PHILIPS. PM3295. Test. Service Manual. CDC-311.电路图.pdf

350 MHzVHF Dual Channel, Dual Time Base Osci I loscope PM3295 Service Manual 482287205305 860207/2/01 PH I LI PS RadioFans.CN 收音机爱 好者资料库 1. SAFETY INSTRUCTIONS Read these pages carefully before installation and use of the instrument. 1.1. INTRODUCTION The following clauses contain information, cautions and warnings which must be followed t o ensure safe operation and to retain the instrument i n a safe condition. Adjustment, maintenance and repair of the instrument shall be carried out only by qualified personnel. 1.2. SAFETY PRECAUTIONS For the correct and safe use of t h i s instrument it is essential that both operating and servicing personnel follow generally-accepted safety procedures i n addition t o the safety precautions specified in t h i s manual. Specific warning and caution statements, where they apply, w i l l be found throughout the manual. Where necessary, the warning and caution statements.and/or symbols are marked on the apparatus. 1.3. CAUTION AND WARNING STATEMENTS CAUTION: is used t o indicate correct operating or maintenance procedures i n order to prevent damage to or destruction of the equipment or other property. WARNING: calls attention to a potential danger that requires correct procedures or practices i n order to prevent i n order t o prevent personal injury. 1.4. SYMBOLS f High voltage - 1000 V (red 1 A Live part Read the operating A instructions. (black/ yellow) Protective earth (black) 0 (grounding) terminal RadioFans.CN 收音机爱 好者资料库 1-2 1.5. IMPAIRED SAFETY-PROTECTION 1.6. 1.6.1. 1.6.2. 1.6.3. 1.6.4. 1.6.5. 1.6.6. Whenever it is likely that safety-protection has been impaired, the instrument must be made inoperative and be secured against any unintended operation. The matter should then be referred to qualified technicians. Safety protection is likely to be impaired if, for example, the instrument fails to perform the intended measurements or shows visible damage. GENERAL CLAUSES WARNING: The opening of covers or removal of parts, except those to which access can be gained by hand, is likely to expose live parts and accessible terminals which can be dangerous to live. The instrument shall be disconnected from all voltage sources before it is opened. Bear in mind that capacitors inside the instrument can hold their charge even if the instrument has been separated from all voltage sources. WARNING: Any interruption of the protective earth conductor inside or outside the instrument, or disconnection of the protective earth terminal, is likely to make the instrument dangerous. Intentional interruption is prohibited. Components which are important for the safety of the instrument may only be renewed by components obtained through your local Philips organisation. (See also section 27). After repair and maintenance in the primary circuit, safety inspection and tests, as mentioned in Section 27 have to be performed. RadioFans.CN 收音机爱 好者资料库 2. 2.1. GENERAL IVFORMATION INTRODUCTION TO THE PX 3295 OSCILLOSCOPE. This compact V.H.F. o s c i l o s c o p e features an extensive bandwidth of 350 MHz and good ergonomic design for its numerous measurement c a p a b i l i t i e s . A unique f e a t u r e is the AUTO SET pushbutton f a c i l i t y , which automatically sets Various controls of the instrument to s u i t the input signal value. In t h i s way, optimum ease of operation is obtained a s the input signal immediately presents a correct, stable display on the bright c.r.t. screen. The microprocessor-controlled front panel gives a wide choice of display p o s s i b i l i t i e s . Fig. 2.1. 