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NEC PG-2740 Service Manual
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NEC PG-2740 Service Manual

NEC PG-2740 Service Manual

Color data monitor
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Before servicing this chassis, it is important that the service
technician read and follow the "Safety Precautions" and "Product
Safety Notice" in this Service Manual.
* For continued X-radiation protection, repiace picture tube with
original type or NEC approved equivalent type.
SHOCK HAZARD - Use an isolation transformer when servicing.
NEC Corporation
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Summary of Contents for NEC PG-2740

  • Page 1 “Safety Precautions" and “Product Safety Notice" in this Service Manual. * For continued X-radiation protection, repiace picture tube with original type or NEC approved equivalent type. SHOCK HAZARD - Use an isolation transformer when servicing. NEC Corporation...
  • Page 2 ..........................................................................................................................................................................................................................................................................................................................................................................................................................
  • Page 3 €> ........................................................................................................
  • Page 4 CAUTION ■i l CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER (OR BACK). NO USER- SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE This symbol warns the user that unin­ This symbol alerts the user that important sulated voltage within the unit may have literature concerning the operation and sufficient magnitude to cause electric...
  • Page 5 AC Leakage Test always make a safety check of the entire instrument, including, but not iimited to, the following items: a. Be sure that no built-in protective devices are de­ fective and/or have been defeated during servicing. (1) Protective shieids are provided on this chassis to protect both the technician and the customer.
  • Page 6 - Do nof alter or add to the 6. Observe original lead dress. Take extra care to assure mechanical or electrical design of this Equipment. De­ correct lead dress in the following areas: a. near sharp sign alterations and additions, including, but not limited edges, b.
  • Page 7 I’appareil dans la prise et r4p4ter le test. faire toujours d’abord un examen de s^curitd de I'appareil en entier comprenant, mais ne s’y limitant pas les points cit6s ci-dessous; a. Verifier qu'aucun des dispositifs de protection ne EXAMEN DE COURANT soit d^fectueux ou n'ait 6t6 endommagd pendant D'EXCITA TION les travaux.
  • Page 8 de masse n'est pas \so\6 du courant diectrique. Les deux systdmes sont ^lectiquement sdpar^s par du Ne pas modifier ni ajouter k ia pi4ce m^chanique ou materiel d'isolation qu'on v^rifiera bien qu’il ne soit 6lectrique de I'equipement. Des modifications ou addi­ tions, comportant, mais ne s*y limitant pas, des modifi­...
  • Page 9 27 Inch Visual size (Diagonal), Type A68KZN696X(T) 108 degree deflection Stripe trio pitch Ph=0.80-0.96mm, Pv=0.75mm Invar mask, Medium-short persistence phosphor Antl-static electricity coating Optical filter coating Dynamic focus Analog Input: Unlimited colors Horizontal: 15.5 KHz to 50 KHz (Automatically) Vertlcal:40 Hz to 120 Hz (Automatically) RGB Horizontal :800 lines/ Vertical:600 lines VIDEO Horlzontal:600 lines RGB: 40 MHz (When No.6 pin of DIP SW 1 set to OFF)
  • Page 10 RGB 1 : OSUB ISpIn RGB 2 : BNC (R, G, B, H/CS and V) 1 .OVp-p. 76 Ohm unbalanced (BNC-Jack), Composite video signal. Sync-negative. Y : l.OVp-p, 75 Ohm unbalanced. Sync-negative. C: 0.28Vp-p, 75 Ohm unbalanced. Color burst level. 1 .OVp-p, 75 Ohm unbalanced (BNC Jack), Composite video signal.
  • Page 11 ® ® ® ® © POWER....Press to power the monitor on and off. © VIDEO 2 Indicator Indicates the VIDEO 2 button (9) is set to re­ © Remote Sensor Window Receives infrared signal from the remote con­ ceive signals from components connected to the VIDEO 2 Input terminal (BNC type or S- trol unit.
  • Page 12 (§> Q’D'Q- 5 " • ' "'I rilngmnir Br=^—I Q® Boo 5 I B I I B B B B B Press to select reception of a component Press and hold T to decrease sound. connected to the VIDEO 1 input terminal Press and hold A to increase sound.
  • Page 13 LOCATDOINl AMP FUMCTIOMS OF COMTROLS ■Q'O’Q <S> iipat ¥l—^ ©• fmam -■ lent).... ® € ® ® ®... ® 75 ... ® ® ® 1©...
  • Page 14 -©^ I ^ twi wi ■ (g^Q - mo KUO tmwui. •ueeRin ■un ® Connect external video component output ® L Connect external component mono audio or here. stereo left channel audio output here. ® S-VIDE0 ® Connect external components with S-CON- Connect external component stereo right NECTOR output here.
  • Page 15 @ 75 n/HIGH Impedance Select Switch... Set to "75 G" during normal operation. In mul­ —«&■ tiple connections using VIDEO 2 IN @ and L®J THROUGH OUT (BNC) ® terminals, set to "HIGH" on all but the last monitor. Set to “75 O”...
  • Page 16 Press POWER ON to turn the monitor on when the STANDBY indicator Is lit. Press POWER OFF to turn the monitor off and the monitor will go into the standby condi* tion. ow Hmm m e VIDE01 Press to select reception of a conventional component or S-connector component con­...
  • Page 17 Used to adjust contrast of video or RGB dis­ play. Press and hold A for higher contrast. ---- ---- ---- ---- Press and hold V for lower contrast. «DTM rsirgn ..Used to adjust brightness of video or RGB ninnan display. □□...

