JPH0215410Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a front-end unit that integrates an electronic tuner peripheral circuit for use in VTR devices and television receivers.

2. Description of the Related Art A circuit for processing an antenna input signal in a VTR device or television receiver is comprised of an electronic tuner for selecting a desired channel from the antenna input signal, an IF pack for processing the IF output of the electronic tuner, and the like. These parts may be integrated into a front end unit 2 using a mounting bracket 1 as shown in FIGS. 4 to 7. By using this front end unit 2, the process of assembling it into the device can be simplified and the internal structure of the device can be made more compact.

In the front end unit 2, an electronic tuner 3 and an IF pack 4 are horizontally fixed side by side to a mounting bracket 1 having an L-shaped cross section, and an external printed circuit board 5 is attached to each shield base 6 of the electronic tuner and the IF pack. Leg pieces 6a, 7a extended from 7
It is fixed by soldering by mating. Peripheral circuit components such as connectors 8 and 9 are attached to this external printed circuit board 5, and external lead-out leads 3a, 3a of the electronic tuner 3 and printed circuit board lead-out portion 4a of the IF pack 4 are implanted and connected. A predetermined signal voltage is supplied to the electronic tuner 3 and the IF pack 4.

The electronic tuner 3 stores a printed circuit board (not shown) on which the tuner parts are assembled in a rectangular frame-shaped shield base 6, and inserts a screwdriver into the front and back openings of the shield base corresponding to the internal adjustment points. It has a structure in which shield covers 11 and 12 are fitted with adjustment holes 10, 10, . . . In addition, the IF pack 4 houses a printed circuit board on which IF circuit components are assembled in a rectangular frame-shaped shield base 7, and adjustment holes 13, 13, . A shield cover 14 is fitted. Mounting brackets for these parts 1
To install the electronic tuner 3, use the adjustment holes 10, 10.
On the side with less, IF pack 4 has shield cover 14
A part of each shield base 6, 7 is screwed 15, 15 to the mounting bracket 1 with the side where is not fitted facing the mounting bracket 1, and leg pieces 6a, which are formed as extensions from each shield base 6, 7, are attached. 7a is inserted into the through hole of the folded-up piece 16 of the mounting fitting 1 and soldered.

Problems to be solved by the invention The above front end 2 has an electronic tuner and
Since the standard is to adjust the IF pack from the front side that does not face the mounting bracket 1, the electronic tuner should be adjusted with the side with many adjustment points facing the front side, and the IF pack should be adjusted from the inside printed circuit board where there are adjustment points such as coil parts. It is installed with the part insertion side facing up.

However, since the IF pack has many adjustment points, we made one adjustment hole in the shield cover 14 to accommodate this.
When 3, 13... are drilled, the shield cover 14
becomes weaker in strength and becomes more likely to vibrate. This causes the capacitance between the shield cover and the internal circuit to fluctuate, making it easy for howling to occur, resulting in a problem of deterioration of reception characteristics. It is conceivable to increase the wall thickness of the shield cover 14 of the IF pack in order to prevent a decrease in strength, but this will increase material costs and processing costs, leading to an increase in costs.

Means for Solving the Problems This invention solves the above-mentioned conventional problem in which the shield cover of the IF pack easily vibrates, and fixes the electronic tuner and the IF pack together in a horizontal position on the mounting bracket. In the front end,
By attaching the IF pack with the part insertion side face where the adjustment points are located facing the mounting bracket, and drilling through holes in the mounting bracket corresponding to each adjustment location.
It has a configuration in which there is no adjustment hole for the shield cover that is fitted into the opening on the opposite side of the IF pack. Since this configuration is based on adjustment from the mounting bracket, the surface of the electronic tuner with more adjustment holes faces the mounting bracket, and adjustment holes are bored in the mounting bracket in correspondence with the adjustment holes.

Effects According to the above configuration means of the present invention, there is no need to provide adjustment holes in the shield cover of the IF pack, so there is no decrease in strength, and the shield cover becomes less likely to vibrate without increasing its wall thickness.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In the front end unit 20 shown in FIGS. 1 to 3, reference numeral 21 denotes a mounting bracket having an L-shaped cross section;
22 is an electronic tuner, 23 is an IF pack, and 24 is an external printed circuit board. To assemble the front end unit, as in the conventional example, the electronic tuner 22 and IF pack 23 are placed horizontally on the mounting bracket 21, and the respective chassis bases 6 and 7 are placed on the mounting bracket 21.
The leg pieces 6a, 7 are screwed to a part of the chassis bases 6, 7, and are extended from the respective chassis bases 6, 7.
a is inserted into a through hole of a folded-up piece (not shown) of the mounting fitting 21 and fixed by soldering. In addition, the external printed circuit board 24 also has a through hole for the external lead 22 of the electronic tuner 22, as in the conventional example.
a, 22a, . . . and the printed circuit board lead-out portion 23a of the IF pack 23, and the leg pieces 6a, 7a, . The above structure of the present invention differs from the conventional example in that the electronic tuner 22 is connected to the adjustment holes 10, 10...
The surface on the shield cover side with a lot of ... is directed toward the mounting bracket 21, and the component insertion side surface of the IF pack 23 is mounted toward the mounting bracket 21. Since the adjustment points of the IF pack 23 are the IF coil and the like, and are all located on the component mounting surface of the internal printed circuit board 25, a shield cover 26 without adjustment holes is fitted into the opening on the opposite side to the mounting bracket. The mounting bracket 21 has adjustment holes 10, 10, . . . of the shield cover 11 facing the mounting bracket side of the electronic tuner 22, and an IF pack 23.
Adjustment holes 27, 27... corresponding to each adjustment location.
to be drilled. Since the mounting bracket 21 is originally quite thick, there is no risk of its strength decreasing.

Effects of the invention According to the invention, since it is only necessary to fit a shield cover without adjustment holes to the IF pack, the strength of this shield cover is improved, making it difficult to vibrate, and eliminating deterioration of electrical characteristics due to howling etc. can do.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention,
FIG. 1 is a perspective view, FIG. 2 is a plan view, and FIG. 3 is a bottom view. 4 to 7 show a conventional example, in which FIG. 4 is a perspective view, FIG. 5 is a plan view, FIG. 6 is a bottom view, and FIG. 7 is a rear view. 10...Shield cover adjustment hole, 11, 12
...Electronic tuner shield cover, 20...Front end unit, 21...Mounting bracket, 22
...Electronic tuner, 23...IF unit, 26
...IF pack shield cover, 27...Mounting bracket adjustment hole.

Claims (1)

[Scope of utility model registration request] An independent electronic tuner and an IF pack are placed and fixed together on a mounting bracket. A shield cover is fitted into the opening on the side not facing the metal fittings, and the electronic tuner and
A front-end unit for a television receiver, characterized in that adjustment holes are formed in the mounting bracket to correspond to the adjustment points of the IF pack, and at least a shield cover without adjustment holes is fitted to the IF pack.