Voltlog #34 - Fluke 77 Teardown & Repair, Varistor Replacement
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- Опубликовано: 17 фев 2016
- In this video I’m opening the Fluke 77 I scored at a recent auction to show and repair a small issue it has. One of the spark gaps used in the input protection circuit had suffered damage probably while protecting the rest of the circuit when a HV signal was applied to it’s input. For the repair the sparkgap was very hard to find so I replaced it with an MOV. For reference, future Fluke 70 series did switch to MOV protection instead of the sparkgaps so it should be fine and continue to function as intended.
The original spark gap part number is Fluke 655134 1500V surge protector.
The replacement MOV part number is Panasonic ERZV10D911 specs 910V 1mA
Fluke 77 Manual:
voltlog.com/y/9tyye
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Excellent presentation… very easy to understand and follow along with no music in the background for distraction . Thank you for your posting!
If anyone needs info...I had a problem with the ceramic capacitor c14 that goes from the varistor to ground, and because of it I had 13m ohm in the resistance mode and it was on the display instead of OL. You drew my attention to the varistor, but then I saw that the capacitor was faulty. Thanks man, good video
The Fluke 77 (original version, which is now referred to as the Series 1 to differentiate it from the newer Model 77 meter) is a classic and a true workhorse. I selected this model in early 1986, when as a new employee at a company, one who was supposed to be the more electronics savvy resource for my department, I was tasked with setting up a small laboratory. I had a limited budget, but I still wanted quality. The 77 seemed the ticket although it was just a basic DMM, no bells and whistles. After getting one in my hands, I liked it so much that I bought one for myself. It is still on my home laboratory bench, and although I also have some newer, nicer, fancier, more precise DMMs, the 77 is my go-to meter for quick measurements. Every 10 years I send it back to Fluke for a touch-up of its calibration, a service I think they still offer for this model to this day. I also bought the 77's big brother (I can't recall the model number at the moment) which looks nearly the same but also tests frequency, capacitance, and maybe one or two other things. It resides in a compartment of a leather electronics tool bag, which has been in the trunk of my car for decades, so I have it handy when I visit company shops or customer sites. It endures all the vibration and temperature extremes of at least -30F to well over 100F, and still works great. Yes, Fluke meters are worth the cost.
Nice! I like how you show soldering techniques.
The small fuse should be a ceramic sand-filled fuse for safety. The glass fuse is incorrect. The rating is 630MA/250V, Fluke number 740670 (replaced by F-630MA/250V-FG).
excellent video.and superb repair.well done.
thanks, i will try your suggestions
This is exactly what mine has done. Great job.
Thanks!
This video is very good.
so Can you upload again manual link of fluke 77?
I tried download but can't access.
Thanks!
Thanks a lot!
hi voltog#34 you have great vidio explanation bro about varistor ,what i wanted to know is how to check varistor or what is the required Oms? or resistance? for a good varistor?
there is no easy way but in normal operation the MOV will have a high resistance and small capacitance. You can also check for short circuit which is a common failure mode.
Ive had a 77 for some 25ish years now and although I've got a couple five other Flukes down through the years I always reach for my 77 first unless the job calls for temps,moisture,etc.that the 77 can't do.. Now my 77 won't do anything and I've tried everything that I know of trying to fix it short of sending it to the Fluke company...
In pratica sono scaricatori e il taglio determina il gap, probabilmente allora non montavano quelli a vuoto perché erano più ingombranti, telaio riuscitissimo e usato in una quantità incredibile di modelli, usato anche per le seconde edizioni, la semplicità e la scocca contribuiscono alla robustezza
Very nice tutorial. It would be great to see a vid on adding a current fuse, MOV protection and other things to a cheap multimeter to give it what could be called a CE ratings. I have a BEST brand which I have taken apart and the circuit board has places to add these items but it lacks through holes for installing these parts. I like this meter but am somewhat reluctant to use it in high voltage, high current testing.