  • Page 18: High Voltage Adjustment

    1. Power Supply Check 2. Horizontal Oscillation Adjustment 2-1. Horizontal adjustment I (DEF SUB PWB single adjustment) 2- 2. Horizontal adjustment II (RGB PWB single adjustment) 3. Vertical Oscillation Adjustment 3- 1. Vertical adjustment I 3- 2. Vertical adjustment II (RGB PWB single adjustment) 4.
  • Page 19 (1) Verify input voltage is 120VAC/60Hz. (2) Verify the following pCOMA/ PWB voltages. DC1 -DCS = 8.5Vdc, DC3-DG5 = 27Vdc, DC4-DC5 = 27Vdc. (3) Verify that pCOMA/ PWB DC2-DC5 = 40Vdc. (1) Input a horizontal frequency of 50.0 KHz to either RGB1 or RGB2. (2) Short connector pins 6 and 4 of “JA"...
  • Page 20 (1) Connect a high voltage probe under the CRT's anode cap User High Voltage probe \whose maximum voltage is rated more than 1.5kV and has internal an impedance Greater than 1000MQ. (2) Input all black video signal. (3) Set the VR of the FBT (DEF/HV PWB T5001) to the MIN position. (4) Adjust VR9003 (DEF SUB PWB) so that the high voltage equals 29±0.3Vdc.
  • Page 21 (1) Input the PAL “DEM" signal and set the color to MAX position. (2) Set the Video Select SW to “PAL". (3) Connect the oscilloscope to TP7002. (4) Adjust VR7402 (Delay Adj.) so that amplitudes of No. 1 and No. 2 are as shown below. (5) Adjust T7401 (Delay Matching Adj) so that amplitudes of No.
  • Page 22 (1) Input the PC-98 (400 line) RGB signal. (2) Set Scan Select to OVERSCAN mode. Adjust either the remote control or VR4002 (DEF SUB PWB) to vertical height is 100% scan. (3) Set the remote control H. Width to MAX position and adjust VR9004 (DEF SUB PWB) so that horizontal width equals 100% scan.
  • Page 23 (1) Set R/G/B GAIN VRs (RGB I/O PWB VR873-VR875) to mechanical center click point. Then, set R/G/B SUB CONT VRs (RGB SUB PWB VR8201-VR8203) Fully counterclockwise. (2) Input NTSC video 1/4 window pattern terminated at 75Q and select Video mode Use the Remote Control to Normalize Contrast.
  • Page 24 (1) Input a sine wave of 1 KHz, 0.5 V rms to the video 1 L-ch audio input terminal. (A video signal is not required to perform this adjustment). (2) Select the video 1. (3) Connect the 8f2 dummy load (10 W rating or more) to the external speaker terminals (L-ch and R-ch). (4) Set the speaker INT/EXT SW to the EXT position.
  • Page 25 SCAN € Signal Name Sync Polarity SELECT VIDEO H (|is) SYNC ON OVER (NTSC) V (ms) VIDEO VIDEO H(tis) SYNC ON OVER (PAL) V (ms) VIDEO VGA1 H(ns) 31.778 3.813 1.589 0.318 26.058 UNDER 350 line V (ms) 14.268 1.716 11.504 0.985 0.064...
  • Page 26 (1) Connect the wire between pin 1 and pin 7 of connector JB on pCOMA/ PWB (PWC-3839) [TEST MODE]. (2) Input the NTSC 1/4 window white signal, terminated at 75Q. (3) Connect your scope probe to the V-CRT B cathode. Use the Remote Control CONTRAST Up/Down but­ tons and verify that the video white to black swing equals 85Vp-p.
  • Page 28 C4 C4 § 8 § § u. u. UJ< § < < <n H UJ < UJ ---------- j.-------- _^v ^ § >■ «.UI UJ <v (SZST (■...
  • Page 29 Sf <0 «o ^ □ 3 5 □ □ □ □ § □ □□□ § §1 3 § § £ s ^ s < piP«r 55& § t: t: S UJ UJ § 8 L—ll_^' Latli € jilJiL ©—1 5§g vu v5 Uj ^ ^ v~ €...
