EEVblog #808 - Fluke 196 Scopemeter Repair

[EEVblog]

Dave repairs a dumpster Fluke 196 Scopemeter handheld oscilloscope that has a faulty LCD screen.

How to repair a faulty hot bar LCD screen flat flex cable connection.
Service Manual with full schematics: http://assets.fluke.com/manuals/192_196_smeng0200.pdf

[BravoV]

There you go, expecting another big wave of price hike on used scopes with broken lcd. 

[max666]

So now with the LCD fixed, you could make use of the service manual by fixing the scope input, Dave.
EEVblog #808 - Fluke 196 Scopemeter Repair - Part 2 

[EEVblog]

There you go, expecting another big wave of price hike on used scopes with broken lcd. 

Holy crap, just checked, membrane keypad for $455!
http://www.ebay.com.au/itm/NEW-FOR-Fluke-192-196-199-Membrane-Keypad-Replacement-523188-/331530524500?hash=item4d30c25754

And as it turns out, this guy repairs this exact fault! Must be common as mud?
http://www.ebay.com.au/itm/Fluke-192-196-199-Scopemeter-LCD-Display-Repair-/230424487426?hash=item35a65ea602

[BravoV]

And as it turns out, this guy repairs this exact fault! Must be common as mud?
http://www.ebay.com.au/itm/Fluke-192-196-199-Scopemeter-LCD-Display-Repair-/230424487426?hash=item35a65ea602

Once he knew or watched your video, he will hate you, just look the number of repairs he sold. 

I guess, this is a good example where you've just made an enemy. LOL

[EEVblog]

Once he knew or watched your video, he will hate you, just look the number of repairs he sold. 

Oh wow, 56!
Says he replaces something though. I don't suspect my repair will be very reliable, I don't trust that conductive adhesive, it came loose for a reason...

[mux]

Pretty much certain that scopemeterrepair.com uses NOS LCDs to replace the existing LCDs. This used to be big business back in the day with lots of standard hitachi graphic LCDs.

You can't really justify the hours spent on such a thing if you can buy OTS identical LCD modules (and maybe an adapter board) for a couple bucks wholesale.

[Wile E. Coyote]

We have the same Fluke 196 in our office. Your rants about Fluke's lack of LCD reparability & support bring back fond memories (Fluke stopped supporting & selling the LCD shortly after we purchased the 196). I think every tech here has had their hand at repairing it with various levels of success. The hot-bar never kept a good connection.

Now we just keep our 196 around as a warning to other Fluke meters should they decide to develop faults. I don't believe any meter should suffer the same fate as our 196.

Although I have to admit, when I saw that you had a repair video for the 196 (and when I peeked at the end of the video and saw the thumbs up), I was hoping you found a solution that we did not think of for a permanent repair! Nope - same Band-Aid repair.

Love the videos & keep up the great work!

-Mike AD0OY

[bktemp]

When repairing hotbar connections, the pressure must be applied until the glue has cooled down.
You can also use a soldering iron set to <200°C with a clean tip for repairing. But you still have the problem applying pressure until the glue has hardened again.

VOGT was a German manufacturer of inductors and transformers. Now it is part of Sumida. Custom built transformers made by VOGT are quite common in all kind of products made in Europe.
Hitachi merged with Mitsubishi and formed Renesas in 2003. That was the end of of Hitachi beeing the most common manufacturer of lcd controllers and drivers.

[Fungus]

When repairing hotbar connections, the pressure must be applied until the glue has cooled down.

That's what I was thinking...

I would have placed a bar of metal (old heatsink, whatever) across the strip using clamps then heat it up and let it cool before releasing.

[han]

Using This one?

[Fungus]

Using This one?

That's perfect! I'll be opening up an eBay repair store in the next few minutes...

[Ampere]

Excellent repair, Dave.

It's a shame that it's more of a meter than a scopemeter, though. Maybe that would make a good followup video?

[AF6LJ]

Good go at it Dave.

[Dave Turner]

I agree with Max66. Please finish the job. Get rid of the EEVBlog curse.

[noidea]

Wow Dave what a coincidence, you post a thread on trying to fix a scopemeter and it's the same night that I decide to summon up the courage to take my 196C apart to try and fix it as well.

