EEVblog

[@chouseification]

Dave, as always - you rock! Your videos are great - I went the app developer route for the most part, and haven't tinkered as much in recent years, but I was the kid who would disassemble then reassemble all their toys. I have been adding components to PCs and then building from scratch for 30+ years; had to be "that guy" in college who fixed folks dead PCs and modded their Playstations for them. :P You and the few of the other KZbin channels have inspired me to get back into it. My gear is now at a 2 channel scope, one variable power supply, rework station with air and solder heads, little 3D printer, and the start of a good selection of Arduino/Pi/TTL components. Got lots of old power supplies to salvage to make a few more power supplies; considering getting a nice IR toaster oven and making a reflow oven... I have all of the digital logic stuff down pat due to decades of coding in tons of languages, but reminding myself about power supplies, safety caps, etc. Thanks again for all of the wonderful videos. I'm going to need to order some reels of components from DigiKey after doing some more practice in DipTrace/KiCad; shipping will be a lot cheaper for me though - MN here. :D

[@leisergeist]

I think Arrow has free 2 day shipping these days, so that might be worth looking at YMMV though, haven't used them yet

[@chouseification]

@@leisergeist, Dave is the one with high shipping costs - as he refers to it, "the Australia tax". My comment was just being silly, as my shipping from DigiKey will be as low as possible; I'm not sure if most of their shipments come from the Thief River Falls, MN warehouse (way the hell up nearly at the Canadian border) or if they have something here in the Twin Cities - but either way, same state in US means pretty low shipping fees. It may cost Dave as much to ship a single reel of SMD components as it does for me a case of the same. Thanks for the tip though - others may find it useful if they're also in regions with expensive shipping.

[@leisergeist]

OH you have a local warehouse, nice! Yeah I guess I didn't read that right haha

[@randynovick7972]

You know, you followed a great, intuitive troubleshooting path. I'm not as good as you, but these little demonstrations you do give me confidence to try a little harder. Thanks for that, Dave. This was great fun to watch.

[@FranLab]

Classic EEVBlog - Make it better than before!

[@MrPnew1]

Fran is in the house

[@tactileslut]

Isn't that just how engineers do repair?

[@sprybug]

Hey Fran, good to see ya around these parts.

[@trendmend]

Ayyyy Fran! Great to see you here :) I loved your videos on the Nimo display! Absolutely amazing work!

[@BerndFelsche]

"Two pins tied together is very common" 😎 it's always common.

[@richfiles]

Ayyyy! I see what you did there! XD

[@garbleduser]

I always use naptha to reactivate the conductive glue. While it is still stuck down, I press down with a piece of warm flat metal. Then I apply swab of naphtha to the to the edge, allowing capillary action to carry it in. I then wait 7 seconds and hit it with the hot bar for 2 seconds, then apply a dragging force (not actual movement) in the direction of the conductors for 2 more seconds. And you're done. What can I say? It works great on zoll defibrillators!

[@EEVblog]

Interesting, sounds like it's worth trying, thanks for sharing.

[@frogz]

i'll have to remember this 1, i would have another lcd tv right now if i knew it, it was missing a few lines and i just made it worse after i made it better haha

[@theplaceto-be]

Garbled User sorry what is naptha?

[@envisionelectronics]

eejanuz S DescriptionNaphtha is a flammable liquid hydrocarbon mixture. Mixtures labelled naphtha have been produced from natural gas condensates, petroleum distillates, and the distillation of coal tar and peat. In different industries and regions naphtha may also be crude oil or refined products such as kerosene. Wikipedia

[@dkupy100]

@@theplaceto-be At least here in the States you can find it in the paint section along with mineral spirits, acetone, etc.

[@eugeneskopal5346]

Dave, LCD screens have different viewable angles looking down from the top or up from the bottom. They probably found that in field use, the view from the bottom was better. So they turned the LCD over. I have encountered this in my projects.

[@Graham_Langley]

That's a very good point. Many years ago I visited a tech firm where someone had had the bright idea of setting an LCD clock into desk next to the visitor signing in book. Only problem was the display was set up for viewing from 12 o'clock - when set into the desk it was viewed from 6 o'clock and completely unreadable as a result.

