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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Sandman on February 18, 2013, 04:38:16 PM

Title: My fix for Agnus :)
Post by: Sandman on February 18, 2013, 04:38:16 PM
Thought I would share a little project I did.

I am sure that many of us have unfortunately broken off a pin on one of are beloved custom chips some which are pretty hard to come by anymore.

I did recently and would like to share some photos of the fix I did.

I machined down until I barely touched the lead that was embedded and then carefully soldered a pin to it.

Works great now thank goodness.
Title: Re: My fix for Agnus :)
Post by: matt3k on February 18, 2013, 05:08:27 PM
Quote from: Sandman;726812
Thought I would share a little project I did.

I am sure that many of us have unfortunately broken off a pin on one of are beloved custom chips some which are pretty hard to come by anymore.

I did recently and would like to share some photos of the fix I did.

I machined down until I barely touched the lead that was embedded and then carefully soldered a pin to it.

Works great now thank goodness.


Great work Sandman!  Your 3000 Motherboard looks really clean and orderly as well.

I broke a chip recently, now thanks to you I know how to repair it...
Title: Re: My fix for Agnus :)
Post by: Ral-Clan on February 18, 2013, 05:14:28 PM
That's nice clean, precise work.  Good to see.
Title: Re: My fix for Agnus :)
Post by: curtis on February 18, 2013, 05:20:40 PM
Very nice fix!

Only wish I had the necessary tools for a repair like that.
Title: Re: My fix for Agnus :)
Post by: yssing on February 18, 2013, 05:59:28 PM
That is a brilliant fix :)
Title: Re: My fix for Agnus :)
Post by: Ral-Clan on February 18, 2013, 06:04:07 PM
I assume you used a dremel tool to expose the contact?
Title: Re: My fix for Agnus :)
Post by: smerf on February 18, 2013, 09:20:43 PM
Hi,

What a fix for Agnus, just drill into her and then pin her. Why didn't I think of that

smerf
Title: Re: My fix for Agnus :)
Post by: Zac67 on February 18, 2013, 09:34:59 PM
On DIP chips, I've carved into the chip package with a sharp knife until a bit of the lead was exposed. Then, using a saw cut a fine groove into the lead and soldered a piece of copper wire into it. For a PLCC socket you need very good precision, so good job on this!
Title: Re: My fix for Agnus :)
Post by: mrknight on February 18, 2013, 11:07:10 PM
Very good! I recently broke a corner pin of an Agnus myself. Not completely off, but it's very, very loose. Got help soldering it so it's ok for now. But I might need to do a more permanent fix and it's good to see how you did it!
Title: Re: My fix for Agnus :)
Post by: Darrin on February 18, 2013, 11:21:26 PM
Wow!  If I tried something like that then I'd end up with a 6" hole striaght through the motherboard.
Title: Re: My fix for Agnus :)
Post by: mrknight on February 19, 2013, 12:45:19 AM
Quote from: Darrin;726879
Wow!  If I tried something like that then I'd end up with a 6" hole striaght through the motherboard.

You better remove the circuit from the motherboard first to avoid damaging it. But to be honest, I damaged the pin while I removed the circuit. Shouldn't have touched it at all it seems...
Title: Re: My fix for Agnus :)
Post by: Zac67 on February 19, 2013, 07:30:43 AM
One more reason to invest in a proper chip-puller and stop prying with those screwdrivers... ;)
(http://www.reichelt.de/bilder/web/artikel_ws/D320/ZANGPLCC.jpg)
Title: Re: My fix for Agnus :)
Post by: mrknight on February 19, 2013, 09:39:53 AM
I did use a PLCC extractor. But it only lift the circuit at the corner. And it was really stuck. I think the tool and the socket could be better designed. Oh well...
Title: Re: My fix for Agnus :)
Post by: spirantho on February 19, 2013, 01:38:04 PM
I did the same thing with one of the ZIP chips for my bridgeboard. Those little blighters lose pins if you so much as look at them the wrong way. I just used a craft knife and (slowly) carved on down through the casing till I got to the metal for the missing pin (which was luckily on the corner). It wasn't a very firm joint but it did until I found a replacement RAM chip!
Title: Re: My fix for Agnus :)
Post by: Ral-Clan on February 19, 2013, 02:00:42 PM
Quote from: mrknight;726937
I did use a PLCC extractor. But it only lift the circuit at the corner. And it was really stuck. I think the tool and the socket could be better designed. Oh well...


