Amiga VGA Cable (with GBS8200)

I don’t own a monitor for my Amiga, so I wanted to connect her to a VGA (lcd) monitor/TV.
I tried several way to get this done, but so far I didn’t got it to work.
Only the composite output of the Amiga was working, but I wanted to have a color image.
So I tried a Amiga to scart cable, but my TV didn’t accept the signal.
Next I tried a Amiga to VGA cable, but this also didn’t work (none of my LCD monitors accepts a 15 kHz video signal.
I looked for another lcd, but I couldn’t find one, so I ordered a GBS8200 video converter on ebay and created a simple Amiga to VGA cable that I could hook up to the GBS8200, The GBS8200 then is connected to a VGA monitor.
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For the cable I took an old VGA cable and cut it in halve.
Then I connected the R,G,B,C-sync and GNG to the 23-pin Amiga video connector.
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This gave me a reasonable image on my lcd monitor.
Only I had some random white pixels on my screen.
I found on the internet that this had to do with the speed of the dram chip used on the GBS8200.
Maybe I will fix it later, but for now I’m happy.

 

 

Smoking Amiga fixed

Today I fixed the Amiga that was smoking.
Last week al parts arrived so I could fix her.
The capacitors are for a higher voltage and therefore a little bigger that the ones I removed.
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After fixing I turned on the Amiga and she gave the kickstart boot image again.
In the top of the picture you can see the connector of my Amiga to scart cable.
But my TV is not accepting this input so I’m still stuck with a gray scale image on my TV.

I also received a GBS8200 board last week, so I can start building another Amiga -> GBS8200 -> VGA adapter.
I will create a post about this, when done

 

Trouble shooting the smoking Amiga

While she is older than 18 years old, she is not allowed to smoke 🙂 .
So I started to look for the reason why she did.

First I measured the resistance between the resistor that smoked (R406) and ground.
It was only 0.2 Ohm, A little to low.
So I checked the schematics and noticed that the capacitor C401 and C402 are also in the circuit.
As Capacitors die after some time, I removed them from the circuit board.
When I checked the capacitor C401 it only measured 0.2 Ohm, while C402 was somewhere in the mega Ohm.
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So I found the reason why R406 was smoking.
I’m now waiting the ordered capacitor and resistor.

Smoke… again….

Yesterday I was building a Amiga to scart cable.
But when I was testing the cable, I had no picture on screen (only as shadow on a black screen).
So I looked on the internet and found that my TV (LG) must be manually changed to RGB mode.
So I turned on my Amiga and TV (cable disconnected) and while I was busy searching for the option, I hear the floppy drive running and noticed a funny smell…

I immediately look at my Amiga and noticed gray/white smoke rising from her.
So I turned her off.

It looks like R406 that started to smoke.
I have to find out what could cause this, and what I need to replace.

I killed a switch.

Last night I was working on a ZX spectrum keyboard replacement when a solder pad broke lose from the switch.
The switches are very tiny, the solder pad are even smaller, so the traces are to small to solder a wire to it.

Now I ordered a new batch of switches as I had just enough of them.
I hope that they will arrive soon.
sometimes it looks like an Asian is cycling to the Netherlands to deliver the package from China (it can take up to 6 or 7 weeks).

switch 4mmx4mm with wires mounted ready to be used in a ZX Spectrum keyboard
switch 4mmx4mm with wires mounted ready to be used in a ZX Spectrum keyboard