The problem with mine seemed less drastic than yours the screen works great but it had recently stopped charging and would not operate from the mains adapter, yet still fired up with what was left in the battery (which is new). I must admit I was a bit more hesitant about taking it apart than you are but I fix air conditioners for a living and don't pull electronic stuff apart every day. So far the problem with mine appears minor, the power input connector is knackered as the centre pin has no continuity through the connector to where it goes down onto the PCB in the top corner.

So if you decide not to go ahead with trying to fix the scope section and are going to dump it I'm in Oz too and would happily dispose of the main board for you 

I also found something really strange, it appears that the cooling fan on the back of the PCU unit has never been plugged in 
I guess I really should start a repair thread on my unit instead of taking yours up.

Cheers

[free_electron]

if the charger doesnt work check out the switching transistor v4102. they fry very easily ... small sot23-6 pin package. obsolete but can be replaced by a fdc666 if you snip off one of the pins. the original transistor has a unique pinout that nobody else uses.

[Supercharged]

Just a little aside: I think below that bodge cap there is a resistor

[Tuomas]

The university where I studied had one lab with a bunch of those scope meters and every single one of them had those horizontal lines all over the display.

Fluke refused to fix them since they were out of warranty. Apparently the lab doesn't buy Fluke equipment anymore.

[AF6LJ]

The university where I studied had one lab with a bunch of those scope meters and every single one of them had those horizontal lines all over the display.

Fluke refused to fix them since they were out of warranty. Apparently the lab doesn't buy Fluke equipment anymore.

There was a number of displays that used similar technology that had the same reliability problems. A piece of amateur radio gear I own is notorious for the displays developing horizontal lines just after warranty.

[krivx]

If anyone is interested, a much longer lasting method for these kind of repairs is to etch away the adhesive and some insulation and solder the cable in place.

http://www.projectvb.com/displayfix.html#Solder

[TheSteve]

Do the various chips that looked like they had a thin heatsink pad on them require heatsinks? Being at least one person has previously tried to fix it they may have removed the heatsinks. Or do the pads make contact with a metal shield when assembled?

[envisionelec]

I actually own a hotbar press for the anisotropic adhesive that is used on these things.

It is literally a PID controlled heating element and a machined copper shape attached to a press with a torque-reading gauge for an arm. It was $4000. 

[German_EE]

There was a number of displays that used similar technology that had the same reliability problems. A piece of amateur radio gear I own is notorious for the displays developing horizontal lines just after warranty.

Let me guess, an Icom IC-756 transceiver

[Radio Tech]

There was a number of displays that used similar technology that had the same reliability problems. A piece of amateur radio gear I own is notorious for the displays developing horizontal lines just after warranty.

Let me guess, an Icom IC-756 transceiver

Same problem with the Kenwood VM-7. Think that model is correct.


Good job Dave. Now fix the scope 

[AF6LJ]

There was a number of displays that used similar technology that had the same reliability problems. A piece of amateur radio gear I own is notorious for the displays developing horizontal lines just after warranty.

Let me guess, an Icom IC-756 transceiver

Indeed and now there is nobody making a replacment display module for the radio.
Thankfully in 2011 I bought a module and replaced it.
Not that great contrast is crap, it is the nature of the module.
One of these days I hope to find something that woks better.

https://forums.qrz.com/index.php?threads/ic-756-display-replacment.302777/

[wblock]

That "anisotropic" glue is amazing stuff.  Well, amazing that it works at all.  Conductive only in the Z axis... but how does that work?  Wikipedia says some of it is stuck together at room temperature, so at least those connectors do not rely on heat to make a chemical change.  Maybe it's something that happens as it cures?  Other web searching just pointed out that yes, it's only conductive in one dimension, but not really how it does that, or how it knows which dimension is which.  A chemical change that goes from edge to edge and so completes in the thinnest dimension first, blocking the others?

[steve30]

Well done Dave . I expected you'd at least make an improvement with the display cable. I attempted to repair one of those cables once, and whilst I didn't fix it completely, I did at least make the display readable.

[NiHaoMike]

There was a number of displays that used similar technology that had the same reliability problems. A piece of amateur radio gear I own is notorious for the displays developing horizontal lines just after warranty.

I once had a tablet with a "static LCD" that failed with lines twice under warranty. The second time, I had them trade it for the version with a conventional LCD.

[Rasz]

Yay another win 

5.7" 320*240 is typical industrial parameters = very expensive
but someone dedicated could do a conversion to this http://andybrown.me.uk/2013/10/19/vivaz-u5-lcd/

hitachi driver bus is slow and simple, pic32/stm32 could easily grab that and convert to another screen, or even stream directly over bt/wifi to a phone/tablet

[Smokey]

Just a little aside: I think below that bodge cap there is a resistor

That's what I was going to say.

