Nad 712 Service Manual

Page 1

712 SERVICE MANUAL

TUNER

NA

SERVICE SAFETY PRECAUTIONS (UL)

1. Use exact replacement parts for critical locations marked fi"
2. Return lead dress to original position and re-install protective covers.
3. Before returning to customer, test for shock hazard; use either mothod A or B:

A. Leakage test cold":
1. Unplug the AC cord; turn power switch ON.
2. Connect one lead of High Voltage insulation Tester to both prongs of the AC plug.
3. Touch other lead to all exposed metal parts.
4. impedance measurement must be 0.3-5.0 Megohms.

B. Leakage test, live" 1
1. Plug unit directly into the AC outlet: do not use isolation transformer.
2. Connect one lead of the Leakage Current Tester to earth ground.

3. Touch other lead to all exposed metal parts.

4. Leakage measurement must be less than 0.5 milliamps.

AMPLIFIER

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SERVICE SAFETY PRECAUTIONS

1. Replacing the fuses

E This symbol located near the fuse indicates that the fuse used is fast operating
type. For continued protection against fire hazard, replace with same type fuse. For
fuse rating refer to the marking adjacent to the symbol.

Reference No Part Number Description

F503-F504AH » 5120-0019-0 Fuse 4A 125V Time Lag LBC (UL/CSA)
F503-F504*B,B1,C 5120-0017-0 Fuse 4A 250V Time Lag HBC (SEMKONDE)
F505-F507*AH 5120-0026-0 Fuse 315mA 250V Time Lag LBC (UL/GSA)
F505-F507'B,Bt ,C 5120-0027-0 Fuse 315mA 250V Time Lag LBC (SEMKONDE)
NOTE :

- <*AH > : USA. CANADIAN MODEL ONLY.
: UK MODEL ONLY.
<*B1 > : AUSTRALIAN MODEL ONLY.
<*C > : EUROPEAN MODEL ONLY.

2. Safety-check out

(Only U.S.A. model)

After correcting the original service problem perform the following safety check before releasing
the set to the customer.

Connect the insulating-resistance tester between the plug of power supply cord and the screw on
the back panel.

Specifications : 3.3 Mohmit 0% at 500V.