EEVblog - 2025-02-04
Part 2 of the Keithley 2302 battery simulator repair of the VFD display. Just a follow-up on testing the actual VFD display itself to see if there is any fault that's not the VFD vacuum. 00:00 - Having another look at the failed Newhaven VFD dispaly module 05:37 - Measurign voltages 07:32 - Oscilloscope probing 08:33 - HELLO capacitor! But not the one I expected. 12:25 - To the SMD cap replacement kit 13:11 - Rail measurements again 14:38 - Big ripple improvement, but lets qild the lilly. 15:53 - Bugger! Ok, let's try the belt'n'braces approach. 17:21 - Winner Winner Extra Chicken Dinner! Forum: https://www.eevblog.com/forum/blog/eevblog-1664-repair-with-junk-bin-parts!-keithley-2302/ How VFD Displays Work: https://www.youtube.com/watch?v=gZIRPJt69sM Hacking a VFD Display: https://www.youtube.com/watch?v=clUVEyi_YNM Web Site: http://www.eevblog.com Hardware Store: https://eevblog.store/ Merch Store: https://www.teepublic.com/stores/eevblog?ref_id=37825 If you find my videos useful you may consider supporting the EEVblog on Patreon: http://www.patreon.com/eevblog Or with crypto: BTC: 33BsprBQNBtHuVzVwDmqWkpDjYnCouwASM ETH: 0x68114e40ff4dcdd384750500501e20acf3875f8c BCH: 35n9KBPw9T7M3NGzpS3t4nUYEf9HbRmkm4 USDC: 0x68114e40ff4dcdd384750500501e20acf3875f8c LTC: MJfK57ujxy55su4XicVGQc9wcEJf6mAoXF Other channels: EEVblog2: http://www.youtube.com/EEVblog2 EEVdiscover: https://www.youtube.com/eevdiscover #ElectronicsCreators
Getter does not stop contaminates from getting in or out of a vacuum tube. It's not a sealant. It is flashed by inductive heating after the tube is sealed and when a gas molecule that escaped from being vacuumed out hits it it chemically combines and is absorbed into the getter.
A getter does not stop gases from entering, it consumes gases that may come from the metals and whatever else inside, if the getter is not turned white, you still have a good vacuum, no if and or buts about it.
I'm also sure it doesn't have "phosphor degradation" - if it did, the digits that are on all the time would be much less bright than a lot of the characters that are hardly ever used - the whole thing looks super uniform to me. I think that's just as bright as the VFD ever was
@@gorak9000 Correct, but the emissive coating on the filament wires burn off after x amount of hours and there is nothing to do about that.
Junk bin wins are precious, and must be thoroughly celebrated & paraded, as the missus needs to be reminded why she allows you to keep so much junk.
Awesome Dave - happy you came back to this one :)
So glad you had a go fixing the original display and great you managed. Totally agree that fitting the most readable, useable display is the way to go as this is a lab test tool you are going to use, not some piece in a historical museum.
VFDs are so cool. Miss 'em.
You can still buy them. Noritake on Mouser, Newark, etc
@@guytech7310 I use Noritake ones myself. There's a product at one of my jobs that had a bunch of failures with those displays, and were throwing them out. It turned out that improper installation in the product lead to the onboard fuse to blow. Being the renegade that I am, I bridged the connection for the fuse and had no issues whatsoever running them in my Arduino projects..
ugh Tantalum tantrums . Excellent work Dave :)
That's not quite right regarding a getter, It's not a seal. In a VFD display, the tungsten (barium) is vaporized after the seals are confirmed. It reacts with and traps residual gases by forming stable compounds, preserving the vacuum for proper tube operation. Basically anything left in there is absorbed. But when broken they go white. Don't scrap the VFD ! I think you should drive the anode a bit harder like you are doing on the backlight to brighten it up and keep the LCD as back up ! anyhow the whole thing is a good weeks worth of chicken dinners. People who shotgun caps also use Autorouters....nuff said.
Not worth my time dicking around adjusting the anode voltage just so I can put the VFD back in and have it have an even shorter life. The LCD will last forever without any dicking around.
