Author Topic: Soldering a internal expansion connector to the medium-sized 464 PCB  (Read 4001 times)

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Offline bjt

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Finally getting round to installing an X-MEM internally in my 464. I have the medium-sized PCB version that looks like this:

http://www.cpcwiki.eu/imgs/b/b3/CPC464_PCB_Top_%28Z70375_MC0044D%29.jpg


Rather than solder wires directly to the solder points by the expansion connector, I'd like to install some headers or a connector of some kind. I have a 50-pin SCSI cable with standard 2.5mm pitch which would be ideal, but the row spacing on the PCB is larger... I guess to accomodate a right-angled Amphenol connector.


Just wondered if anyone had installed a connector here and if so how they tackled it. I was wondering if I could get a right-angle 50-pin header and bend one row of pins to meet the larger spacing on the PCB. Or maybe an SMT header block. Or maybe an Amphenol connector is the only thing with the right row spacing.

Offline Bryce

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It's a pain in the arse to do, but I've done this on several computers. There's some pictures of the results here: 464+ Mod
I've put the cable under the PCB in this case because I had additional expansions installed above the PCB.

Bryce.

Offline gerald

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The only way to have an connector would be to make a adaptor board that convert centronic pitch (2.16mm) to the IDC pitch 2.54mm.
The centronic side will be the trickiest one as you will not find any header/connector, you will have to make it from single pins.


Offline TotO

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May be use the external edge connector and return inside if you don't want to keep it outside.
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Offline Bryce

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The only way to have an connector would be to make a adaptor board that convert centronic pitch (2.16mm) to the IDC pitch 2.54mm.
The centronic side will be the trickiest one as you will not find any header/connector, you will have to make it from single pins.

Na, there's a much easier solution. These SMD connectors reach the contacts. You can solder this onto the tops of the Centronics holes:  SL 2X36G SMD2,54: 2x36pol.-SMD-Stiftleiste, gerade, RM 2,54 bei reichelt
I did this on one of the mods I did.

Bryce.

Offline bjt

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Good call on the SMD header, I was looking at those earlier. Will report back with results. I would use the edge connector but I want to keep it free for a DDI-1.

Offline Dizrythmia

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There is a lot of space under the board of your average 464. I was thinking it would be a great opportunity to install an internal X-MEM, X-MASS, or anything else you needed. If anyone does it I would love to see very detailed step by step instructions. VERY detailed :)

Offline Bryce

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There is a lot of space under the board of your average 464. I was thinking it would be a great opportunity to install an internal X-MEM, X-MASS, or anything else you needed. If anyone does it I would love to see very detailed step by step instructions. VERY detailed :)

There's enough space for the cable, but not for any PCBs.

Bryce.

Offline TotO

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An external MotherX4 for adding modern expansions (X-MEM + X-MASS + ...) And a Edge slot for the DDI-1.
No hack and enough power supply for all the expansions.

Amstrad DDI-1 and MotherX4
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Offline Bryce

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Yeah, but the challenge of packing them all inside is all part of the fun :)

Bryce.

Offline TotO

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Sure... But, the problematic should be to not be able to plug the DDI-1 too.  ;D
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Offline Bryce

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Why? The original external port is still fully functional.

Bryce.

Offline TotO

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The original problematic is the DDI-1 as no passthrough connector.
So, a solution is to put the X-MEM expansion inside to left free the slot for it.
But it is fine to know that is not the only way to resolve the problematic.

As bjd said: "I would use the edge connector but I want to keep it free for a DDI-1"
« Last Edit: 12:08, 07 October 15 by TotO »
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Offline bjt

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But it is fine to know that is not the only way to resolve the problematic.


Yep, your MotherX4->edge adaptor is great, especially for most people who wouldn't dream of opening their CPC.
For more adventurous types the X-MEM is ideal for internal mounting  ;D


Also I have the DDI-1 remake which sticks too much as it is!

Offline bjt

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These were the cheapest I could find at Farnell (part 2452470). Still over £5 for the pair though  :picard: 



Offline bjt

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Unfortunately it seems that the pitch difference is too great, even if I bent the solder contacts. Did you have this issue Bryce?



Also noticed the copper ground plane is lifting on the underside of the board, not good.




Offline Bryce

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I don't remember what pitch I used, I just pulled one out of the box that fit correctly. Obviously it was a 2mm pitch and not 2.54 pitch as I thought, sorry.

The ground plane isn't lifting, this is completely normal for old electronics, it looked like that since day 1. It's due to the fact that the didn't use HAL (Hot air leveling) back then when they tin-plated the PCB. Larger areas then have the problem that the tin tends to gather in the middle when it's cooling. If you scratch off some of the green solder mask you'll find that the "bubbles" are actually solid tin.

Bryce.

Edit: I just checked the datasheet and the pitch is 2.16 - Very strange, now I'm really not sure how I bodged it, because I don't think there's a header with that pitch. If the person who I did this for (nearly sure it was someone here), could they take a picture of the mod?
« Last Edit: 10:43, 13 October 15 by Bryce »

Offline bjt

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Not to worry. I decided to just solder the ribbon cable on in the end.


Perhaps a 2mm pitch header could be bent enough to reach the holes. The other option would be a centronics connector, but I don't know if there's enough room for a male & female centronics inside the case.


Good to know my PCB isn't falling to bits  :laugh: