<<forty 2 调整方法>>转自作者原网站，基本上能看懂了。供大家参考。
adjustments:
apparatuses necessary to the adjustment:
- dummy load 50 ohms/10 watts - wattmeter, tos' meter - universal controller
- frequency meter 30 mhz - oscilloscope 40 mhz - generator hf (not essential)
before very powering, to check the value of all the components in place. not to confuse the coils moulded with resistances, and to pay well attention to the code of location of the condensers. to seek the poor contacts and the lapses of memory of welding.
initially, not to place the integrated circuits in their support. to if required connect a load of 50 ohms/10 watts in the catch antenna.
to energize and to check the presence of the continuous tensions controlled at the boundaries of the zener diodes and the regulators. the values are indicated on the diagrams in the small rectangular boxes, and do not have to be higher or lower of more than 5% than the registered values. to extinguish and set up the integrated circuits.
receiving adjustment:
to preset p1, p3 and ca1 with semi-race, ca2 with a quarter of the total capacity.
to energize. after the time of initialization, to regulate posting on 7.070.0. the step value is regulated by successive supports on the pushbutton “step”. by a support prolonged on “filter” one posts the value of the filter in service. the change of value is done by means of the rotary coder. to select 2.4 khz. to validate by a short support on “filter”.
pot1 with semi-race, it must y have breath in the loudspeaker. to check that the attenuator is except service and to regulate ca1, l4 and l5 to have the maximum of breath. to take again this adjustment several times to have a frank and single maximum. to perfect possibly thereafter, either with the generator hf, or on the reception of a weak station.
the value of adjustable resistance p1 determines the level of attenuation hf. less resistance increases the attenuation. the attenuator is brought into service by a support prolonged on “attn”. the outage is done in the same way. to regulate the evening when the disturbing signals are very powerful.
the adjustment of bfo (ca2) to decode the lower edge line (lsb), is a function of the value of the frequency of resonance of quartz. and this one is variable according to the manufacturers. this is why it is imperative to take all quartz, x1 with x10, of the same series, the same manufacturer. for the adjustment of ca2, to proceed as follows: to place ca2 to the maximum of value (closed ca2). to measure the frequency of oscillation on pin 7 of ic2. to note this frequency. to add the value of 1,8 khz, and to regulate ca2 until reading this last value on the frequency meter. example: ca2 to the maximum of value, posted frequency 4915,410 khz. 4915,410 + 1,8 = 4917,210 khz. thus to vary ca2 until reading 4917,210 khz on the frequency meter. for the purists, some further information: why add 1,8 khz? this is the corrected central value, of the initial width of the quartz filter. why corrected since the calculated width of the filter is 4 khz, and that this central value should be 2 khz? quartz resounds on its frequency of resonance series with a capacity in series of 30 pf. as ca2 (closed to the maximum) is not that of 22 pf, the 200 hz lacks correspond to the 8 missing pf.
checking of the correct operation of the cag (automatic gain control): without signal at the entry of the receiver, the tensions on pins 2 of ic1 and ic2 must be 1,40 volts. to inject a signal of 50 ?v at the entry, the tension on 2 of ic1 must be close to 1,02 volts, and the tension on 2 of ic2 must be close to 0,88 volts. the values are not very critical, it is on the other hand imperative that these values decrease when the level of the signal at the entry increases.
to check the receiver by connecting an antenna, and to regulate p3 so that there is no distortion on the audible signals (normally with semi race).
to reinject a signal of 50 ?v at the entry, to regulate p9 to light the bar graph to the eighth diode, corresponding to s9. if the s3 rider is in place on the turntable front face, all the led diodes up to the maximum value ignite. s3 except, only the led diode of the maximum value ignites. what can be useful during the use on battery.
