the fuse sizes are copper tracks, as are other designations - no silkscreening on this PCB. The larger fuse is given as 10A on the PCB but elsewhere as 11A.



Under the cover is a custom chip for range switching, true-rms conversion, and ADC, plus the Analog Devices REF43 voltage reference. Note the guard tracks around the thick film voltage divider, also the way that the pins on the IC have been laid out in sequence - one of the benefits from designing your own ASICs.



Upper part of the underside. The square grey part with a corner cut off is the bleeper. Pads for calibration switch to the right of it. To the left is an unpopulated footprint for the supercap which is used for memory retention on the 189 - it's notorious for leaking. Backlight connector at bottom left. I'm not sure what the unpopulated DIL pads at bottom right are for - they're not populated in the 189. EDIT - the part above it is a 93C55 serial EEPROM (calibration constants?) - but as the empty pads are parallelled horizontally I'm don't think they're for this in an alternative package. Perhaps they're for a 2 x 4 surface mount header for ICSP, JTAG, or something similar (although I would have thought a pin or two more would be needed).



LT1307 DC-DC converter driving a transformer. It appears to generate three separate output rails based on the output diodes and caps. I think I read something saying that it can run the batteries down to above 1 volt each, which seems pretty good. The transformer is by Coiltronics, who appear now to be owned by Cooper Bussmann.



IR tx / rx on the top edge.



The CSB455J is a 455kHz ceramic resonator by Murata. Not sure what it's for - possibly the LCD - it seems to be connected to the LCD driver which is on the other side of the board. Note the red dots of adhesive, almost certainly applied with a syringe.

I think that's enough for one post. I'll do the other side of the PCB in another post.

[bigsky]

Next lot of pics:



Top side of the PCB with the LCD assembly removed. The input socket assembly is very similar to the 87V, despite the different case design.



LCD module underside showing zebra strips.



Top-notch input protection as expected.



10A current shunt and associated parts.



Thick-film voltage divider with guard tracks.



Top view showing guard tracks.



Main ICs. The left one is probably the processor - could it be an MSP430? Note the empty footprint above it, presumably for the memory chip on a 189. The right chip looks like an LCD driver. The 12.5MHz crystal between them is by Fox Electronics.

[bigsky]

Final lot of pictures for now. I'll take some ones with the voltage reference tomorrow.



Rev 007 PCB. Is Kalex3 the project or PCB codename?



Assembly rev 015 ?



Blast shields on case rear fitting into isolation slots on PCB.



Case front showing standard Fluke switch design. Note the screening and contact top centre. The slot between the switch and the buttons is where the voltage divider fits - a clever design touch.

[bigsky]

That's all for now. Fire away with your comments! I've appreciated the replies to my questions on the forum and wanted to contribute something back - I wasn't able to find any photos of the insides of a 187, and only a few of the 189, so I'm pleased to provide them. I'll take some more pics with the voltage reference tomorrow.

I am very impressed with the 187 - the construction is excellent (although I prefer a separate holster) and the accuracy, as you'll see, is superb. I wish Fluke would re-issue it using lower power parts.

[krivx]

Are the images not showing for everyone else?

[bigsky]

Are the images not showing for everyone else?

Sorry, it looks like I've messed up. The pics worked for me when I was logged in, but I logged out and they disappeared, even when I logged back in again. Is there any way of uploading images to the forum and them calling them up with an bbcode tag so I can put them in-line with the text?

[krivx]

I think you can just attach multiple images and they are shown at the bottom of the post? If you want to refer to them using bbcode I guess you could use an external free image host, Imgur.com maybe?

[SeanB]

Put as attachment to post ( or a few posts) then go back to the page and open it in another tab. Then edit it in that tab and use the image tag to drop in the URL ( weird one with the =image in it on each thumbnail) and save the lot again. then they all show up for all.

[bigsky]

Put as attachment to post ( or a few posts) then go back to the page and open it in another tab. Then edit it in that tab and use the image tag to drop in the URL ( weird one with the =image in it on each thumbnail) and save the lot again. then they all show up for all.

That's basically what I did - here's an example of the tags I used:

Code: [Select]

[img]https://www.eevblog.com/forum/testgear/fluke-187/?action=dlattach;attach=114562;image[/img]
I think I shouldn't have unticked the files in the attachment list after I added them as links - I reckon that deleted them off the server. I didn't want all the thumbnails at the end of each post, but if that's the only way of doing it, then so be it. Please let me know what I should do.

[SeanB]

Unticking does it, it removed the file off the server.  Use a Flickr account, upload the pics and then grab the BBcode for them to insert direct.

[bigsky]

Thanks, SeanB, I think I'll reupload them here and put up with the thumbnails - I see others have done the same. It means I don't have to worry about another account with an image host.

[bigsky]

I've redone the first lot of pictures - can someone confirm that they can see them, and then I'll redo the rest.

[krivx]

Looking good 

[bigsky]

OK, all sorted. If a moderator is reading this or someone can contact one, perhaps these last few posts about the broken images can be deleted as they don't really add anything to this thread.

[KGB]

• Is there any way of displaying the firmware revision? (like you can on an 87V)

Hi.

Have you tried this?:
Push down the RANGE button and simultaneously turn the meter on, (my 189 says 2.02).

And an interesting thing, animated display test:
Push down the HOLD and the BLUE button and simultaneously turn the meter on and wait a bit, must be hold down the buttons.

It may also work on the 187.

Cheers.

[retiredcaps]

Push down the RANGE button and simultaneously turn the meter on, (my 189 says 2.02).

I get 2.02 on my 187 as well. Thanks for sharing this tip.

[retiredcaps]

Remove the batteries for long term storage.

Yes, good advice.  My used 187 had corroded battery terminals from the previous owner due to leaking batteries.

PS. Don't forget you can set the backlight timer and autopower off via menu settings to extend battery life.

[retiredcaps]

Close up of fuse contacts

Excellent photos and thanks for doing it.

On the fuse photo above, it looks like there is some stray metal shavings from removing the fuse from the holder?  If yes, I suggest you clean them out otherwise there is a small risk of shorting things out if they move into the more dense SMD section?

Or is that dust?

[miguelvp]

Or grey beard dandruff

[Muttley Snickers]

Not sure what country he is in, But he might want to
check that shit out with a geiger counter.

 

Muttley