Fluke 83-V with 'blown input protection' - Page 1
Forum section: electronics / repair

author: TopLoser
author_rank: Unknown
timestamp: November 17, 2014, 08:38:00 pm
content: Sent a Fluke 83-V back to Fluke for repair recently, seemed to work ok apart from ohms range read 100K with probes open circuit.It was diagnosed with ''blown input protection', repair cost £160+VAT not covered by warranty. They wanted £45 'inspection fee' to return it so i told them to scrap it.Well, today it arrived on my desk with a bill for £0. Still has the fault but at least we can have a go it fixing it eh Mr Retiredcaps??!!!Had a quick look inside and there's nothing blown apart or melted, just a couple of blue things looking a bit toasty.Sooo... what next?!

author: TheBay
author_rank: Unknown
timestamp: November 17, 2014, 08:45:46 pm
content: Get probing!

author: TheBay
author_rank: Unknown
timestamp: November 17, 2014, 08:52:21 pm
content: And for some useful input those blue things are MOV's they shouldn't look toasty! I think they have done their job and need replacing. Probably been fed some high voltage out of its range or on the wrong setting! iirc those side mounted pcbs are a resistor network for reference?Haven't used an 87 for years. I had one when I worked for leisure link as an engineer repairing jukeboxes, fruit machines, pinball, arcade machines etcetera.

author: TopLoser
author_rank: Unknown
timestamp: November 17, 2014, 08:59:48 pm
content: https://www.eevblog.com/forum/testgear/fixing-a-fluke-87v/15/Looks like 3 new 575vac MOVs are in order. I'll snip them out for now and see if the ohms range works.

author: TheBay
author_rank: Unknown
timestamp: November 17, 2014, 09:01:42 pm
content: Snip them out and see if it at least gives a different reading.

author: TopLoser
author_rank: Unknown
timestamp: November 17, 2014, 09:08:50 pm
content: Beat you to it!Ohms range just fine now. 3 new MOV's on order at £0.56 each.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: November 17, 2014, 09:11:49 pm
content: I've changed a lot of them.

author: TopLoser
author_rank: Unknown
timestamp: November 17, 2014, 09:15:17 pm
content: Quote from: TheBay on November 17, 2014, 08:52:21 pmAhhh the good old days, I spent 5 years of my life buying and selling pinball machines. Plus the inevitable and endless repairs of the bloody things...I only ever dealt with Bally/Williams DMD machines 1990's onwards, not of that old EM crap. You got access to any machines now? I'd happily swap some test gear for pinball machines....

author: TheBay
author_rank: Unknown
timestamp: November 17, 2014, 09:21:51 pm
content: Quote from: TopLoser on November 17, 2014, 09:15:17 pmGlad you fixed the meter, I guess I was right... Or we both wereDo you want it's clothes back nowYes the good old days, no nothing any more! Did have all sorts in my old house.So you will be all to familiar with screen burn on the Williams machines LED or was it VFD displays....Would love to get one though, can't beat the electro mechanical aspect of them.Currently on the hunt for jukeboxes to repair. Only want vinyl though, Late70's or 80s. Not interested in the old valve lo fi stuff or early transistor. Has to have a CPU.Though not sure if you are familiar with jukeboxes. The old NSM performer grand CD was a work of art.

author: retiredcaps
author_rank: Super Contributor
timestamp: November 17, 2014, 09:55:37 pm
content: In addition to checking the MOVs, I would also check, in circuit is fine initially, that the fusible resistor and PTC (both circled in red) are okay. It only takes 10 seconds to check each.A good PTC should measure around 1.1k ohm and the fusible resistor should be around 1k ohm.I suspect the reason Fluke quoted such a high repair charge is because they want to make darn sure nothing else is bad/blown due to liability reasons. That is, if they only replace the obviously bad MOVs and don't check anything else, this could cause serious injury to the user. Thus, they probably have to check everything including calibration for the meter and thus the high fix fee.And yes, Fluke won't repair the unit for free under its "lifetime" warranty for MOVs that are blown presumably due to misuse/high voltage wrt to what is documented in the manual.

author: retiredcaps
author_rank: Super Contributor
timestamp: November 17, 2014, 09:57:35 pm
content: Quote from: TopLoser on November 17, 2014, 08:59:48 pmAlsohttps://www.eevblog.com/forum/testgear/fluke-87-v-mystery-low-impedance-input/

author: retiredcaps
author_rank: Super Contributor
timestamp: November 17, 2014, 10:00:29 pm
content: Quote from: TopLoser on November 17, 2014, 09:08:50 pmCan you share/list the part you ordered please?With various new suppliers or stuff going out of stock or requiring a minimum 1000 order, it is handy to know what iscurrentlyavailable that meets the correct specifications.PS. Aren't you glad I suggested you try to fix it? For less than a cup of coffee, you have a working 83V again!

author: TopLoser
author_rank: Unknown
timestamp: November 17, 2014, 10:18:00 pm
content: Quote from: retiredcaps on November 17, 2014, 09:55:37 pmIf you look carefully you can see that Fluke have very kindly marked all 5 of those components with a little black line!They were very nice, returned it free of charge despite me asking them to scrap it instead of paying the inspection fee.