Many thanks to Mickle T. over at the EEVblog Forum for reverse engineering the R6581 and coming up with a well documented upgrade to OLED. www.eevblog.com/forum/repair/advantest-r6581-vfd-replacement/ My next move on this (you know me, I can't keep my hands of this sort of thing!) is either a dual OLED display (side by side), a large TFT OLED or just bare minimum perhaps a proper Pcb to mount the OLED and STM32 board for a much more 'professional' upgrade, and easier for everyone. Hmmmm! Ian.
Well done, and kudos to the clever chap who engineered the clean replacement and documented it so nicely! I wonder if there is enough room to make a similar mod to the HP 3478 5-½ digit multimeter from heaven with the LCD display from hell…
From what I read the 3478A shares its part number: LCD P/N = 5061-5212 HP 3478A HP 6622A HP 6630A/B Other than that there is the Nixie conversion on the EEVblog forum which I am sure you particularly would like…..:) hackaday.com/2019/10/30/multimeter-display-perked-up-with-nixies-leds-and-neon-tubes/ Ian
I did a similar display replacement project for a Fluke 8050A DMM, though in that case, it was BCD digit data and digit select signals that I had to eavesdrop on. Once you have the actual numeric data, you can add new features like Min/Max, or in the case of a Relative display, showing the original base value in smaller digits, elsewhere. I used a color TFT display, and have slightly different colors for different modes (Voltage, Current, Resistance, etc.) If you're in there hacking on the code, there's likely other "features" you can add that were originally impractical/expensive with the old VFD display technology. It was great fun to rehabilitate that old DMM - might only be 4.5 digits but nicely usable as a "daily driver". It's now looking sharp with nicely rendered fonts on the display, rather than the 7 segments it replaced.
You say that you couldn't find a larger OLED display. Maybe you could contact whoever designed the new screen if they could design one that drives two slightly shorter screens side by side
Great result, Ian. I like the yellow display best and could definitely see a brightness increase with the increase Iref. I had wondered about changing the perspex but saw Defpom's reply that it is part of the front panel membrane - that's a shame. Regards, David
I love the amber-yellow look, great mod! I'm not a fan of OLED displays in things that have largely unchanging displays, as they burn in like anything. Maybe they have improved. The OLED display in my Denon bluray player made in 2018 is completely burned in, some pixels barely light at all, looks horrible.
You can remove the front polarizer on the OLED. It takes 50% of the brightness and just makes the display non-reflective. As the display sits behind the smoked glass you don't need it. OLED doesn't need a polarizer filter, but as this is a standard product in the industry it is used. Try removing it, it's super easy to peel off.
I tried it, I had a spare yellow OLED so modified one and switched between them and there is very little difference, at least with my resistor mod on the original one and the standard one with the polarizer removed. I guess would be worth doing for those without the resistor mod.
The first idea that came to my mind was to replace the smoked shield with translucent glass. Then maybe add some bezel around the smaller display with spray paint.
Yep, but I don't really want to cut up the front panel.......you never know somebody might start making VFD's for this unit just like they did for the 3458A 8.5digit DMM.
Great work Ian and the original project author, would be awesome to use some of the newer phone displays! Would be very bright and very high resolution.
This would have been a good one for a wide tft. I've stopped using oled displays as they always seem to burn out quite quickly. The emulation on it looks great though
Honestly couldn't see a change on the white but I did notice it on yellow, but barely. I don't know if I would bother based on the awesome mod video, but your in your lab and will be staring at it allday, if I had an 8.5 digit meter I would stare at, power or no power ! EDIT:- forgot to say how awesome it looked would love to see green though. Also watch this space ! good luck with your code
The yellow was certainly the way to go, as it showed the brightness increase better too, and the contrast is better as well. What a beautiful instrument (he said jealously) and what a very nice conversion of the display. It's a shame that these VFD's go dim, they're beautiful when working well. But very well done and a very enjoyable video, as usual!
