JVC TM-H and DT-V thread

[charlizardon]

Now I'm wondering if it can also fix the flagging issues the PC Engine seems to have with this monitor? I would test it if I had one, but I don't

I have a Duo and just did some testing. The RGB2COMP does nothing to prevent flagging (on its own), but I can assure you that an RGB interface outputting RGBHV takes care of the problem.

[Anonygoose]

Hello friends

Need your input on this fix I accidentally discovered for the horrible horizontal linearity on the DTV monitors.

I am talking about what we all suffer from which is the left side of the screen is wider than the right, resulting in wobble and distortion when H scroll.

Long story short (maybe not so short), I had a 1710CG with a bad flyback and a dead tube, and a good 1900CG tube with a good flyback but bad main board that I couldn't fix.

Both main boards seem identical except for the flyback, a film cap and diode on the main board in the deflection circuit, and unpopulated cap on the S. Correction board.

So I swapped the flyback from the 1900 to the 1710, as well as the S. Correction board and the film cap and diode mentioned in the picture below. Resulted in a near perfect H-Lin.

While I thought the S. Correction board was the culprit for bad H-Lin, eventually I needed to put back the 1710 S. Board as the 19 one had issues. When I did that the H-Lin remained fixed.

Please have a look at the picture below and let me know your thoughts.

Would like someone technical to explain what the purpose of the cap is, and how much of a role does the flyback play in this scenario and the H-Lin fix.

Would like to also know if this can be applied to a 1910CG where a higher pF cap can used to also fix H-Lin there.

Many thanks

https://imgur.com/a/jaQz1ls

[atohmdiy]

I have a TM-H1900G that is new old stock, the tube have around 200 hours. I mod it for RGB but even if the image is pretty good, this bloody linearity problem on the left force me to put it storage. From what i read here and there, all these monitor have this issue. JVC just didn't care.

For some times i hunted for a Panasonic tube as i heard they have excellent geometry and linearity.
I found an Olympus OEV 201 (same as the Panasonic MT-M1980) and i can confirm their reputation. It's funny considering how simple this monitor is, there is absolutely nothing to adjust the geometry or linearity, no trimpot and such. This thing is a masterpiece of simplicity and efficiency.
JVC should have kept Panasonic instead of doing their own stuff

But i really would like to find a way to correct the issue, because except that this monitor is very good and it's nos. I have a friend that is an electronic engineer, we tried to dig the schematic a little but he doesn't know CRT too much so he couldn't helped me. If someone find a way to overcome this issue, i would gladly try it on mine, i'm sure many owner of these TM-H monitors would enjoy it.

[Pasky]

Oh yeah it's this

https://github.com/Adewotta/PicoSync

Will probably fix the issue

Interesting, I'm willing to give this a shot.

Getting all the parts for this Picosync device on Tuesday, will attempt to test it out this week and will post results. Really hope this fixes the flagging for most systems with the tv.

[jd213]

Hope it works out, I've got a couple arcade boards myself that have flagging issues on my 20L5 (which I've been putting off repairing), although they don't bother me too much.

[Pasky]

Oh yeah it's this

https://github.com/Adewotta/PicoSync

Will probably fix the issue

Interesting, I'm willing to give this a shot.

Getting all the parts for this Picosync device on Tuesday, will attempt to test it out this week and will post results. Really hope this fixes the flagging for most systems with the tv.

Happy to report that the PicoSync device fixed the flagging for me on every system I've tried so far (Taito F3/CPS1/CPS2/PGM/snes/nes/genesis/tg16/pce).

Cheers for the one that suggested it.

EDIT:

I should mention that the sync straight from my misterFPGA/consoles/supergun does not work with the device and I recieve a black screen. I'm running the input for the PicoSync from the output of my extron SC210 and the output of the PicoSync to the television. I imagine any sort sync leveler like an lm1881 would work fine in place of the SC210.

[fernan1234]

Nice. Thanks for confirming. I'm not able to build a Picosync myself so if anyone ever gets in the mood to build a few and sell them out, let me know!

[Pasky]

Nice. Thanks for confirming. I'm not able to build a Picosync myself so if anyone ever gets in the mood to build a few and sell them out, let me know!

You could set this up yourself easily without any soldering skills using BNC breakouts and some jumper wires. Both around $10 on amazon. I bought the Rasperry Pico's off ebay for $3

[fernan1234]

You could set this up yourself easily without any soldering skills using BNC breakouts and some jumper wires. Both around $10 on amazon. I bought the Rasperry Pico's off ebay for $3

Oh didn't realize it, could definitely do this. Thanks for the tip!

[Pasky]

You could set this up yourself easily without any soldering skills using BNC breakouts and some jumper wires. Both around $10 on amazon. I bought the Rasperry Pico's off ebay for $3

Oh didn't realize it, could definitely do this. Thanks for the tip!

Sure no problem, if you buy off ebay be sure to buy the appropriate power supply for it. There was an ebay seller selling the pico's with a usb C type plug which was perfect for me. JUst picked up a 3.5A usb C power supply for the rapserry pi 4 which worked perfect.

Extremely satisfied with this solution considering how small the Pico's are.

[Betonmischer]

So, I want to do a proper calibration on my DT-V1710CG as per the service manual. I have all the required tools, except for the signal generator. The manual explicitly calls for a component 1080i/60 input. Moreover, at certain steps only the Y signal has to be connected. But I don't have any device that would output component of this resolution, let alone a real signal generator. I wonder if I could use the DCI input instead, which I already have connected to a computer via an HDMI to SDI converter.

[fernan1234]

So, I want to do a proper calibration on my DT-V1710CG as per the service manual. I have all the required tools, except for the signal generator. The manual explicitly calls for a component 1080i/60 input. Moreover, at certain steps only the Y signal has to be connected. But I don't have any device that would output component of this resolution, let alone a real signal generator. I wonder if I could use the DCI input instead, which I already have connected to a computer via an HDMI to SDI converter.

You can calibrate with anything that produces a reliable signal. I wouldn't overthink it and just go with something like an Xbox360 or a PS3 outputting 1080i paired with a good DAC (ideally one that has been measured to be fairly accurate, but anything that seems to not bias colors in an obvious way or crush blacks should be fine).

[Pasky]

Was toying around with the JVC using the Mister and noticed some posts about a bouncing screen using the PS1. Tried it out and my TV does it as well. What's causing it? I notice it only seems to happen during certain screens, such as the PS1's bios bootup and menu and some in-game menu's like title screens, but then also goes away. I'm assuming it's because it's happening only during a certain resolution or something. Any known fixes?

[Betonmischer]

You can calibrate with anything that produces a reliable signal. I wouldn't overthink it and just go with something like an Xbox360 or a PS3 outputting 1080i paired with a good DAC (ideally one that has been measured to be fairly accurate, but anything that seems to not bias colors in an obvious way or crush blacks should be fine).

Thanks. I think I'm gonna try some of the old graphics cards I have which are supposed to have a YPbPr out with breakout cables.