On 11/8/2011 8:31 AM, Zitt Zitterkopf wrote:
> Zonn,
> Xcellent Feedback! Many thanks!
>
> Yes. Q1E is tied to the Front Panel board which is part of the switch
> matrix. I'm waiting on corrected wiring diagrams from Dave.
> My gut tells me the Emitter is tied to the 200ohm pot which in turn
> drives RGB out.
>
> The problem with this RGB out circuit as is... is that the 200ohm
> slider pot doesn't appear to exist anymore. The best I could find from
> Digikey is either a 250 expensive rotary pot. Or a 5K slider pot. I'm
> wondering if I could use one of the spare opamps to emulate the 200ohm
> pot from a 5k slider pot. But the KISS methodology tells me it's
> smater to just to the 250 rotary pot. Thoughts?
The emitter follower was a nice cheap way to drive low impedance lines
since transistors were cheaper than op-amps. But as you mention, in your
case the transistor is more expensive than the two unused op-amps you
already have.
I'd suggest the linked schematic as a large improvement over the current
design, which if I understand the undocumented part of the schematic,
should do the same thing.
http://zonn.com/misc/x-y_rgb_output.pdf
The current design looks like it drives a 200 ohm slider to ground, and
the output of the slider is used to drive the RGB inputs, allowing you
to adjust the drive voltage from 4.3V to GND. This ends up being a
brightness / contrast control. The linked schematic does the same thing
with your 5K pot, and a lower drive impedance than the original design.
(It's the same output design as the ZVG, using the same op-amps. My
original ZVG prototype used emitter followers, this design is much
better.) This design will give you a 0 to 4V output, which is the exact
spec used by the X/Y monitors. If you'd like a higher output voltage you
can lower the 1.2K resistor, but you were already using that value and
that value gives you a near perfect 4 volts.
Caveats with this design:
- You must use a 74HC08, the 7408's and 74LS08's, pull the voltage high
through an internal resistor that would change the output voltage, you'd
need to recalculate the 1.2K resistor.
- I didn't have a 74HC08 in my library and didn't want to create one, so
pretend like the NAND gate is an AND gate.
>
> The opamps are TL084B . Thanks for the tip regarding opamp
> strapping... will make these changes tonight after work.
The TL084's already have a 128ohm resistors in series with their
outputs, don't worry about adding any more resistance, they'll work fine
as designed.
-Zonn
>
> ------------------------------------------------------------------------
> Date: Tue, 8 Nov 2011 02:28:20 -0800
> From: mlists@zonn.com
> To: vectorlist@vectorlist.org
> Subject: Re: VECTOR: Wico XY Pattern Generator - Decoding Switches
>
> It looks like Q1 is missing a resistor on its emitter to ground, and a
> wire going somewhere (is this the Z-axis driver?). Without these the
> whole U12B circuit doesn't do anything, and you can remove it.
>
> Depending upon the op-amps you're using, you might want to put some
> 10~50ohm resistors on the outputs of the the op-amps that drive the
> monitors. (U14 B&C and U16 B&C). They will keep the op-amp from
> oscillating when driving long wires, and will give some protection if
> (or should I say when) the outputs are shorted to ground, a voltage,
> or each other. Some op amps have these resistors built in. Your
> schematic doesn't mention the op-amp's value so I couldn't look them up.
>
> Use 74HCxxx series. they're fast, low power, and will be more noise
> resistant than the 74xx or 74LSxx devices.
>
> The proper way to terminate unused op-amp sections (U14D & U16D) is to
> tie the '-' input to the output (like U16D), and tie the '+' to
> ground. This forces the output to ground (instead of +12V or -12V).
> This will usually result in lower power consumption, and prevents
> disasters if the output accidentally gets shorted by the probe of a
> voltmeter or oscilloscope.
>
> -Zonn
>
> On 11/7/2011 10:52 PM, Zitt Zitterkopf wrote:
>
> All,
> If you’re interested in the re-capture of Dave’s Wico Schematics;
> I’ve temporarily posted them there:
> http://Pinball-Mods.com/blogs/wp-content/uploads/2011/11/XYPattern.pdf
> <http://pinball-mods.com/blogs/wp-content/uploads/2011/11/XYPattern.pdf>
> Still to-do:
> 1) Determine 7493 wiring vs Dave’s schematics.
> 2) Front Panel board integration – pending Switch Decode.
> 3) Simulate Opamps for circuit understanding.
> 4) Power Supply: pending power measurements – if someone will
> volunteer to get them.
