Troubleshooting vacuum fluorescent display problems

[@jamestom2510]

As Adie Lawson said below, you make it so easy. I have a situation in my JVC hifi after installing a bluetooth upgrade i "ACCIDENTALY" dropped a screw on the back of a main board and shorted a PNP transistor and now the phosphourescent display is reading a troubling 8888888888 and every display segment is on. The trouble is trying to locate a KTA1046-y transistor and the only unit that was economical to get in a decent delivery window of 3 weeks was from england, the ones in china would take over 2 months....... nothing like modern times.

[@adielawson7179]

You make this so easy! I have a timer (pioneer DT 510), that the vfd shows 13:00, then after a minute, it shows normal time display. Where should I start looking so I can fix this?

[@nixietubes]

Your intro is so dated but i love it so much

[@wadehicks9270]

How you liking the new scope ? As for myself I think their kinda cool but their nothing like the old analogs lol

[@HMartindeCampo]

I see why the display was not lighting up, would it be the same possible issue if the display is lighting up but very dim and an equally dim?? The right side of the display lights up a little more than the left side. This is for a very high-end Carver receiver, so I have to repair this she’s a classic‼️

[@mrmagnetoscope]

Is this a common issue on VCRs? I got a Panasonic NV-HD100PX (yes, it's the K deck) and the display doesn't light on. Plus it had that common issue of the cracked plastic piece on the loading motor, which I managed to fix with super glue.

[@toddreich1377]

Hi. I am working on VFD clock radio. I have the service manual. The display appears to be working fine. The Hi is very visible and the Lo is really only visible when the room light are out, an maybe that is the way it is intended to work. Is there another a way to communicate with you? It is a Panasonic RC-6610.

[@masoudmontazery907]

Good luck sir...

[@jordandoe2768]

Any idea what would cause a VFD to go dark when your finger gets close to it? you dont even have to touch your finger to the glass, just moving your finger close to the tube will cause the segments to get wiped, after a while they will come back, this issue has been driving me crazy, I dont want to just condemn the tube but given its a bit weak anyway it sure looks like the tube is the issue but Ive never seen one do that when you get your finger close to it, any clues on that? Thanks

[@RegiPavan]

Burnt resistors are hard to spot... nicely done

[@12voltvids]

Especially flame proof and fuse resistors.

[@MrSh4W]

Any help regarding a Kenwood KE 7090 Graphic Equalizer? On standby mode you can see like red lines that glow, never happened before, ive replaced all capacitors but still the same results

[@MC-ph7gr]

Hi. Thx for the great video. I have a question. I have a Sony Lbt-V902. There is 2 problems with the tuner and equalizer displays. Tuner: Some characters of the tuner display are dimer then the other ones. Equalizer: Right channel display is dimer then the left one on the spectrum analizer display. Are these fixable without changing the displays which are impossible to find replacements? THX

[@TheRadiogeek]

Question for you. When a cap goes bad and leaks on the PCB should the board be cleaned? Will the goo from the cap eat away the PCB over time or not? I enjoy your videos on repair. Thanks.

[@12voltvids]

Yes it will damage traces. The electrolytic is slightly corrosive.

[@infinitecanadian]

I think that about 75% to 95% of problems with electronics can be rectified somehow if you have things like a 3d printer or the ability to etch a printed circuit board, but if a vacuum florescent display suffers a catastrophic failure (like being vented), it's all over, unless it's a video cassette recorder that has an on screen display or something.

[@itsmesb4399]

I have a Sony RDR HXD710 which has a very dim display but it’s brighter towards the edges. Everything else on the unit is fine. It’s got an always on display though, so do you think it’s a warn out display or something to do with the power circuitry such as capacitors?

[@12voltvids]

The display tubes do eventually wear out. The cathode wires eventually drop in emission and the brightness falls.

[@MrSh4W]

How do you make a VFD brighter mines started going dim on an old kenwood equaliser?

[@12voltvids]

If the voltages are correct then it is the tube that is getting weak. They are a vacuum tube, they do get dim as the emission from the cathode decreases.

[@Bluethunderboom]

Where does this console was made?

[@VintageElectronicsGeek]

A weak VFD is not the same as this correct? That's caused by just the phosphorous getting old?

