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Re: S-100 VDP prototype board PCBs are here
I had a look at the uPD7720 V2 ECB circuit and I can see where the
BT478 color output pins are taken to the VGA connector. Were the color
outputs of the BT478 meant to be used the same way on the S-100 VDP
On Feb 10, 8:15 am, Elsid <le...@swiftdsl.com.au> wrote:
> Thanks for the info about the FMS6141.
> I'll give it a try using the 2N3904 first.
> I was trying to undersand how the BT478 is being used in the circuit.
> Is it being used as a digitizer or external DAC?
> I can't see the RED, GRE and BLU pins being taken out to any header in
> the circuit.
> On Feb 9, 10:42 am, "Neil Breeden" <nbre...@comcast.net> wrote:
> > The FMS6141 is a video filter, as I recall you can leave it off and go with
> > the 2N3904 based amp instead, it needs to be one or the other, not both.
> > I ordered the 6141 from Digikey -http://search.digikey.com/us/en/products/FMS6141CSX/FMS6141CSXCT-ND/1...
> > Note that I have NOT verified the info below, it is based on looking at the
> > schematic.
> > If you use the FMS6141 I believe these other parts are needed as well:
> > P36 FMS4161
> > R28 0 Ohm (wire jumper)
> > R29 470 Ohm
> > C24 0.1uF
> > R30 75 Ohm
> > R31 75 Ohm
> > C26 220uF
> > C27 0.1uF
> > Jumper L1 (this will supply VCC to the FMS6141) or use an Inductor bead to
> > limit noise back onto VCC
> > If you are not using the FMS4161 then you will also need:
> > Q1 2N3904
> > C25 22uF
> > L1 Inductor Bead
> > Again this is a guess based on what I see in the schematic; there was a
> > discussion some time ago on another thread about a similar design on another
> > board; I haven't been able to find that discussion however.
> > -Neil
> > -----Original Message-----
> > From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On
> > Behalf Of Elsid
> > Sent: Wednesday, February 08, 2012 12:53 PM
> > To: N8VEM-S100
> > Subject: [N8VEM-S100:698] Re: S-100 VDP prototype board PCBs are here
> > When I checked my parts for the VDP I discovered I'd forgotten the
> > FMS6141 IC.
> > There doesn't seem to be anything available locally that will do the job.
> > It'll take about a week to come in from RS Components. I know they are a bit
> > pricey, but they don't have a minimum order for their free delivery if you
> > order online in Australia, unlike Element 14 or XON(Mouser agents) or
> > Digikey. (I don't have any association with RS)
> > Leon
> > On Feb 8, 8:08 am, Elsid <le...@swiftdsl.com.au> wrote:
> > > Hi Neil,
> > > I think I have most if not all of the parts for the VDP now.
> > > I will most likely build the board this weekend.
> > > What were you going to try as far as software?
> > > I thought I'd try building a text driver for CP/M 3 first, though it
> > > would be nice to see MSX running on an S-100 machine.
> > > Leon
> > > On Feb 8, 4:37 am, "Neil Breeden" <nbre...@comcast.net> wrote:
> > > > I'm wondering who else is testing / building an S-100 VDP board?
> > > > I have my board assembled and all the parts in hand with the
> > > > exception of one part, the 1.2V zener/voltage reference. Nobody in
> > > > my area stocks the voltage reference listed in the schematic, I'm
> > > > waiting to get an order above the minimum on Digikey so I can kick off
> > an order.
> > > > -Neil
> > > > From: n8vem...@googlegroups.com
> > > > [mailto:n8vem...@googlegroups.com] On Behalf Of Andrew Lynch
> > > > Sent: Thursday, December 29, 2011 4:35 PM
> > > > To: n8vem...@googlegroups.com
> > > > Subject: [N8VEM-S100:634] S-100 VDP prototype board PCBs are here
> > > > Hi!
> > > > I've already sent S-100 VDP prototype board PCBs to Dave and Neil
> > > > for build and test.
> > > > However if anyone else would like to participate in the build and
> > > > test phase please let me know.
> > > > This is going to be a fun project and has the potential for somewhat
> > > > VGA compatibility.
> > > > It also lays the foundation for a potential MSX2 compatibility for
> > > > the S-100 bus.
> > > > That's unprecedented AFAIK. It could be very interesting!
> > > > It is not recommended for new builders though -- this will be "blood
> > > > and guts" all the way!
> > > > Thanks and have a nice day!
> > > > Andrew Lynch- Hide quoted text -
> > > - Show quoted text-- Hide quoted text -
> > - Show quoted text -- Hide quoted text -
> - Show quoted text -