Fluke 75 multimeter repair part 2: The fix!

[@Tobinindustrial]

Brilliant repair. Looks just like a new display. I would have never guessed you could do such a thing to bring back the clarity of the digital screen. Congratulations on salvaging your fluke multimeter

[@Radiocruncher]

Thanks Andy. I had no idea that this was even possible so hats off to Ahmed for suggesting it. Thanks for watching

[@Tobinindustrial]

Indeed.... That was a big save right there. Thanks Ahmed.

[@helifynoe9930]

I have a very old Fluke 75 which has a different PCB layout, and only requires one small fuse. Anyhow, the front clear plastic cover of the display was scratched somewhat. So I removed it and sanded it down to remove the scratches, and then buffed it back up to being shiny and transparent again. Looks much better.

[@radio-ged4626]

Very interesting. I didn't know the polarizing filter was separate to the display.

[@Radiocruncher]

Yes it was a bit of a revelation and could of saved me a lot of work and extra expense if I knew about it before

[@retro1970style]

Very usefull video. My Fluke 77 display is now like new. Much apreciated, thank you

[@Radiocruncher]

Great stuff. Glad I was able to help. Thanks for watching

[@ninaevans4501]

Thanks for that Graham, much appreciated. Keep up the great repair videos. Nina.

[@conwaynoel3715]

I have an almost identical ALTI hc799 that I bought in 1988 . It has memory a hfe readout as well as a function to differentiate between l PNP and NPN transistors . I paid thirty quid for it ( I got a mate of mine who had a credit card to buy it ! ) It has never let me down and it's display is as good as day one. I wouldn't change it for anything. I cannot find any info on it online so I suppose it's long out of production. But it is some piece of kit . Korean made by the way.

[@Radiocruncher]

Nice one Conway. Not seen one of those before though

[@rictutanes]

Exellent repair, thanks sir for sharing your skill in fixing aged LCD display. I have the same model fluke 77 since 1985 and now it appears dark in center display. How to determain the position of polarazing film to get the right disply as you did?

[@Radiocruncher]

Hi. Thanks for the kind comments. You will have to experiment with the polarising film to get it in the right orientation before sticking it down

[@rictutanes]

Good day sir@@Radiocruncher thank you, by the way is there any specs given as a reference to purchase or is it commonly named polarizing film?

[@dbrown51967]

an excellent repair i never considered changing the polarizing film. i wondered why you didn't get back to me for the display no worries though i'm happy you got it sorted and i will start using it as i don't like my other dvm.

[@Radiocruncher]

Hi Darren. I did send you an email with my details but never heard back from you so looks like an email gremlin has struck. I was interested in the other radios you might have lurking. I have updated my email on KZbin if you want to drop me a message. All the best Graham

[@dbrown51967]

hi graham. yes i will drop you a message later in the week yes i have a few odd radio's lurking that you can have, all the best, darren.

[@nor4277]

You just save you from buying a new one ,maybe some day you may want to buy a new one ,I just bought my first fluke,18B+ I been wanting a fluke for a long time and I just bought a Hakko soldering Iron at the same time It takes a lot of money for decent equipment . Nice save on your meter ,it's good when we talk with each other and help each other .

[@Radiocruncher]

Hi Ron. yes it was great to be able to fix it so easily. I never knew about the polarising film

[@ninaevans4501]

You're a clever bloke Graham. We have a 6.4 microfarad 25 volt polarized axial electrolytic capacitor inside a Grundig Party Boy 208 transistor radio. What value capacitor can it be safely replaced with? The old one reads 7.89 microfarads with an ESR of 5.6 ohms. I reckon this capacitor is shot. Secondly, where can I get hold of "thumb wheel" volume control knobs. I have an A-Meltone Planet transistor radio with a broken thumb wheel volume control

[@Radiocruncher]

Hi Nina. I'm not that clever! It's an unusual value so might be in a critical area. You could try an10uf axial but I would go for a radial and stretch it to fit. This one looks good uk.rs-online.com/web/p/aluminium-capacitors/8399370/. I have had trouble with a Dynatron Tourist with a similar volume control. A few viewers found some that may work. JohnS Van Ryssen1 month ago Dear Graham, Enjoy the videos. edgewise 10K with internal o/o switch on e_bay numbers 181754360861 and 252503269655_ Hong Kong and Manchester Also 50K similar format 181802112884 Hong Kong. Link to my video kzbin.info/www/bejne/o57PiHmqhLmqnJI Good luck Graham

[@chandraMohan-wo5ji]

Nice tutorial sir. May u give the link for polaroid ? Mine face same problem too.

[@Radiocruncher]

Try this www.ebay.co.uk/sch/sis.html?_nkw=5x+Cellphone+Polarizer+Polarizing+Diffusor+Film+Sheets+For+Samsung+Galaxy+Note+4&_id=291706043124&&_trksid=p2057872.m2749.l2658

[@redcatimaging]

What a difference :). Great repair that saved you a new display :). Didn't know that the polarising film can age like this, pretty interesting :).

[@Radiocruncher]

I didn't realise it either until a viewer pointed it out. It's like new again now. Thanks for watching

[@ninaevans4501]

Thanks for your help Graham. The Grundig Party Boy 208 radio is now repaired. The capacitor that I needed was ordered last night, it came through first thing this morning! How's that for service!? The only other problem was a stuck tuning capacitor, but that was sorted with a pair of bull nosed pliers and a tin of WD40 (plus a bit of care)! These old Grundigs have quite a nice sound, but do you know where I can get a battery eliminator for these old sets as the batteries are getting harder to come by and are expensive?

