A3000 sync/video issue

[jammarob]

I know, another "A3000 with leaking battery" thread.

Fortunately, the leaking battery was removed years ago, however, the previous owner did NOT clean up the acid.

It has started to develop multiple video issues. First, the 31KHz video output stopped working. 15KHz RGB is fine.


Here is a photo of some of the corrosion:


Do you guys have any ideas of possible specific chips or parts to check? This thing was working beautifully a year ago, but it seems like it is slowly bleeding to death .

[matt3k]

Once a 3000D get's damage from the battery, she can be real work to fix.

The 3k has 3 layers that you need to be concerned about, best bet is to:
1. Review the schematic and see if you can jumper around damage.
2. Try a Indivision ECS and see if you can work around it that way.

Your dealing with the the acid damage, try to neutralize the motherboard if you haven't.  

Sometimes you can find a broken trace or read the schematic and test around it to get it sorted out.  

Shame, for some crazy reason the 3k is the most neglected big box Amigas, and also the most desirable.

Most of the 3k's I come across have battery damage and have issues.  Shame really...

Good Luck!

As a last resort you can send it to the few souls out there that repair Amiga's...

[Oldsmobile_Mike]

Second the above.  Clean it thoroughly and try an Indivision ECS.  they're only about $100 from AmigaKit, and will give you additional video modes you don't get with the straight 31KHz output from Amber.  Since they take signals straight off the Denise chip fingers crossed that that won't be affected by the battery damage.  Good luck and let us know how it works out!  

[jammarob]

Thanks guys! Will the Endivision ECS allow me to continue using 15KHz video? I do like having this connected to the PVM.

I have pulled the Denise chip and it is clean as a bell, however, the socket looks like someone's science experiment. I think I will need to pull the socket with green pins and replace, for starters...

[Oldsmobile_Mike]

If there is corrosion inside your socket, perhaps just replacing the socket will resolve all your issues?  Tough to do however, depending on your skills...

Indivision outputs all video modes at 31KHz or higher via HD15 VGA connector.  Normal 15KHz modes (NTSC, PAL) are scan doubled.  Allows connection to any modern monitor.  It will also give you 800x600x16 colors, 1024x768x4 colors, and a few other widescreen modes: HD720, stuff like that.  Great product!  (as you can tell from my sig I own several of them)

BTW - Workbench 3.9 with all the Boing Bag updates includes the updated monitor drivers, so you don't have to scrape them together like I had to do with my earlier build, LOL.  

[jammarob]

The Denise socket is definitely corroded. All of the pins are very green.

I can pull it myself, but I will have to borrow a friends Hakko desoldering station.

[amiman99]

I have an A3000 that I got on Ebay with a corrosion problem (sold as working BTW :/ ), intermittent problems, 31khz would jump around, no boot when warm etc.
I fixed the problem by removing solder from around the acid damage with solder sucker and re-flowing it with a fresh one.
Works pretty good now.

Replacing the socket would probably improve your chances of making it work again.

[jammarob]

So a quick update:

This weekend I pulled all of the socketed chips in the video section and inspected the chips and the sockets.

I replaced the 48-pin DIP sockets for Paula and Denise, as they were both corroded. The PLCC socket for Fat Agnus was also replaced as a precaution.

I am still seeing some weird sync issues. Does anyone know what this part is:



It looks like a potentiometer of some kind, and it is heavily corroded on my board. The sync jumps around if I try to adjust it.

Vsync is 60Hz as it should be, but Hsync in 31KHz mode is measuring at 48KHz!

15 KHz is now working fine though!

[jammarob]

So after some thought, I think I am just going to get an Indivision adapter. I hate that the onboard video is not working 100%, but this will certainly resolve the issue.

At least all of the sockets for the video ICs (except for Amber) are new and no longer green with corrosion.

[Kawazu]

Send it to Anthony.
http://amiga.serveftp.net/

[jammarob]

Send it to Anthony.
http://amiga.serveftp.net/

I appreciate the suggestion, but shipping + the cost of the repair would well exceed the price of the Indivision.

[smerf]

So a quick update:

This weekend I pulled all of the socketed chips in the video section and inspected the chips and the sockets.

I replaced the 48-pin DIP sockets for Paula and Denise, as they were both corroded. The PLCC socket for Fat Agnus was also replaced as a precaution.

I am still seeing some weird sync issues. Does anyone know what this part is:



Vsync is 60Hz as it should be, but Hsync in 31KHz mode is measuring at 48KHz!

It looks like a potentiometer of some kind, and it is heavily corroded on my board. The sync jumps around if I try to adjust it.


Looking for the sync adjustment in the wrong place, the thing you are looking at I believe if I remember right is a fuse for the clock I think. The sync you want to adjust is in the back of the Amiga between the switch and the VGI connector, HOkay

smerf