Fluke 187, 189 or 87 IV schematic

[Jay_Diddy_B]

Hi,

I have a broken Fluke 187 DMM. It looks pretty badly broken. The 100 Ohm resistor and one of the PTCs is badly burned.

Does anybody have the schematic?

Many thanks !!

Jay_Diddy_B

[retiredcaps]

There are no public schematics of the 187 that I know of.

The PTC is likely 1k ohm 1000V.  I believe the YS4020 is the correct part, but availability is another question.

I am willing to make suggestions on how to repair this, but you will have to be more specific what is working and not and upload some pictures so we can see the damage.

For the testing purposes, you can remove the PTC and put in a 1k ohm resistor.

[miguelvp]

Does their lifetime warranty cover this? and if not how expensive is to get them to repair it/exchange the board, is it a flat fee?

[nukie]

Lifetime means 7 years after Fluke discontinued manufacturing the product.

[Wytnucls]

Is it this one? 

[Muttley Snickers]

You could at least warn people in advance before posting such disturbing images, I cant even finish my dinner after seeing this, just horrendous, expect I will need therapy.

Any idea on how this happened Wytnucls.


Muttley

[Wytnucls]

Sorry to spoil your 'roo burger. Couldn't tell you, posted on Chinese site. No worries, she'll come right.

[tautech]

You'd have wanted to have been holding it in you left hand, I'd say.
Set on DCV, it must have been a good big transient, 187 would be rated to 1 KV DC wouldn't it. 

[saturation]

WHOA. Fluke may honor the lifetime warranty if you provide a survival story, it makes good PR.

Appears to be the source, not much data:

http://www.hkepc.com/forum/viewthread.php?tid=1466954&rpid=23176415&ordertype=0&page=1#pid23176415

Is it this one? 

[Jay_Diddy_B]

Hi Group,

My unit is not as badly damaged as the one shown by Wytnucls  This one will probably appear on eBay with 'Removed from working environment - unable to test'

This is the input section of mine:



There is obvious damage to the 1k flameproof resistor and the PTC.

Here is a picture of my other 187:



This what it should look like.


I found that the meter was drawing excessive current from the battery, around 400mA from 6V supply. I found that an IC was getting hot. I removed the IC in this picture:



Here is a picture of my good unit:



The IC is marked PCP1.
It is a 5 pin SOT23 package.

The pins are connected

1 - Input

2 - GND

3 - GND

4 - ADJ it is connected to a voltage divider, measures 1.3V on my good unit

5 - Output, Measures 5.2V on my good unit.


I have been unable to decode the marking PCP1.

With this chip removed I do get some sensible indications on the LCD. The display reads 0.00 but indicates ac, dc etc. when the range switch is rotated.


Regards,

Jay_Diddy_B

[retiredcaps]

The 1K resistor might a fusible resistor as per modemhead's blog. 

http://mrmodemhead.com/blog/fluke-87-fusible-resistor/

I have a few of those NTE F2W210 if you need one.

Almost all the current Fluke handheld models use the same green colored fusible resistor.

Since you have obvious input protection damage, I suggest checking the MOVs. They should read open circuit (0L) when measured in circuit with the other 187.  If they read anything but 0L, desolder them to verify.

Right now, I can't find anything to identify PCP1. My best guess right now based on your pinout description is some sort of adjustable voltage regulator?  If the 8 pin IC below the PCP1 in your last photo is a LMC60??, then perhaps the LMC60 datasheet might give more clues or we might find a Fluke instrument that uses the LMC60 that has a schematic?

I'll try to search a bit more later tonight on what PCP1 might be.

[retiredcaps]

I forgot to ask for a high resolution photo (2k+ if possible) of that PCP1 IC and its surrounding components.

[EVS]

Hi Jay_Diddy_B.
Maybe it's mark PCPI = TPS77001 (50-mA Adjustable Low-Dropout Regulator) ?

[retiredcaps]

Hi Jay_Diddy_B.
Maybe it's mark PCPI = TPS77001 (50-mA Adjustable Low-Dropout Regulator) ?