[@SianaGearz]

The spec on Newhaven LCD says it's a 6 o'clock model. The original is probably same.

[@listerdave1240]

I have successfully used Z-axis conductive tape to fix a similar display. First thoroughly clean off all the conductive glue from the PCB and the ribbon, then just stick a piece of the double sided tape over the contacts and then attach the ribbon onto it and hold it down for a minute or two. It is scary expensive if you buy a whole reel from but there are many on eBay selling short strips of it, which is all you need really. Look for "3M Z-Axis Conductive Tape 9703". It can also be used to temporarily 'solder' SMD chips without actually soldering them. Doesn't work in all situations but if there isn't high current or very high frequencies involved it seems to work fine.

[@martinkleine3287]

In the manual on Page 2: „ADJUSTING THE LCD DISPLAY CONTRAST Switch the analyzer ON. Before pressing any other keys, press and hold the [] key to adjust the display contrast to suit your angle of view. The [] will make it lighter“

[@wktodd]

I was shouting something similar at the screen :-)

[@EEVblog]

Yep, keep watching the video...

[@stuartmcconnachie]

EEVblog Don’t turn it on, take it apart... but before you do that RTFM! 😉

[@Retep4565]

Real men don't read manuals.

[@cannesahs]

@@Retep4565 They write manuals

[@marcus_w0]

You're the only engineer, making money with fixing his own stuff :)

[@evilgremlin]

Actually, you can buy new anisotropic conductive tape on Ali, about 70$ for a reel. I know guys who fix LCD's with it, replacing/regluing decoders. They even do custom resistive touchscreens, cutting out of bigger ones and gluing new hand-made FLC in. The thing is tape degrades from overheating and don't stick while underheated. Also, you need to apply decent amount of pressure. So, generally, it's even trickier than soldering sandwiched chips.

[@swp466]

Nothing was happening with the first trimmer because there's a 0 ohm resistor (R6) across it. If you remove R6, then the first trimmer should help.

[@chef1arjunaidi]

Your electronic detective work is just brilliant! Good on ya, Dave.

[@roberthorwat6747]

Thanks Dave, another great vid. Saved me a ton of time as I am now not even going to bother trying to re adhere the hot bar strip in the display of my multi function display in the dashboard of my 2003 vintage banger. Others on various car forums have tried and failed and now I know why. New OE replacements will almost certainly cost more than the value of the vehicle - if there are any left on the parts shelves lol.

[@silverknight5880]

12:14 there is a VR1 timmer in the bottom left of the screen on the main board.

[@EEVblog]

That's in the analog section, nothing to do with the LCD.

[@silverknight5880]

@@EEVblog Thanks for clearing that up Dave! Your content is always the duck's guts!

[@n2n8sda]

Nice one. Impressed you did some extra reshoot at the end

[@EEVblog]

Free happy ending with every video.

[@WobblycogsUk]

As someone who is just beginning to learn electronics what you just did looks close to someone performing a miracle!

[@SianaGearz]

nnnno.

[@loydsa]

Nice job Dave, interesting to see your diagnostic process. Regards Sarah

[@gaellafond6367]

28:38 There is a bubble in the flex cable on the side that join with the LCD. It seems to match with the line that was failing.

[@Fridelain]

Screw down (nuts and bolts) a metal or plastic strip over it to sandwich it down. of course that requires crear space on the PCB at each side to drill the holes, or cutting the traces at each side and running some bodge wires.

[@angelioto007]

I don't wanna be that guy, but i think that the first pot you've soldered in is the contrast pot, there was just a 0ohm R6, that was bridging the gap so the contrast could be received remotely, and that R6 was just shorting out your pot.

[@MrEkg98]

I think this is my favorite video dave. You show your troubleshooting. Love it.

