Rasterlist Archives: RE: Getting a stable picture on the Amiga 1

From: Bill Karkula <wkarkula_at_comcast.net>
Date: Fri Apr 19 2013 - 14:07:45 EDT

I gave up on the 1084 monitors about two years ago - they kept dying on me
and I got tired of repairing them. Mine were 1084S and I never had any sync
issues (when they worked). I now have a couple of Sony PVM 1354Q Monitors
(one is a backup which I have never needed) and am much happier.

Best Regards,

Bill Karkula

email: wkarkula@comcast.net mobile: (847) 323-2366 home office: (708)
301-2998

-----Original Message-----
From: owner-rasterlist@vectorlist.org
[mailto:owner-rasterlist@vectorlist.org] On Behalf Of Matthew Rossiter
Sent: Friday, April 19, 2013 12:48 PM
To: rasterlist@vectorlist.org
Subject: Re: RASTER: Getting a stable picture on the Amiga 1084D monitor

I have the 1084S model, not the D by the way. I should have double-checked.
I think D is the PAL version.

On 4/19/2013 9:48 AM, Matthew Rossiter 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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>
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RE: Getting a stable picture on the Amiga 1084D monitor