350 MHz V.H.F. oscilloscope PM3295. The oscilloscope is provided with integrated c i r c u i t s (including thin- film c i r c u i t s ) , which guarantee highly-stable operation. Furthermore, connection t o the l o c a l mains is simplified by a tapless switched-mode power supply t h a t covers most voltage ranges i n use: 90 V . . . 264 V a.c. A l l these features make t h i s oscilloscope suitable for a wide range Of measuring applications. 2-2 2.2 CHARACTERISTICS A. Performance Characteristics - Properties expressed i n numerical values with stated tolerance are guaranteed by PHILIPS. Specified non-tolerance numerical values indicate those t h a t could be nominally expected from the mean of a range of i d e n t i c a l instruments. - This specification is valid a f t e r t h e instrument has warmed up f o r 30 minutes (reference temperature 2 3 O C ) . - For d e f i n i t i o n s of terms, reference i s made t o IEC Publication 351-1. B. Safety Characteristics This apparatus has been designed and tested i n accordance with: Safety Class I requirements of I E C Publication 348 Safety Requirements for Electronic Measuring c _ i Apparatus, UL 1244 and CSA 556B. b The instrument has been supplied i n a safe condition C. I n i t i a l Characteristics Height Without Feat and Accessory Pouch 170 mm ( 6 , 7 i n ) Feet and accessory pouch included 240 mm ( 9 , 4 i n ) Width 340 mm (13,4 i n ) Depth Handle Excluded 523 mm (20,6 i n ) With Extended handle 625 mm ( 2 4 , 6 ) Add 10 mm ( 0 , 4 i n ) f o r feet Add 46 mm (1,8 i n ) f o r handle Add 35 mm ( 1 , 4 i n ) f o r protective front cover. Mass 13,9 kg (30,7 l b ) - Operating positions: a ) Horizontally on bottom f e e t b ) Vertically on rear f e e t c) On t h e carrying handle i n three sloping positions= 1Z0, 20 and 25 D. CONTENTS 2.2.1. Display 2.2.2. Vertical channel or Y-axis 2.2.3. Channel A and B 2.2.4. Trigger view 2.2.5. Horizontal deflection or X-axis 86-02-07 2-3 2.2.6. 2.2.7. 2.2.8. 2.2.9. 2.2.10. 2.2.11. 2.2.12. 2.2.13. 2.2.14. 2.2.15. 2.2.16. 2.2.17. -Main time-base Delayed t ime-b a s e Main time-base t r i g g e r i n g Delayed time-base triggering Blanking o r Z-axis Auto s e t t i n g Cursors CRT text Calibrator Power supply Sundries Environmental c h a r a c t e r i s t i c s 2.2.18. Safety 2.2.19. Accesories CHARACTERISTIC SPECIFICATION 2.2.1. DISPLAY Cathode Ray Tube Measuring Area 80mm x loom (h. x w.) Screen type: (basic version) GH (P31) ( 0 pt ional ) GM (P7) BE (P11) Total Acceleration Volt age : 24kV Max. Writing Speed (photographic) t y p i c a l 4cm/ns G r a t i c u l e - Illumination i n t e r n a l , fixed continuously variab 1 e ADDITIONAL INFORMATIION 140mm Rectangular single beam tube with h e l i c a l v e r t i c a l d e f l e c t i o n system. 8 divisions x 10 d i v i s i o n s Measured i n c e n t r a l 5 d i v x 5 d i v of screen; i n absence of contrast f i l t e r . Single Shot; Phosphor: GH; no prefogging; Lens aperture F:1,2; object t o image r a t i o 1:0,5; Film: Polaroid type 612 (20 000 ASA). - Engravings : division l i n e s A t l c m Horizontal and vertical. t i c k marks dots percentages 0 r t hog ona 1 it y Trace Rot at ion: Min. Range 2.2.2. VERTICAL DEFLECTION OR Y-AXIS A t 2mm On vert. and hor. central axes and on hor. l i n e s at 2cm and 6cm from top. A t 2mm On dotted l i n e s at 1,5cm and 6,5cm from top. 100, 90, 10, 0% To f a c i l i t a t e rise and f a l l time measurements. 