[@MichaelBerthelsen]

8:58 "as tight as a nun's nasty"😂😂😂 Followed by advice to use a screw-driver or just your finger, and then an LMFAO reference... You're the man!😂😂

[@jamesgrimwood1285]

Yeah that's a new Davism I've not heard before :)

[@lawrencebillson6224]

Pretty common to hear in Australian workshops. Also “dry as”

[@GiveAcademy]

I clipped the part just after... you know.. the "wiggle wiggle wiggle... yea... look at that... beautiful... no pads lifted... thank you very much, I'm a professional. "

[@MichaelBerthelsen]

@@GiveAcademy That entire part of the video just needs its own video...😂

[@MattStum]

@@jamesgrimwood1285 I think he's trying to catch up with AvE :)

[@deltekkie7646]

Hi. This is so funny. I just sent you an email asking how to fix the exact same problem with a keyboard that I replaced an LCD in. I noticed in the data sheet that they reccomend -13V>10Krec>10pot81Kpot

[@rath6599]

It's upside down cause you're in 'Straya, mate!

[@inigoselwood9382]

Loving the JLC PCB pen visible at 14:19, Dave

[@brianblasius]

Hello, kindly do a video about feedthrough capacitors.

[@1117johnson]

Wow, I don’t know what really happened here, but it is entertaining to watch you fixing stuff.

[@Damien.D]

Nope; You cant solder to glass traces on LCD panels to replace hot glued ribbons of death. Tried that too. This brand new fix is just perfect.

[@SianaGearz]

Can you get maybe new ribbons or alternative connection methods to that glass substrate?

[@pshq]

It reminds me how my dad managed to repair such sticky ribbon cable (in an lcd kitchen timer) by pushing some matches against the tape and closing that inside the case so the matches are pushing the tape quite heavily to make good contact with the pcb.

[@GamingWithNikolas]

I don't know jackshit about Electronics but I have been loving watching your videos over the past few days.

[@EEVblog]

Thanks

[@GamingWithNikolas]

@@EEVblog Holly crap you responded. That just made my day. I wish I knew what your talking about, don't understand most of wha you say. I only have the most basic of electronic understandings.

[@Darieee]

Very satisfying end to this one!

[@muzzaball]

Love watching you work Dave!!

[@ElmerFuddGun]

That crystal cutout mounting is quite interesting. I don't recall seeing that before but I'm guessing it was done so that every component is soldered on the top side to reduce a production step. - 4:19

[@EEVblog]

It's relatively common for through hole parts to minimise height profile. in this case though you don't want solder joints on the other side because the LCD backlight has to sit flat.

[@wannabetechnician7451]

way more satisfying repair than the previous 'hot fix', great!!

[@stuartmcconnachie]

Isn’t the connector only on the other side because the display is rotated 180 degrees? The command set usually contains a command to specify which way is “up”, so anything you write to it still goes left to right, top to bottom, regardless of chosen orientation. So yes, as you say “flip done in software” but mainly in the display chipset - because after you tell it the orientation all the other commands and data are identical.

[@unh0lyav3ng3r8]

Accidentally short it and it looks great!

[@ZylonFPV]

Nice, I’m glad you revisited it at the end and then ended up with a nicer solution. Also I was scared when you were going to live the pot on the board but the end resistor solution looked super neat and durable 🙂

[@techman2471]

I had great timing,. I am number 555 to like this video:)!

[@tubical71]

I´m 3055 :) :)

[@vaporlock32578]

I was number 3.1 K LOL..

[@IlBiggo]

I noticed a 55.5 KHz parasite frequency in your comment .-D

[@neut1121]

prove it

[@Norstator]

These T6963C ones also work in Korg Wavestation, Korg 01/W, Kawai K5000 and many other synthesizers as a replacement.

[@WacKEDmaN]

Nice job Dave! flat flex cracked in 2 on my flip top donkey kong back in the day...im still devastated!

[@EEVblog]

I had a Donkey Kong and DK Jr

[@codebeat4192]

Always amazed by different implementations of the 'same'.

[@DragonTamerCos]

Beautiful solution. I would of cut the wire to pin 4 and att some extra copper to solder to a resistance value to bring it down to -7v. But that probably wouldn't of wroked.

[@Phantomthecat]

Fairly common failure one type of generator controller we use - mind you, they last 10 odd years of being abused, but it’s a pain when it happens and a new controller is $5K.... Normally the machine is scrapped around that time anyway due to high hours, etc. Might have a go at replacing the screen in one. 👍. Nothing to lose.

