For EVF and EVH 2-way systems:
Use only the test points on the GREEN side of the Access Card
1. Test the woofer: Place one test lead securely on each of the RED test points on the Access
Card. A properly functioning woofer will read approximately 5.0 ohms DCR, ±0.5 ohm (See
Figure 3). A significantly higher reading indicates an open voice coil, meaning the woofer
must be replaced. A significantly lower reading indicates a voice coil that is shorting, mean-
ing the woofer must be replaced.
2. Test the compression driver: Place one test lead securely on each of the YELLOW test
points on the Access Card. A properly functioning compression driver will read approxi-
mately 4.3 ohms DCR, ±0.5 ohm (See Figure 4). A significantly higher reading indicates an
open voice coil, meaning the compression driver must be replaced. A significantly lower
reading indicates a voice coil that is shorting, meaning the compression driver must be re-
placed.
3. Test the PTP (Power Tracking Protection) network: Place one test lead securely on each of
the GREEN test points on the Access Card. A properly functioning PTP will read no more
than 2 ohms (See Figure 5). If the reading is higher, replace the SK-3 lamps on the cross-
over PCB.
4. Unplug the Access Card and re-install the switch card in exactly the same position it was in
originally. If applicable, Re-attach the security cover, gland nut cover, or NL4 cover.
Figure 3:
EVF/EVH Woofer Test
Figure 4:
EVF/EVH Compression
Driver Test
Figure 5:
EVF/EVH Protection
Network Test
ImpoRTANT! You are testing for DC resistance (DCR). Do NoT CoNFUsE DCR wITH ImpEDANCE!
simple DCR measurements will identify most common failures.
Experienced technicians may perform more
sophisticated tests by connecting specialized test gear in place of the ohm meter.
ImpoRTANT! Never connect an amplifier to a pTp test point!
wARNING! Compression drivers are easily destroyed by improper testing. Never connect a battery or
other power source directly to a compression driver! Any testing beyond the DCR measurements outlined
here is conducted at your own risk. Drivers destroyed by improper testing are not covered under warranty!
Note: EVF low-frequency systems have no PTP or compression drivers, and use different woof-
ers. See the chart on page 4 for correct DCR values.
5.0
4.3
1.1