There is also a wee hardware mod for the original VFD to increase brightness by cutting the brightness control line……but it only gives a small increase. Others have tried the filament trick but again, when the VFD is as bad as mine there’s no saving it!
theres the W256064 oled module, its 5.5 inch so a little bigger. but its quite expensive compared to the oled used here. i tried converting my 34401A but the oled wasnt bright enough.. i bought a china vfd instead didnt know you could mod it for higher brightness!
Have you checked if that resistor is the same value for different colours display ? I had to compare LED's (red blue and green) to adjust their current so that they are the same brightness for the eye, and found that the green needed at least 3x less current for that same brightness, and that could be a worthwhile difference in burn out time.
Like the yellow, through the smoked screen it has a sort of old school plasma effect. I'm working on a piece of equipment with bad display, there's a raspberry pi nano conversion with oled quite similar to your project. Regarding the old vfd I would have run a dremel disc down the pins, not sure there's any point in keeping a duff vfd?
Really not trying to teach a mother to suck eggs, but have you tried overdriving the heater wires on the old VFD for a few seconds to burn off the crud? Can bring a dim display back to life sometimes, although granted it's not a long term solution. Always look forward to your videos, Ian - really nice presentation.
Great mod. What was the v across the original Iref. The ch recognition you talk about at the end would be the icing on the cake. As you say, you could store it and add some Comms: Bluetooth or WiFi.
I never measured the voltage across the iREF resistor before or after. I could probably do it on one of the other OLEDs I have lying around.....I'll have a look.
Waht about using two OLED displays? It seems as if the display is devided into two sections - a wider one with all the digits on the left and a rather narrow one to the right where one can reead "VDC" f. ex. - if you use the one you have for the wider part end get a smaller one, that also could be used in portrait mode, if that fits better... you then "just" 🙂would have to modify the source code to split up the data and control stream for the both sections... Just thinking 😀
Interesting that they expected the 3v3 regulators to share the current. I expect that the regulator with the lowest output voltage will just let the other take all the current. The lower output regulator will shut off as that's the only way it can bring down the output voltage. Due to tolerances there will always be a difference between two of the same parts.
Worse than that they advertise them as 3.3V to 5V capable.......so expect an LDO volt drop when running at 3.3V. Yep, cheap Chinese!.....but they still work!
@@IanScottJohnston never understand why they expect them to power share, something they are never going to do very well. would have been better to fit a higher power rated component in the first place. The one with the highest reference voltage will take the most if not all of the current. As i said the one with the lowest reference voltage will just shut down it's supply of current to the load as it expects this to reduce the output voltage. Maybe an output resistor like we used to fit to paralleled output transistors in power supplies.
@@IanScottJohnston I was thinking may be it was for reliability! when the first one burns out due to being overloaded the second takes over and the pcb lasts a little longer 🙂
Shame there is no TFT version of that panel. The Samsung S8 has so many problems with the OLED getting old that China made a TFT replacement. I liked blue best - lol -. PS: got to the end and he mentioned TFT - lol -.
I agree, the blue looked very much like the VFD. Also, the blue may have been a bit brighter if the protective film were pulled off. But! It's not my instrument! lol
Only part that worries me is that I have had a few bluepills die over relatively small voltage spikes. Maybe just bad luck (and to be fair I think these bluepills are also faked quite a bit so maybe the ones that failed were of that genre). Other then that that is damn nice.
It was the exact same display as Ian used, I also had to change the jumpers to set it to 4 wire SPI etc., only difference is I ended up using the green one.
@@TheDefpom It’s worth changing that resistor, the camera doesn’t seem to capture the brightness increase very well at all. The yellow looks great in real life…….you’d hardly notice it’s behind a smoked perspex screen really.
Good job. Would it be possible to split the readings over 2 oled displays. Range etc on second display. Only a thought as it would be beyond my ability
I thought of that......and was one reason I looked so closely at the code.......but I don't think two of the same OLEDs will shoehorn in side by side. Maybe two smaller ones though.....hmmm?