[@allalphazerobeta8643]

Hmm, I'm in the market for quality generator at a good price. Will have to look for one with blown LCD...

[@Phantomthecat]

All Alpha Zero Beta you don’t want one of ours after we have finished with them - 8 to 10 years old in a Hire fleet - most have 25,000 hours or more on them.

[@leisergeist]

Before you throw money into it, if the LCDs are like the replacement Dave got - no shite hot bar cables, just zebra strips, you can try cleaning the rubber contact strips with isopropyl, torque down the case tabs, and it might be good as new! YMMV, but it's a pretty good last resort before buying a new one :)

[@PicaDelphon]

Nice little Head Scratcher of a Fix, and Lucky to find the LCD part.. Good learning Fix..

[@dbtx]

Had a similarly good time putting a new HD44780 40x2 screen in the old Korg M1 because of mismatched negative voltage rail, so the new eBay one had wrong range for the contrast knob to work well... in the end I put the new 'compatible' LCD in an M1r (by jumping a couple resistors to tweak the voltage) and donated the matching PCB from the black-on-green module in the M1r (also with original 44780!) to fix the dead green-on-black module in the keyboard. NB: it had only died because I did a tremendously stupid thing involving an ATMEGA328 and an LM317 and of course a pot.

[@SianaGearz]

I think the error was too much pot.

[@derofromdown-under2832]

Great circuit analysis Dave, well done!!! A bit of a bodge job, looking like it was purchased from the Who Flug Dat factory in China, but since it works well, all is good... 10/10

[@davecc0000]

Always nice to hear that the pros miss something like that (software control) and 'fess up to it. Thanks for the fix-it vid. Always like to see your fixing stuff vids.

[@lezbriddon]

PSA group (citroen/peugeot) used a lot of lcd's with those awful glue on connectors always having lines go out on the lcd, every fix known to man trying to keep them running but always repairs were no better than temporary

[@imgertberg5344]

Great Scott! said just after the pot replacement

[@funkyironman69]

Good video Dave.

[@DreitTheDarkDragon]

Dave, try to disconnect output of negative voltage source that is on display and connect it via wire with contrast setting pin on connector. I guess you bought 3.3V display instead of 5V display (or something like that), so it have 3.3V source build in (that inductor you mentioned) and it will make mess when two voltage sources will fight each other. EDIT - nevermind, you solved it already

[@stevetobias4890]

Great fix. They should cater for screens needing replacement though.

[@raymondrynehart]

you need more vids like this one fault and repairs, love it.

[@gusbert]

Yeh, contrast control on these "older" LCDs is a nightmare. Sometimes the module will have on-board negative voltage generation, sometimes it is also temperature compensated, sometimes neither. I remember designing an external temperature compensation circuit so that the characters were always viewable so software control was not necessary, but it was always somewhat a compromise.

[@yoksel99]

11:03 - pretty how you do it soldering job on that LED cathode wire. Guessing the flux is still nowhere to find after the flood disaster :)

[@felenov]

Upside down LCD? All the electrons gonna fall out! That is nice solution

[@PlasmaHH]

I have seen people with 3d printers create little clip on tab thingies over the cable to provide enough downwards force to keep them connected. There is not always the space though...

[@Ratzfaz]

Upsidedown mounted, jerk, it's the australian Version ;-)

[@maicod]

everything falls out in Australia :)

[@IlBiggo]

@@maicod Yeah, that's why he must desolder stuff upside down, or the components will fall up to the ceiling.

[@apollorobb]

I bet the contrast difference in the new module to old is due to much greater efficiency in the new LCD displays

[@MrOtaku187]

This vid had more twist and turns than a flick at the cinema ;)

[@TheGFS]

You need to break more of your stuff, these repair videos are awesome :)

[@AL_O0]

I have a hot bar LCD on the heating system control panel and it has basically been losing lines since it was installed

[@aajpeter]

I bet there's a key combo to soft-adjust the contrast from the front panel...watches the rest... even better, nice bodge!

