Record currents must be adjusted to maximize the reproduced signal on the type of tape to be recorded on, metal and/or oxide. This procedure is written to optimize the recording current, thus providing maximum playback signal using limited test equipment.

The minimum equipment required is:
•  A video generator that can output a 50% flat field, preferably in either the Y, CTDM or Y, R-Y, B-Y format. If the composite format is the only format available, it can be used.
•  An oscilloscope.

I. Preliminary steps for either metal or oxide tape:
1. Throughout this procedure there is reference to RP (record play) and CO (Confidence) heads. When applying this procedure to the BVW-75 machine it should be understood that CO refers to the dynamic tracking (DT) heads. All other references to boards, test points and RVs are identical for the BVW-70 and BVW-75 machines.
2. Remove the insulator and shields above the RP29 boards for access to the pot adjustment slots.
3. Set the video generator to output the 50% flat field and the recorder's input select switch for the inputted generator format. Connect the appropriate cable/cables from generator to machine input/inputs.
4. Set the recorder's Confidence switch to the "On" position.
5. When adjusting the luminance (Y) record current pots, connect one scope probe to the DM56 board's TP26 @ B-1 for triggering. Connect the other scope probe to the DM56's TP30 @ B-1 for viewing the reproduced Y RF envelope. (While recording, you will be viewing the simultaneous CO head playback signals.) The CO-Y-A head corresponds to the low portion of the square wave on TP26.
6. When adjusting the chroma (C) record current pots, move the scope probe at the DM56's TP26 to TP317 @ F-1 and the scope probe at the DM56's TP30 to TP321 @ F-1. The CO-C-A head corresponds to the low portion of the square wave on TP317.

II. For recording on metal tape:
a) Luminance Head Current Adjustment:
1. Adjust RP29 (luminance) RV1 (RP-Y-A head, metal tape record current) to maximize the CO-Y-A head RF envelope on the scope. The CO-Y-A head RF envelope increases as the head current increases and will decrease as head current continues to increase passing its optimized setting. Head current increases as RV1's slot is turned CW as viewed from the trace side. After the peak level is found, then set RP29 RV1 slightly CCW so that the reproduced level just begins to drop.
2. If the peak RF envelope is not found (RF envelope stabilizes at a fixed maximum level as recording current increases), the recording current should be set at the lowest setting that produces the maximum RF envelope. As the record current is increased, peaks and valleys may appear on the RF envelope, which can obliterate the reproduced signal. This is due to current in the RP head windings coupling to the CO preamp windings. In this case, the record current should be set at the lowest setting that produces the maximum RF envelope.
3. Similarly adjust RP29 RV3 (RP-Y-B head, metal tape record current).

b) Chroma Head Current Adjustment:
1. For the chroma heads, adjust RP29A (CHROMA) RV101 (RP-C-A head, metal tape record current) in a similar fashion.
2. Adjust RP29A RV103 (RP-C-B head, metal tape record current) in a similar fashion.

III. For recording on oxide tape:
1. Set RP29 pot RV2 (RP-Y-A head, oxide tape record current) to maximize the CO-Y-A head envelope.
2. Set RP29 RV4 (RP-Y-B head, oxide tape record current) to maximize the CO-Y-B head envelope.
3. Set RP29A RV102 (RP-C-A head, oxide tape record current) to maximize the CO-C-A head envelope.
4. Set RP29A RV104 (RP-C-B head, oxide tape record current) to maximize the CO-C-B head envelope.