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Top Panel Information and

Secondary Controls

On the top of the chassis behind the front panel a

recessed panel contains the secondary controls.

When the MR 80 is installed in the cabinet access to
this panel may be gained by depressing the two

PANLOC buttons and slipping the unit partially for-

ward.

Preset 1 thru 4

The PRESET tuning adjustments are used to set

the received frequency for each preset. To set a
preset to the desired station, touch the correspond-

ing preset pad and at the same time adjust the

preset control on the top panel for the desired fre-

quency indication. You must touch the pad while

tuning to hold the frequency lock circuit inactive,
otherwise erroneous tuning will result.

Preselect

The RF PRESELECT switch switches an addi-

tional tuned circuit between the antenna and the

first RF stage to immunize against overload. Use the

preselector in very strong signal areas.

Input

The INPUT switch selects either an antenna or

cable as the RF input source. The CABLE input may
also be used as a second antenna input.

Lock

This switch will disable the lock  c i r c u i t s only

when the main tuning knob is in use. Use the ON

position for all normal reception. Switch to the OFF
position when the received station has a deep fade.

This prevents the frequency lock circuit from chang-

ing tuning to lock to an adjacent stronger station.

De-emphasis

The 50/75

m

s button selects the correct de-

emphasis for your country. 75

m

s is used on the North

American continent and 50

m

s is used in Western

Europe and the Far East. 25

m

s de-emphasis is also

available by depressing the button marked

Note: The normal operating position of the five

pushbutton switches is for the switches to be in the
out or up position.

Signal Strength

Use this control to set the signal strength column

to  f u l l scale for the strongest station in your area.

This control is a sensitivity adjustment for the solid

state signal strength indicator. It merely adjusts the

height of the column. It does not affect the sensitiv-
ity of the tuner.

8

Summary of Contents for MR80

Page 1: ...Reading Time 32 Minutes Price 2 00 THE MclNTOSH MR 80 DIGITAL FM TUNER...

Page 2: ...the rear panel of the chassis Record that serial number here Serial Number The model serial number and purchase date are important to you for any future service Record the purchase date here Purchase...

Page 3: ...RACT CER TIFICATE must be presented when the instrument is taken to the service agency 3 Always have service done by a Mclntosh authorized service agency If the instrument is modified or damaged as a...

Page 4: ...tenna jack A flexible folded dipole antenna supplied with your MR 80 may be used in urban or in high signal strength areas The flexibility of the thin flat wire assembly permits it to be placed under...

Page 5: ...R 2ND 75W ANTENNA LEAD IN FM ANTENNA OPTIONAL 75W ANTENNA LEAD IN REMOTE CONTROL PUSH BUTTON POWER AMPLIFIER PREAMPLIFIER LEFT SPEAKER RIGHT SPEAKER 5 MAXIMUM PERFORMANCE INDICATOR OR OSCILLOSCOPE TO...

Page 6: ...4 These touch pads located to the left of the fre quency display select one of the four preset sta tions Just touch to operate A small rectangle will light above the pad indicating which preset has b...

Page 7: ...ono reception In the STEREO position the tuner automatically switches from mono to stereo mode when a pre determined signal to noise ratio has been reached In the MONO position all stations will be re...

Page 8: ...INPUT switch selects either an antenna or cable as the RF input source The CABLE input may also be used as a second antenna input Lock This switch will disable the lock circuits only when the main tun...

Page 9: ...on 110dB Narrow 8dB 90dB Super Narrow 60dB 110dB Tuner IM RF 23dBm for 2 signals 1MHz apart Tuner Intercept Point 10dBm 75W ImageRejection 90dB Maximum Signal Input 8 volts across 75W 1W antenna termi...

Page 10: ...Performance Charts SIGNALINPUT 10 SIGNAL INPUT...

Page 11: ...11 FREQUENCY IN HERTZ FREQUENCY IN HERTZ FREQUENCY IN HERTZ...

Page 12: ...12 FREQUENCY IN HERTZ FREQUENCY IN HERTZ FREQUENCY IN HERTZ...

Page 13: ...13 FREQUENCY IN HERTZ FREQUENCY IN HERTZ FREQUENCY IN HERTZ...

Page 14: ...on ordinary tuners Constant delay design techniques are used in the 4 pole 4 zero crystal filter used in the SUPER NAR ROW position However due to the extreme selec tivity delay distortion is very sli...

Page 15: ...is for use with an external noise reduction adapter An electronically switched filter circuit im plemented with two J FETs of a quad J FET package is used to reduce out of phase noise when in the ste...

Page 16: ...he scan circuitry on the tuning control logic board The logic circuitry will then select the auto scan circuit and start searching for the next acceptable station The direction of scan will be the las...

Page 17: ...and in hibit the lock circuit under these conditions On the top cover control panel is a manual lock ON OFF switch that inhibits the lock circuit only if the tuner is in the main tuning knob mode This...

Page 18: ...the IF offset by adding the negative of the IF frequency The gate signal is derived from a stable 200kHz crystal oscillator and a binary divider made from LS integrated circuits Two other signals are...

Page 19: ...19...

Page 20: ...Block Diagram 20 MclNTOSH MR 80...

Page 21: ...DIGITAL FM TUNER 21...

Page 22: ...MBERS ST BINGHAMTON N Y 13903 9990 607 723 3512 The continuous improvement of its products is the policy of Mclntosh Laboratory Incorporated who reserve the right to improve design and price without n...

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