FT2800M.pdf

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1、1 Introduction This manual provides technical information necessary for servicing the FT-2800M FM Transceiver. Servicing this equipment requires expertise in handling surface-mount chip components. Attempts by non-qualified per- sons to service this equipment may result in permanent damage not cover

2、ed by the warranty, and may be illegal in some countries. Two PCB layout diagrams are provided for each double-sided circuit board in the Transceiver. Each side of is referred to by the type of the majority of components installed on that side (“leaded” or “chip-only”). In most cases one side has on

3、ly chip components, and the other has either a mixture of both chip and leaded components (trimmers, coils, electrolytic capacitors, ICs, etc.), or leaded components only. While we believe the technical information in this manual to be correct, VERTEX STANDARD assumes no liability for damage that ma

4、y occur as a result of typographical or other errors that may be present. Your cooperation in pointing out any inconsistencies in the technical information would be appreciated. 2003 VERTEX STANDARD CO., LTD.EH014N90A Technical Supplement Specifications. 2 Exploded View after passing through Q315 (N

5、JM2902V) which consists of amplifier, pre-emphasis, limiter (IDC instantaneous deviation control) and lowpass filter, to Q319 (M6364FP) which is adjusted for opti- mum deviation level and delivered to the TX VCO Q322. The speech signal from the microphone and CTCSS are FM modulated by the TX VCO of

6、the synthesizer, while DCS audio is modulated by the reference frequency os- cillator of the synthesizer. Synthesizer output, after passing through diode switch D311 (1SS321), is amplified by pri- drivers Q317 (2SC3356) and Q314 (RD00HVS1), driver Q313 (2SK3075), and power amplifier Q305 (RD70HVS1)

7、to obtain full RF output. The RF energy then passes through antenna switch D303 (XB15A407) and a low- pass filter circuit and finally to the antenna connector. RF output power from the final amplifier is sampled by C318 and C324 and is rectified by D302 (1SS321). The resulting DC is fed through Auto

8、matic Power Con- troller Q309 (UMT1N), Q312 (DTC114), and Q311 (2SB1197) to transmitter RF amplifier Q305 and is used to provide control of the power output. Generation of spurious products by the transmitter is min- imized by the fundamental carrier frequency being equal to the final transmitting f

9、requency, modulated directly in the transmit VCO. Additionally harmonic suppression is provided by a low- pass filter consisting of L303, L305, C303, C309, C310, and C316, resulting in more than 60 dB of harmonic sup- pression prior to delivery of the RF 9 Alignment Introduction and Precautions The

10、FT-2800M has been carefully aligned at the factory for the specified performance at the 144 MHz amateur band. Realignment should therefore not be necessary ex- cept in the event of a component failure. All component replacement and service should be performed only by an authorized Vertex Standard re

11、presentative, or the warranty policy may be voided. The following procedures cover the sometimes critical and tedious adjustments that are not normally required once the transceiver has left the factory. However, if damage occurs and some parts are replaced, realignment may be required. If a sudden

12、problem occurs during normal oper- ation, it is likely due to component failure; realignment should not be done until after the faulty component has been replaced. We recommend that servicing be performed only by au- thorized Vertex Standard service technicians who are ex- perienced with the circuit

13、ry and fully equipped for repair and alignment. Therefore, if a fault is suspected, contact the dealer from whom the transceiver was purchased for instructions regarding repair. Authorized Vertex Standard service technicians realign all circuits and make complete performance checks to ensure complia

14、nce with factory specifications after replacing any faulty components. Those who do undertake any of the following alignments are cautioned to proceed at their own risk. Problems caused by unauthorized attempts at realignment are not covered by the warranty policy. Also, Vertex Standard must re- ser

15、ve the right to change circuits and alignment proce- dures in the interest of improved performance, without notifying owners. Under no circumstances should any alignment be attempt- ed unless the normal function and operation of the trans- ceiver are clearly understood, the cause of the malfunc- tio

16、n has been clearly pinpointed and any faulty compo- nents replaced, and the need for realignment determined to be absolutely necessary. Required Test Equipment The following test equipment (and thorough familiarity with its correct use) is necessary for complete realign- ment. Correction of problems

17、 caused by misalignment resulting from use of improper test equipment is not cov- ered under the warranty policy. While most steps do not require all of the equipment listed, the interactions of some adjustments may require that more complex adjustments be performed afterwards. Do not attempt to per

18、form only a single step unless it is clearly isolated electrically from all other steps. Have all test equipment ready before be- ginning, and follow all of the steps in a section in the order presented. ? Regulated DC Power Supply: adjustable from 10 to 17 VDC, 15 A ? RF Signal Generator with calib

19、rated output level at 200 MHz ? Frequency Counter: 0.1 ppm accuracy at 200 MHz ? AF Signal Generator ? SINAD Meter ? Deviation Meter (linear detector) ? AF Milivoltmeter ? AF Dummy Load: 8-Ohm, 5 W ? DC Voltmeter: high impedance ? Inline Wattmeter with 5% accuracy at 200 MHz ? 50-Ohm non-reactive Du

