Hi
After recapping my BBC B and Acorn A3000(usual battery damage) with help from Stardot, I have been trying to repair my childhood Videomaster Star Chess game.https://retroordenadoresorty-blogspot-c ... _tr_pto=sc
I re-tuned to the analogue RF signal on an old TV (which I know used to work with the console), I can just about see a garbled picture (black and white only). Sound is working fine through the console speaker.
The console has an LM1889N IC https://pdf1.alldatasheet.com/datasheet ... 1889N.html in the top right and I thought it may be possible to pull a composite signal from this(assuming the fault is later in the circuit). I would be happy with black and white to start with but this is way beyond my knowledge. Does anyone know if this would be possible and how I may go about it?
I tried replacing the LM1889N but that made no difference.
Appreciate any help!
LM1889N Composite Video?
- 1024MAK
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Re: LM1889N Composite Video?
Would need the schematic circuit diagram, as there are a number of configurations for the LM1889N. It has different sections that can be used differently depending on the requirements.
Mark
Mark
For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
BeebWiki - for answers to many questions...
Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems
BeebWiki - for answers to many questions...
Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems
Re: LM1889N Composite Video?
OK thanks for responding. There does not appear to be any circuit diagrams already so I would need to start from scratch. It is only a single sided PCB but there is a soldered shield which I will need to remove. I will need to find some suitable circuit diagram apps....there seem to be quite a few for Linux but will take me some time to plot out the whole circuit board!
- 1024MAK
- Posts: 12807
- Joined: Mon Apr 18, 2011 5:46 pm
- Location: Looking forward to summer in Somerset, UK...
- Contact:
Re: LM1889N Composite Video?
For Linux, for making schematics I use gschem, part of gEDA (link). It does take a little getting used to. But once you have the hang of it, it's quite quick and easy.
Although when reverse engineering, I draw on paper using a propelling pencil, but with the chips drawn in pen.
Only when I'm happy that I have recorded the circuit correctly do I redraw in in gschem.
Mark
Although when reverse engineering, I draw on paper using a propelling pencil, but with the chips drawn in pen.
Only when I'm happy that I have recorded the circuit correctly do I redraw in in gschem.
Mark
For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
BeebWiki - for answers to many questions...
Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems
BeebWiki - for answers to many questions...
Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems
Re: LM1889N Composite Video?
Thanks for the link and advice. This will take some time!1024MAK wrote: ↑Mon Feb 05, 2024 10:27 pm For Linux, for making schematics I use gschem, part of gEDA (link). It does take a little getting used to. But once you have the hang of it, it's quite quick and easy.
Although when reverse engineering, I draw on paper using a propelling pencil, but with the chips drawn in pen.
Only when I'm happy that I have recorded the circuit correctly do I redraw in in gschem.
Mark