[@Bodragon]

Why don't you desolder the trimmer pot, measure the resistance it is at for that good constrast point and then replace it with a fixed resistor? EDIT: I should really watch all the way through before commenting. I see you do this later on albeit in a slightly different way.

[@dipi71]

26:41 The »1« digit on the left upper side (in »CH1«) is still missing a pixel on its bottom serif. But this seems a design choice (or oversight) of whomever coded the font bitmaps into memory. It irks me.

[@EEVblog]

You'll live.

[@leisergeist]

Huh, that's weird! They certainly had room for it...

[@petaks01]

Excellent video as usual Dave.

[@hoffmannolsen]

Would love to see you fix a dimmed VFD Display. Someone told me to burn the kathodes with a higher power just low enough so they won’t melt but just sort of glow. That should remove any oxidation I guess and bring back brightness. Anyway great video.

[@envisionelectronics]

Per Hoffmann Olsen I posted this fix on the EEVBLOG forums years ago (username envisionelec). Someone else reported success, too. I’ve had varying success over the years but it’s worth a shot!

[@hoffmannolsen]

@@envisionelectronics Thanks, this is your posting: www.eevblog.com/forum/chat/vacuum-fluorescent-display-rejuvenation/msg272424/#msg272424

[@PhilXavierSierraJones]

That's a bummer. Pretty sure I had a GPS compass or some other device that had this problem too.

[@TrebleWing]

Really enjoyed this repair a lot!

[@zx8401ztv]

Keep the old zebra strips dave. I have an old micronta multimeter with the same glued on ribbon, as it was bad at the pcb end i made a two screw bar clamp to keep the connection pressurised. It's a bodge but it works great :-D

[@TheAnalogKid2]

Yup, physical pressure. Still good after 10+ years.

[@leisergeist]

I've noticed they usually have a memory effect after being squished between contacts for years The PCB pads kind of imprint on them, and they never really make good contact unless they're in the same position on the same board :(

[@zx8401ztv]

TheAnalogKid2 Well my old meter was done 3 years ago, the display has every segment and the contrast is still good :-D. The art of bodging is not dead lol :-D.

[@silvestrenet]

Wonderful Dave!

[@drivejapan6293]

Was there a reason you didn't just remove the zero ohm jumper on the driver board and put the resistor there to get into the software contrasts range for the new display?

[@nonyourbuz5805]

...the contrast seemed a little better with your first pot installed?....

[@h0ll0wm9n]

Good on ya, Dave, for giving it 'nother go!

[@MrLeo3D]

Thanks Dave for very helpful info, I'm having a problem with my Korg Karma synth having 260x64 lcd (also from around year 2000). Its having random blank vertical lines, very few replacements online and even then they are selling for as almost the cost of whole synth. Your video has made my thoughts strong that there could be a workaround like this if general maintenance fails. As per online photos the Korg lcd has flexible cable on top instead of side like your old lcd. Do you think that my lcd problem might be due to flexible cable or something else like chip issue and that the lcd MUST be replaced?

[@4BoltClevo]

should have gone a sexy oled display - i love the yellow on black monochrome ones

[@ve3krp]

Great video Dave... I love these types of fixes...

[@khashmeshab]

If you look carefully and compare @2:09 you'd see that there's only one type and the connector is on one side. The other module is rotated 180° before taking picture of it! 😅

[@SianaGearz]

Why do people keep making comments which are redundant with the contents of the video?

[@khashmeshab]

@@SianaGearz I can only say for myself that I am trolling! I don't know about others.

[@SianaGearz]

@@khashmeshab A good troll makes the audience feel like they're losing their mind. But what does making yourself seem like an imbecile accomplish?

[@khashmeshab]

@@SianaGearz A good troll makes you feed him by replying to him. It seems that I was successful ;-)

[@SianaGearz]

@@khashmeshab You are aware that it's been mutual?

[@AG-ze8sj]

Dave, you are doing electronic fault finding and repair, not witchcraft. You started doing some voltage measurement earlier when you started, but failed miserably when you were trying to fix the contrast. Your contrast fix was based mostly on guesswork, you never measured voltages when you were experimenting with trim pots. Bad example for young players learning fault finding.