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Many thanks to Mickle T. over at the EEVblog Forum for reverse engineering the R6581 and coming up with a well documented upgrade to OLED.
www.eevblog.com/forum/repair/advantest-r6581-vfd-replacement/
My next move on this (you know me, I can't keep my hands of this sort of thing!) is either a dual OLED display (side by side), a large TFT OLED or just bare minimum perhaps a proper Pcb to mount the OLED and STM32 board for a much more 'professional' upgrade, and easier for everyone. Hmmmm!
Ian.
Tons of great and clever people on the EEVblog forum!
Well done, and kudos to the clever chap who engineered the clean replacement and documented it so nicely! I wonder if there is enough room to make a similar mod to the HP 3478 5-½ digit multimeter from heaven with the LCD display from hell…
From what I read the 3478A shares its part number:
LCD P/N = 5061-5212
HP 3478A
HP 6622A
HP 6630A/B
Other than that there is the Nixie conversion on the EEVblog forum which I am sure you particularly would like…..:)
hackaday.com/2019/10/30/multimeter-display-perked-up-with-nixies-leds-and-neon-tubes/
Ian
@@IanScottJohnston Nixie conversion - Hell yeah!
The blue one, at least on camera, looked closer to the original colour of a VFD tbh
Loving the rich colour on the yellow
Love the mounting solution, why work hard when you can work smart
I see a huge difference. Looks so nice and retro
Awesome work!
Awsome upgrade giving new life to an otherwise very good condition piece of kit, well done.
We've all got GAS. I'm a musician and can't help myself with a new bit of gear. Love your videos Ian. Keep 'em coming.
I like that. But deciphering the code and rewriting for other display types is definitely above and beyond the call of duty.
Yes can see the change in brightness Ian, and I agree, I like the Yellow. Bob
Good Job Ian!! I always get some small takeaways and the copper wire mounting simplicity is a brilliant idea...cheers!!
Yep, I've got a plastic bucket of copper wire reels of all different sizes for just such an occasion...:-)
I did a similar display replacement project for a Fluke 8050A DMM, though in that case, it was BCD digit data and digit select signals that I had to eavesdrop on. Once you have the actual numeric data, you can add new features like Min/Max, or in the case of a Relative display, showing the original base value in smaller digits, elsewhere. I used a color TFT display, and have slightly different colors for different modes (Voltage, Current, Resistance, etc.) If you're in there hacking on the code, there's likely other "features" you can add that were originally impractical/expensive with the old VFD display technology.
It was great fun to rehabilitate that old DMM - might only be 4.5 digits but nicely usable as a "daily driver". It's now looking sharp with nicely rendered fonts on the display, rather than the 7 segments it replaced.
I really like the yellow; puts me in mind of old hospital equipment 😀
Blue was the better option keeping it more in line with the original. Upgrade was good though.
You say that you couldn't find a larger OLED display. Maybe you could contact whoever designed the new screen if they could design one that drives two slightly shorter screens side by side
Great result, Ian. I like the yellow display best and could definitely see a brightness increase with the increase Iref. I had wondered about changing the perspex but saw Defpom's reply that it is part of the front panel membrane - that's a shame. Regards, David
Thank you for this very instructive video, well done Ian!
Thanks also to MickleT for his great work.
Maybe the seller saw your name and was interested in a new video. Nice one Ian.
I love the amber-yellow look, great mod! I'm not a fan of OLED displays in things that have largely unchanging displays, as they burn in like anything. Maybe they have improved. The OLED display in my Denon bluray player made in 2018 is completely burned in, some pixels barely light at all, looks horrible.
Gorgeous! Thanks for the great show.
You might want to check the memory battery and replace it, I got mine as the battery was flat and gave errors on boot up.
You can remove the front polarizer on the OLED. It takes 50% of the brightness and just makes the display non-reflective. As the display sits behind the smoked glass you don't need it. OLED doesn't need a polarizer filter, but as this is a standard product in the industry it is used. Try removing it, it's super easy to peel off.
Interesting, I’ll have a look.
I tried it, I had a spare yellow OLED so modified one and switched between them and there is very little difference, at least with my resistor mod on the original one and the standard one with the polarizer removed.
