SukkoPera's Open Source Hardware: A500/A600 Chip/Fast RAM Expansions

[Lemaru]

Originally Posted by katarakt

The only thing what is not so great is the PLCC68 socket, without screw it'll jump out from the CPU after max. 10 minutes !...i'll have to find a screw now and hope it'll keep holding with only one screw. Maybe an other socket will hold the ramexpansion better, but i don't think so...all those socket are looking very similar.

You can get a much better fit if you sand the surface of the PLCC socket down until it is level with the tips of the metal pins. This allows it to sit lower on the 68000 and grip the pins better. The same thing has to be done with vampire boards

[katarakt]

I'll maybe doing this, but you can only sand it down 0,5-1 mm at maximum and you have to use some non-electrical duct tape underneath because there are some vias maybe hitting the pins. But anyways this is a great ram expansion

[Lemaru]

Not sure why you think any vias will hit the pins. I have sanded down a few sockets, and never had an issue. No tape is needed

The Vampires and the Furia cards come with their sockets already sanded down to improve the fit. Again, no tape is used

[SukkoPera]

Glad it works for you, but I have tested my expansions throughly before releasing them, so I knew it would work .

Attached is a solution to hold the board down. It's just as awful-looking as effective .

Please report if anybody finds a better socket, I'd be happy to recommend it on the project page. I'll be adding the sanding recommendations for the moment, thanks!

[katarakt]

Thanks for the pic. I prefer a better solution. I think it will hold with a screw and 2 washers, one on the upper and one on the lower side. I'll use a plastic spacer too cutted to the exact length. As a screw i think, how is it called in english? Tapping-Screw? ...2.2 X 13 mm should fit i think (should be the screw what comes as a kit with these ACA620 accelerators).

[Lemaru]

Originally Posted by SukkoPera

Please report if anybody finds a better socket, I'd be happy to recommend it on the project page. I'll be adding the sanding recommendations for the moment, thanks!

I use an Augat PCS-068A socket. I have also replaced the socket on my Vampire with one. Once the edge of the socket is sanded down level with the top of the pins inside it, then it fits so well you can actually lift the whole Amiga by the card itself.

(I believe this socket was also used on the Furia I used to have).

Here's a quick clip of my vampire after the socket change. Note that there are no nuts on the screws to hold it down (I just couldn't be bothered to remove the motherboard to remove the screws totally)

https://youtu.be/NS7EkMx1xYY

[katarakt]

Thanks Lemaru for socket info, this looks amazing. Seems hard to find here, only expensive UK/US stock. Haven't found them on digikey and mouser

[Lemaru]

It looks like they may have been discontinued, so only available on eBay.

Where are you located as I possibly have a spare one. What I do with mine is rub them on sandpaper until the edge is flush with pins. Remove the small little nubs from inside the socket (as these can prevent the socket sitting all the way down on the chip) and then file out the small notch needed to sit over the resistor on the motherboard.

There is another socket that people over on the A1k forum suggested in the long Vampire thread. This may be easier to find. I'll see if I can dig out the info.

[Lemaru]

Here's the thread about sockets over on A1k. They say the Augat one doesn't fit the vampire as the pins are too thick. Whilst this is true, I managed to get it to fit on mine but it took a long time to slowly press it into place. They fit these RAM OCBs fine though.

https://www.a1k.org/forum/index.php?.../#post-1192051

This is the alternative socket they recommend which is meant to be a good fit (I haven't tried myself as I use the Augat ones). It may be easier for you to find.

https://www.buerklin.com/de/Produkte...A0mm/p/15B5274

I can send you a spare Augat one but the postage is probably more than it's worth to source locally.

[SukkoPera]

Any chance of you making a video of how you rework the socket so that it fits better? That would be really helpful!

[katarakt]

Thank you very much Lemaru! As i'm not a big vampire fan i haven't read too deep in the A1k vampire thread so i missed this.

But...i sanded the socket down and now it holds !! It holds very good now, i can lift the pcb with the ramexpansion like you showed in your vampire video. Amazing, i've measured with a digital caliber before and after sanding it's only 0,5mm lower but it makes a big big difference. Everything is fine now, even with my china socket

Anyway, i'm going to add a screw and spacer for safety. No cable tie needed. For you folks, my measuring says the parts which are needed should be:

plasic spacer M3 x 8 mm lenght
tapping-screw M2.2 x 12 mm lenght

It will take it's time to arrive after ordering the parts but i'll check it and let you know. If these values are correct, SukkoPera can add the information to his Github

Running systest 1 hour, everything is fine

...wanted to show some pictures from the sanded socket but what the hell, i can't upload any pictures because only 10 MB attachments on EAB allowed in total? ...is there a way to increase this

[Lemaru]

Originally Posted by SukkoPera

Any chance of you making a video of how you rework the socket so that it fits better? That would be really helpful!

I'll try and take a photo or two tomorrow to show you what I mean as I will have to find a socket out.

[Lemaru]

Originally Posted by katarakt

Thank you very much Lemaru! As i'm not a big vampire fan i haven't read too deep in the A1k vampire thread so i missed this.

But...i sanded the socket down and now it holds !! It holds very good now, i can lift the pcb with the ramexpansion like you showed in your vampire video. Amazing, i've measured with a digital caliber before and after sanding it's only 0,5mm lower but it makes a big big difference. Everything is fine now, even with my china socket

Glad it helped. My card kept causing my machine to crash until I done this and now it's stable and doesn't pop off. I found once it's on there then the screws are not really needed anymore. Doesn't hurt for peace of mind though

[Lemaru]

Originally Posted by SukkoPera

Any chance of you making a video of how you rework the socket so that it fits better? That would be really helpful!

I have taken a few photos of an old socket and highlighted what to do to get a really good fit.

1. Remove the small nubs from the inside of the socket so that the inner of the socket is totally flat. These nubs are highlighted in the image Nubs.jpg

2. Rub the socket on sandpaper until the edge of the socket is level with the tips of the internal metal pins. (Only 0.5mm to 1mm usually needs removing depending on the socket. The area to sand down has been highlighted in red in the image Sand.jpg. In the image Sand2.jpg I have highlighted the area in red which needs to be removed, down to level with the pins (highlighted in yellow)

3. File out a small notch in the corner of the socket to allow for socket to sit over the SMD resistor on the motherboard. Highlighted in the image Notch.jpg

I hope that helps

[katarakt]

I've uploaded my pictures to my filehoster...in a few months i'll delete these:

[SukkoPera]

Thanks a lot! If you agree, I'll put all of this on the project github page, with credits of course.

[katarakt]

No problem, you have my support SukkoPera

[Lemaru]

Originally Posted by SukkoPera

Thanks a lot! If you agree, I'll put all of this on the project github page, with credits of course.

No problem, if it helps others then all good

[majinga]

Originally Posted by Lemaru

...
1. ...

2. ...

3. ...

I've managed to do the first and the third step. But I was not sure how to do the 2nd without scraping out the pins.

[katarakt]

Just put a sandpaper (i think i've used corn 150) on the desk, put the socket upside down and move the socket in a circle on the sandpaper until the pins appear. I'ts easy.