20、mmy Load: ? 100 watts at 200 MHz ? VHF Sampling Coupler Set up the test equipment as shown for the transceiver alignment, and apply 13.8 VDC power to the transceiver. Alignment Preparation & Precautions A dummy load and inline wattmeter must be connected to the antenna jack in all procedures that ca

21、ll for transmis- sion, except where specified otherwise. Correct alignment is not possible with an antenna. After completing one step, read the following step to determine whether the same test equipment will be required. If not, remove the test equipment (except dummy load and wattmeter, if connect

22、- ed) before proceeding. Correct alignment requires that the ambient temperature in the repair shop be the same as that of the transceiver and test equipment, and that this temperature be held con- stant between 68 oC and 86 oF (20 oC 30 oC). When the transceiver is brought into the shop from hot or

23、 cold air it should be allowed some time for thermal equaliza- tion with the environment before alignment. If possible, alignments should be made with oscillator shields and cir- cuit boards firmly affixed in place. Also, the test equip- ment must be thoroughly warmed up before beginning. Notes: Sig

24、nal levels in dB referred to in alignment are based on 0 dB = 0.5 V. 10 Entering the Alignment mode Alignment of the FT-2800M is performed using a front- panel software-based procedure. To perform alignment of the transceiver, it must first be placed in the “Align- ment Mode,” in which the adjustmen

25、ts will be made and then stored into memory. To enter the Alignment mode: 1. Press and hold in the LOW key and D/MR key while turning the radio on. Once the radio is on, re- lease these two keys. 2. Press and hold the MHz key for one second to acti- vate the “Set” (Menu) mode. 3. Rotate the DIAL kno

26、b to select “35 D/ASMT,” then press the MHz key. 4. You will now note the appearance of “REF” on the display, this signifies that the transceiver is now in the “Alignment mode.” PLL Reference Frequency (REF) 1. Tune the transceiver to 146.000 MHz. 2. Set the transceiver to Alignment mode, then rotat

27、e the DIAL knob to set the Alignment parameter to “REF.” 3. Press the PTT switch to activate the transmitter, and press the REV or D/MR key, as needed, so that the counter frequency reading is 146.000 MHz. 4. Press and hold the LOW key for one second to save the new setting. 5. Press and hold the MH

28、z key for one second to exit to the normal operation. PLL VCO 1. Connect the DC voltmeter to TP-RVC on the RF Unit. 2. Tune the frequency to 146.000 MHz. 3. Adjust L330 on the RF Unit for 1.5 V on the DC volt- meter. 4. Connect the DC voltmeter to TP-TVC on the RF Unit. 5. Press the PTT switch to ac

29、tivate the transmitter, and adjust L329 on the RF Unit for 1.3 V on the DC volt- meter. RF Front-end Tuning (TUN137/TUN146/TUN160/TUN173) 1. Connect the DC voltmeter to the Test Point (RSSI: Pin 6 of J307) on the RF Unit. 2. Tune the transceiver to 137.050 MHz. 3. Set the transceiver to Alignment mo

30、de, then rotate the DIAL knob to set the Alignment parameter to “TUN137.” 4. Inject a 137.050 MHz signal at a level of 5 dB (with 1 kHz modulation 3.5 kHz deviation) from the RF Signal Generator. 5. Press the REV or D/MR key for maximum deflec- tion of the DC voltmeter. 6. Press and hold the LOW key

31、 for one second to save the new setting, then press and hold the MHz key for one second to exit to the normal operation. 7. Tune the transceiver to 146.050 MHz. 8. Set the transceiver to Alignment mode, then rotate the DIAL knob to set the Alignment parameter to “TUN146.” Alignment RF UNIT ALIGNMNT

32、POINTS L329 RSSI L330 TP-TVC TP-RVC 11 9. Inject a 146.050 MHz signal at a level of 5 dB (with 1 kHz modulation 3.5 kHz deviation) from the RF Signal Generator. 10. Press the REV or D/MR key for maximum def4lection of the DC voltmeter and maximum de- flection of the SINAD meter. 11. Press and hold t

33、he LOW key for one second to save the new setting, then press and hold the MHz key for one second to exit to the normal operation. 12. Tune the transceiver to 160.050 MHz. 13. Set the transceiver to Alignment mode, then rotate the DIAL knob to set the Alignment parameter to “TUN160.” 14. Inject a 16

34、0.050 MHz signal at a level of 5 dB (with 1 kHz modulation 3.5 kHz deviation) from the RF Signal Generator. 15. Press the REV or D/MR key for maximum deflec- tion of the DC voltmeter voltmeter at the higher side of the bandpass filter peaks. 16. Press and hold the LOW key for one second to save the

