Re: 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
> 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] *On Behalf Of *Zitt Zitterkopf
> *Sent:* Monday, November 07, 2011 5:37 PM
> *To:* 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
> To: 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] *On Behalf Of *John Robertson
> *Sent:* Monday, November 07, 2011 4:49 PM
> *To:* 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"
>

---------------------------------------------------------------------------
** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
** Please direct other questions, comments, or problems to chris@westnet.com
Received on Tue Nov 8 05:28:28 2011