Odd OSSC interference - Has anybody experienced this?

All information relating to connecting your ST to a modern TV/monitor.
User avatar
rubber_jonnie
Site Admin
Site Admin
Posts: 10465
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Odd OSSC interference - Has anybody experienced this?

Post by rubber_jonnie »

I was working on aggregating my cabling last night in my retro area and noticed a strange thing with my Atari 800XL.

If you look in the black area of the picture below, you can see looking closely some 'dotty' areas which seem to be interference:

IMG_20210930_085524.jpg
IMG_20210930_085524.jpg (233.67 KiB) Viewed 2812 times

These run up the black border of the screen and cross into the main blue screen and run across in kind of bars, which slowly roll up the screen, then flip back to the bottom and start again. They are more prominent on the left hand side of the screen where all the input connectors are.

In the photo, the 800XL is plugged into the TV via SCART and the OSSC is switched on and plugged into the same TV using HDMI. If I switch off the OSSC or unplug the HDMI cable the interference goes away.

What is strange is that if I plug the Atari SCART into the OSSC, I get the same interference, and changing HDMI cables makes no difference either. I will try a swap for a better shielded HDMI cable, but because it also affects the composite input, I kind of think it's some kind of crosstalk inside the TV.

Also of note is that I usually have my BBC B connected to the OSSC and that has a clear bright image with no interference.

BTW at this point I have single connections only, so one device connected to OSSC at a time, but if I have the OSSC just powered on, with no device connected other than the HDMI to the TV, the interference is still there.

I'd be interested in everyone's opinions as it's currently getting in the way of my big cable tidy up.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Steve
Posts: 2570
Joined: Fri Sep 15, 2017 11:49 am

Re: Odd OSSC interference - Has anybody experienced this?

Post by Steve »

I am thinking the issue could be a fault with the TV. Try the ossc in a different TV to rule it out perhaps?
User avatar
rubber_jonnie
Site Admin
Site Admin
Posts: 10465
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: Odd OSSC interference - Has anybody experienced this?

Post by rubber_jonnie »

Steve wrote: Thu Sep 30, 2021 1:39 pm I am thinking the issue could be a fault with the TV. Try the ossc in a different TV to rule it out perhaps?
I'd thought the same, but awkward to do so despite there being 3 other TV's in the house!!!

I will figure something out regarding testing. I could simply try an HD computer display as the problem is picked up if I use the Atari via the OSSC too.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
User avatar
rubber_jonnie
Site Admin
Site Admin
Posts: 10465
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: Odd OSSC interference - Has anybody experienced this?

Post by rubber_jonnie »

@Steve

Hmm, over lunch I connected my work display via HDMI with the Atari 800XL plugged into the OSSC SCART with a totally different HDMI cable (2 actually) and I still get the interference.

Very weird as my 65XE has the same problem. BBC not when connected to the TV via SCART and OSSC switched on and connected via HDMI with no input. Bleh

:dizzy:
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Steve
Posts: 2570
Joined: Fri Sep 15, 2017 11:49 am

Re: Odd OSSC interference - Has anybody experienced this?

Post by Steve »

I'm struggling to understand your last message precisely. Are you saying that you're getting interference with the OSSC plugged into the monitor, but the machine itself is just plugged in with SCART? Not into the ossc? I would try a different power adaptor for the OSSC, just to rule the power adaptor out.

You've also tried on two different monitors now? So it seems OSSC related... and since it isn't on the OSSC hdmi channel, then it could be some strange electrical cross-talk going on... which is why I'm thinking power adaptor...
Steve
Posts: 2570
Joined: Fri Sep 15, 2017 11:49 am

Re: Odd OSSC interference - Has anybody experienced this?

Post by Steve »

FYI, I did a little google search... this interference looks similar... : https://videogameperfection.com/forums/ ... -problems/

Seems that they found it was a bad power supply on the same electrical outlet, causing interference across devices.
User avatar
rubber_jonnie
Site Admin
Site Admin
Posts: 10465
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: Odd OSSC interference - Has anybody experienced this?

Post by rubber_jonnie »

Steve wrote: Thu Sep 30, 2021 4:29 pm I'm struggling to understand your last message precisely. Are you saying that you're getting interference with the OSSC plugged into the monitor, but the machine itself is just plugged in with SCART? Not into the ossc? I would try a different power adaptor for the OSSC, just to rule the power adaptor out.

You've also tried on two different monitors now? So it seems OSSC related... and since it isn't on the OSSC hdmi channel, then it could be some strange electrical cross-talk going on... which is why I'm thinking power adaptor...
No, plugged into the OSSC SCART socket directly. If it was power I'd expect it to happen on every device using the OSSC, but that isn't the case as the BBC is crystal clear.

For Atari 800XL you can substitute my 65XE as it does the same.

Scenrario 1.

OSSC has no devices connected to it. It is connected to the TV using an HDMI cable.
Atari 800XL is Connected to the TV using SCART and has a sharp clear picture.
I turn on the OSSC and get interference on the TV over the Atari's display.
Unplugging the HDMI cable from the OSSC or the TV stops the interference.

Scenario 2.

OSSC has the Atari 800XL plugged into it using SCART. The OSSC has HDMI plugged into a computer display, not the TV.
The Atari still has interference. Different display entirely.

Scenario 3.

The BBC is connected to the TV using SCART. The OSSC is not connected to any computer, but is connected to the TV using HDMI.
No interference. BBC image is not the best, but it is ok.

Scenario 4.

The BBC is connected to the OSSC using SCART. The OSSC is connected to the TV using HDMI.
No interference and the best picture I ever get out of the BBC ever.

I am wondering if it is related to the fact the Ataris have VBXL/XE installed so may be picking something up, but it doesn't really explain why it goes away when the HDMI cable is unplugged and the Atari is plugged directly into the TV avoiding the OSSC altogether.

:dizzy:
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Steve
Posts: 2570
Joined: Fri Sep 15, 2017 11:49 am

Re: Odd OSSC interference - Has anybody experienced this?

Post by Steve »

Electrical interference is being picked up by the Atari's and transmitted through their SCART cables... My money is on a noisy power adaptor somewhere... Need to start eliminating adaptors, swap the Ataris... Swap the OSSCs... see what changes. Seems ground-loop related... the HDMI cable making the ground loop between the machines, power adaptors & ossc.
User avatar
rubber_jonnie
Site Admin
Site Admin
Posts: 10465
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: Odd OSSC interference - Has anybody experienced this?

Post by rubber_jonnie »

Steve wrote: Thu Sep 30, 2021 4:59 pm Electrical interference is being picked up by the Atari's and transmitted through their SCART cables... My money is on a noisy power adaptor somewhere... Need to start eliminating adaptors, swap the Ataris... Swap the OSSCs... see what changes.
If I was using the Atari via the OSSC I'd be all over that, but the Atari has a brand new PSU from Lotharek and isn't going via the OSSC, but picks up the problem when the OSSC is just switched on.

Well, I have nothing to lose so I will see if a different OSSC PSU helps, or swapping out the Atari PSU as I have another new one and also the original brick, though I am a bit worried about trying that one since it's as old as the XE!!!

Nothing ventured as they say.

Need to get this sorted so I can feed as much a possible thru the OSSC or Retrotink that's on the way.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
User avatar
exxos
Site Admin
Site Admin
Posts: 23491
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: Odd OSSC interference - Has anybody experienced this?

Post by exxos »

There was a similar thread not long ago https://www.exxosforum.co.uk/forum/viewt ... =23&t=3681

I don't think there is a solution as it appears the ossc itself has issues.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Post Reply

Return to “DISPLAYS & CONVERTERS”