> 5) PCB Layout.
> 6) BOM Generation.
> Changes w/regards to Dave’s schematics:
> A) Decoupling caps for each IC.
> B) 0ohm “202 solder shorts” for unconnected pins of TTL gates at
> U2, U3, U5, and the “top” of R30 (R3). So they can be reversed if
> necessary.
> C) Passives are likely to have different RefDez.
> D) IC Power Supply pins are shown at decoupling grid.
> E) “Bussed” Address pins.
> F) Unused Gates are “strapped” to a known state.
> G) 74xx TTL logic is becoming obsolete. Plan to use 74HC logic or
> 74LS logic – haven’t decided.
> My plan is to have the board manufactured by batchpcb.com as a
> dual sided board.
> Surface Mount ( yes; I can hear the screams of horror ) as I want
> to minimize PCB size – thereby cost.
> I’d appreciate any “peer reviews” of the schematic page.
> As far as open source for the schematics / pcb; I’m concerned
> w/regards to the original owners of the design. IE can’t really
> open source a product I don’t own, can I?
> Besides, Dave hasn’t really given his blessing to the project
> given the source of the schematics are via his work.
> John
> *From:* Zitt Zitterkopf <mailto:zittware@hotmail.com>
> *Sent:* Monday, November 07, 2011 9:48 PM
> *To:* vectorlist@vectorlist.org <mailto:vectorlist@vectorlist.org>
> *Subject:* Re: VECTOR: Wico XY Pattern Generator - Decoding Switches
> David,
> Many thanks. I’ll put a shorting block to the R3 topside so it can
> be disconnected – I’m pretty sure it should be there; even tho TTL
> generally defaults to “high” if unconnected.
> I found the problem I discovered – It wasn’t with the 7490; but
> all the 7493s. For some reason your pinouts via PADS appear wrong.
> http://www.ti.com/lit/ds/symlink/sn7493a.pdf
> Fortunately; the QA is right ... but QB/C/D are incorrect . On the
> 93; they are not wired as in the 92... 90 and 93 do share the same
> pinouts tho.
> So; are the pin NAMEs right; or are the pin numbers? looks like
> the same “mistake” is present on U3/U4/U5.
> I’ll go ahead and wire up the opamps – thanks for the info.
> John
> *From:* David Fish <mailto:dfish_1@comcast.net>
> *Sent:* Monday, November 07, 2011 8:43 PM
> *To:* vectorlist@vectorlist.org <mailto:vectorlist@vectorlist.org>
> *Subject:* RE: VECTOR: Wico XY Pattern Generator - Decoding Switches
>
> John,
>
> >>@A-7 on page 1; R3 topside is listed as a NC.
>
> Weird but that’s the way it is on my board. Maybe they forgot to
> add a +5V jumper.
>
> >>I think you had Q2 and Q3 pins swapped
>
> The pinout for the 7490 is correct QA=12, QB=9, QC=8 and QD=11.
> The PADS library part used Q0-Q3 instead of QA-QD.
>
> >>The Power supplies weren't pictured for U14, 15, and 16.
>
> Good catch. They’re powered by +/-12V, but that’s not shown on
> the schematic.
>
> I think the connector issue stems from the fact that they have the
> two identical connectors numbered opposite of each other. The main
> board 8-pin connector is 1 thru 8 L->R while the switch board is
> 1->8 R-L. I wonder if I plugged my cable back in wrong? There’s no
> labels and the keys are symmetric (stupid). Will look into this
> more tomorrow.
>
> Dave
>
> *From:*owner-vectorlist@vectorlist.org
> <mailto:owner-vectorlist@vectorlist.org>
> [mailto:owner-vectorlist@vectorlist.org] *On Behalf Of *Zitt
> Zitterkopf
> *Sent:* Monday, November 07, 2011 5:37 PM
> *To:* vectorlist@vectorlist.org <mailto:vectorlist@vectorlist.org>
> *Subject:* RE: VECTOR: Wico XY Pattern Generator - Decoding Switches
>
> Dave - You rock! Thanks to everyone else too.
> I've schematic captured based upon your schematics; Dave - many
> thanks. The only peices I haven't captured are the PSU, the 2nd
> page, and diode switch matrix.
>
> Some questions came up while "re-engineering" the schematics.
>
> @A-7 on page 1; R3 topside is listed as a NC... I'm guessing this
> is incorrect as why would anyone put a resistor without a second
> conection?
> My Guess is that R3 ties to +5V like the other two (R4, R5).
