Amiga Video Toaster
/ Flyer FAQs
Amiga Video Toaster
Calibration and Maintenance
Center Frequency Adjustment Procedure
Product: Video Toaster
Platforms: 2000 3000 3000T 4000 4000T
Center Frequency Adjustment Procedure:
The Video Toaster is equipped with a variable capacitor
called the Center Frequency Capacitor. This is something
of a "master sync" control for the card,
and may need adjusted from time to time.
Any calibration is best done when the equipment is
fully warmed up. Thirty minutes after power-up should
be fine.
You will need a very small flathead screwdriver or
a TV tuner tool, and a multimeter (See Toaster Maintenance
Tools List). The procedure is as follows:
-
The cover of the computer must be open so that
the Video Toaster card is accessible. Just removing
the cover does this in the A2000 and A3000. In
the A4000 and in Amiga tower models, cards which
are blocking access to the side of the Toaster
on which "VIDEO TOASTER" or "VIDEO
TOASTER 4000" is stenciled on the half-size
Toaster RAM card must be removed.
Note: This includes the Flyer, in Flyer-equipped
systems. If the Flyer is placed on non-conductive
material, the cable between the Flyer and the Toaster
may be left attached, so that the Preview output
can still be used.
-
A camera feeding live video, or color bars from
a color bar generator must be the source on input
#1. Other inputs may be detached. The video must
be coming direct, not through a TBC, switcher,
or any other device.
-
Program and preview monitors must be hooked up.
(See note in Step 1, if you have a Flyer.)
-
The Switcher software must also be running during
the adjustment. If running the software results
in a "Toaster Not Responding" or "Toaster
Unable to Genlock" error message, do not cancel
the message or click on continue! As long as the
message is on screen then the software is sending
an activation signal to the Toaster, and the adjustment
may be done.
-
On the VT 4000 card the CF capacitor ("cap")
is labeled "Center Freq", and is located
in the middle of the card, on the inner surface
of the Toaster motherboard near the tall metal
case of a timing crystal. The CF cap itself looks
like a flathead screw on a three-legged aluminum
carrier.
On the VT2000 card, the CF cap is in the same
location but is not labeled. The easiest way to
find it is to look on the small portion of the
main board that is not concealed by the two smaller
component cards, right above where the Toaster
RAM card has the words "Video Toaster" stencilled.
On either model Toaster, less than an inch away,
moving towards the front of the computer, is a
solder dot on the circuit board labeled "ERR1".
This is the voltage test point for the CF cap.
The CF cap is a single turn device, meaning that
when you have turned it all the way around once,
you start over again going through the same set
of values. In other words, you can't get lost,
it's like a clock hand, not a screw.
-
Adjusting center frequency has two phases, a rough
adjustment which is done visually, and the fine
adjustment which is done with a multimeter (See
the "Toaster Maintenance Tools list").
-
Rough adjustment is done by turning CF until
all monitors, program, preview, and RGB, show
clean stable video. This will be best with
the solder blob marker on the CF cap at the
10 o'clock position and the slot angled toward
the one o'clock position.
-
Fine adjustment is done by attaching the ground
lead of a voltage meter to the chassis of the
computer, the positive lead to the ERR1 test
point, and tweaking the voltage level to -2.1
VDC. Tolerance is +/- .1VDC. Be sure that video
remains good on the monitors while doing the
fine adjustment.
You should Autohue the Toaster after a Center Frequency
adjustment has been done.
Notes:
If you find yourself having to repeat the adjustment
more often than once a year on a stable system, where
equipment attached remains the same all the time, and
the environment is controlled, then you may wish to
consider having the Toaster checked at NewTek, as the
need for frequent adjustment in such circumstances
can indicate a problem in the CF circuitry.
On the other hand, CF is sensitive to changes in the
equipment configuration and in the environment. It
is not unusual to have to redo the adjustment if you
move the Toaster card into another host computer, or
if you change the source being used on input 1. If
the environment does not have controlled temperature
and humidity, (dry, maintained between 60 and 70 degrees
F), then the Toaster may need to be adjusted more often.
An immediate check for possible trouble with the CF
circuit is that once you have set your CF adjustment,
you power the system up and down a few times, and run
the Toaster software each time, and check the voltage.
If there is a consistent drift in one direction away
from from the proper voltage, i.e. it keeps going up
a little each time, or it keeps going down a little
each time, then the CF circuit may be problematic.
If CF drifts far enough to render the card inoperable
again with just a few reboots, and you get the old
Toaster Not Responding blues, you need to arrange for
an RMA with NewTek.
If your Toaster's ability to sync properly varies
with the operating temperature of the system, i.e.
it will not sync until the system warms up, or it syncs
fine when the system is first turned on but loses sync
after the system warms up, then the CF adjustment may
be marginal, and you should definitely do the adjustment.
If the problem remains after you have done a good center
frequency adjustment, then a component or solder joint
in the center frequency circuit may have a problem,
and you should get an RMA.
