Patches and discussion for Ensoniq VFX family

b_j_glover wrote:

> the picture exactly where they are though. Can someone confirm that 
> there are twelve individual separate points on each side that have to 
> be bridged...? Or is there a single point on one side going to two 
> points on the other side at the top of the board, or what...? 

With multi-layer boards, whenever you've got a hole through the board, 
all the layers are interconnected.  This used to be done by pressing a 
copper rivet into place but is now more commonly done by plating the 
inside of the hole.

If the board has been badly overheated when the original connector was 
removed, it's possible that the through-hole plating has been ripped 
out.  This is Not A Good Thing.  Fortunately the boards in the VFX are 
(as far as I can tell) only double-sided - some more complex boards have 
copper tracks sandwiched inside the fibreglass, which is built up in 
layers - so it's easy to repair.

With a suitable soldering iron (a little 15W pointy one, not some 
whacking great thing that you use to solder the battery terminals on 
your car) and a solder sucker, carefully clean up all the pads.  Then 
cut little wire links to join the board halves.  Trim the insulation 
back about 6mm (1/4") from the ends, twist it up and tin it - this is 
very important if you want the joint to be mechanically good as well as 
electrically good!  Now feed the tinned end of the wire through the 
hole, leaving a little bare bit on the top side of the PCB.  Solder the 
wire to both sides of the PCB, just in case the through-hole plating is 
gone.

If you find that one of the pads has been ripped off, you'll probably 
see where the trace leads back from the edge of the board to whatever 
it's supposed to connect.  If that happens, run a wire from the nearest 
pad along that trace that's still good, to the next board.

Once you're done, check *very* carefully to make sure that all the 
joints are good, and that there are no stray wires or blobs of solder 
shorting out any pins.  It's worth checking the whole board over, just 
to be sure.

I recommend that you get some scrap PCB to practice soldering and 
desoldering on, and be prepared to burn your fingers and ruin some 
components while you're learning!  If you're not comfortable with the 
fine work needed to do this (it's not *that* bad but if the smallest 
thing you've soldered is a 1/4" jack then it's pretty tiny) then I 
suggest you get someone with more soldering experience to help you. 
There are lots of articles on the Internet that will show you how to 
solder, and what constitutes a good or bad solder joint.  Keep 
practicing and before long it will be as easy as writing your name.

Gordon