I guess would be worth doing for those without the resistor mod.
@@IanScottJohnston So either you can remove the polarizer or risk burning out the display earlier I guess? :D
@@zaprodk dying to know how long the OLEDs will last with my mod.
@@IanScottJohnston Glue a few new ones in the cabinet for future burn outs. Every technique wil be obsolete one day.
The first idea that came to my mind was to replace the smoked shield with translucent glass. Then maybe add some bezel around the smaller display with spray paint.
Yep, but I don't really want to cut up the front panel.......you never know somebody might start making VFD's for this unit just like they did for the 3458A 8.5digit DMM.
Great work Ian and the original project author, would be awesome to use some of the newer phone displays! Would be very bright and very high resolution.
Phone-displays are custom and with no datasheet/documentation available sadly.
This would have been a good one for a wide tft. I've stopped using oled displays as they always seem to burn out quite quickly. The emulation on it looks great though
The newer generation ones will supposedly be better in that regard, but we're obviously stuck with the older ones if we want cheaper ones.
I thought they suffered from screen burn as well just like old crt's
Honestly couldn't see a change on the white but I did notice it on yellow, but barely. I don't know if I would bother based on the awesome mod video, but your in your lab and will be staring at it allday, if I had an 8.5 digit meter I would stare at, power or no power ! EDIT:- forgot to say how awesome it looked would love to see green though. Also watch this space ! good luck with your code
Cheese!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@@fredflintstone1 SQUEAK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Hi Stranger !!
In person it is more noticeable, camera just not picking it up.
Hi Mr squeak, I could not see a difference either.
By the way got a comment from Fred yesterday.
Woof
gotta love some cow sound generator action!
started to think Ian lived in a farm yard.
That's really neat ! great job ! 🔥
The yellow was certainly the way to go, as it showed the brightness increase better too, and the contrast is better as well. What a beautiful instrument (he said jealously) and what a very nice conversion of the display. It's a shame that these VFD's go dim, they're beautiful when working well. But very well done and a very enjoyable video, as usual!
You can increase the brightness of VFDs by increasing the filament voltage but do it carefully.
There is also a wee hardware mod for the original VFD to increase brightness by cutting the brightness control line……but it only gives a small increase. Others have tried the filament trick but again, when the VFD is as bad as mine there’s no saving it!
Interesting, do you think the charge pumps on the OLED would add additional noise in such a sensitive gear ?
theres the W256064 oled module, its 5.5 inch so a little bigger. but its quite expensive compared to the oled used here.
i tried converting my 34401A but the oled wasnt bright enough.. i bought a china vfd instead didnt know you could mod it for higher brightness!
Have you checked if that resistor is the same value for different colours display ? I had to compare LED's (red blue and green) to adjust their current so that they are the same brightness for the eye, and found that the green needed at least 3x less current for that same brightness, and that could be a worthwhile difference in burn out time.
Yes, they are all 680k on the various colours I have now. Green, Yellow, Blue & White.
Like the yellow, through the smoked screen it has a sort of old school plasma effect. I'm working on a piece of equipment with bad display, there's a raspberry pi nano conversion with oled quite similar to your project. Regarding the old vfd I would have run a dremel disc down the pins, not sure there's any point in keeping a duff vfd?
You need a metal screen between the the display driver board and the transformer, you can see strobing on the display
That's on camera only due to the 60fps of the camera. It's rock steady in person.
Really not trying to teach a mother to suck eggs, but have you tried overdriving the heater wires on the old VFD for a few seconds to burn off the crud? Can bring a dim display back to life sometimes, although granted it's not a long term solution. Always look forward to your videos, Ian - really nice presentation.
Others have tried with this exact VFD with only a slight improvement. This VFD is far too far gone for it.
The meter is meant to be oppened with it's faceplate on the table, sliding it's cover upwards.
Great mod. What was the v across the original Iref. The ch recognition you talk about at the end would be the icing on the cake. As you say, you could store it and add some Comms: Bluetooth or WiFi.