@@EEVblogunless it goes black like ones made in the 1980s.
One could buy a new vfd, but they are very expensive to source unless you can score a surplus one. I might even have one in the bin but shipping to Australia is expensive unless it's needed.
@@paulmcgrath2175 "buy a new vfd, but they are very expensive"
Not really, NewHaven & Mouser sells the same model for about $42 New (M0216SD-162SDAR8). They are more expensive then LCDs, but not very expensive.
The first pcb I built had tantalum caps. Needless to say, i didn't know at that time they were marked backward from other caps. Talk about traps for young players. Boy.. did I learn in a hurry when i tried powering it. Firecrackers, those little buggers are!
Tantalum caps aren't marked backward from other caps that have the same shape, though.
The only ones I'm aware of are not polarized, unlike tantalums.
By marked backwards he means that the + pin is marked on tantalum caps. On electrolytic caps, the - pin is marked.
@ Because those electrolytic caps are round. It's the shape that dictates where the mark goes.
I learned about tantalum capacitor markings the hard way.
Bookmarking this. I love VFDs, especially the 16-segment ones. No LCD display can compare in sheer timeless classiness.
Unless it's dim, and then it kinda sucks.
Timeless? The degradation timer is always running...
@@ulrichfrank4270A friend have a Pioneer timer with VFD display running 24/7 since 1980 with zero service. Brightness is bot bad so far.
Your diagnostic skills are alot better than mine thats for sure @@EEVblog
Don’t forget you have those Sequre desoldering tweezers Dave, save you ripping pads of those SMD caps.
Yeah, didn't have it set up ready though, I was lazy. I think the PCB doesn't use the best quality laminate glue.
we gonna need to see that weller wmrt in action tho!!! its very good and you must get it (top secret info- i am at trefort highschool until further notice ('gonna be banned soon')
Hot air rework station repairs all SMT!
Love a good VFD
Only if its bright...
@@EEVblog He specifically said "a GOOD vfd", it isn't good if it isn't bright. ;)
But he didn't fondle the nipple!
Love the repair videos :)
Nice come-a-gutsa on that cap indeed! So good to see it work again. I'd keep the VFD in, it's a thing of beauty, joy for ever.
I love the look of VFDs
Nice video. I love the VFD personally but the LCD does look good enough.
LCD for the win!
❤❤❤
So much more legible.
VFD's are cool, but that one was super dim and crappy. LCD looks great.
It’s a good feeling when you can use something out of the junk bin. Especially if it’s been in the bin for a very long time.
Awesome repair. Yea as long as your happy with your repair that should be all that matters. Any time you can repair something its great and a repair that cost no money is perfect. Cant shake a stick at that for sure. Thanks for showing it. Love and prayers to you and your family. Love ya Brother !!
It wasn't fully repaired and that box of capacitors wasn't free.
@@Throckmorton.Scribblemonger Keithley 2302 battery simulator was fully repaired with a free lcd module from his stash.
@ This video is about the repair of the VFD, it literally says it in the title. The VFD wasn't fuly repaired.
Great video worth the watch.
I think you made the right call sticking with the LCD. Pretty sure we've all endured the joy of burned out VFDs in microwaves, cars, test equipment.. Beautiful to look at but man is it a horrible tech 😂
.. Would be cool of you replaced the polariser to invert the segments tho 😉
A blue LCD might look better as well
@@monkev1199 Blue/white LCD's look so damn cheap! - And the contrast on them is "meh" at best. I absolutely prefer the white/black or yellow-green/black displays.
At the beginning of the last video, the first thing that came to my mind was: wouldn't it be easier to replace this with an LCD rather than buying an expensive fluorescent display? And you came to the same conclusion at the end.
By the middle of this video, I thought, no way, why replace a perfectly working LCD with this dim, half-dead display? And I’m glad you decided to keep the LCD.
All these steampunk fluorescent displays are fine for novelty projects, but not for tools where reliability and longevity matter.
Excellent.
Works okay at no load, goes spastic as the load increases....yup. The high ESR pulls the voltage down as it draws more current. It was probably resetting the driver chip every time it tried to power itself on.
