Male PLCC plugs - Page 1
Forum section: electronics / projects

author: TomS_
author_rank: Frequent Contributor
timestamp: May 06, 2021, 03:15:32 pm
content: Hi all.Im working on a reverse engineering project involving an old Cisco router. Onboard are 4 PLCC sockets for holding boot ROMs, but the factory boot ROMs are 8mbit in size, and the WE/ pin of a typical smaller ROM is replaced with another address line.Ive implemented a fiddly hack by cutting a trace and running some mod wires with a jumper to allow me to switch between the original address line and a constant high, allowing me to easily switch back and forth.But its a very fiddly mod, and Im looking at other options to perhaps produce a small daughter board that would plug into the PLCC sockets and allow me to handle this hack in another way and make it easier for other people to use these old routers without needing to go to board level modifications.The only problem is that most male PLCC plugs that I can find a are quite pricey, since I will need potentially 4 of them (might be able to get away with 2). So Im wondering if anyone knows of a source of "cheaper" parts?These are the types of plugs I am looking for, but at a more "hobbyist friendly" price:https://www.warwickts.com/4308/W9324-ZC160-44-Way-PLCC-PlugAppreciate suggestions. Thanks!

author: artag
author_rank: Super Contributor
timestamp: May 06, 2021, 03:51:41 pm
content: Those are cheap compared with ones I remember from Emulation technology

author: Benta
author_rank: Super Contributor
timestamp: May 06, 2021, 05:00:49 pm
content: ^^^ This.A steal compared with what they used to cost. You have to understand these are really low-volume parts.

author: ajb
author_rank: Super Contributor
timestamp: May 06, 2021, 05:36:14 pm
content: I wonder if the contacts on that linked plug are close in size to standard 1.27mm header pins. If so you might be able to bodge something up with a PCB or two and some single-row headers, maybe with a little castellated PCB in the middle to back up the pins against the spring force from the socket contacts. Or maybe just install the headers in a PCB and use a 3D printed part for the plug body.

author: Benta
author_rank: Super Contributor
timestamp: May 06, 2021, 05:56:22 pm
content: The Motorola MCU emulator cables/headers for PLCC sockets back in the 90s were four pieces of striped PCB (for each side of the PLCC) with epoxy filling in the middle.Looked decidedly one-off/homemade, but back then nothing else was available. Worked great.

author: TomS_
author_rank: Frequent Contributor
timestamp: May 07, 2021, 06:47:58 am
content: Interesting idea bout using some PCB...The contacts in the socket dont appear to stick out far enough to make contact, but if the traces were built up with a thick layer of solder it might just work.Almost tempted to give this a try - as fiddly as it would be to put together it would certainly be inexpensive materials wise.

author: technix
author_rank: Super Contributor
timestamp: May 07, 2021, 08:31:31 am
content: If the PLCC socket itself is the through hole type, you can convert it into a PGA-style shim layer using round-hole pin sockets. Then you can either place a PLCC socket into the PGA shim to use the original chips, or plug in round-pin PGA style PCB for modern projects.

author: TomS_
author_rank: Frequent Contributor
timestamp: May 07, 2021, 11:35:49 am
content: I wish it were that simpleUnfortunately they are surface mounted, so I have to find a more elaborate way to get into it. At least beyond my current router anyway - Ive already cut traces and soldered bodges on this one to try out and verify all of my theories etc. But if I happen to do more in the future, or someone else wants to try it, then it would be nice to be able to do it with some "plug and play" hardware.

author: TomS_
author_rank: Frequent Contributor
timestamp: May 07, 2021, 12:18:08 pm
content: Looking around that site some more I came across some other adapters which are a bit more stomachable price wise (about half price). The downside is that the MoQ is 10, but I could have them in about a week and not have to fiddle around trying to solder bits of PCB together. Guess it depends how much I value my time.