I see this is your first post and I think you have a winner on the identification.   

Good job and welcome.

http://www.ti.com/lit/ds/symlink/tps770.pdf

[Jay_Diddy_B]

Hi group,

Hi Jay_Diddy_B.
Maybe it's mark PCPI = TPS77001 (50-mA Adjustable Low-Dropout Regulator) ?

EVS,

I think you have the right part. Thank you very much !! And welcome to the forum.




I did some more checking on the circuit board. I found the protection transistors on the input to the main chip were damaged. I removed the transistors.

I am pretty sure that the main chip which is marked with Fluke part number 669918 is damaged.

This unit may become a 'parts unit'


Regards,

Jay_Diddy_B

[retiredcaps]

I did some more checking on the circuit board. I found the protection transistors on the input to the main chip were damaged. I removed the transistors.

I am pretty sure that the main chip which is marked with Fluke part number 669918 is damaged.

For my education, what protection transistors are you referring to?

And yes, if the main chip is damaged, there are no replaceable parts from Fluke.

[johnyaya]

Does anybody know the replacement part number for the ceramic chip capacitor
that is connected to the Big green 100k Ohm resisters?  One is positioned vertical and one is horizonal.

Thanks

[retiredcaps]

Does anybody know the replacement part number for the ceramic chip capacitor
that is connected to the Big green 100k Ohm resisters?  One is positioned vertical and one is horizonal.

Silly question, what is exactly wrong with your meter to suspect those two chips?  Does it turn on?  Does it measure DCV and ohms correctly?

[johnyaya]

It’s not at all a silly question. Usually a ceramic capacitor the looks as nice in the photo I posted wouldn’t be suspect. I was at work, so I used someone else’s photo.  See my new upload. My meter is a 89 iv it use to work before I forgot to remove it from the bench when I fired up my full wave Cockroft-Walton generator. I have only completed five stages, so it only puts out approximately 135,000 vdc right now. I don’t think the meter took a full hit but it stays all zeros with the leads shorted or when testing volts. I haven’t tried amps yet but I know the 1ohm fuseable resister is bad. The YS4020 ohms out ok though. Any more part or troubleshooting info would be greatly appreciated.

[retiredcaps]

I don’t think the meter took a full hit but it stays all zeros with the leads shorted or when testing volts. I haven’t tried amps yet but I know the 1ohm fuseable resister is bad. The YS4020 ohms out ok though.

My suggestions.

1. I think you mean 1k ohm fusible restor, not 1 ohm.  For testing purposes only, you can put in a 1k ohm resistor.

2. The YS4020 is a PTC and should be around 1.1k ohm.  I don't think Fluke uses that part in the original meter, but it's something I found when looking for a replacement.

3. Does the ceramic capacitor have continuity to both sides of the pad?  If you measure the good one, does the capacitance match the bad one?

If not and the capacitor is bad, maybe put in a random smd capacitor that is approximately the same size for test purposes.

4. After #1 and #3, see if meter measures a 1.5 AA cell.

[johnyaya]

She's a goner.

Thanks for your help.

[lowimpedance]

  That's pretty conclusive evidence, my condolences.

[Muttley Snickers]

Tis but a scratch 

A member is asking for a broken 189 in the Buy/ Sell/ Wanted section but they didn't specify which parts they were after so it could still be worth something, might be worth asking anyway.

https://www.eevblog.com/forum/buysellwanted/wanted-non-working-fluke-189/

[coromonadalix]

sad to see it busted,  the fluke asic  is unobtanium

[joeqsmith]

...
My meter is a 89 iv it use to work before I forgot to remove it from the bench when I fired up my full wave Cockroft-Walton generator. I have only completed five stages, so it only puts out approximately 135,000 vdc right now. I don’t think the meter took a full hit but it stays all zeros with the leads shorted or when testing volts.
...

Classic!!   From your pictures of the damage, I would like to see a few pictures of your generator that did it in. 

I've been looking for a good case and the switch contacts.  Put it up on eBay, someone will want it.