[@12voltvids]

Usually it is the rare earth coating on the filament that goes south and causes low emission. This one didn't work because a resistor in the filament circuit was open, so no current across filament to heat it.

[@TechnicFreakJulian]

Can you make a video how to fix this cause I'm having an Kenwood tuner were the display is dimmer than it should be. Pls. make a video about this

[@Gaspar.Albertengo]

Hi. I have an VFD on my car and suddenly it filaments started glowing orange. What do you think, it's wasted or can be repaired?

[@12voltvids]

If they are glowing then there is too much current flowing through them. They normally do glow very faintly as they are hot cathodes. They have to be hot to work, but not to the point that they become an incandescent light bulb.

[@subigirlawd_7307]

Godlike!

[@installedsound906]

I have a Sony STR-K670P Home AV amplifier. It's still going great without any bad solder, though I noticed the display is quite a bit dimmer than it should be, but still legible. The matching DVD for it almost is blinding in brightness in comparison to the amp. Is this a case of it worn out, or do you think there is any servicing I can do to restore it somewhat again? I have tried the DIMMER button, but it just makes it darker. Thanks

[@installedsound906]

The upper part of the display is dimmer than the bottom part, and there are some faint red thin lines, I think it gets brighter at the bottom at one of those.

[@12voltvids]

It could be the tube wearing out. If the supply voltages to the tube are correct, and there is low emission then it is the tube. Those glowing wires you see is the cathode (filament) that is heated so that it looses electrons that are attracted to the positive charged anodes (segments that light up)As the cathode wires wear out, (actually the chemical coating on the wires) they emit less electrons. It is also possible for then to actually break. This you would be able to see if you remove the dark filter in front of the tube so you can see the glass tube. If one of the filaments at the top was broken, then there would be no emission at that part of the tube and it would be darker.I built one of those ICE TUBE clocks last year, and the seconds digit is dimmer than the rest, but in this case they use a buck converter to generate the 40 volts needed by the display, and the pulse duration is very short, and as the digits scan left to right, by the time the multiplex scan gets to the seconds digit the voltage is discharging from the capacitor. I contacted the kit manufacture, and they said a new converter transistor was needed and sent me an upgraded part, and it made a slight difference. Of course if I power it up with an external supply it works fine. My feeling is the choise to use a buck converter was a bad one as there is not quite enough power. They should have driven a proper transformer to create the 60vdc supply rather than a simple buck converter. When I measure the average voltage with a meter it is fine, but the scope tells the truth, the voltage starts at about 60, and then as the digits scan drops to about 20 as the capacitor discharges. My multi meter reads generally 45ish as they are not fast enough to catch the ripple.

[@installedsound906]

I'll check it over with my meter when I get home. The unit is only from 2005, so it's odd that it has this fault. I mean it's not that old. But, I bought this about a month ago used off eBay so I have no idea on the history of it. Thanks for your reply :-)

[@12voltvids]

Ebay... OK you said enough. I have never received anything that works properly off ebay, or for that matter Amazon. Every piece of equipment I have ever bought has one thing or another wrong with it.

[@installedsound906]

Other than the display issue it's fine. I'll tear it apart tomorrow and see if I can find out whether it's repairable.

[@geojor]

great, thanks ...

[@YoStu242]

I have perfectly good JVC HR-XV3 VHS/DVD player that only has dead display. I took a look inside but couldn't see anything obvious like leaking or bulged capacitors (that's where my skills end) and seems like everything has to be dismantled to get the power supply board out because it's under the DVD rack. I wish I was electronics god too lol

[@DAVIDGREGORYKERR]

should the voltage on the heater be around 3v, I have a calculator with a florescent display it it appears to be 3v

[@12voltvids]

Yes about 3V

[@paolomarcelogalvan1938]

What about if all supply is good and complete but no display. What is the main trouble?

[@12voltvids]

If voltage is correct there is only 1 thing left. The display tube

[@paolomarcelogalvan1938]

@@12voltvids it can be repair it the display tube?

[@12voltvids]

@@paolomarcelogalvan1938 Sure, replace the tube. Good luck finding one.

[@salmansh8]

I have a Sony MHC-881 with dim display problem. Can someone help?

[@andypalm7061]

Nice job. How about if it was just a "dim" looking display?? Only reason i ask is,i have a sony MHC-2200 system that seems (to me), that the display is on the Dim side. I was going to re-cap the whole thing anyway....but. ugh.

