GxT Ferret 901 User Manual

Tach/Sync
Adapter

Battery

Compartment

TM

901

Indicator

Lights

Select

Button

Stackable

Banana

Jacks

Inductive

Pickup

OPERATOR’S MANUAL

Adapter Operation

The SELECT button powers the 901 and selects the mode of operation. Pressing
the SELECT button steps the unit through the test modes. After one minute of
no signal the 901 will automatically turn the power off to save the battery.

RPM Mode

1. Plug the banana plugs into the Digital Multimeter (DMM) or other tester.
RED to the positive input ; BLACK to the negative or COMMON input.

2. Select the Volts or millivolts DC setting on the DMM.

3. Connect the Spark Pickup around any single Sparkwire. This includes
Distributors and Direct Ignition Systems with 2 outputs (DIS2). On Coil­Per-Plug systems, connect the pic kup around any single primary drive wire
that feeds the coil. See “Getting a Stable Reading” for more details.

4. Use the SELECT button to set the proper mode. The “#1 Sync” light should
be OFF. Use the “Conv (4c)” mode for 4 stroke engines with distributors or
Coil-Per-Plug. Use the “D.I.S.(2c)” mode for 2 stroke and DIS2 engines.

5. Read RPM. One milliv olt is 1 RPM (e .g. 690mV = 690 RPM). When using
a Volt DC scale each volt is equal to 1000 RPM ( e .g. 1.85 V = 1850 RPM).

SYNC Mode

In Sync mode the 901 generates a sharp digital pulse. It can be used on DMM’ s
that have an RPM function, or used as a trigger for a LabScope.

1. Plug the banana plugs into the DMM, LabScope, or other tester. RED to
the positive input ; BLACK to the negative or COMMON input.

2. Select the RPM setting on the DMM.

3. Connect the Spark Pickup around any single Sparkwire. This includes
Distributors, Direct Ignition Systems with 2 outputs (DIS2 ). On Coil-Per­Plug systems, connect the pickup around any single primary drive wire that
feeds the coil. See “Getting a Stable Reading” for more details.

4. Use the SELECT button to set the proper mode. The “#1 Sync” light should
be ON. Use the “Conv (4c)” mode for 4 stroke engines with distributors or
Coil-Per-Plug. Use the “D.I.S.(2c)” mode for 2 stroke and DIS2 engines.

5. Read RPM . Each time a spark is detected that “#1 Sync” light will blink
OFF briefly.

NOTE: in DIS2 mode the 901 will provide a Sync pulse each engine cycle.
However this pulse may be generated when Cylinder #1 fires OR when the
cylinder sharing a coil with Cylinder #1 fires. When analyzing y our test results if
a cylinder shows a problem remember to check its companion cylinder