35、new setting, then press and hold the MHz key for one second to exit to the normal operation. 17. Tune the transceiver to 173.050 MHz. 18. Set the transceiver to Alignment mode, then rotate the DIAL knob to set the Alignment parameter to “TUN173.” 19. Inject a 173.050 MHz signal at a level of 5 dB (w

36、ith 1 kHz modulation 3.5 kHz deviation) from the RF Signal Generator. 20. Press the REV or D/MR key for maximum deflec- tion of the DC voltmeter at the higher side of the bandpass filter peaks. 21. Press and hold the LOW key for one second to save the new setting, then press and hold the MHz key for

37、 one second to exit to the normal operation. S-Meter Sensitivity (SMTL 10/SMTL 2) 1. Set the transceiver to Alignment mode, then rotate the DIAL knob to set the Alignment parameter to “SMTL 10.” 2. Inject a 146.050 MHz signal at a level of +25 dB (with 1 kHz modulation 3.5 kHz deviation) from the RF

38、 Signal Generator. 3. Press and hold the LOW key for one second to save the new setting. 4. Rotate the DIAL knob one click to clockwise to set the Alignment parameter to “SMTL 2.” 5. Reduce the RF Signal Generator output level to 5 dB. 6. Press and hold the LOW key for one second to save the new set

39、ting. 7. Press and hold the MHz key for one second to exit to the normal operation. TX Power Output (TXPW H/TXPW M/TXPW L2/TXPW L1) 1. Tune the transceiver to 146.000 MHz, and set the Transmitter Power Level to “HIGH.” 2. Set the transceiver to Alignment mode, then rotate the DIAL knob to set the Al

40、ignment parameter to “TXPW H.” 3. Press the PTT switch to activate the transmitter, and press the REV or D/MR key for 65 Watts on the wattmeter, and confirm that supply current remains below 12.5 A. 4. Press and hold the LOW key for one second to save the new setting, then rotate the DIAL knob one c

41、lick to clockwise to set the Alignment parameter to “TXPW M.” 5. Press the PTT switch to activate the transmitter, and press the REV or D/MR key for 25 Watts on the wattmeter, and confirm that supply current remains below 7.5 A. 6. Press and hold the LOW key for one second to save the new setting, t

42、hen rotate the DIAL knob one click to clockwise to set the Alignment parameter to “TXPWL2.” 7. Press the PTT switch to activate the transmitter, and press the REV or D/MR key for 10 Watts on the wattmeter, and confirm that supply current remains below 5 A. 8. Press and hold the LOW key for one secon

43、d to save the new setting, then rotate the DIAL knob one click to clockwise to set the Alignment parameter to “TXPWL1.” 9. Press the PTT switch to activate the transmitter, and press the REV or D/MR key for 5 Watts on the wattmeter, and confirm that supply current remains below 4 A. 10. Press and ho

44、ld the LOW key for one second to save Alignment 12 the new setting, then press and hold the MHz key for one second to exit to the normal operation. TX Deviation (MODWFM/MODNFM) 1. Tune the transceiver to 146.000 MHz. 2. Inject a 1 kHz audio tone at a level of 60 mV from the Audio Generator. 3. Set t

45、he transceiver to Alignment mode, then rotate the DIAL knob to set the Alignment parameter to “MODWFM.” 4. Press the PTT switch to activate the transmitter, and press the REV or D/MR key so that the deviation meter reading is 4.2 kHz. 5. Press and hold the LOW key for one second to save the new sett

46、ing, then rotate the DIAL knob one click to clockwise to set the Alignment parameter to “MODNFM.” 6. Press the PTT switch to activate the transmitter, and press the REV or D/MR key so that the deviation meter reading is 2.1 kHz. 7. Press and hold the LOW key for one second to save the new setting, t

47、hen press and hold the MHz key for one second to exit to the normal operation. CTCSS TX Deviation (TONE W/TONE N) 1. Tune the transceiver to 146.000 MHz. 2. Set the CTCSS tone to 100 Hz. ? Press and hold the MHz key for one second to activate the “Set” (Menu) mode. ? Rotate the DIAL knob to select “

48、27 SQ TNF.” ? Press the MHz key momentarily, then rotate the DIAL knob to select to 100.0 (Hz). ? Press and hold the MHz key for one second to exit to the normal operation 3. Set the transceiver to Alignment mode, then rotate the DIAL knob to set the Alignment parameter to “TONE W.” 4. Press the PTT

49、 switch to activate the transmitter, and press the REV or D/MR key so that the deviation meter reading is 0.6 kHz. 5. Press and hold the LOW key for one second to save the new setting, then rotate the DIAL knob one click to counter clockwise to set the Alignment parameter to “TONE N.” 6. Press the PTT switch to activate the transmitter, and press the REV or D/MR key so that the deviation meter reading is 0.3 kHz. 7. Press and hold the LOW key for one second to save the new setting, then press and hold the MHz key for one second to e