Picasso II Burnt Out Resistor caused by LCD Monitor?

sunnykwan

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I was testing my A3000 & Picasso II Ver 1.4 setup with a LCD monitors....17in Samsung SyncMaster 171S, Dell 15in....when I noticed the screen output became unstable & jittery.

A resistor near the VGA input port looked burnt out. I could not tell its value but a helpful Amigan on the English Amiga Forum sent a large PIC of the Picasso showing the culprit resistor.

DSC00072.jpg


DSC00073.jpg


DSC00074.jpg


http://www.amiga-resistance.info/download_photos/picassoii_1_big.jpg

I could replace the bad resistor but I read some threads regarding problems with LCDs due to Picasso Pin 9 5V output.

http://www.amiga.org/forums/showthread.php?t=40918

http://eabmobile.abime.net/showthread.php?p=590549#post590549

http://www.amiga.org/forums/showthread.php?t=36308&highlight=picasso+resistor

Could this have caused the burnt out resistor on my Picasso II?
If I replace the resistor and continue to use LCD would the problem return again? The threads implies leaving out or removing the Picasso resistor. Will the Picasso be killed if I continue to use LCD monitors?

---------- Post added at 14:01 ---------- Previous post was at 13:57 ----------

Oooops Posted in the wrong section, Sorry. Please Move to hardware problems Amiga.
 

TheCorfiot

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The Picasso does indeed output +5V on pin 9 and if you examine the cable on any good old CRT monitor, guess what??? The pin is missing.
To make matters worse this +5V is taken directly from the Zorro slot which can supply a fair bit of current, hence the burnout & worst case scenario damge to your LCD screen.

To use the Picasso II with an LCD simply remove this restor & leave the line unconnected.. As I did with my Picasso II many moons ago

TC :)
 

sunnykwan

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Ok I already removed the burnt resistor but will not replace it. Why does the Picasso II have such a dangerous feature....to make smoke signals? Kind of scary since I was planning to upgrade my LCDs to share between PC/WinUAE & Amiga. Does the other Amiga Gfx cards have this problem?
 

TheCorfiot

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@sunny

It's simply down to age my friend, If you google around you will find that the original VGA spec has +5V available on Pin 9
And older CRT monitors make allownce for this via their missing pin 9.

TC :)
 

chiark

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Not just original, the modern spec... However, it should be current limited to 1mA so I can't see how that would burn out that resistor. It's a good job it took that out and not a trace on the Z2 bus though!
 

TheCorfiot

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Not just original, the modern spec... However, it should be current limited to 1mA so I can't see how that would burn out that resistor. It's a good job it took that out and not a trace on the Z2 bus though!

I agree Nick, it's not current limited though, It's the first thing I stumbled across when I fitted a Picasso II in my A2000, the other side of the resistor goes to the ZII edge connector :nuts: (via a set of Relay contacts if memory serves)

TC :)
 

psodas

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“Devices that comply with the DDC host system standard typically provide supply voltage on pin #9 of the standard 15-pin VGA connector. The voltage is 5V ±5% and supplies a minimum of 300mA to a maximum of 1A.”
 

Zetr0

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unfortunately on my A2000 my Zorro port would be able to thump out 35Amps!!!

yeah.... thats cooking somthing!!!!


to be honest... I think thats the 3rd time in my life I have seen a carbon based resistor blow as impressive as that.
 

sunnykwan

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Well it seems the Picasso II does not like the Samsung SyncMaster 171s LCD I planned to use between A3000 and PC. The Picasso LCD pic is still unstable, flashes horizontal bands when I open Workbench draws. In contrast a Samsung SyncMaster 750S CRT display is clear, crisp and rock solid...so the signal is fine. I will use the CRT until a new LCD replacement is found.

Anyone suggest modern Picasso II friendly LCDs....brands & models?
 

chiark

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It sounds very much like you need to configure the right monitor settings for your P2 card - it should work fine with pretty much anything

Rerun the setup, and change the monitor information to match your current monitor?
 

sunnykwan

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I've recently upgraded to a Cybervision 64 4MB to support the A3000's Zorro 3...much faster than Zorro 2 PicassoII.

I am using Asus VW266H 25.5" 2ms 1920x1200 20000:1 DVI/HDMI LCD Monitor to share between a PC and A3000..it works great with CV64 and PicassoII.

I am thinking about selling the Picasso II which includes original disks, manual and box.
 
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