>
> IIRC; something was "off" when I wired U2 @ D-6. I think you had
> Q2 and Q3 pins swapped. I'll look for sure when I get home.
>
> The Power supplies weren't pictured for U14, 15, and 16. These
> Opamps are tied to the +12 and -12 rails?
> I plan on simulating the opamps to try to gain insight as to what
> they are doing.
>
> Seems odd that the DAC08s are driven from a non-linear voltage
> rail. IE V+ is 5V and V- is -12V. I'd have thunk they rails would
> be symetrical. IE +/-12V. Maybe the opamps linearize it?
>
> Can anyone get me some rail power measurements?
> I'm going to try and do away with the transformer and linear
> regulators in favor of a more complex (yeah; I know K.I.S.S) PWM
> psu which puts our all three rails.
> If I knew what the average current was for each rail; a small PWM
> might be nice and cheap.
>
> I *so* wish this was an opensource hardware project ... I'd so
> like to release my PCB and schematics (assuming it works) to the
> public.
> <sigh>
>
> John
>
> ------------------------------------------------------------------------
>
> From: dfish_1@comcast.net <mailto:dfish_1@comcast.net>
> To: vectorlist@vectorlist.org <mailto:vectorlist@vectorlist.org>
> Subject: RE: VECTOR: Wico XY Pattern Generator - Decoding Switches
> Date: Mon, 7 Nov 2011 17:05:13 -0500
>
> John,
>
> I already have mine apart on my desk. I’m looking at it now. I’m
> taking lots of pictures.
>
> Dave
>
> *From:*owner-vectorlist@vectorlist.org
> <mailto:owner-vectorlist@vectorlist.org>
> [mailto:owner-vectorlist@vectorlist.org] *On Behalf Of *John Robertson
> *Sent:* Monday, November 07, 2011 4:49 PM
> *To:* vectorlist@vectorlist.org <mailto:vectorlist@vectorlist.org>
> *Subject:* Re: VECTOR: Wico XY Pattern Generator - Decoding Switches
>
> David Fish wrote:
>
> John,
>
> Before you mirror the schematics let me take a look at them in
> depth. It was a looooooong time ago when I drew them.
>
> Unfortunately, I no longer have the schematic source file or
> access to PADS schematic cap even if I did. I looked at them
> online and yes, something looks screwy about the switch board to
> main board connector pinout. I’m thinking there’s a reversed
> connector involved here. I’ll let everyone know what I find.
>
> Dave
>
> I have a working WICO XY Pattern Generator if you need any
> pictures (either of you) just let me know and I'll crack it open...
>
> John :-#)#
>
> *From:*owner-vectorlist@vectorlist.org
> <mailto:owner-vectorlist@vectorlist.org>
> [mailto:owner-vectorlist@vectorlist.org] *On Behalf Of *Mark Shostak
> *Sent:* Monday, November 07, 2011 2:44 PM
> *To:* vectorlist@vectorlist.org <mailto:vectorlist@vectorlist.org>
> *Subject:* Re: VECTOR: Wico XY Pattern Generator - Decoding Switches
>
> You can mirror the schematics from ionpool
>
> On Mon, Nov 7, 2011 at 12:43 PM, John Robertson <pinball@telus.net
> <mailto:pinball@telus.net>> wrote:
>
> Zitt Zitterkopf wrote:
>
> I’m looking at the schematics for the Wico XY Pattern Generator;
> and can seem to figure out how the Front panel PCB connects to the
> Main Board.
>
> At A-8 on the main schematics page; it shows P3-1-8 as connected
> to the D Flip Flops and the A10 of the U7/U8 pattern generating roms.
>
> However, P3 doesn’t seem to connect correctly to the “cable”
> connected to the front panel board at B-8 on the second page.
>
> It appears that the diode matrix appears to drive set/clear to
> Dflip flop U6-A which controls A9 on the ROMs.
>
> But I’m unsure of the encoding given I can figure out how “P3”
> connects to the Front panel board.
>
> Anyone have an idea?
>
> John
>
> Do you have a copy of the schematics so I can put them up on TTL?
> The manual (such as it is) is there along with images of the Eproms.
>
> ftp://ftp.flippers.com/TTL/TestEquipment/WICO
>
> Thanks,
>
> John :-#)#
>
> --
>
> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
>
> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
>
> www.flippers.com <http://www.flippers.com/>
>
> "Old pinballers never die, they just flip out"
>
>
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Received on Tue Nov 8 23:20:05 2011
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