VERY Dim video output from Amiga 4000

[Tchucolate]

Before making this video, please watch (this section) as you'll get an idea of the issue....

[ Show youtube player ]

When I filmed that, I had to post process it A LOT to increase its brightness to acceptable levels for this video. I had assumed that the issue was to do with the RGB to SCART cable (unlikely) or that my trusty SAMSUNG LED with SCART was on its way out (more likely).

However, today, I tested this by plugging in my A500, and the video looks bright and clear, as I remember it. So, A4000 has a problem :/

Calling on the ancient wisdom of the Amiga collective. Would anyone know what this is a symptom of?

My guess, if I were someone else, would be that capacitors were going down the swaney, and providing too low voltage. However, I had this machine re-capped just last year. So its very unlikely this is the issue. However, the recap was because of some leakage in the video area, however, I was lucky in that it seemed to be early days. I have cleaned that area, so Im surprised if its on-going corrosion.

Anyway, over to you guys. Wondering if Christ Edwards lurks here, as I would assume he might recognise the issue...

[Rob68K]

When I dug out my A1000 for the first time in over 30 years and plugged it into the SCART socket of a small early 2000's 4:3 Samsung LCD TV, the workbench prompt was so dark I could hardly see it.
I then plugged it into a 2006 Pioneer Plasma and it was fine.
Maybe it's a Samsung thing?

[Tchucolate]

Originally Posted by Rob68K

.Maybe it's a Samsung thing?

Don't think so. As when I first got this 4000, it was broken, and when I fixed it. First sign of life was the 3.0 Kickstart ROM screen. I DISTINCTLY remember it was as I remembered it 30+ years ago, vibrant purple, with the tick and all that.

To give you an idea of how bad it is. Right now its booted, and its sunny outside. Curtains are drawn, but quite a bit of ambient light. And I literally cannot work out where the cursor is on the screen.

5 mins earlier I was using my A500 on the exact same monitor and it was fine. I wonder if there are Capacitors or the like, which can fail and cause this. I THINK it could be resistors, maybe they are slowly failing and increasing in resistance. Is that a thing?

[Karlos]

Resistors, when used within their power tolerances, should last a long time. The electroytic capacitors from this era were dubious though. If I had to guess, it would be something like the wrong supply voltage to the analogue side of the video DAC which could be the result of something drying out.

[Tchucolate]

Originally Posted by Karlos

Resistors, when used within their power tolerances, should last a long time. The electroytic capacitors from this era were dubious though. If I had to guess, it would be something like the wrong supply voltage to the analogue side of the video DAC which could be the result of something drying out.

Because this machine was dead when I received it. First thing I did was to get it recapped by some professionals. So I would assume that any issues with those Caps, would have had very little chance to effect anything in that area.

I might be wrong though.

To be clear, this machine was working fine until last week, when I started testing a Fastlane Z3 SCSI card in it. Since then it has gradually dimmed. Today its so dim I think soon I wont have any visible image.