fluke 179 need help identifying part

[Nightryder13]

hello all, well I messed up and sent over 1kV through the meter and now all the readings are messed up.    I get 5k Ohms with nothing connected to it and only 60v when I should be getting 120v. After opening up the meter and testing it I am pretty sure that the parts that are messed up are the red components pictured. The numbers on them are 1399 and underneath that 01/52. I tried to cross reference them but came up with nothing and even went to a local supply place and they couldn't cross reference it either. Two people mentioned them possibly being a tantalum capacitor and it appears to be made by littelfuse but that's as far as we got.  I was hoping that someone here would have knowledge of what they are and most importantly where I can get a hold of some replacements. Any help would be appreciated.

[ataradov]

They are Metal-Oxide Varistors (MOVs). And the logo indeed looks like Littelfuse. But I can't identify exact part number.

01/52 would be a date of manufacture - the last week of 2001, so the part is quite old.

[retiredcaps]

Those MOVs should measure infinite resistance using another working meter.  You can measure them in circuit first.  If they don't measure infinite resistance, desolder them to verify.

The meter will work without the 3 MOVs, but you will have no input protection.  If the meter works accurately and correctly without the MOVs, then you can go searching for the replacements.

Report your findings and we can suggest replacements.

You might also want to measure the PTC.  It should be around 1.0 or 1.1k ohms.

[Nightryder13]

So after removing the 3 MOV's and testing them 2 of them are indeed bad. I wasn't aware that the meter would work without them and I wouldn't want to use it that way but it's fine for testing. I tested voltage and ohms and it appears to be working exactly like it should.   So now the process of finding appropriate replacements. If you or anyone else knows where to get them please point me in the right direction.

[ataradov]

So after removing the 3 MOV's and testing them 2 of them are indeed bad.

So they did exactly what they supposed to do

If you or anyone else knows where to get them please point me in the right direction.

Contact Littelfuse and ask them. They must have a replacement part, since the ones you have are clearly obsolete by now and it looks like they have scraped old datasheets.

[retiredcaps]

There are at least 3 different major revisions of the Fluke 170 series.  Post a picture of the entire pcb and report its pcb revision number.

Latter versions of the 170 series share the same input protection components as recent Fluke handheld meters and we can find suitable, but not exact, replacements.

[Nightryder13]

here are the front and back full board pictures. on the front it says "assy rev 012" and on the back at the top it says  "17x-3001 rev 009"

[Nightryder13]

more pics

[ataradov]

Why not actually contact Littelfuse and ask them what is the replacement part number is? Or at least the parameters of the existing one. They clearly scraped all the old datasheets, so they must respond to requests like this.

[retiredcaps]

TLDR; 1399 = VARISTOR,910, ±+-10%,1.0MA, V910LSX1399

I asked modemhead to check out his early generation Fluke 179 (rev 7) to see if his MOVs had the same markings. He was kind enough to include a picture (attached).

After some searching, the H in Harris. 

As some of you know, the 170 predecessor was the Fluke 70 series. Then I found this thread

https://www.electronicspoint.com/threads/where-to-get-fluke-spares-surge-protectors.136603/

to confirm it was Harris.

This led me to open my Fluke 75 II.  The printing on the MOVs were hard to see, but I can clearly see H and 1399.
The service manual for the Fluke 75 II states VARISTOR,910, ±+-10%,1.0MA, V910LSX1399

http://assets.fluke.com/manuals/77______smeng0100.pdf

Additionally, the service manual for the Fluke 77 III has the same specifications.  So it looks like the MOV specs were carried over from the II to the III to the early revision/generation 170 series.

That is why I asked for pictures and the revision number.  All the above helped me piece together the above.

[ataradov]

Going a bit further, a search on a part number shows this - http://www.voltlog.com/voltlog-34-fluke-77-teardown-repair-varistor-replacement/ , which recommends a replacement part number  https://www.digikey.com/products/en?keywords=ERZV10D911, which looks reasonable.

[retiredcaps]

Part 2

Since I also happen to have a Fluke 77 III, I checked the MOVs on there.  They are made by Epcos marked K575 (blue colored) which are the same ones found in the Fluke 87V and other modern generation Fluke handheld meters.

https://www.eevblog.com/forum/testgear/fluke-87-v-mystery-low-impedance-input/

The above thread suggests

http://www.digikey.com/product-detail/en/V575LA10P/F3771-ND/1009609

is a match and the digikey listing for that Varistor Voltage (Typ) is 910V.  So if the Fluke 910 description refers to Varistor Voltage then we know that the latest generation Fluke handheld meters use the same MOVs as the Harris 1399 back from the Fluke 77 II service manual.

That is, Epcos K575 = Harris/Littelfuse 1399.

Mouser has them in stock for 65 cents each.

http://www.mouser.com/ProductDetail/Littelfuse/V575LA10P/

[retiredcaps]

BTW, even though 2 tested bad and 1 is good, I suggest replacing all of them.  They are only 65 to 74 cents each depending on which one you buy.

[retiredcaps]

The voltlog video/blog is discussed here in this post

https://www.eevblog.com/forum/repair/fluke-77-repair-teardown/

[Nightryder13]

I had sent an email to Littelfuse asking for the specs and possible replacement number as stated but have yet to receive any communication back. Thanks to everybody's very diligent research into this though I won't have to wait to hear back. Thanks for the info and links, I hope that this thread will help anybody else stumbling across the same issue in the future. Oh and I was going to replace all of them already so no worries there. Now my only problem is that work was going to cover some of the cost for a new meter but now that this one will be fixed they won't, hahah oh well it's more gratifying to fix something   Thanks again everybody.

[retiredcaps]

One last thing I forgot to mention.  Check your serial number to see if your Fluke 179 is subject to recall.  Details at

https://www.eevblog.com/forum/repair/multimeter-repair-time-again!-fluke-177-reads-8-ohms/

Robomeds, a member here, got his used 177 replaced for free with a brand new one from Fluke.