[@Radiocruncher]

Nina Evans that's great news Nina. RS are next day if u order b4 8pm and free delivery with no minimum order. I use them for everything. There are many circuits out there for making a power supply. I would suggest using pp3,s in parallel though. I don't have one of those radios but looking at the pictures you could get maybe 3 or 4 which would give a long lifetime and you could probably even rig up some rechargeable ones. Good luck. Graham

[@richardpope9985]

I have this exact same problem with my Fluke 73. Can you advise where you purchased the polarizing sheet ?

[@Radiocruncher]

Hi Richard. I bought it on eBay. A quick search for polarising film will bring up loads of them. Try this www.ebay.co.uk/sch/sis.html?_nkw=5x+Cellphone+Polarizer+Polarizing+Diffusor+Film+Sheets+For+Samsung+Galaxy+Note+4&_id=291706043124&&_trksid=p2057872.m2749.l2658 Thanks for watching and good luck

[@SoddingaboutSi]

Good fix. There should be a bias pin to adjust polarisation of the screen. It may be open circuit?

[@Radiocruncher]

Thanks Simon. I have got the service manual somewhere but couldn't see any adjustment for polarisation. The old film I peeled off had turned a horrible yellow colour with age. I'm really pleased with the result. If you can suggest any adjustments then I'd happily have a crack at it.

[@joevelc.sabado4921]

i have that Fluke 75. but the case is allready borken. if you have any replace to buy the case. thank you.

[@Radiocruncher]

Hi Joevel. Sorry but I don’t have a spare case. Are you able to glue yours up?

[@regortex3364]

Great video, I just got a malfunctioning 75 today, I did a quick test by testing a 9V battery, the display reads 3 or 4 volts (fresh battery) and then quickly drops to zero, bad resistor or cap maybe? I’m not a tech by any stretch, if anyone watching this can pass any knowledge, I’d be grateful as I’d love to get this meter working.

[@Radiocruncher]

I think the 1st thing to check are the switch contacts on the rotary switch. Download the service manual as there are some trouble shooting steps in there which will help

[@regortex3364]

@@Radiocruncher - I cleaned the contacts with a Q-Tip and some isopropyl alcohol, it didn’t help but I’ll try again. Thanks for the info on the service manual, I’ll check that out.

[@Radiocruncher]

@@regortex3364 good luck and let me know how you get on

[@andrewlittleboy8532]

Wow, looks new. Well done Graham. So it was the polarising filter that failed. I wonder it the filter you have is an inverting filter, like them watches you see that are inverted?

[@Radiocruncher]

Thanks Andrew. It certainly was the old polarising film that had aged and had a yellow tinge when I took it off. I was amazed at how sharp and dark the digits are now. The polarising filter I bought was for a Samsung Note 4. I got a few sheets as that is the model of my phone as well. After this repair can I assume that all LCD displays have a polarising film on them? Not sure but I'm sure someone will know. Thanks for watching. Graham

[@andrewlittleboy8532]

Radiocruncher every LCD screen I've ever dismantled has had a polarising film in front of the display from watches to LCD TVs so you must be right. ATB Andrew

[@Radiocruncher]

Thanks for the info Andrew. I think this is the first LCD I've worked on

[@MrBobWareham]

That is the same meter I have and would not be without it just wish the continuity piezo was lowder on mine any suggestions? Thanks Bob-UK

[@Radiocruncher]

They are great meters Bob. Ive had this one from new I think back in the 80's. I don't think you can do much about the sound but might be worth having a look at the service manual. Regards Graham

[@MrBobWareham]

Thanks will see if I can get a service manual for it, if you have any film leftover I would like it thanks Graham

[@Radiocruncher]

If you drop me a message to [e-mail] i have a copy of the service manual i can email to you. I can also sort some of that film. Regards Graham

[@evanleebodies]

Great vid Graham, I was loathe to replace my trusty 30 year Fluke 75 with its fading display. This fix makes the replacement of the elastomeric connectors unnecessary.

[@Radiocruncher]

Glad I was able to help Evan

[@evanleebodies]

@@Radiocruncher Having carried out the replacement of the polariser film I am now able to report that it is much easier to apply the self adhesive side of the film to the underside of the transparent plastic window of the the case. This negates the need to stick 2 pieces of film back to back and also maintains the distance between the top of the LCD and the bottom of the bezel.

[@Radiocruncher]

@@evanleebodies Nice work. I did mess mine up a bit and had to use 2 pieces but got the desired effect

[@Э.О-п6д]

Hello . Please tell me where you can buy a display for this multimeter. Thanks in advance.

[@Radiocruncher]

I don’t think you can still buy a display for one. I used polarising film for mine which I bought from an eBay seller

[@muhammadzawar9521]

I have fluke 75 series II.Please guide me my DMM is dead since i measure high range current i have change its fuse but it is still dead.

[@Radiocruncher]

Hi Muhammad. I’m sorry but I’m not very familiar with the electronics on the Fluke 75. If the fuse has been changed and it’s still not working I would suggest you download the service manual and try to follow the circuit through to find the fault. Thanks for watching

[@muhammadzawar9521]

@@Radiocruncher OK Thanks.

[@ninaevans4501]

Now go and have your lunch gorgeous! LOL!!!! :O

[@Radiocruncher]

Haha thanks Nina.

[@midimagic7097]

You could just wear glasses. !