adjustment of the synthetizer:
the synthetizer, if it were correctly assembled, must function as of the powering. to check led d13. if it flickers, the synthetizer is not locked. régler ca4 until having a glare fixes of d6 (to use a nonmetal screwdriver). to be more precise, with a voltmeter connected at exit 6 of ic11, to regulate ca4 to have 2,53 volts for a posted frequency 7.070.0. to pass in high limit of the band (7,300 mhz), then low (7,000 mhz) and to check that the synthetizer remains vérouillé. in the contrary case to take again the adjustment of ca4 slightly.
it is also necessary to check the exactitude of the posted frequency. it is necessary to compare with another calibrated receiver, with precise posting of the frequency. if the difference is lower than 100 hz, precise fitting is done with adjustable condenser ca5. if the difference is higher than 100 hz, it will be necessary to configure ic8 to indicate the correction of error to him. with this intention, to extinguish the apparatus then to relight it while pressing simultaneously on the pushbutton “laughs”. bill-poster lcd posts “shift +00.0 k”. this stage it is necessary to return the value of the shift in frequency noted between the posting of the synthetizer and that of the receiver of reference. using the coder to post this shift (with the steps of 100 hz). while pressing on the pushbutton “step” one chooses between a positive or negative shift. the memorizing of the selected value is done while pressing on the pushbutton “laughs”. to carry out tests while comparing with the receiver standard or a generator hf. the shift will remain in memory and will be active with each powering. to finish while correcting with ca5 to be pile on the good frequency. it is easier to make than to explain.
adjustment of the transmitter:
the adjustment of the transmitter requires a little more attention.
presettings: p2, p4 and p5 at least (at bottom in the contrary direction of the needles of a watch), p6 with semi race
rider on s1 and not of rider on s2, which makes it possible to feed the totality of the receiver while passing in emission, without feeding for as much the stage of power emission.
to connect a dummy load 50 ohms/10 watts. to insert a wattmeter tos' meter.
oscilloscope connected on pin 6 of ic7, to regulate p2 in order to have a signal of 200 with 220mv peak with peak, allowed maximum value by the sa612 not to generate distortions at exit.
to press on the pedal of the microphone. while acting on ca3, one hears the signal of the carrying emission. to adjust ca3 with the null beat heard in the receiver of forty2. by increasing the micro profit with p5, one intends oneself to speak. attention with making this adjustment well not to be shifted in emission compared to the correspondent. the ideal is to measure the frequency on pin 7 of ic6 and to regulate ca3 on the same frequency as previously with ca2 (4917,210 khz in our example).
to remove the rider placed on s1 and to place it on s2 (position of the rider under normal operation).
p5 at bottom in the contrary direction of the needles of a watch (micro profit with zero), p6 with semi-race. to press on the pedal of the microphone. oscilloscope connected in parallel on the exit antenna, to visualize the signal of residue of carrying. to regulate p6 at least signal. without slackening the pedal of the microphone, presetting l7 and l8 to the maximum of signal.
to increase the value of p5 while whistling in the microphone. the signal must increase on the wattmeter until reaching a maximum value between 3 and 5 watts hf. not too much not to push this adjustment, the quality of the modulation depends on it. if the needle of the wattmeter deviates up to 5 watts on a whistle, it should not exceed 2 watts while speaking normally. no fear, the power peak is well of 5 watts!
the q6 transistor is a transistor hf with great profit. this is interesting to be able to leave 5 watts with a minimum stages of amplification, but can also lead this transistor car-to oscillate. if such is the case, to place a condenser of 10 nf in series with a resistance of 1 k between base and collector of q6, cabled under the circuit and with shortest. on the contrary, if the assembly of origin car-does not oscillate, one can try to replace r23 and r24 by straps, which will make it possible to leave the maximum of power hf (as on my prototypes).
for the adjustment of the compressor of modulation, the best position is between a quarter and a third of the value of p4. with each one to pay its tests, but attention not not to be pushed too much!
the bar graph also makes it possible to post the power of relative exit in emission. to regulate p7 for the deviation corresponding to that of the wattmeter of reference.
