[bni]

I lifted pin 8 using a small needle and that did indeed fix my issue. Temperatures on U6 and U8 are normal now and OSSC seem stable. No audio anymore thru the OSSC of course.

As to what could have caused the damage in the first place. I mentioned I recently got a new Amiga 1200 and this issue happened sort of the same time as I got it, although not sure.

Is it possible for the sound output from my Amiga could have destroyed the ADC in my OSSC? Or is it more likely this was coincidental and I just had bad luck with a failing chip?

[bni]

ok, I noticed just before when testing, that in the 2 minutes it does work, before components gets too hot, there is no sound. And now I remember just before the OSSC broke down there was some ‘crackling’ in the speakers that I never noticed before.

I have nothing to lose with this board really as warranty is gone and sending for repairs is about the same expense as getting new one.

I don’t really have the skills, those pins looks awfully small for the tools I have. What would be expected to happen if I cut pin 8?

[bni]

I checked those, and yes U8 gets also very hot, up to 90C

I studied it with magnifying glass, didn’t see any obvious damage or suspected shorts of the pins.

[bni]

Yes it gets hot displaying the test pattern. I measured 90C with nothing connected. It does not seem to matter if anything is connected or not.

Over the last 2 years I have only ever used the SCART input with my Amigas and RGB-to-SCART cable. Been using Line2x on my PC monitor and Line4x with my 4K TV.

[bni]

Thanks for the suggestion marqs

Just measured this on the PSU:
Not connected to the board: 5.01 V
Connected to the board and board powered on: 4.97 V

So no issue here?

btw the PSU I use is the one sold with my OSSC from videogameperfection.com in 2018

[bni]

I found some posts an video talking about “unattenuated RGB sync line” and that some devices can damage the OSSC.

I recently got a new Amiga (A1200) and the OSSC breaking down coincided approximately with that, after having used it for 2 years with an A500 without problems.

Anxious now to get a new OSSC if that will break too. In that case is it covered by warranty? Im not using some obscure arcade board or someting its just a standard A1200

Relised now this post is in the DIY forum, but my OSSC is bought complete from videogameperfection.com in august 2018

[bni]

I measured the temperature on U6 to reach 90 degrees celsius, surely that cant be normal.

Couldn’t measure voltages, noting registered, but maybe I’m doing it wrong.

Could it be that there is a short between the pins to U6, there are 3 solders that are very close to each other on one side of U6

[bni]

Also I want to add it will malfunction also after a few minutes if I just power it on and leave without anything connected to the AV1

[bni]

I have this problem on my 2 years old 1.6 OSSC

All of a sudden it has started to lose sync after 2 minutes, and display garbage characters on its LCD. If I restart it it wont even give the checkerboard test image. If I wait 10 minutes it will work 2 minutes again.

I took it out of the case and notice U6 is very hot, I burned my finger tip, ouch.

Has been working flawless for 2 years but now it’s useless.

Considering buying a new one when they get back in stock, because I really like it. Has there been any improvements made on the board or will I encounter this issue again with new board?

[bni]

I did some more experiments with Line 4x mode, and I think I found the optimal settings:

Line 4x (Generic 4:3)
H. samplerate 1560
H. synclen 72
H. backporch 170
H. active 1280
V. synclen 3
V. backporch 30
V. active 270

Mainly what I did from defaults was decrease V. active a little bit, and then centered the picture with V. backporch.

This gives a “4:3 1080p” mode that the 4K TV handles optimally (scaling and motion).

Picture was a bit dark now, so I Increased brightness in OSSC a bit from 128 to 138 for all three colors (R/Pr G/Y B/Pb offset)

Here is some photos of the result (colors are off from camera, doesnt really do it justice):

[bni]

Hi, This is a report of my findings with the OSSC I got a few weeks ago:

My Hardware:
Amiga 500
OSSC latest rev and firmware
65″ LG C7 OLED TV

Default settings gave me ok picture but hitchy/jumpy scrolling, and not pixel perfect. Hard to say if the jumpyness was caused by TV having trouble with scaling the default resolution or if it was from OSSC.

After tweaking the settings the picture is jaw dropping if I may say so. Black is black, pixels are 1:1 mapped and scrolling is super smooth. The true blacks really bring out the graphics from Amiga demos and games.

Its def. worth it to tweak the settings for the Amiga with OSSC.

Im using the settings (sort of) from one of jarps posts in this thread:
Line3x mode (Default 4:3 setting)
H. samplerate 1818
H. synclen 72
H. backporch 198
H. active 1440
V. synclen 3
V. backporch 24
V. active 288

This gives a 1280×855 resolution that the TV then scales to 2160p. I have no idea if these settings are optimal, I just used info from this thread and some experimentation. If anyone have suggestions how to improve Im very interested in that.

Remaining issues:
Settings captures the whole overscan area on the left side, and I guess that is interesting, but somewhat distracting in some demos.

Aspect Ratio looks ok, but im not sure it is 100% accurate.

I want to enable Line4x mode instead, but have not been able to find settings that looks good. Anyone have any idea what values to start with?

[Author]

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