C.E. Niehoff & Co. N1126-2 Filter Replacement Instructions User Manual

Page 2

1. Reference disassembly steps on page 1.

2. Remove and discard hardware and defective diode
module.

3. Clean housing surface to remove old heatsink

compound. Surface must be clean and flat before

applying new heatsink compound.

4. Apply a layer of heat sink compound, such as GC/

Waldon HSC # 10-8109 zinc oxide filled silicone or

its equivalent on the back of the new diode module

between the module and housing surface.

5. Install new diode module in orientation shown in

Figure 3. Stack mounting hardware on mounting

studs: nut, disc spring washer, flat washer. Torque

nuts to 12.5 Nm/9.2 lb. ft.

6. After diode module is secured in place, reference

reassembly instructions on page 1.

Diode module tests:

II0120A

Page 2 of 2

C. E. Niehoff & Co. • 2021 Lee Street • Evanston, IL 60202 Tech Services Hotline 800-643-4633

TESTED

CIRCUIT

TABLE C–4 C704 Diode Module Tests

REMOVE PHASE LEADS. USE DIODE TEST SCALE ON DMM.

REPEAT TESTS FOR EACH MODULE. SEE FIGURE C–11.

METER

(+) LEAD

CONNECTION

EXPECTED

READING

(+) side diode

(–) side diode

(+) side diode

(–) side diode

(+) side diode

(–) side diode

METER

(–) LEAD

CONNECTION

Terminal A

Terminal A
Terminal B

Terminal B

Terminal C

Terminal D

Terminals E & F
Terminal D

Terminals E & F

<1.0 volts
(fl ow)
OL (blocking)
<1.0 volts
(fl ow)
OL (blocking)
<1.0 volts
(fl ow)
OL (blocking)

Terminal A
Terminal A

Terminal B

Terminal C

Terminal D
Terminals E & F

(+) side diode
(–) side diode

OL (blocking)
<1.0 volts
(fl ow)
OL (blocking)
<1.0 volts
(fl ow)
OL (blocking)
<1.0 volts
(fl ow)

TABLE 1 Diode Module Tests

USE DIODE TEST SCALE ON DMM.

SEE FIGURE 3.

TEST

NO.

2
3

4
5

7
8

11
12

To replace diode module:

Figure 3 – Diode Module Terminal Designations