Amiga 2000 battery PCB and CPU socket damage

[Nitz76]

I repaired my 1989 A2000 back in 2006 for a bad battery leakage. I thought I cleaned the PCB properly with a special battery spill cleaning formula but some remained on the CPU socket.

I had a black/green/yellow... screen at boot-up since a week or two.  After a general cleaning with a scilicone based contact cleaner, I made it work intermittantly. I then isolated the issue to the CPU.

Seeing the socket leads being very corroded, I decided to replace it. Some of these 64 pin sockets are still available from Digikey at a reasonnable price.

Unsoldering this thing was quite a challenge since the lead used back then was not RoHS at all! :eek:

I managed to remove it bit by bit by cutting it in 4 parts. I felt like a dentist removing a wisdom tooth!

Well, after cleansing and all, tada!!



Soldering back the new machined socket was easy as 1-2-3.
It worked right-a-way!

Ok now back to my RGB to YPbPr circuit...

http://www.retronicdesign.com/en/new-product-in-developpement-amiga-rgb-to-ypbpr-components-video-converter/

Cheers!

[Nitz76]

Yup, nice idea.

I used a simple solder vacuum like this one:


And some wick to finish the job.

The liquid flux also gave a strong hand to clean the pads while re-tinning.

I flushed the flux with a vaporised flux remover.

[Nitz76]

Is there an estimated price for the RGB-Componet convertor yet?

Glad my battery wasn't that bad to damage the board after 25 years :laughing:



Need one asap :hammer:

http://www.amiga.org/forums/showthread.php?t=71661

The prototype works nicely.  It needs some small fine-tunning to maintain the picture quality throughout any conditions. I.E. cap values for clean frequency response.

I'm still having level shifting issues while passing from a dark picture to a bright one.

But the signal/output is extremely clean!








Sell price has not been decided yet but should not exceed 60$ CDN + shipping. Worst piece to get, you guessed it, the DB-23!

[Nitz76]

Looks like the one I have, the shop I worked at bought a half dozen in the late 1980's.

Yup... Still sold at your local electronic store in 2016!

I'm looking for a real Weller unsolder tool with integrated vaccum but that's expensive! I choose a nice Weller solder iron instead with variable temp. control.

Most of my tools we're bought back in 1999-2000 when I did my degree in electronics. Still top shape.

Only my old Scope "Tektronix 485B" was replaced by a digitial Rigol DS1102E. It's not a Tektronix but still does a very nice job for a fraction of the price.

[Nitz76]

I'm using an old video test utility called VTOT "Video tools on tap" to generate the SMPTE color bars.

The rendering is near perfect but the whole color scheme is drifting when I suddently drag the dark window downwards.  I suspect a DC effect near the VSYNC portion.  Maybe capacitors or ...?

Original version had 220uF coupling caps. That was ugly.  I then tried the opposite, 0,1uF. Image was sharp but every sharp shape were bleeding. Now I put 10uF.  It's the best I got up to now.  I've been suggested to use 0,22uF.

Any analog guru out there? :afro:

[Nitz76]

I find the big sockets like these its easier to carefully pry the plastic frame off then desolder each pin one at a time.


I'm not sure "a few still available at digikey" is a good way to describe it, makes it sound like they only have a few left and when they are gone they are gone which isn't the case.  These are still a standard stocked part, if there were only a few left there would have been a notification of its discontinuance.

I still need to get time to work on mine some more, seems the battery damaged more than just the socket.

It's just not the flavor of the month... There is a small quatity available for "small or single orders". You can order a batch but there is a one month lead time.

[Nitz76]

Analogue design happens to be one of my jobs....

Sounds like a matter of working out the capacitor time constants with regard to the AC coupling.  Send me a copy of the schematic and a scope capture of the signal you're expecting to couple and I'll have a look for you.  Contact: http://amiga.serveftp.net

For a video pattern generator, search for TestCardRTG on Aminet - Barry Walker and I developed this a few years back.

Thanks!

I'll send you my schematic so you can give me your two cents.