User manual MCINTOSH MR500

[. . . ] Contents SERVICE CONTRACT INFORMATION 1 INTRODUCTION 2 INSTALLATION 3, 4 BACK PANEL CONNECTIONS AND CONTROLS 5, 6 USING THE FRONT PANEL CONTROLS 7, 8 HOW THE CIRCUITS WORK 9, 10 PERFORMANCE LIMITS 11 PERFORMANCE CHARTS. . 12, 13 BLOCK DIAGRAM 14 FM STATION LOG 15 The Mclntosh compact Family The MR 500 Digital FM Tuner complements the performance and appearance of all Mclntosh products. It is specifically designed to match the industry's leading compacts -- the Mclntosh MC 502 Power Amplifier and the Mclntosh C 504 Preamplifier. Separate, flexibile Mclntosh quality components that are particularly useful where space is limited. 1 MR 500 DIGITAL FM TUNER The MR 500 FM Tuner is designed to perform to its specifications for many years. [. . . ] In some cases, it may be necessary to "position" the antenna for best signal reception. Any indoor antenna may be ineffective in houses having metal siding or metal foil insulation. 120V AC OUTLET Provides a 120 volt AC power outlet with up to 300 watts available for additional equipment that has its own AC power switch. AC POWER CORD Connect the AC power cord to a 120 volt, 50 to 60 Hz power line receptacle. The power used by the MR 500 is 15 watts. 6 Using the Front Panel Controls On the front panel of the MR 500 there are: volume control with tuner on/off AC power switch, 6 momentary feather touch push buttons for selecting preset stations, a jack for headphone listening, 1 on/off push button for between station noise muting, 4 momentary tuning assistance feather touch push buttons, a digital frequency display, 6 preset station indicators, an all solid state tuning indicator and the manual tuning knob and indicator. VOLUME CONTROL WITH AC POWER SWITCH the desired station with the manual tuning knob, or the SCAN tuning. Then, while pressing the ENTER push button press one of the upper row, numbered push buttons. Release both push buttons and the station tuning is recorded in the electronic memory for instantaneous recall. Because the memory is retained when the MR 500 is turned off, upon turn on it will operate in the same mode of operation and station tuning as when turned off. THE ELECTRONIC MEMORY CHARGING BATTERY POWER SUPPLY The VOLUME control has been precision tracked troughout the listening range (0 to -65 dB) for accurate stereo balance. The output level of the VARIABLE OUTPUT jacks and the front panel HEADPHONE jack is controlled by the VOLUME control. Rotate the tuning knob until the frequency of the desired station shows on the digital frequency display. A station is correctly tuned when the center arrow indicator at the bottom of the tuning indicator illuminates. On each side of the center arrow are arrows marked + and -, one of which will light as a station is approached to indicate tuning above ( + ) or below (-) the center of the station. When the center arrow lights, the station is center channel tuned, the FM AFL (automatic frequency lock) circuit is activated and the tuner is locked to the FM station. Mclntosh AFL will give the best FM reception with lowest background noise, lowest distortion and best stereo separation. Because of the locking action of the AFL circuit, the tuning knob can be turned, mechanically, slightly away from the frequency of the station without detuning. This makes tuning very easy but can cause the tuner to lose the station when power is turned off and on again. To prevent this, stop rotation of the tuning knob as soon as the center arrow is lighted. A momentary press on either the SCAN or preset station push buttons deactivates the manual tuning knob and activates the tuning method selected. SCAN The tuner will automatically precisely tune the next station up or down the spectrum depending which SCAN push button is pressed. When the remote scan cable is inserted in the rear panel receptacle, a momentary press of the push button on the end of the remote scan cable will activate the tuner scan-up circuits. TUNING INDICATOR Accuracy of tuning and signal strength is indicated by the 14 LED tuning indicator. [. . . ] A low power amplifier with less than . 01% harmonic distortion drives headphones output and the variable output jacks. A light dependent resistor, whose light source is time controlled, connects the tuner outputs approximately two seconds after the power is turned on to allow all circuits to stabilize before sound can be heard. FREQUENCY COUNTER POWER SUPPLY The + 15, - 15, and + 5 volt supplies use IC three terminal regulators, while the +33 volt supply uses a zener diode regulator. This insures proper operation of the tuner even during periods of low AC line voltages. The frequency counter consists of two IC's. One is an Emitter Coupled Logic (ECL) buffer circuit and divide by 100 prescaler. [. . . ]