[Monittosan]

Its the same deal with the fluke 120 series except the flat bar is even harder to access.
I had a go at repairing one nearly a year ago with a soldering iron and its still working fine. I did want a 196c - 199C but I guess thats not going to happen now Dave 

you can rework the LCD ribbon cable with a soldering iron on its lowest temp setting.
The challenge is getting to the vertical ribbon cable as its behind the glass

before



After


[/quote]

[PA4TIM]

Nice video, I'm glad to know these strips are more or less repairable.

I have a dead Fluke 192 from a customer here. But I'm stuck. I hoped to see/learn some troubleshoot techniques but the 192 differs a lot. Non the less it would be great to see a follow up video.

The 192 has three Fluke Asics and one of them is a huge bga. The firmware and SRAM is on a piggy back and one of those bga's reacted on pressure so I reballed it. Now it charges, beeps when powered on, the 3 clocks do what they should do according the tests in the manual. And following the manual trouble shoot part and my measurements the problem seems to be missing or corrupt firmware and/or defective memory.

The manual now wants software and an interface to check things.

But these scopes are a pain in the ass because those asics work together.  The psu ASIC fires some parts of the psu for charging and "booting" . That in turn starts the digital asic and that digital ASIC then starts the rest of the psu ASIC etc. (or something like that, it is resting for 2 months now, the owner try's to get the interface/software so I do this from memory)  A bit a chicken and egg situation. 

For the electronics scopemeter-porn aficionado's,  I repaired a Tektronix equivalent in the meantime. (pictures:  http://schneiderelectronicsrepair.nl/?p=212 )

 

[gordo51]

Two successful repairs in a row. Dave is on a roll.
I have an older 100MHz scopemeter that refuses to run on the battery even though I have two different fully charged batteries.
The internal connections appear to be fine and I cannot see anything like a fuse so nothing obvious.
Any ideas out there? 

[AF6LJ]

There was a number of displays that used similar technology that had the same reliability problems. A piece of amateur radio gear I own is notorious for the displays developing horizontal lines just after warranty.

I once had a tablet with a "static LCD" that failed with lines twice under warranty. The second time, I had them trade it for the version with a conventional LCD.

My IC-756 was my first encounter with those displays, When I read about their high failure rate and started seeing the same display in point of sale terminals failing I was rather unhappy. There were a few other issues I had with the radio and after spending 2.2 K$ on the radio I was not happy. I know they have become more reliable but the way they are put together doesn't give me a lot of confidence.

[mcleod]

Do the various chips that looked like they had a thin heatsink pad on them require heatsinks? Being at least one person has previously tried to fix it they may have removed the heatsinks. Or do the pads make contact with a metal shield when assembled?

Yes, they need heatsinks. There is a large sheet metal shield/heatsink that covers that section of the scope from the factory. It is not in the case, but a separate piece. Obviously, some clown lost it or was too lazy to replace it.

There are also shields/heatsinks that cover the scope input sections and the meter section.

[Assafl]

The heat sink is part of the shield cans. There should be an angled piece inside connected to the can that presses on the ASIC. Therefore the heat pad is required.

If you do get a battery remember to charge it and use the scope meter at least on a semi weekly basis or the batteries die rather quickly.

[memeruiz]

Hi Dave,

I don't know if you could finish fixing the Scope completely.

A couple of things:

1) Keyboard membrane fails a lot. Sometimes the scopes seem unresponsive, when in reality is the keyboard that is not working.
I fixed this by using a fixed PCB instead of a membrane one: 

https://www.ebay.com/itm/Fluke-192-196-199-Scopemeter-Keypad-Contact-Board-Replaces-Foil/231220134535?hash=item35d5cb4287:g:u~0AAOxyOalTYqZ8

2) The sticky tapes that you found on the ICs are actually for connecting to the metal back of the scope. They come into contact when you rescrew the scope. It happened to me that the scope freezes if some of these ICs overheat. Check that. Or reapply heat transfer paste there. Those tapes looked toasted and old.

What I want is to upgrade my old 196 scope with the newest firmware. Mine is so old that it can not be upgraded by the user according to fluke. Apparently the board must be modified. If you could take a detailed picture of the main board, both sides, that would be great to take a look into my scope and see if it is possible to upgrade at home.

All the best!