I never measured the voltage across the iREF resistor before or after. I could probably do it on one of the other OLEDs I have lying around.....I'll have a look.
I think what I would do is 3d print a case for the new display and keep the unit stock, and just keep the new display separate.
Excelentt Job
Would storing the character data and symbols instead of bitbanging tie the new firmware to this DMM ?
Waht about using two OLED displays? It seems as if the display is devided into two sections - a wider one with all the digits on the left and a rather narrow one to the right where one can reead "VDC" f. ex. - if you use the one you have for the wider part end get a smaller one, that also could be used in portrait mode, if that fits better... you then "just" 🙂would have to modify the source code to split up the data and control stream for the both sections... Just thinking 😀
You can get some SSD1325 displays 2.4" size, two of these side-by-side would work for the size?
If I am looking at the same/similar ones then 128x64 x2off = 256x64 so no pixel advantage.
I think 256x64 is fine, it just needs stretched to 4". I think I will try getting quotes for custom OLEDs. You can get low qty orders via Shenzhen.
Interesting that they expected the 3v3 regulators to share the current. I expect that the regulator with the lowest output voltage will just let the other take all the current. The lower output regulator will shut off as that's the only way it can bring down the output voltage. Due to tolerances there will always be a difference between two of the same parts.
Worse than that they advertise them as 3.3V to 5V capable.......so expect an LDO volt drop when running at 3.3V. Yep, cheap Chinese!.....but they still work!
@@IanScottJohnston never understand why they expect them to power share, something they are never going to do very well. would have been better to fit a higher power rated component in the first place. The one with the highest reference voltage will take the most if not all of the current. As i said the one with the lowest reference voltage will just shut down it's supply of current to the load as it expects this to reduce the output voltage. Maybe an output resistor like we used to fit to paralleled output transistors in power supplies.
Ballast resistors for load sharing would help.
@@IanScottJohnston I was thinking may be it was for reliability! when the first one burns out due to being overloaded the second takes over and the pcb lasts a little longer 🙂
Has anyone tried removing the smoked screen and increasing the voltage to the VFD display to make it brighter?
The VFDs get so dim there is no reviving them.......too far gone I'm afraid.
I liked white best tbh. But through camera and in person are two different perspectives i guess
Yes, in person the yellow just looks fresh, the white looks a little greyed out.
I rather like the yellow
Me too!
We live in a fantastic time, data conversion can be done in low level software. 20 years ago we were bit banging 4Mhz chips in opcode.
Shame there is no TFT version of that panel. The Samsung S8 has so many problems with the OLED getting old that China made a TFT replacement.
I liked blue best - lol -.
PS: got to the end and he mentioned TFT - lol -.
I agree, the blue looked very much like the VFD. Also, the blue may have been a bit brighter if the protective film were pulled off. But! It's not my instrument! lol
Only part that worries me is that I have had a few bluepills die over relatively small voltage spikes. Maybe just bad luck (and to be fair I think these bluepills are also faked quite a bit so maybe the ones that failed were of that genre).
Other then that that is damn nice.
You can use a Zener diode to clamp the voltage if you're worried about spikes.
I am sure Defpom fitted a larger display.
He showed a larger display on his workbench, but fitted the same as me.
It was the exact same display as Ian used, I also had to change the jumpers to set it to 4 wire SPI etc., only difference is I ended up using the green one.
@@TheDefpom It’s worth changing that resistor, the camera doesn’t seem to capture the brightness increase very well at all. The yellow looks great in real life…….you’d hardly notice it’s behind a smoked perspex screen really.
change the window plastic
You cant easily, it is all part of the entire front panel membrane.
@@TheDefpom that’s bad, it looked like it was installed from the back - too bad
Hwhile
Good job. Would it be possible to split the readings over 2 oled displays. Range etc on second display. Only a thought as it would be beyond my ability
I thought of that......and was one reason I looked so closely at the code.......but I don't think two of the same OLEDs will shoehorn in side by side. Maybe two smaller ones though.....hmmm?