+Joseph Nicholas you mean the parts are marked in the silkscreen but there are no holes? Anyway, when you work with high voltages or any high energy circuits it is best to use a proper rated multimeter, one that can ensure your safety if something goes wrong.
Yes, the current fuse is marked but not there. I have ordered a MOV with the correct voltage and would like to put in a PTC too. The case has lots of room, so adding circuit protection shouldn´t be a problem. Your video gives me more a better idea how a MOV is used in an ac circuit. Thanks.
I have the Fluke 75 , checking voltage 575v 3 phase. After second phase, the display shows a number even no test. The battery, fuse, rotary seem ok. Even at ohm function should read OL but some number showing. Any ideas as to why this may be?
There is a reason why fluke cuts a slot in that part. All the others do not have it so it may be more than a spark gap
great video, my fluke 77 displays all display characters regardless of the selector position, any suggestions on how to fix?
+Steve Tripoli In a situation where you get intermittent segments it's worth cleaning the zebra strip contacts and the pcb pads with some IPA, don't use too much. But in your case if all digits are on it might be a software problem, or maybe the on/off switch stays pressed at all times and the meter is in some test mode ? try cleaning that key also.
very nice video! question: which kind of screwdriver are you using in this video? it looks very good
UNIOR
Boss Can I know where can get fluke 115 circuit diagram. My meter got power problem. After change can't on back.. Try to help me.. Thanks
Where did you get the schematic? I have a Fluke 73 and 77 and I would like to do some maintenance.
Working at Goodwill I brought my own Fluke 77 (purchased Fluke in 1985 when I worked at Specialty Electronics in Atlanta where I sold them.). At Goodwill I was testing an electric fence transfomer and thought my Fluke was set on AC...but it was DC. I heard a small "click" and the fluke was dead. I thought maybe the fuses protected it, but that was not the case. Something else is blown. I can barely see some kind of display. If I knew what part was blown I could chase down the part and do a little surgery myself. I have purchased a replacement Fuke 77 off of ebay. In the meantime, I have not tossed my original Fluke to E-waste. I still hope someone can help me figure it out and bring it back to life. Goodwill won't replace it, they cannot even pay competitive wages.
Can U tell a bit on your lab equip? I noticed some HP toys on the shelf and something else near it. :)
HP E3611A power supply, HP 3478A multimeter, Gophert CPS-3205C power supply.. these were all shown in separate videos at some point on my channel.
Hello friend, how are you doing? My fluke 233 has shorted and the fuse has blown. It's not working now, only the red voltage light is on. I left it off for a few days and the light went out, but then came back on. Is it memory? Do you know what it is?
The link to the manual does not work for me. Can you fix the link? Thanks.
exodus.poly.edu/~kurt/manuals/manuals/Fluke/FLUKE%2077,%2075,%2073,%2070,%2023,%2021%20Series%20II%20Service.pdf
Bien
I have one and like to work with it
Manufactured 1982.
how do I know the equipment is Category 3? based on internal circuits ...
Bagus mana dengan fluke 25
Can you tell us how much you paid for the meter? Got a real good deal I bet.
+Rob Prebil It was in a pack with some other multimeters, I don't have a price for this one.. You should watch this video where I show the whole pack: ruclips.net/video/PV3c-AYyirA/видео.html
Thanks!
Relics...
Reprobate
@@Viper81766 sillón.
хорошо было если на русском
My Fluke 233 his dead kkkkk....Red light only....
Boa tarde, estudo eletrônica e ganhei um FLUKE 77- do meu professor só tem um detalhe,
não está medindo AC- nem DC - Gostaria de solicitar sua ajuda, e se é possível me enviar esse material de folhas que é mostrado no vídeo, sem mais agradeço muito pela atenção um grande e forte abraço. segue e:mail para responder estudante.hd@gmail.com
Hi. I have a fluke 77 that sounds when I select the continuity function with not leads connected. I checked and I found this part broken drive.google.com/drive/folders/1IYKnqIpnDW1cQxQynd608evI36eL2aOf?usp=drive_link Do you know what part it is?