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:

1) 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.

2) 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.

3) Program and preview monitors must be hooked up. (See note in Step 1, if you have a Flyer.)

4) 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.

5) 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.

6) 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").

A. 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.

B. 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.