Re: Getting a stable picture on the Amiga 1084D monitor

Matt,

I would be interested in any solutions you find.

I use a 1084S and it can sync to maybe 2/3 of the boards I attach. I recapped the monitor and did find one cap had a bad solder joint but the recap didn't help with the 1/3 of boards that will not sync. I found a vertical sync pot on the chassis and moved that outside the monitor case but it has made very little difference in the boards I can sync to. Another 1084S seemed to have similar results, AFAIR.

I think the 1084 came in many different variations from different manufacturers as the schematics I have found online don't seem to match my monitor too well. This may explain the variety in results for arcade boards.

Franklin

on Apr 19, 2013, Matthew Rossiter <matt@rossiters.com> wrote:
>
>
>Thanks, yeah, maybe it's time for a cap kit. I did build a little
>circuit that gave me a perfect 15Khz signal just like the game board but
>the picture was worse so I scraped the idea. I tried with a 90% duty
>cycle and then 75% but it just wouldn't sync.
>
>Matt
>
>On 4/18/2013 9:36 PM, David Shoemaker wrote:
>> I use a 1084 (non D) on my bench. It has the DB9 input.
>>
>> It syncs to most everything I throw at it without any real issue. Only down
>> side is it can't do mid res games (for that I have a Nec Multisync 3D)
>>
>> Maybe you need to cap kit it? With the warm up time that is the first thing
>> I would look at.
>>
>> David
>>
>> -----Original Message-----
>> From: owner-rasterlist@vectorlist.org
>> [mailto:owner-rasterlist@vectorlist.org] On Behalf Of Matthew Rossiter
>> Sent: Thursday, April 18, 2013 11:23 AM
>> To: rasterlist@vectorlist.org
>> Subject: RASTER: Getting a stable picture on the Amiga 1084D monitor
>>
>> I use an Amiga 1084D monitor for testing. I also use an RGB converter
>> hooked up to a flat panel computer monitor, which works great but if there's
>> a problem with the video signal that I'm trying to troubleshoot it much
>> easier to see the problem on an old school monitor.
>>
>> The problem with the Amiga is that it's hard to get a steady picture on many
>> games. Atari boards are usually rock solid. After about 30 minutes of warm
>> up time the picture will finally hold.
>>
>> Does anyone have a solution to resolve this problem already?
>>
>> I'm not an expert by any stretch of the imagination but here's what I
>> thought.
>>
>> I'm testing a Warp-Warp board (for example) and it's sending out a sync
>> signal about 15.5 kHz, which might be slightly higher than what the monitor
>> expects. I'm thinking of making a simple astable circuit using a 555 timer
>> with a 90% duty cycle, negative sync pulse, and with a potentiometer to
>> adjust the frequency slightly and just use that as the RGB sync. Then maybe
>> add an inverter for games that use a positive sync pulse?
>>
>> I have some other ideas, but just thought I'd throw this out there.
>>
>> Matt
>>
>>
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Received on Fri Apr 19 14:19:12 2013