Vectorlist Archives: RE: Re: Wico XY Pattern Generator

From: David Shoemaker <davids_at_oz.net>
Date: Wed Jan 09 2013 - 01:00:54 EST

Hey John, did you ever try the FabB or get the vector raggedness figured out?

David

-----Original Message-----
From: owner-vectorlist@vectorlist.org [mailto:owner-vectorlist@vectorlist.org] On Behalf Of Zitt Zitterkopf
Sent: Saturday, August 18, 2012 4:27 PM
To: vectorlist@vectorlist.org
Subject: VECTOR: Re: Wico XY Pattern Generator - It's alive!

I've finally completed FabB's PCB and posted the schematics, board files,
BOMs to my blog at:
http://pinball-mods.com/blogs/?p=243

It's opensource and you can even order a PCB from BatchPCB if you desire.
I appreciate the help of MrFish, Roger, and the countless others who offered
their $0.02 thru-out the process.

I haven't built FabB yet; but the changes were fairly low risk. Having said
that; YMMV.
John

-----Original Message-----
From: Zitt Zitterkopf
Sent: Monday, March 05, 2012 10:46 PM
To: vectorlist@vectorlist.org
Subject: VECTOR: Re: Wico XY Pattern Generator - It's alive!

This weekend I put the vector generator to work by converging my G08.

Pictures of the test patterns posted:
http://forums.arcade-museum.com/showthread.php?t=225710&page=2

At this point I'm not sure if the odd vectors / none straight vectors are
the result of a software problem (EPROM images) or a hardware problem.

It's possible the software isn't reacting well with the faster hardware (HC
logic, better opamps); but unsure.
John

-----Original Message-----
Bet most of you forgot about the XY Pattern Generator project... I’m sure
some of you thought it was vaporware...
Welp; It took longer than expected; but after several off/on months of
debug – I finally got it working.
During debug board#1; I managed to short +12 to +5 frying all the logic.

So I restarted with my second board and built/debugged a section at a time.

Here’s what I posted to KLOV’s forums where I started a picture Worklog:

Several months ago I posted in my Star Trek Captains' Chair worklog that I
intended to modernize a old XY Pattern Generator design on the interwebs.
Many of the guys on VectorList provided valuable insight into the
interworkings of the circuit... and provided many layers of helpful advice.

The result was the following schematics and a set of FabA prototype boards
from BatchPCB.com as a dual sided board.
Surface Mount ( yes; I can hear the screams of horror ) as I wanted to
minimize PCB size – thereby cost.

If your interested in the prototype schematics; they are here:
http://pinball-mods.com/blogs/wp-content/uploads/2011/11/XYPattern.pdf

I'm pleased to report that tonight I finally debugged the last problem (that
I know about).
There is a small list of issues I had to work thru; but for the most part
the design worked almost out of the box.

1) The clock generator circuit (3.578MHz xtal) and U1ABC was not "locking".
This was due to the buffered logic of the newer 74HC* logic. Some research
on the internet indicated I needed a 150pf cap from pin1 U1A to ground to
allow the clock generator to excite enough to lock. Another recommendation
was to use a Unbuffered HC inverter... which I'll incorporate into the next
revision of the schematics.

2) The -12V buck converting power supply wasn't outputting the correct
voltage. It'd start out at ~11V.... the drop to ~5V over several minutes. On
my debugged board; shorting R26 (10meg ohm) allows the -12V to become rock
steady at -11.8V. Unsure here; the Maxim EE sim was very specific on the
10meg ohm value... but the maxim datasheet indicated two modes for VL to
operate in. So for now will error on the practical side.

3) The 5V regulator did not have enough copper to heatsink to. Next revision
of the FAB will have a large 5V copper heatsink built into the board. For my
prototype; I thermal epoxied a small heatsink from a old motherboard onto
the top of the regulator to give it some thermal sink.

4) The Linear POT datasheet was missing details regarding the LED side of
the POT. One hole was off and will need to be moved.

Things I still need to do:
1) Hook it up to my G08 and align me some guns.
2) check the +12V portion of the buck converter. Right now I'm using the
backup +12V linear regulator (U9).
3) Modify schematics and board for FabB (learnings above).
4) Create an enclosure to house the unit.

Nice to haves:
A) Retrofit EPROM sockets to toggle A11 for a 27C32 eprom(s)... allowing for
more user designed test patterns.
B) Rename topside adj pots to indicate X and Y.
C) make 3pin jumpers so the jumpers can be mecahnically sound output swing
is not shorted

PCB pictures and Oscope captures are posted at the KLOV worklog for your
reading enjoyment:
http://forums.arcade-museum.com/showthread.php?t=225710

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RE: Re: Wico XY Pattern Generator - It's alive!