@Thread

Like I mentioned in a previous post. If you think EAB is tough then try Amibay:

https://forum.amiga.org/index.php?topic=76404.msg858819

NOTE:
In this case Flop did commit an infraction of the Amibay rules. The reason he was not given any warning is because of Amibay's "Zero Tolerance" ban policy.

I got banned off EAB because you lot are getting back handers off a certain reseller. I’m on Amibay, and must say it’s 100% better over there! It’s great over here too! Also note those attempting to join EAB just getting banned. Time to open your eyes.

I tried heating the C460D and C460C Capacitors and it made no difference.

I measured the voltage coming out of these two, and its showing 3.9v, which seems way above the 1.5 - 2.5v your sheet indicates is correct.

I also checked the SPEC sheet for the DAC, and unless I am mistaken, I THINK the RGB signals ARE going out in spec, have a look at its SPEC doc
https://www.analog.com/media/en/technical-documentation/data-sheets/adv7120.pdf

And you'll see it is saying the outputs are in the 20-30mV range...

This being the case, I am begining to wonder if my RGB to SCART cable is the issue. Maybe it working on the A500 is a false positive. Because it APPEARS the RGB output is correct.

I wondering, if anyone else has an A4000 out there that can measure its RGB pins and see what they output when a light grey Workbench is displayed.

When you add this bit, please can you include setting it to read/write and mounting on the Amiga side? I do this and it allows me to update the version of Emu68 without taking the card out. I'm not in front of my machine right now, but I'm happy to contribute the steps if you want.

Added, hopefully it makes sense and easy to follow.

PS32-Lite amiga.org Wiki

The too dark image is the result of the analogue levels on the R, G, B outputs being too low, and there's usually three factors involved:
1. Incorrect DAC reference voltage, though you've confirmed this is correct at 1.2V

2. If C460C or C460D has become resistive, which can happen, it will be pulling COMP (DAC pin 40) lower than expected, my service notes (attached) show this typically measures 1.7 - 2.5VDC

3. Some kind of impedance mismatch with your monitor, resulting in the R, G, B levels being excessively low, though that's unlikely given the monitor works correctly with the A500


It's not common for the DAC ICs to just 'go dim'.  They typically either work, or they don't.  And it's rare for these ICs to fail.  I've been repairing Amigas for around 30 years and I don't recall seeing a single DAC failure.

I'd suggest using my notes attached for reference, or compare with another A4000.  Pay attention to the DC level on DAC pin 40 to begin with, try removing C460C (100nF) on the bottom side and see if that makes any difference.  You may also find that heating the ceramic capacitors with hot air can temporarily 'fix' the resistive condition, which usually returns once it cools.

You could also check you have video data on all 24 digital inputs to the DAC, though that doesn't match the fault description.

But after bending all pins straight again the A2000 is back up and running again ^^

I'd suggest replacing the entire PLCC socket unless you're very confident it's perfect.  IC sockets are notorious for causing all sorts of horrible intermittent problems.

Any suggestions on other things I could do?

Depends what you want to do long term.  There are plenty of interesting options in terms of the PiStorm and Vampire expansions.