EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Meth on April 16, 2016, 04:25:40 pm
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Hi all,
I recently purchased a used Fluke 87-IV from a certain auction site.
With regards to the operation, it's running firmware V1.01 and the display and back-light work perfectly.
Generally it looks like it's working OK based on rudimentary tests.
The C measurement worked fine for the 100n cap I tried out.
The date/time storage works fine when I remove the main batteries so the internal battery seems to work OK.
I've started cleaning it up by stripping it down and using general APC and toothpaste/toothbrush combo to get rid of the grime (and following mrmodemhead's excellent blog post).
This has been working very well so far but I've not done the front yet as that requires removing the dial etc and I haven't found the time yet..
However I have a few questions:
1) Is there anywhere I can get some replacement battery contacts for (less than a kings ransom) here in the UK? I've tried contacting Fluke but they wanted over £50 just to consider looking at it....I was cheekily hoping they would be able to pop some in the post :) Really I only need the 3 inner contacts and not the outer ones that connect to the PCB.
2) It has some (probably permanent) marker pen writing over it. I've got it off the hard plastic stand but any tips to remove it from the softer rubbery coating?
3) Any other tips to help check the meter out by measuring the internal component values at the front end etc? I've had no luck finding a decent service manual except the usual ones mentioned on here that aren't very detailed. I know there where some posts on either here or badcaps but couldn't find them again when I went searching.
Thanks in advance!
Tim
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1) The replacement contacts are expensive as I found out (about $50 USD on ebay - complete rip-off)
https://www.eevblog.com/forum/chat/fluke-187-corroded-battery-terminals-how-to-clean/ (https://www.eevblog.com/forum/chat/fluke-187-corroded-battery-terminals-how-to-clean/)
I looked around for some compatible replacements and found some possibly substitions on digikey. They aren't identical, but they are probably workable. Have a look at the Keystone Electronics catalog.
http://www.keyelco.com/category.cfm/Keyelco/Battery-Coin-Cell-Holders-Contacts-Clips/id/404 (http://www.keyelco.com/category.cfm/Keyelco/Battery-Coin-Cell-Holders-Contacts-Clips/id/404)
2) See
https://www.eevblog.com/forum/testgear/cleaning-permanent-marker-from-yellow-fluke-cases/ (https://www.eevblog.com/forum/testgear/cleaning-permanent-marker-from-yellow-fluke-cases/)
3)
a) Check to make sure the fuses are okay.
b) Check to make sure the input protection components are okay by measuring them. You want to check the PTC, fusible resistor and MOVs.
c) There is no publicly available service manual for the 87IV/89IV/187/189 that I know of.
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Thanks for the reply!
I'd already read the eevblog links you'd posted, but it's good to have them at hand in one place :)
The battery terminals you posted look good - the problem with mine is they look like they've been snapped off, and the repair was to bend the remainder out. I knew this from the auction when I bought it but assumed I could get hold of replacements fairly easily. Luckily, like in your post, the corrosion is limited to the contacts themselves and hasn't made it near the main PCB.
Thanks for the hints on the MOVs etc - again I think I'd seen a post that specified what values to look for but have been unable to find it using the search.
I recall that I should be seeing either 10K or 1K on some of the components but alas I cannot find the post and I don't have the unit to hand during the weekend.
Thanks again.
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Thanks for the hints on the MOVs etc - again I think I'd seen a post that specified what values to look for but have been unable to find it using the search.
See reply #2 at
https://www.eevblog.com/forum/testgear/fluke-87-v-mystery-low-impedance-input/ (https://www.eevblog.com/forum/testgear/fluke-87-v-mystery-low-impedance-input/)
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That's wonderful thank you very much, I knew I'd seen it as I'd researched before I bought the meter but then when it came I couldn't find anything again! :palm:
I'll upload my pictures this week from my phone to show my progress :)
Edit: I made a few resistance measurements that are annotated on the attached picture:
A - 1M
B - 1.3ohm
C - 1M
D - open
E - open
F - 99.2K
G - 3.5K
H - 1.2K
I - 99.0K
J - 99.1K
Anything there that takes your fancy? From what I've seen I think these are all OK? :)
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Small update: Good results obtained with toothpaste (hopefully you can see which half I did and didn't clean!)
It's since been fully done as I had the meter apart - I've still got some writing to remove from it that is being very stubborn but I've not tried anything more abrasive on it yet.
If anyone has any input on the front end measurements I made I'd be most grateful too.
Thanks!
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Edit: I made a few resistance measurements that are annotated on the attached picture:
A - 1M
B - 1.3ohm
C - 1M
D - open
E - open
F - 99.2K
G - 3.5K
H - 1.2K
I - 99.0K
J - 99.1K
Anything there that takes your fancy? From what I've seen I think these are all OK? :)
I didn't see your edits because it doesn't show up as a new post, but all those measurements look okay to me.
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The yellow component between the two red MOVs is a spark gap. It should measure infinite/open resistance.
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Ah yes sorry about that! I originally edited the post as I didn't want to start double-posting in case it was against the rules here.
But then as it had been a while I thought it was probably OK to add a new post below.
Thanks for checking the measurements - I did also measure the spark-gap as open so that's a good sign.
So far it's behaved really well for me so looks like I did OK with this one - a good addition to my test gear I think!
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Small update: Good results obtained with toothpaste (hopefully you can see which half I did and didn't clean!)
I use gojo. See
http://mrmodemhead.com/blog/dirty-multimeter-clean-up/ (http://mrmodemhead.com/blog/dirty-multimeter-clean-up/)