Author Topic: 6128 weird video output  (Read 3320 times)

0 Members and 1 Guest are viewing this topic.

Offline Sautebroussailles

  • CPC464
  • **
  • Posts: 4
  • Country: be
  • Liked: 0
  • Likes Given: 0
6128 weird video output
« on: 16:11, 05 February 20 »
Hello,

Recently, my Schneider CPC6128 has been displaying (pun) a curious behavior.
But let me explain.

For the last year or so, it has been connected,to my Sony 20" PVM, along with other retro hardware, and I occasionaly played a few games on it, with much delight and no trouble.

However, in the last couple of months, a few odd things revealed themselves:
- I couldn't launch the Batman Begins demo anymore.
- When Pinball Dreams was released I got it but it would crash upon being launched
- more recently, I wanted to try Shadows of sergoth, and all I got was a black screen.

All the while I could still play other older games.

I must add that I use a HxC floppy emulator with my CPCs.
I first suspected that I somehow failed to convert those games properly to the .hfe format, so I tried again, not to avail.

But then I thought about the fact that the games did seem to load, but crashed on execution. Hence I wondered if the display device could have anything to do with it.

As a result, I disconnected the 6128 from the PVM to try out the faithful ol' CTM644, and then the plot thickened...

After a couple minutes on the CTM644, a few things happened:
- Batman begins runs just fine.
- Pinball Dreams started to work correctly, and boys does it work, but that's another topic.
- The Shadows of Sergoth title screen was displayed and the game itself launched, but somehow the screen was displayed "too low" on the monitor
- From then on, when the CPC is turned on, the "Locomotive Basic" text is displayed at about the middle of the monitor display area.
- other games that I played even a few days before have the same weird display.

I then proceeded to connect back to the PVM, but the behavior remained the same.
Same thing on the Commodore 1083S, that I tried because it has more geometry tuning auhority, and I thought I could tweak it into displaying the "bottom" of the screen. Well that failed too.

So to sum up, when a simingly standard screenmode is used, the screen starts being displayed at the middle of the monitor, so the bottom of it is not visible,Bbut when more hardcore ride-the-beam custom screenmode is used, it's displayed correctly.
Can you guys make some sense out of it ?Is it possible that some kind of feedback signal can be issued from a given display device back to the CPC and somehow changes its display behavior?
For the time being i'm trying with my 6128+, but it has problems of its own (keyboard). Well that's another story.
CPC464, CPC6128, 6128+, GX4000, PCW8256 - HxC,MotherX4/X-Mem/X-Mass/Mini-Booster

Offline GUNHED

  • 6128 Plus
  • ******
  • Posts: 2.795
  • Country: de
  • Reincarnation of TFM
    • FutureOS - The quickest OS for the CPC and Plus
  • Liked: 1300
  • Likes Given: 3034
Re: 6128 weird video output
« Reply #1 on: 23:17, 05 February 20 »
Try:
- Stronger PSU (of course still 5 Volts, but maybe 2 Ampere)
- Check BASIC / OS ROMs
- Verify with 2nd keyboard


Hope it's not the GA itself.
http://futureos.de --> Get the revolutionary FutureOS (Update: 2021.01.24)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.07.15)

Offline Bryce

  • The Hardware Guy.
  • Supporter
  • 6128 Plus
  • *
  • Posts: 12.441
  • Country: wf
  • It's not broken, it just hasn't been fixed yet.
    • index.php?action=treasury
  • Liked: 4712
  • Likes Given: 488
Re: 6128 weird video output
« Reply #2 on: 09:52, 06 February 20 »
I'd go with GUNHEDs first suggestion. Try powering the CPC with the CTM, but use the PVM as the display.

Bryce.

Offline Sautebroussailles

  • CPC464
  • **
  • Posts: 4
  • Country: be
  • Liked: 0
  • Likes Given: 0
Re: 6128 weird video output
« Reply #3 on: 11:44, 06 February 20 »
Hmmm, interesting.The cpc is actually powered by the same power adapter as my HxC, since I usually don't use the CTM644 anymore.
I'll check the adapter's specs.However, I resolved the keyboard issue on my 6128+ and it's working happily with the very same power adapter/HxC.
Now maybe it doesn't have the same power requirements as the regular 6128...

Another thing: when I connected the 6128 to the CTM644, I forgot to connect the 12V connector, but I figured it wasn't a big deal since the internal 3" drive is currently removed and the HxC has its own PSU.

Was I wrong ?
Anyway, thanks both of you for the suggestions.
« Last Edit: 11:46, 06 February 20 by Sautebroussailles »
CPC464, CPC6128, 6128+, GX4000, PCW8256 - HxC,MotherX4/X-Mem/X-Mass/Mini-Booster

Offline Bryce

  • The Hardware Guy.
  • Supporter
  • 6128 Plus
  • *
  • Posts: 12.441
  • Country: wf
  • It's not broken, it just hasn't been fixed yet.
    • index.php?action=treasury
  • Liked: 4712
  • Likes Given: 488
Re: 6128 weird video output
« Reply #4 on: 11:53, 06 February 20 »
The second supply (12V) is only needed for the disk drives motor, so there's no need to connect it if the 6128 doesn't have a 3in drive installed.

Bryce.

Offline GUNHED

  • 6128 Plus
  • ******
  • Posts: 2.795
  • Country: de
  • Reincarnation of TFM
    • FutureOS - The quickest OS for the CPC and Plus
  • Liked: 1300
  • Likes Given: 3034
Re: 6128 weird video output
« Reply #5 on: 15:59, 06 February 20 »
As Bryce told. Without a 3" internal drive the 12 Volts are not needed. Quite in contrast, it may even be beneficial to not use them for testing. Why? When having an 3" internal and start the drive motor, it sometimes draws much power. This can be seen with green monitors especially.


The HxC indeed need a serious amount of power. Yes, please check the Ampere you need. Bryce can tell you if you're fine.  :)
http://futureos.de --> Get the revolutionary FutureOS (Update: 2021.01.24)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.07.15)