Hitachi AX M7 WUN Service Manual

Page 1

HITACHI

@

SERVICE MANUAL

_, MANUEL DENTRETIEN
E ' WARTUNGSHANDBUCH

CAUTION:

Before servicing this chassis, it is important that the service
technician read the Safety Precautions and Product Safety
Notices in this service manual.

ATTENTION:

Avant deffectuer Ientretien du chaassis, Ie technicien doit lire
les «Precautions de sécurité» et les «Notices de sécurité du
produit» présentés dans Ie présent manuel.

VORSICHT:

Vor Offnen des Gehauses hat der Service-Ingenieur die
,,Sicherheitshinweise und ,,Hinweise zur Produktsicherheit in
diesem Wartungshandbuch zu lesen.

SM0094

AXM7E
AXM7EBS
AXM7UC
AXM7W
AXM7WUN

CD MECHANISM RD-DRL008-M
MD MECHANISM MUM-98X

Data contained within this

Service manual is subject to
alteration for improvement.

Les données fournies dans le
present manuel dentretien
peuvent faire lobjet de
modifications en vue de
perfectionner le produit.

Die in diesem
Wartungshandbuch
enthaltenen Spezifikationen

konnen sich zwecks

Verbesserungen andem.

November 1999

Page 2

SAFETY PRECAUTIONS

WARNING: The following precautions must be observed.

ALL PRODUCTS

1.

2.

3.

Before any service is performed on the chassis an isolation transformer should be inserted
between the power line and the product.

When replacing the chassis in the cabinet, ensure all the protective devices are put back in
place.

When service is required, observe the original lead dressing. Extra precaution should be
taken to ensure correct lead dressing in any high voltage circuitry area.

. Many electrical and mechanical parts in HITACHI products have special safety related

characteristics. These characteristics are often not evident from visual inspection, nor can
the protection afforded by them necessarily be obtained by using replacement components
rated for higher voltage, wattage, etc. Replacement parts which have these special safety
characteristics are identified by marking with a A on the schematics and the replacement
parts list.

The use of a substitute replacement component that does not have the same safety
characteristics as the HITACHI recommended replacement one, shown in the parts list,
may create electrical shock, fire, X-radiation, or other hazards.

. Always replace original spacers and maintain lead lengths. Furthermore, where a short

circuit has occurred, replace those components that indicate evidence of overheating.

. Insulation resistance should not be less than 2M ohms at 500V DC between the main poles

and any accessible metal parts.

. No flashover or breakdown should occur during the dielectric strength test, applying 3kV

AC or 4.25kV DC for two seconds between the main poles and accessible metal parts.

. Before returning a serviced product to the customer, the service technician must

thoroughly test the unit to be certain that it is completely safe to operate without danger
of electrical shock. The service technician must make sure that no protective device built
into the instrument by the manufacturer has become defective, or inadvertently damaged
during servicing.

CE MARK

1.

HITACHI products may contain the CE mark on the rating plate indicating that the product
contains parts that have been specifically approved to provide electromagnetic
compatibility to designated levels.

. When replacing any part in this product, please use only the correct part itemised in the

parts list to ensure this standard is maintained, and take care to replace lead dressing to
its original state, as this can have a bearing on the electromagnetic radiation/immunity.

PICTU RE TUBE

1.

3.

The line output stage can develop voltages in excess of 25kV; if the E.H.T. cap is required
to be removed, discharge the anode to chassis via a high value resistor, prior to its
removal from the picture tube.

. High voltage should always be kept at the rated value of the chassis and no higher.

Operating at higher voltages may cause a failure of the picture tube or high voltage
supply, and also, under certain circumstances could produce X-radiation levels moderately
in excess of design levels. The high voltage must not, under any circumstances, exceed
29kV on the chassis (except for projection Televisions).

The primary source of X-radiation in the product is the picture tube. The picture tube
utilised for the above mentioned function in this chassis is specially constructed to limit X-
radiation. For continued X-radiation protection, replace tube with the same type as the
original HITACHI approved type

4. Keep the picture tube away from the body while handling. Do not install, remove, or
handle the picture tube in any manner unless shatterproof goggles are worn. People not
so equipped should be kept away while picture tubes are handled

LASERS

If the product contains a laser avoid direct exposure to the beam when the cover is open or
when interlocks are defeated or have failed.

Page 13

Removal of FL DISP P.W.B. Board

1. Remove 10 screws (D and 2 screws @.

2. Gently pull the Volume knob away from the front panel, and release the nut. Detach the
FL DISP P.W.B. board from the front panel cover.