A4K simply refuses to output to a PC monitor

[dandelion]

I've been pulling my hair out all weekend trying to get my Amiga 4000 to display a picture on a PC monitor. I know the monitor is capable of showing Amiga 30kHz displays because I use it for my a1200 (using the Multiscan driver).

When I plug the same adaptor into the a4k and attempt to use Multiscan the monitor waits to receive a signal and then just goes into sleep mode. Nothing on the screen at all. I've tried different drivers with it, i've tried including VGAOnly and leaving it out of the drivers drawer. I've tried JUST using VGAOnly. I really believe i've tried everything but I simply can't get a picture.

When the machine is plugged into the TV via a SCART and I change to multiscan productivity or dblpal I get the wavy broken colour image that you'd expect.

I really am at a loss! I'd just buy a graphics card but am worried there's a serious fault in the video output hardware

[JurassicCamper]

You need VGA only and Multiscan driver in your Devs:Monitors directory

[dandelion]

Okay, so I got home last night, removed everything from sys:devs/monitors apart from VGAOnly and Multiscan. Selected multiscan productivity in screenmode, saved the changes. Plugged in my monitor and turned back on the computer...nothing. My Amiga 4000 just doesn't want to output a picture to the monitor. This is starting to scare me a bit.

Now what can I try?!

[KennyR]

If the signal is getting through at the wrong frequency, your monitor should flash this up in the screen in its OSD. Going straight into DPMS standby means it's not getting any output at all, not even bad output.
 
Is it possible it might be the adaptor you use to plug a 9 pin VGA cable into the Amiga's 15 pin video port that is defective? You didn't mention such an adaptor but I guess you use one (I could be wrong, I've never seen an A4000 in my life).

[dandelion]

Well...I thought that perhaps it was the adaptor (yes, Amiga 4000's have a standard "big" video out port). However, the adaptor certainly works with my a1200 (tried it again just yesterday - with the same monitor and it's fine). I'm really confused. I thought that perhaps it's a loose connection but jiggling the adaptor doesn't help and there's no such problems when using the SCART lead connected to the Amiga 4000's video out. I'm at a loss - and bloody worried that some video circuitry is knackered.

[PaSha]

Have a look at http://www.titan.co.nz/amigaak/AA060200.htm
Maybe some jumpers on the A4000's mainboard are incorrectly set, such as sync on green or DAC sync. Some A4000's seem to have been shipped with the jumpers set to sync on green.

-Paul

[dandelion]

That was a useful link - but what interested me more was not the motherboard jumper settings but the section on "Connecting to VGA monitors".

Could it be that the Amiga 4000 VGA adaptor is different to the one I was using with the a1200 (I think I bought it from Eyetech but it was ages ago). I'm quite sure my adaptor is simply linking the pins as required between the 23pin and 15pin input and outputs. It seems to suggest on that Amiga 4000 technical guide that some buffering components are need for Amiga 4000 VGA output. Perhaps this is the problem!

[Gopal]

I use vgaonly and dblntsc on my a4000. I don´t remember what kind of trouble I had with multiscan. But I had some problems with it. I´m at work now so I can´t test my setup.

[dandelion]

Well..I think my problem might be partially solved. Someone has just offered to sell me a Cyberstorm 64/3D at quite a nice price. Hopefully this will output a signal to the monitor!!! Then if I can come across a Scandoubler then that will also allow me to output my 15kHz modes to the VGA monitor - thus covering the entire set. I think this is logical.

Does everyone agree that this should solve the problem?

[stefcep]

Yes a CV64/3D is a good choice.  I read that VGA adaptors come in two varieties: with logic and without Logic.  I have no idea what this means, but you might need one or the other..

[ritty]

Dandelion ... keep your hair , bet you look good with it...
  vga and svga  sync. to 37htz and up ...  the cbyerstorm bd will /with the cyberstorm lib. will create the solution for you...
 I had both a 3000Tower and a 4000Tower , the 4000Tower was never up to the 3000T.. even with both of them having a warp engines  and cybergraphics / storm board(s)...the RTG boards enable you to have a multisync and multiscan  without that troublesome doubler... I hooked up a 21" Nokia 445 monitor..with a dot pitch of .22 and ran the output up to 110htz@1600x1600 resolution ... talk about a Beautiful screen... and a hell of a refresh rate ...

 I forgot some details since this was all back in '94 and I have 'part-timers' disease ...lol..  but try a cyberstorm , which i gather you want or have and the lastest update cybervision libraries .. I used a five lead output cable to the monitor .. its better than a composite cable.......... five leads are(bk, gy, yellow, blu,cyan ... have the cable  made if you have to ... you can't beat the fabulous color you can tweak your monitor... have fun .... I'm sure the newer techie here can explain it better than I ...good luck.. :python:

[ritty]

dandelion ..PS: about the 4000 differing from 1200 ... that has to do with video card differences via aga  on the 2 entirely different outputs ... thats why 1200 folks go to tower boxes for extra cards and excellerators ..more power .. btw... make sure all your scsi cards are the lastest and will address the support for SVGA monitors ... OR    try a special monitor that will multi sync/scan from 15htz to 75 or more .. I forgot the name of the japanese company that makes that monitor... couldn't spell it anyhow ... but they are fairly common with 3D rendering people...and video toaster folks ...   basically what you are doing is bypassing the AGA chipset and going with a accellerator that supports a HIRES monitior with Mutisync AND Multiscan ... read my other post also ...