Patches and discussion for Ensoniq VFX family

Thanks for the advice. What I'm planning to do is create the 12 
connections across the back of the board, as shown in the "VFX Cal 
Error Repair" document in the files section:

http://f1.grp.yahoofs.com/v1/MIkqSdiPWBaEZD0ruTF8BSM6fG-
NDq96QzI2CPFPmNjmoM7_5ojS1QhYq-IYq4Ry-dPLXTHKfRoY4VR111bNUpKoT3QL--
Y/Tools%20and%20service/Poly%20board%20separation%20fix/VFX%20Cal%
20Error%20Repair.pdf

But my problem is that I can't tell from the illustration what's 
going on at the top of the picture. On my VFX, it looks as though the 
connection points on at least one side (left or right) are joined 
together on the PCB itself at the top. The top two on each side are 
certainly joined by a blob of solder at the moment, and I'm wondering 
if they do indeed need to be separated. (I'm only talking about one 
surface here.)

Thanks

Ben


--- In Ensoniq-VFX-SD@yahoogroups.com, Gordon JC Pearce MM3YEQ 
<gordon@...> wrote:
>
> 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
>