EEVblog 1515 - Dumpster Tektronix TDS540D 500MHz Oscilloscope LCD Upgrade

Part 2 in the dumpster Tektronix 4CH 500MHz TDS540S oscilloscope.
Replacing the CRT with an LCD had a few issues...

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[EEVblog]

The results of a poll on Twitter said to move this video from the 2nd channel to the main channel here, so here it is.

[RingingResonance]

On eevblog, some brilliant people were successful in converting these older scopes into the better models via some 0ohm resistor settings, adding some chips on the video side, and changing some thing on the acquisition board to get full 1ghz bandwidth. I helped make the change necessary to use the NuColor CRT's and their respective driver boards. I even managed to use a B&W CRT to replace the original NuColor CRT after cutting off the LCD shutter, making a CRT adapter, and modding the case a little bit to fit the slightly longer CRT with the LCD shutter in front of it.

More recently, I made a 'copy' of the flyback transformer for another project that needed one. I had several of the CRT driver boards and one with a bad flyback transformer I was able to remove the core from. I measured it's dimensions and designed a spool that can be 3D printed, wound, and then placed into a new case. I haven't used this for replacing any of the flyback transformers in any of my scopes, but I did use it for driving a 5FP7 radar tube. Worked really well after figuring out how to properly insulate the windings.

[mickeyfilmer]

Every video is a learning curve for me and I'm in me 60's. -so Dave proves that you're never too old to learn.

[johnwest]

I need to park myself in front of your dumpster. Although I've done pretty well over the years in the dumpsters here in Boulder, Colorado, USA.

[florianhofmann]

I have upgraded my TDS724A, which had a colour CRT, with the same screen and also had to adjust the clock setting for it to work. I used a LM7812 bolted to the chassis to drop down the 24V CRT supply. I also backed those Dallas NVRAMs up via GPIB. Feels like home seeing Dave work on something this familiar. Have a good one everybody!

[MicheIIePucca]

I used a black felt marker to color a LCD frame in an arcade cabinet and it was behind slightly tinted glass. A black felt works well just to hide it.

[thomasesr]

The reason that this scope had that failure mode is because it is a DIVA scope, which means that it needs a Fan to work.

[johnwest]

I always plug in the fans these days when I have the boxes open, because the fans are critical components to keep expensive devices from blowing up in modern gear so the designers make sure the fans are working during their power-up self-tests, and it's a piece of cake to monitor fan current these days.

[ehsnils]

4:36 - those Dallas modules are actually potted an ordinary chip with a 3V Lithium coin cell and they can be "hacked" by cutting open the +3V and ground positions on the chip, cutting one of the leads to the old battery and then connect an external coin cell battery. I have done that with a Compaq 386sx computer and it worked great. I found the instructions on the net somewhere like 5 years ago or more and it was actually quite simple to fix it. The potted IC just have those battery legs bent upwards inside the potting.

[GapRecordingsNamibia]

I think Dave could use a 3D printer in the lab, a printed bezel would stop the metal from the LCD peaking through and would give you a means of securing one part to the other, and believe me once you have a 3D printer you start making up ideas to use it for.... Very handy they

[MattAtHazmat]

Years ago (~2000), I had Tektronix "upgrade" the memory on my work TDS784D. It was just a software unlock of memory already installed.

[derekfoulk]

People like these types of scopes because they actually have soul. Older, full of cool chips and does everything you would ever need. Btw the manuals for this thing dates back to good old 92'!!

[systemloc]

Yeah!! Been waiting ages to see you do this hack!! Glad it's on the main channel, I may have missed it. Thanks for taking this on!

[bluefoxtv]

Nice little upgrade. For a bit i was confused as to why you did not use the power from the fan. But then you showed the fan and it was 24 Volt.

[McTroyd]

+1 vote for a Safe Operating Area scope video! I had never heard that term used in that context.

[PhonePhreakz]

Great video would love to see more modification/repair videos Dave!

[JenkinsUSA]

@3:13 Poor diagnostic workflow when the fan isn’t included as a failure point. Sucks even more when $$ are dropped on a processor board and the issue still exists. Great video!

[nnsda]

Glad you moved it to main channel, hadn't come up in my feed... I'm laughing at that fan issue.. I did EXACTLY the same thing on some other hardware a few years ago.. flow chart said "can you hear the fan" and I thought no I took it out as the bearings shot and it wasn't spinning, it's only a 2 wire fan I'll change it when the things running... .. a day later of testing I put a new fan on and the thing worked fine!!!!

That "can you hear the fan spin" should come with an asterisk highlighting the unit wont work without one connected.

[RingingResonance]

Also in certain DPO modes, these B&W scopes will show a color trace out the VGA port! I think it's if you set it to manual persistence in the trace menu.

[roboman]

There may be an opportunity to push your own voltage into the backlight circuit and artificially increase the brightness. I would not be surprised if that thing can handle 11 or 12v instead of 9.8.