[@12voltvids]

Check your voltages, if they are low then it could be a capacitor issue or dc-dc converter if it uses one. If the drive voltages to the display are normal, then the display could be getting weak.

[@andypalm7061]

Thanks,I'll be doing just that then. It's old,but i love that thing. It just sounds good for only 30 Watts.

[@12voltvids]

People put too much emphasis on re-capping thinking that it will fix everything. Electrolytic caps do fail, but not at the rate that everyone thinks.I just overhauled my 37 year old Betamax. You know how many parts I put in it? Zero, none. Not 1 single part or capacitor. I figured that I would find bad ones, and I am sure they are all getting pretty dry now, as some of the circuits had drifted off frequency, but a little tweak and it was recording and playing fine. Mind you I am not using this machine, and likely never will use it again, it was more of a project to see if the unit would work after sitting untouched since 1986. 30 years and even the belts and rubber was mostly OK.I have about 8 gigs of raw footage to edit, and I will post this old interesting VCR from history.Back to the capacitors, I only change capacitors that I suspect are bad after measuring the ESR on my meter, or if they are showing visual signs that they are bad. (Bulged can, leaking electrolytic ect.)

[@andypalm7061]

wow. 37 years! point made

[@geezberry8889]

after replacing the resistor you should have measured the filaments again so i can understand what it should be

[@12voltvids]

Filaments typically have about 2vac on them but some designs use DC filaments so measuring really wouldn't accomplish much because it depends on the design you are dealing with and how it is wired.

[@geezberry8889]

@@12voltvids i'm trying to determine if the vfd on this expensive piece of gear (Lexicon M300) is dead or if the PS needs addressing. I have to understand how to test this VFD. thanks

[@12voltvids]

@@geezberry8889 you will typically see ac on filaments or and there may be a -dc applied as well as the AC to hear them. Then the anodes get a + voltage. Then there is the screen. There Are many types of display. Direct drive and multiplexed. It could be a power supply issue, driver issue or a display.

[@zx8401ztv]

A good 23 years old, doesnt look that old really. Many years ago i had a frends vcr here, the display had gone off but the machine worked. Near the front there was a small metal box with transformer and parts inside, it was the display h.v supply, the aluminium top cap that sat on the round transformer had become unglued and shorted the feed, i left the cap out and replaced a micro fuse N30, all was happy again :-D. Daft faults lol.

[@12voltvids]

That would have been a Hitachi made machine. Dc-dc converter failure is what that module was. It also generated the hv tuner control voltage on some older machines with voltage synthesis tuners. Those were the ones that have the trimmer pots to set the stations.

[@zx8401ztv]

Yep i think it was, it worked very well, my frend never had another problem with it again :-). My favorite was the panasonic Nv333, very forgiving when playing tapes.

[@Penfold8]

7/28 that's my birthday 😊

[@Rhythmattica]

Listening to this, it's an electronics tutorial narrated by Ben Affleck.....

[@mikedrz]

Great video, I love VFD's. I've got a different issue with mine, mine pulses the grids that are supposed to be off. I don't know if it's a power supply issue or just the display. Here's a 5 second video of it happening. kzbin.info/www/bejne/bGmlpodjgtGijZI

[@12voltvids]

Well I can tell you what it definitely isn't. The display. They don't fail like that. They are a vacuum tube, basically a direct heated triode. It is likely a bad filter capacitor in one of the supply curcuits. I had a weird one with a display issue. Watch this one: kzbin.info/www/bejne/qpS6gqmNfpqKe8k Might give you an idea. This was one where an electrolytic capacitor actually shorted.

[@mikedrz]

I recapped all the electrolytics I could find the the PS, but no dice, and I measured 11 VAC on the 32 Volt rail. Dunno what the heck is going on there, oh well.

[@12voltvids]

You shouldn't have AC on the 32 volt rail. How are your diodes? AC should only be present on the filament

[@mikedrz]

I pulled the rectifier diodes and they all pass a diode test. However the resistance across one of them is 800K ohms while the others all measure around 4 Megs. I don't know if that means anything.

[@12voltvids]

Normally silicon diodes will pass current witha .6v drop across the junction in one direction, and apear as open in the other.