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Tektronix TDS744 CRT to LCD color converter FPGA module DIY
ltarjanyi75:
Wow, nice design and work! Clever idea with the supports!
What do you plug into that big connector with the strip cable? Is it connected to J5 connector pins?
Tantratron:
--- Quote from: TerrySt on November 25, 2023, 08:03:18 pm ---I bread-boarded the FPGA and lvds interface and it works fine. I have now made a pcb with all of the circuitry and am working on trying to make it work.
One problem I've found is that I haven't been able to find a PLCC socket that fits down over the RAMDAC chip well enough to make good electrical contact and stay mechanically attached. I have purchased several through-hole and smt versions of the 44 pin PLCC socket and none of them work well. I can see from the photos that Vincent sanded the top of the socket down. That helps some. Also, you have to remove some small standoff posts from the inside of the socket so that the RAMDAC chip fits deeper into the socket. Those changes barely work, but there isn't a really solid fit. I have been working on re-shaping the contacts in the through-hole socket and am able to get what looks like a reasonably good connection.
--- End quote ---
Hello Terry,
It is great to see first Vincent from France then Lazlo from Hungary and now yourself in USA trying to come up with another open source variant for this very topic.
As I've mentionned earlier this year here https://www.eevblog.com/forum/testgear/tektronix-tds744-crt-to-color-converter-fpga-module-diy/msg4639096/#msg4639096, I initially bought in 2021 one kit from Simmcomm labs for my TDS794D. Later french university test center asked me to repair and hack their failed TDS540C then one year later, their mono-CRT failed so I recommended they order same kit to Simmcomm labs. I did made the all repair and installation for them. Then later in 2022 a german customer asked my company for two reconditionned and hacked (one TDS580C and one TDS784C). Same story where I suggested them to order 2 kits from Simmcomm labs but they ordered 3 kits, they offered me as an extra payment one kit which I've later installed in my TDS784D.
Personnaly I'm more a radio guy and digital signal processing guy so digital video processing, I do not know very much but find interesting. Anyway, I still use two Simcomm Labs LCD-TFT kits, they work fine except in my opinion the low contrast quality of the G065VN01 V2 LCD panel. Ideally going after OLED or another brand would be a plus but again, the commercial kit works. The onwer of Simmconn lbas told me it is impossible to beat the contrast of NuColor tektronix technology so it is a choice of lower consumption, lighter weight, less failure to go with LCD-TFT medium visual quality.
Reading part of your post suddenly brings some explanation why it was hard for me to install the QFP socket onto the U199 chip. It is very tricky installation, can get loose in no time depending how you press it. No idea what part number Simmconn labs is using but I wonder if they did not sand it partially but for sure, I'm not trying to remove it to install later unless really needed (i.e. main PSU repair). The removal from J5 is no problem of course, the PLCC-44 reverse socket paradigm really is very wierd.
Now legally I'm wondering what this sentence means, namely in my invoice slip which I've paid to Simmcon labs. It is written The Xilinx FPGA design in the NewScope-5/6/7/8/9 kit is released under GPL 2.0 licence, which means that you have written offer to receive the source code of the FPGA design. The source code is available upon request. The schematics, PCB layout and firmware remain proprietary
The kits came with 4 electronic parts: LCD panel, the power plug connected to J5, the FPGA plug connected into U199 chip and respective cables. Does the previous sentence voids or makes it illegal to check and communicate the voltage values (i.e. power rails), to reuse the concept of receive power from J5 connector, the paradigm to PLLC-44 connect the U199 chip ?
N.B. I think it will be very hard to beat the price of the kit in USA even though it is quite expensive, my question is really about how far legally some of us can really say redo or improve say a prototype or commercialize ?
Albert
TERRA Operative:
That GPL 2.0 statement is probably because Simmconn Labs is using a library or code that is also GPL 2.0, so their code needs to be released under the same license.
I wonder if is worth getting the source and checking it for any hints or tricks for us here?
TerrySt:
--- Quote from: ltarjanyi75 on November 26, 2023, 06:19:39 pm ---Wow, nice design and work! Clever idea with the supports!
What do you plug into that big connector with the strip cable? Is it connected to J5 connector pins?
--- End quote ---
Yes, it plugs into the connector that was used to connect to the crt power supply before it was removed. I am just using the 25 volt supply voltage from it, but I’m sure also using the 5v supply would work.
Terry
ltarjanyi75:
--- Quote from: TERRA Operative on November 27, 2023, 12:30:23 am ---I wonder if is worth getting the source and checking it for any hints or tricks for us here?
--- End quote ---
It would be interesting how they handled the sync issue Terry mentioned. However it will be questionable what really they would share with anyone, if something at all.
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