It occurred to me, would Keithley really use a VFD module from that supplier? I'll bet you half a pound of smoked brisket that isn't the original display, someone already replaced it once.
VFDs are gorgeous though. I love the old school look of them.
Probably right on the border of some threshold, and the subtle difference in the cap pushed it over the line.
Love this stuff always learning something .Cheers from Roma Western QLD
Gotta love a free repair, that’s why I keep lots of old stuff. The missus is not very happy about it though
Nice one Dave, great job mate.
😁👍
Greetings from Ireland 👋😁☘
21:31 At cerain angles, you can see characters burnt into the display. So at least part of the brightness drop comes from phosphor degradation. Maybe this is not a very high quality VFD after all. Yes, it might have been on 24/7 for years, so does my mini hifi since 1997, and no burn on the VFD. The brightness is not the same as it was, but still usable. Some Japanese VFDs have incredible lifespan, any other MFGs are unpredictable.
nice video again. Thank you
I work more or less every day with VFD...no one has issue with logic, all not working items have issue with the "high" voltage power supply, generally with output capacitor. As usual, very godies video !
Good ol' Capacitor spray and pray . lol.
I noticed on 4:30 a small tin blob/ball between the legs of the main chip. Almost halfway (bit to the left). On every shot where it didn't work it was still there, but on the last shot (when it worked) the ball was gone.
Interesting. Might not be conductive
It's always the caps (except when it isn't). So I was right yesterday on the other video!
It looks like the controller IC has two shorted pins. You can spot them on 4:34 and they are located near the D and # symbols on the green sticker. On 23:21 it looks like the short isn't there anymore.
Obviously, you should just have begun by replacing all the caps on that board in the first place. Can't go wrong with that approach!
Careful, that sticker may be loadbearing 😆
New VFD for the win
Feel I should explain the ‘getter’ (the shiny mark inside the VFD) when the device is manufactured a little pan (under where this mark is) is filled with the inactive getter material, then once the vacuum is pulled into the device and it’s sealed the little pan is heated by induction, this evaporates the getter with then reacts with any remaining (unwanted) gas within the envelope, this leaves the mirror effect on the glass as the getter material cools. It then will continue to absorb over the life of the device as no sealed system is perfect, and if the mirrored area appears white then that’s a good indication that the sealed system has failed.
Remember, it's not hoarding if you need it eventually 😁
You know what they say. It's always a capacitor.
Which is of course an overstatement, it's a cap problem only about 95.7% of the time, at most.
There is also a nice OLED version. With black background en white numbers
My objective rule of thumb, if a tantalum isn't on fire, it probally didnt fail. Glad to see it proven once again! ;)
The output cap has a higher voltage rating. voltage, temp and lifetime rating are somewhat interchangeable, that's why it lasted longer
There's also very little ripple current on it. The anode current on a VFD like this one is only a few milliamps.
Well done.
15:50 any arduino with lcd example sketch would allow to test that display. Why to bother with soldering/desoldering?
Oh Oh Murphy was sleepy again today!!!. Was that a coincidence? 😂😂😂😂😂😂
If this was mine, I'd put the original unit somewhere firmly attached inside the case if there's room. I do the same with PC case blanking plates and modular power supply cables. Future me has thanked past me quite a few times for stuff like this :)
❤
@faust-cr3jk - 2025-02-04
Dave actually fixed something. Unbelievable!
@dav1dbone - 2025-02-05
Rumour has it, if you break a tube in the southern hemisphere, the getter easily catches 40 billion oxygen atoms, Dave has been monitored by Guinness World records getting 89 billion, they reckon he was helped since more than half fell out because it was upside down
@RandomUser2401 - 2025-02-05
yeah. not a lot of these.
lots of talk for a recap though.
@EEVblog - 2025-02-05
@@RandomUser2401 You must be new here, welcome.
@Schroefdoppie - 2025-02-05
@RandomUser2401 Dave? "waffling"? Surely not 😂😂😂
@BobSacamano-dy3wg - 2025-02-05
17:25 Nobody was more surprised than Dave.