New Retrotink 2x v.3.2 and Commodore 64 interference issue

[James-F]

I’m seeing really bad horizontal jailbars with the newer RetroTINK f/w

This is caused by PAL chroma subcarrier phase changing each line (+45 -45 deg), and these horizontal chroma lines should not be visible.
These lines are visible because they have slightly out-of-spec PAL chroma signal from of the C64, ie, not exactly +-45 deg.
With a ‘modern’ DVD player with Composite or S-Video that outputs clean PAL chroma, and you will see no horizontal lines on solid colors.
Note that this kind or minor hue shift in each altering line was invisible on a CRT especially with interlaced content so it was much more tolerable.
Anyway, the solution was to enable comb filtering on S-Video on PAL signals, which lowers slightly vertical chroma resolution but removes this horizontal banding.

I have to say that fixing one very poor signal console while making the image worse for all other consoles, is not a good solution either.

[BuckoA51]

That’s certainly true although the C64 is probably the most popular retro system where RGB is not available, even via modding. Even the component video mod requires effectively replacing components with FPGA simulations, so it’s certainly one to give special consideration to.

[Midge]

If possible can this firmware be tested for one of the Atari 8 bit XL or XE series of home computers please as they use the same S-VIDEO monitor(superior quality to C64) output.I have a active paid for order placed for the retrotink but it’s on hold until i know when firmware is ready

[handsfelloff]

the C64 is probably the most popular retro system where RGB is not available, even via modding

Absolutely so many c64 users still around 🙂 MSSIAH sequencer on the c64 is why I am here purchasing the Tink hardware. Having read positive reviews (rev 3.1) regarding the Tink’s handling the c64 video signal I bought a 3.2 unit (before this thread unfolded) . Rev. 3.2 has made some essential fixes and great additional support, which is much appreciated.

I’ll submit my own opinion that given the c64 is such a popular retro system maintaining support is essential. Reinstating the comb filtered input as an additional S-Video Noisy” mode sounds wholly reasonable, we’ll gladly take a slightly filtered yet clean video.

Providing users a s-video choice of transparent or filtered for less stable input such as that produced by the VIC II. I am hopeful from what has been said in this thread already that’s the plan.

[Midge]

So far as i know its the early models of the C64 people should be aiming for as different revs VIC II chips were just cost cutting chips
Supposedly it’s ceramic versions with the gold pins that work the best

[James-F]

It’s weird that I don’t see moving lines on grey screen

Not weird at all.
Grey screen has no chroma information at all.

@Kalel80
Try to boot the RT2x v3.2 in DVI mode by holding 2X/FIL button while plugging the microUSB power cord.
Shouldn’t change how the image looks if the TV handles YCbCr Limited and RGB Full equally well.

Also, seems like the horizontal jailbars BuckoA51 is seeing are not related to the diagonal noise lines you are seeing and the images you’ve posted.
These horizontal interweaved lines are easily fixed by comb filtering, but the diagonal lines you reported look like severe interference.

@BuckoA51
Can you take a photo (or a hdmi screengrab) of the horizontal lines you see with the C64?
That would help me differentiate between the two noise types.

[BuckoA51]

I don’t have a frame grabber hooked up right now but I’ll see what the phone managed to capture.

[Kalel80]

@James-F
Okay. I tried DVI mode and I didn’t saw any difference on the screen.

[Kalel80]

Hi, I tested one of my C64C computer more and saw that adjusting frequency on C64 motherboard CT1 trimmer capacitor I almost got rid of moving noise lines. It’s very sensitive and that noise (moving lines) is changing at different speed and angle when I trim that. I don’t know what’s the deal, but trimming C64 motherboard crystal frequency is doing something with Retrotink.

But with my C64 Reloaded MK2 board I can’t fine tune device crystal frequency, however I saw that moving lines changing or dissapear when I touch the top of Retrotink X2 boards own crystal. I just wondering that might this problem be faulty crystal on my Retrotink? Or bad cap? I had same kind issue with PcEngine few years ago. Back then I noticed similar moving noise lines than now and then these lines changing speed and direction allways when I put finger on the top of Pc Engine motherboard crystal. I changed the new crystal and that fixed the issue.

I noticed that v3.1 board version and v3.2 version have different looking crystal? Would that be possible to get know those crystals exact parts?

[Author]

Posts