[@EEVblog]

It's not a bad example, it's just one way of doing it, I got the win without any measuring.

[@brianr5355]

So, the old LCD has zebra strips that are to big on the bottom.What is stopping you from removing the hotbar cable, snipping the extra bit of zebra strip and making the connection that way? just for testing... ( or do the lands not line up well enough to make this work?)

[@eagerestwolf]

Couldn’t you have also replaced the 0 ohm resistor with a 4k3 on the driver board? Seems like that would have been a cleaner solution.

[@90msg90]

What's gonna happen in episode #1630? You're gonna take a hammer to the PM300?

[@phinok.m.628]

Huh, I think I would have removed the contrast pin on the pin header of the LCD board itself instead of removing the jumper in the driver board, that way you would have only had to modify the LCD board. But in either case, software control is of course better then messing around with a pot...

[@drgusman]

You could also have used z-axis conductive tape to repair the old display.

[@lightmagick]

On the original module was it possible that one of the pins was connected to another one? I ask this because when you were checking the voltages @13:44 and shorted two of them together it looked like it came good.

[@EEVblog]

Only temporarily came good as the Vo supply was shorted and transitioned through the correct voltage.

[@lightmagick]

@@EEVblog ah I see.

[@gorillaau]

Well done, Dave. Nicely Battle won!

[@mwpaus]

Should have looked at Crystalfontz, Dave... they have the 240x64 in the other colours in stock, and are cheaper.

[@EEVblog]

Checked, not cheaper. US$50 + US$49 postage to Oz

[@mwpaus]

Ah yes, i forgot about postage :(

[@envisionelectronics]

Also CrystalFontz is, on the whole, a lesser quality display. I spent a lot of time testing displays from several major players before choosing Newhaven for one of my designs and then finally going to Newhaven’s OEM to get even better pricing.

[@mwpaus]

Lesser quality? In what way?

[@EEVblog]

Mark W - Yep, the "Australia Tax"

[@MoreCharactersThanNeeded]

You don't wiggle the desoldering gun before trigger when unsoldering?

[@sanches2]

the value that matters is always the one that's missing in your inventory :)

[@eigenvector7035]

20:39 whats wrong with that 1 in "CH1" ?

[@punker4Real]

A better question is why did they skip out on one resistor?

[@riccardoz2953]

Amazing video, ,more amazing than usual amazing others your videos. damn u rock Dave. sadly im to the other side of the earth ... italy ! Keep rocking man !

[@PunakiviAddikti]

This is why people should use through hole LCDs, or those ones with metal frames and conductive rubber strips. If you tear or melt one of those tab strips it's just gone, no way to repair.

[@jenzbrettschneider8838]

Nice your Lab is looking like Mine

[@WillArtie]

Nice one DJ!

[@thehighwayman78]

Excellent! Honestly my first thought was, maybe it's software driven :)

[@Caffeine_Addict_2020]

Question, why can't you use conductivity testing to check and see where the traces are running? Why is it necessary to track the traces visually? Apologies if this is a stupid question, I'm a pretty novice electrical engineer. Also what do you mean by ferphy? Love the videos though man! Your vids are entertaining and I feel like I learn so much at the same time

[@SianaGearz]

Yeah no you don't usually need to follow traces visually like that, you just guess where things might end up from glancing at the layout and then buzz them. But on video it makes sense to show them, right? Not just tell that they buzz. But be aware that continuity testing can produce spurious readings. I mean depends on the multimeter, but a diode might buzz in one direction; a MOSFET with gate left floating and gate left charged will buzz on any multimeter in at least one direction.

[@scaleop4]

nice fix dave

[@user-vn7ce5ig1z]

7:30 - Odd Tinkering recently restored a GameBoy where the screen was missing half of the columns. He reflowed the solder on the tab to fix it, but near the end of the video, one line (which he said took 30m to fix last time) was missing again and he had to reflow it again. My concern is that if he fixed it and it died again once, why would he assume it won't again? 🤔 Why do they even use these things when they are such junk? 😒

[@NICK-uy3nl]

Nice detective work Dave, IF you had access to the Hitachi H8 firmware, it would be very easy to switch to larger fonts for the display