90 + or -0,5 Measured at centre of screen. (Angle between X and Y axes, when traces are written i n X and Y direction alternately; deflection frequency: 50. .60Hz) 1 2 O Screwdriver adjustment; direction of screwdriver rotation same as direction of trace rotation. Either X- o r Y trace can be aligned with graticule, when environmental magnetic f i e l d is within 0,lmT. Deflection Sources Ch .A; Ch.B; Both channels can be inverted, Ch.A and (allowing for A-B and B-A i n Ch.B added added position). Trigger View (MTB) Deflection Modes: 1 Channel only; Alternate; Any combination of sources. Chopped - Display Time 350ns Each source ( i n chopped mode). - Display Blanking 15011s After each display t i m e (in chopped mode). Visual Signal Delay 2011s (typical) A t Maximum intensity and w e l l focused display. 86-02-07 Delav Difference between Ch.A typ 2ns o r B and ext. Trigg. V i e w Channel Isolation: of Deselected Channel 1OO:l between Selected 50: 1 Channels Y-Signal Output: - Source - Coupling =DTB Trigger Source = DTB Trigger Coupling - Voltage into 1M.Ohm 20mV/div + o r - 10% i n t o 50 Ohm 10mV/DIV +or -10% - Freq. response d.c . t y p i c a l 300K1z (-3dB) 2.2.3. CHANNELS A AND B Input connector BNC with Probe Read Out Ring 2-5 Trigger View delayed with resp. t o Ch. A or B. A t 100MHz; input t o deselected channel equivalent t o 8 divisions or less. A t 350MHz; channels with equal V/div settings; input to either channel equivalent t o 8 divisions or less Available at BNC on rear of instrument. Y Signal Output is not affected by BW limiter. Ch.A or Ch.B coupling eventually cascaded with DTB trigger coupling Max. output + o r - 80mV (160mV peak to peak). Max. output + o r - 40mV (80mV peak to peak). Terminated with 50 Ohm. A t reference temperature. For influence of Trigger Coupling see 2.2.9. Probe Read Out causes instrument to change V/div Indication, Input Impedance and Attenuator Setting according to probe (when f i t t e d with a Probe Indicator) I- 2-6 Input impedance ( i n High Z position): R parallel C parallel Max. input Cap. Difference Input Impedance ( i n 50 Ohm position) :R parallel VSWR (typical) Input Coup1 ing A Max. Input Voltage : - In High Z position (d.c. + a.c. pk.) - In 50 Ohm position (d.c.) (a.c. r.m.s.) (a.c. peak) For Frequency 1MHz see Fig.2.2 1M.Ohm +or- 1% I n DC position of Input 9 PF 50 Ohm + o r - 1% 1,3:1 d.c.; a.c.; 0 300V 5v 5v I 50V 1 Coupling. In AC pos. of Input Coupling: 18 nF i n Series with R. par i n 0 position of input coupling: R par.= i n f i n i t e Difference between Channel A, Channel B, EXT MTB Trigger and EXT DTB Trigger Inputs. In DC, AC and 0 position of input coupling. A t 350MHz i n AC and DC pos. of input coupling In 0 position: channel disconnected from input BNC and connected to ground. Apparatus should be properly grounded through the protective- ground conductor of the power cord Up t o 1MHz; for 1MHz see Fig. 2.3. Max 50mJ during any lOOms interval. Deflection coefficient - Steps 1mV . 5V/div In a 1-2-5 sequence of 12 steps; - Error l i m i t (Ambient: 5. 4OoC) +or- 2% (When Channel is used f o r X deflection: see 2.2.5, f o r Trigger View: see 2.2.4. - Vernier Ratio 1:2,5 Uncalibr . ; continuously variable between steps. 24div but max. l0OV 20div but max. l0OV 8 d i v Centered around Hor. Centre l i n e on screen 2-7 Dynamic Range : When used f o r Y d e f l . (for X d e f l . see 2.2.5.) Compression at l i m i t s of dynamic range: 7% - up t o LOOMHZ i n CAL position of vernier Vernier i n 1:2,5 posit ion - up t o 350MHz (-3dB) LF Linearity: Within boundaries of dynamic range. Measured at 50kHz. 0 , l d i v on 2 d i v 2 d i v center screen signal shifted within boundaries of graticule. Max. Compression o r Expansion + o r - 8 d i v S h i f t Range From screen center; (for X d e f l . see 2.2.5.) Frequency Response ( i n 50 Ohm position): When used-for Y d e f l . (for X d e f l . see 2.2.5.) Z source: 50 Ohm. - Lower