I agree.

I used a PLCC extractor to remove an Agnus, but it was so firmly in the socket that I could easily pick up the whole Amiga by it if I had wanted.  And when wiggling it gently to remove the chip, the whole motherboard would have flexed back and forth if I hadn't exerted pressure on it with my other hand.
Title: Re: My fix for Agnus :)
Post by: Sandman on February 19, 2013, 09:53:38 PM
Quote from: Zac67;726931
One more reason to invest in a proper chip-puller and stop prying with those screwdrivers... ;)
(http://www.reichelt.de/bilder/web/artikel_ws/D320/ZANGPLCC.jpg)




IMHO, I think those chip pullers are more problems then they're worth.....never use'em.  They alway manage to nick the corner of the chip no matter how careful you are.

I usually pull the MB and desolder the 2 empty holes near the middle of the chip and use a couple of small nails inserted head first to gently press the chip out.  Works great.
Title: Re: My fix for Agnus :)
Post by: Zac67 on February 19, 2013, 10:05:39 PM
Back when I routinely fixed A500s (those golden times... ;)) I had a plate with screws fitting into the PCB holes - just put the board on the plate, push it down and send Agnus popping out.
Title: Re: My fix for Agnus :)
Post by: Ral-Clan on February 20, 2013, 03:13:19 AM
Quote from: Zac67;727002
Back when I routinely fixed A500s (those golden times... ;)) I had a plate with screws fitting into the PCB holes - just put the board on the plate, push it down and send Agnus popping out.


Ah!  I wondered if those holes could be used to push the chip out.  I almost tried to push the chip out that way, but after it started to look like it was going to take quite a bit of pressure I got scared and ordered a PLCC puller online.
Title: Re: My fix for Agnus :)
Post by: madgrizzle on January 27, 2018, 03:17:20 AM
To raise a post from the dead, I just finished doing the exact same thing for the amber with a broken pin.  I used my drill press and the smallest bit I had in my arsenal to carve away the casing.   Warning, people aren't selling replacement amber chips anymore (at least cheaper than the $125), so be careful with yours.
Title: Re: My fix for Agnus :)
Post by: kirk_m on January 27, 2018, 03:12:56 PM
Quote from: madgrizzle;835453
To raise a post from the dead, I just finished doing the exact same thing for the amber with a broken pin.  I used my drill press and the smallest bit I had in my arsenal to carve away the casing.   Warning, people aren't selling replacement amber chips anymore (at least cheaper than the $125), so be careful with yours.


What are you using as a replacement pin?
Title: Re: My fix for Agnus :)
Post by: madgrizzle on January 27, 2018, 04:48:48 PM
Quote from: kirk_m;835466
What are you using as a replacement pin?


This was the trickiest part.  I had a DIP chip for an old GVP firmware and took a pin off there.  With lots of bending and snipping, I managed to get it into a shape that could be soldered.  Incredibly small but I managed to succeed.  The thick part of the pin went into the slot I had carved into the casing, and the thin part looped around the side to the bottom.  Ultimately, I ended up snipping too much of the thin part off trying to get the right length and it doesn't really curl around the bottom, but the contact is made on the side, not the bottom.  

It managed to stayed in place when I pressed it into the socket.  Not sure I could remove the chip and it stay on, however.  I hope my graphics issue (streaking lines) is not amber related.