[Amiga600] Video Problem

Hello all !

First i'm new to Amiga Scene (previously owner of AT*** STF), because i've a friend who *Loves* Amiga, for his birthday i decided to offer an Amiga 600, I found it on a clearance sale , with power supply, but no floppies, and no cables...
Secondly, I'm french, so, excuse me for my bad english.

So, i've a problem with this A600, at power on, all seems good (Only Power led is ON, caps lock OFF but responding if i press the key, and Floppy "ticks" after 30 seconds to 1 minute) but i've NO video (either no sound) using Composite or RF (i've tested it on 2 LCD TV)
After a search on this forum, i opened the beast, wich is really in good condition (very clean PCB, little rust on RF...that's all) and I've replaced all capacitors . SMD caps was replaced by 'normal size' one with same capacity, voltages was higher (eg. instead of 10µF / 35V i used 10µF / 50V)
But the problem is the same, always no Video.
So I'm lost...
Thanks for your help !

[Franchute13]

Originally Posted by christophe62110

Hello all !

First i'm new to Amiga Scene (previously owner of AT*** STF), because i've a friend who *Loves* Amiga, for his birthday i decided to offer an Amiga 600, I found it on a clearance sale , with power supply, but no floppies, and no cables...
Secondly, I'm french, so, excuse me for my bad english.

So, i've a problem with this A600, at power on, all seems good (Only Power led is ON, caps lock OFF but responding if i press the key, and Floppy "ticks" after 30 seconds to 1 minute) but i've NO video (either no sound) using Composite or RF (i've tested it on 2 LCD TV)
After a search on this forum, i opened the beast, wich is really in good condition (very clean PCB, little rust on RF...that's all) and I've replaced all capacitors . SMD caps was replaced by 'normal size' one with same capacity, voltages was higher (eg. instead of 10µF / 35V i used 10µF / 50V)
But the problem is the same, always no Video.
So I'm lost...
Thanks for your help !

Hello christophe.
Welcome to the forum.
Perhaps the RF output may not work. Your TV with SCART input / Euro connector?
If yes, look to assemble a cable.
http://www.ianstedman.co.uk/Amiga/am...iga_scart.html
Or you can also try a Amiga monitor if some friend has.
Sorry for my English

Thank you Franchute13, so, if i understand, I cannot use the composite output nor the RF on LCD TV ?

My TV's has Scart/Euro connector and composite (3 RCA (Yellow/Red and White) input, so i'll try to make the cable v1.1A (for troublesome TV's) to see if i have better results.

Stay tuned !

[Amiga1992]

You can, but it's garbage.
If your TV has SCART RGB, use that for the best quality possible.

I understand Akira,and i'll make a a cable ASAP.

But additionnally, i've succeeding in having picture in composite, using a blackmagic intensity device, the result is here :
[ Show youtube player ]
so, is there a problem with composite ? or graphic circuit ?

[Amiga1992]

I think your video encoder is the problem, it might have gotten loose or is just faulty. Try to change/fix it.
If that's the problem you won't even get RGB signal out of the machine.

Also check for the solder joints on the video chips, just in case.

[cpiac64]

use 3 rca cable and set av3 on tv

cpiac64 : no working, i already tried this.
@akira : new test today : big thanks to my brother, he gave me our old CRT TV (of 1995 !!) wich is perfectly working (i try my super nintendo to be sure sure). So my problem still the same on it, what you see in my youtube video is now, what i get on my CRT TV. So akira, what chip I need to replace ? (solder joints are checked and are in OK condition).

[Amiga1992]

I would suspect first and foremost the Sony video encoder, Sony CXA1145M.
It's somewhere near the caps that are close to the power plug.
Maybe when you replaced the plugs you damaged something in this area, or the previous caps already leaked and damaged the video encoder?

OK it's U12 on my mainboard , it's the chip wich have an other component above it my mainboard is rev. 1.5) anyway, what is this component ? a capacitor ? because if it's a capacitor, i have not replaced it !

Big thanks for your previous response BTW

[demolition]

It is a capacitor but it probably doesn't need replacing. This kind (almost) never dies. If RGB works but composite does not, then the CXA is likely at fault since there are not many other components in play here. The delay line components (square metal boxes on the far left) needed by the CXA also sometimes gets attacked by 'green fur' due to leaking capacitors in the power supply section. I would inspect this area closely.

ok, i understand... so, for now, i'll make an RGB->scart cable to see if I have the same problem, i'm hoping that the CSYNC PIN on this cable doesn't need the CXA to correctly send the composite synchronization to the SCART (in fact, i'm hoping that the RGB output doen't need at all the CXA :-) )

[Amiga1992]

Yeah I am not 100% sure the RGB output doesn't need the CXA at all, but I am not super knowledgeable in this kind of matters.

Glad my info was of help though. Good luck diagnosing your machine and post back with your findings.

[NovaCoder]

Or you could just get an Indivision ECS and bypass the original graphical chipset completely

http://amigakit.leamancomputing.com/...roducts_id=918

Thanks for this advice but i prefer testing RGB cable before :-). With blueprints of a600 i found that CSYNC of RGB output doesn't come from CXA. So maybe thé chance be with me this time.