Transition Point of BW Input Coupling i n DC position. Input Coupling i n AC posit ion. d .c. lOHz (-3dB) - Upper Transition Point of BW (Ambient:5. .4OoC) 3 50MHz (-3dB) 1mV and 2mV/div positions excluded (see 2.2.3. ) Freq. Resp. ( i n H i . Z pos. through probe) : When used f o r Y d e f l . (for X d e f l . see 2.2.5. Z source: 25 Ohm. (Probe according t o 2.2.19.) - Lower t r a n s i t i o n Point of BW d.c. 1Hz or less (-3dB) Input Coupling i n DC position. Input Coupling i n AC position. - Upper Transition Point of BW (Ambient:5. .40C) 350MHz (-3dB) 1mV and 2mV/div positions excluded (see 2.2.3.). Freq. Resp. ( i n 1mV and 2mV/div pos.): When used f o r Y d e f l . (for X d e f l . see 2 . 2 . 5 . ) . Typical value at 25OC Upper Transition Point of BW 70MHz (-3dB) 25-10-1985 2 -8 Bandwidth L i m i t e r : . - Starting point of HF rejection - Slope Pulse Response ( i n 50 Ohm position): - Rise Time (Ambient : 5. . . 4OoC ) 20Mhz (-3dB) 6dB/octave When used f o r Y deflection; Z source: 50 Ohm. Measured over central 6 div. Ins o r less 1mV and 2mV/div excluded, (see 2.2.3.) (Calculated from Bandwidth x Rise Time = 0,35) - Pulse Aberrations: -5% or less Tested with a Ins Rise Time ddUA24ZTj - -1 T i l t pulse fl;.c 20 *+bL coupling excluded. 2% or less Effects of AC pos. of input - Pulse response ( i n H i . Z pos. through probe) - Rise Time (Ambient: 5. .4OoC) - Pulse Aberrations: over shoot Rise Time ( i n 1mV and 2mV/div pos. ) When used f o r Y defl: Z source 25 Ohm. Measured over c e n t r a l 6 divisions Ins or less 1mV and 2mV/div excluded, see 2.2.3. (Calculated from Bandwidth x Rise T i m e = 0,35). Tested with a Ins Rise T i m e pul s e 6% or less 5ns o r less When used f o r Y d e f l . Measured over c e n t r a l 6 divisions. 86-0 2-0 7 2-9 Max. Base Line Inst a b i l i t y : Jump (Ambient 5. .40C) when switching t o added mode posit ions switch 0,4 d i v o r 2 mV Whichever is greater posit ion between DC and 0 PO s i t ion when rotating vernier 0,8 div o r 1,2mV Whichever is greater 0,5 div o r 3 mV 0,2 div o r 1 mV) between any V/div 1 when using INVertor 1 between AC and DC 1 0,l div or 1 mV 0,l div or 1 mV Whichever is greater; Input externally grounded Measured i n 20mV/div position. D r i f t 0, ldiv/h Tempera t ur e 0,05div/K coefficient Common Mode Reject ion Rat i o : - at lMHz - at 50MHz Both channels at same a t t enuator- s e t t i n g ; vernier of V/div s e t t i n g adjusted f o r best CMMR; measured with max. 8 div input at each channel, (+ o r - 4div around zero). 1OO:l 20: 1 2.2.4. TRIGGER VIEW Signal Source = Trigger COMPosite = Channel A, unless Source MTB only Channel B is displayed. Deflect ion coefficient: Ch.A o r Ch.B see 2.2.3. Except e r r o r l i m i t . EXT EXT : 10 lV/div 1 0 OmV / d iv Error L i m i t + o r - 5% For all sources except LINE (Ambient:5 . 40C) Dynamic Range: Compression at l i m i t s of Dynamic Range: 7% up t o 1OOMH.z 24div up t o 350MHz 8div 86 -0 2 -0 7 - 2-10 Line deflection 6 div or more Trigger Source: LINE; 49Hz<Line Freq.<61Hz Frequency response: Trigger coupling: DC, HF REJection: OFF, Bandwidth L i m i t e r : OFF. Trigger source: INT (Ambient: 5. . 4OoC) d.c.300MHz Channel A o r B i n 50 Ohm position. Z of Signal Source: 50 Ohm. Trigger source:EXT (Ambient:5. .40C) d.c.350MHz Z of Signal Source: 25 Ohm. Pulse Response Rise Time (Ambient : 5. . 4OoC) Trigg. Coupling: DC, HF REJection: OFF, Band Width L i m i t e r : OFF Distortion due to peak t o peak leveling may be visible, when i n AUTO position of trigger selector and at trpgger frequencies <100Hz. (Calculated from Bandwidth x Rise Time = 0,35). Trigger source: INT 1 , 2 ns Z of Signal