Yes, I will use ribbon cables with DIL40/DIL24 connectors in each end.
Worst case, I'll just put it on top like it is now.
________________________________
From: oscar-synth-owners-bounce@xxxxxxxxxxxxx
<oscar-synth-owners-bounce@xxxxxxxxxxxxx> on behalf of Bob Grieb
<dmarc-noreply@xxxxxxxxxxxxx>
Sent: Monday, October 12, 2020 2:29 PM
To: oscar-synth-owners@xxxxxxxxxxxxx <oscar-synth-owners@xxxxxxxxxxxxx>
Subject: [oscar-synth-owners] Re: Daughterboard to main board connections
I would make sure you are not locked into a specific length
of cable by soldering something in place. In case it doesn't
work reliably, you want to be able to shorten the cables.
Bob
On 10/12/2020 5:07 AM, Peter Lakowitz wrote:
Yes, maybe it is better just to solder a socket to the underside just to be
safe. Then the cables won't be longer than 20 cm or so. (8 inch). Better safe
than sorry perhaps.
/ Peter
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on behalf of Bob Grieb
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Sent: Monday, October 12, 2020 12:56 AM
To: oscar-synth-owners@xxxxxxxxxxxxx<mailto:oscar-synth-owners@xxxxxxxxxxxxx>
<oscar-synth-owners@xxxxxxxxxxxxx><mailto:oscar-synth-owners@xxxxxxxxxxxxx>
Subject: [oscar-synth-owners] Re: Daughterboard to main board connections
Interesting.
Connecting to the bottoms of the two boards
keeps the cables shorter, I think, which is what you want.
All of the CPU and the wave SRAM signals go through those
cables, so you really want to keep them short, since ribbon
cables tend to couple adjacent wires with capacitance.
Glad I put all those bypass caps on the new MIDI board...
Bob
On 10/11/2020 6:37 PM, Peter Lakowitz wrote:
One of the OSCar's I have seviced (not mine) had already this done by a
previous tech (see imgs). Really nice work and it worked perfect. I was
thinking of accessing from the top though, it will be an extra 10 cm or so, but
I think it still will be OK. It is still rather short lengths we are talking
about.
But I will se exactly how I will do it when I begin. Maybe the underside is the
best after all.
/ Peter
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on behalf of Bob Grieb
<dmarc-noreply@xxxxxxxxxxxxx><mailto:dmarc-noreply@freelistsorg>
Sent: Sunday, October 11, 2020 11:18 PM
To: oscar-synth-owners@xxxxxxxxxxxxx<mailto:oscar-synth-owners@xxxxxxxxxxxxx>
<oscar-synth-owners@xxxxxxxxxxxxx><mailto:oscar-synth-owners@xxxxxxxxxxxxx>
Subject: [oscar-synth-owners] Re: Daughterboard to main board connections
Peter,
I hope you will take some photos of your installation.
If it works well, I would like to document that method on
my web site. Please keep the ribbon cables as short as possible
to preserve signal integrity. You could put IC sockets on the
underside of the OSCar pcb instead of having to run the cables
around the edge of the board. Of course then you would have to
plug them into the underside of the MIDI Board, I guess.
Bob
On 10/11/2020 5:05 PM, Peter Lakowitz wrote:
Just food for thoughts - I will be mounting my card in the bottom of my OSCar
connecting it with a flat cable to the socket on the main board.
Re. desoldering; I'd like to recommend the SS-02 solder sucker, I have been
using it for several years now and it is really fantastic compared to other
brands. Mainly because of the silicone tip that makes it really easy to use.
I've serviced two OSCars with it, desoldering all the crappy old IC-sockets
without accidents or lifted traces.
https://toolguyd.com/engineer-solder-sucker/
[https://toolguyd.com/blog/wp-content/uploads/2019/01/Engineer-Solder-Sucker.jpg]<https://toolguyd.com/engineer-solder-sucker/>
Engineer Solder Sucker – a Great Desoldering
Pump<https://toolguyd.com/engineer-solder-sucker/>
Here’s a good desoldering pump
toolguyd.com
/ Peter
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on behalf of Bob Grieb
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Sent: Sunday, October 11, 2020 4:13 PM
To: oscar-synth-owners@xxxxxxxxxxxxx<mailto:oscar-synth-owners@xxxxxxxxxxxxx>
<oscar-synth-owners@xxxxxxxxxxxxx><mailto:oscar-synth-owners@xxxxxxxxxxxxx>
Subject: [oscar-synth-owners] Re: Daughterboard to main board connections
A few things about de-soldering:
Suction devices can suck a trace right off of the pcb if
it's heated at the same time.
I prefer using de-soldering braid most of the time.
But this braid is available in several widths. I see people
on you tube using the wide braid for something like an IC socket
pin. This is not a great idea, as the wider the braid, the more heat
you have to apply to get it to wick properly. So the thinner braid
is better to protect the pcb, but it fills up with solder faster of course,
so you need to use a lot more of it.
Also, some de-soldering braid just doesn't work very well at all.
I use Chemtronics yellow (color specifies width) and also white, which
is the finer one. 80-2-5 is the yellow part number. It works better
than
some other ones I have tried.
Recently I had to change the socket for the DAC on the OSCar as it was
not making a reliable connection and the sound was cutting out. I
cut the cross ribs of the socket first, then rocked the two sides back
and forth to break the pins off, then removed each pin by itself.
This technique is easier on the pcb than getting all of the pins free at
the same time to pull the socket out. There was no damage
to the pcb traces at all.
Bob
On 10/11/2020 2:13 AM, Lennart Regebro wrote:
OK, so I got my new MIDI board, thanks!
I also got a bunch of eproms. I ordered three 256kbit since they were
cheap, I figured that was cheaper than buying an UV eraser, so I can
betatest two versions before the final, before getting that eraser.
:-P
So I'm going to order the parts soon, but I'm unsure on what to buy
for the connections to the main board. Today I have wire wrap
connectors going down into the main boards sockets which is the
non-machined style socket (I think it may be called dual wipe
sockets?)
It seems to me that the normal straight header style (like the
PBC36SFAN from the parts list) should be of a similar size to the wire
wrap pins? But I'm not sure, because the datasheets are quite unclear.
So that should work, right?
I'm in any case not soldering anything to the main board, and I would
recommend others to also not do that unless they have a desoldering
iron, and plenty of experience.
As so much with the OSCar, different synths may have very different
parts, but I learned to my own detriment that my main board will melt
if you just look at it with a soldering iron in your hand, so I would
urge people to not change any sockets unless absolutely necessary.