  • Page 30 “r Siffni 3 < £ S qr O s;, V~ Ui ¥ !■ § 9 © ■i <; ^ •s <...
  • Page 31 (B> oo o •I □ □ □ □□□ The specified display of Model No., serial No., Description, date code, and factory ID shall be automatically printed (marked). PG-2740 (AAA section) 13 points Model No. (OOO section). Serial No. 00000000 13 points (□□□...
  • Page 32 Cut the left section together with the cardboard paper, insert it in the polyethylene bag (DHHS) ^24M0291 []) to­ gether with the DHH card (24L29490), and put it at the □ .i specified point on the right top on the left side of the o o o cardbaoard.
  • Page 33 E-1) Right Side Remove the label shown at left from the cardboard and apply it to the left top on the left of the cardboard. (How­ ever, the cardback of the broken line portion shown at © left must be applied by not removing it.) ..
  • Page 34 Insert the ®, (§), ©, and ©sections (with the cardboard) of the DHHS card (24L2949Q) and the serial number label (24L2948Q) inside, fold the top end section of the polyethylene bag (DHHS), seal it, and remove the back cardboard. Then, apply the label to the right top on the right side of the cardboard with it laid to the right. Serial number label printed (242948D) w •...
  • Page 36 M o / f 3 4 9 8 / ^ ^cJc)OOOOc>3if ■...
  • Page 37 ®HA3®H04 HC3 O0F3 (28) CZ) • CONNECTOR board in...
  • Page 38 ^ § L_ 4) ® 4) 4) 4) 4) <D «/) L I I 8 8 ' 8 g 3 <D^< o°o > <N ~^Hi^ tn^ sit; §§§ JtAA. "sa -vsv (8'9'u) isvaiNOo ens ■VJ iveus srs “ i § 4( s Vio- 3SVHd...
  • Page 39 -VA—i u (/) 2 O u K < < 52 ai r^r>r\ rv'Y'Vw^ <N I~55 §i=iB K9“ s < qp=' £ «n <N °-S“f g 2d>- UiUJUlUJUJ <s = o 4>“ 4>- <s o<x 0&3 3f ^ < ? 8 u.
  • Page 40 <s <N ♦ nfio ---- •B hifjii saii|§ >- iiO/NO lisl z8i< “5SS 5-ti, §S§gs5 f 885« M M ♦ » ♦ M M M M M ♦ 4>- ?<!>- i<s g4>- z> UJ w ^ < 5«- cogaaFi?. j(»*N SStL liiii o o o...
  • Page 42 ► RGB I/O PWB PWC-3835 SCHEMATIC OIAGRAM i—i-i-O— fUfi fuiafui 1BSS33 RGBl SIGNAL ^i/alixt TERMINATE ■O (U7-121 ■<s> CD----- <s> (M7-121 <s> >K: ~>K: ~V<: ID BIT 2 seo3 TO BIT 1 SVgSSro CZ3----- ID BIT 0 ^*i/altxi < KB 1 IO-«uO 18 pinl »17 <s>...
  • Page 43 R87B VAfUABLe naei CS71 C97a 0. I RB7I >R8Sa !? n we.egaM f • fca-ssaa MAWAOPOff POXMA ICVtBAOt IPI m tn PF4 tn TO vxoeo I/O MB...
  • Page 44 » taVlBAO< tPl \7l\tEX IP>_ Q6001 C8MS cbioi •m eeoia ZDeioi 0.01 fua. oeioi gSr© SKIT© (0002' 163293 R80I1 163203 CLAMP CTL BUFFER 4.7K Sneioa 4. 7K SlOK C6103 RBll -vw----- qj»» en. 10000 (0113 (0112 2.» aioeT 1°-°' _ eaio7 ZDB102 “1 ?5‘*r...
  • Page 45 O-Ot ______ (0497 00407 08407 (0419 2SC1740S 189299 (0401 [no ix «404 FFER ft"OUT (0410 ree4oi ____ 103999 713401 00410 IC8301 183299 ---- M513B7P R0401 CMja 0*01 P T«. (04 IB RGB AMP 08419 f»^«UFFEn 1S32S9 ----- C&901 0.01 0.01 -a—* ------ 15“...
  • Page 46 VIDEO I/O PWB PWC-3837 SCHEMATIC DIAGRAM IC701 LVA521S m?lESS3 VIDEO 1/2 SW/ Ivioeo «t«ti BNC INPUT 5'lxl i M70ll inzLfLf Y OIOWL P> OJT OO 220K n ;; jazA- S®ixl i M703I inifLf zusA- Z20K 0703 183233 nup CM vuOJ IC702 LVA521S 1332!
  • Page 47 IC7001 IC7003 HCFlOll UPC7BM09H NTSC IC7002 COMB FILTER LVA522S REGULATOR C7018 C7019 ^— Y SWITCH j r X lo/r ”rr CTOlO S»1 0. t 07003 Q7C 01 - SV I l,‘ „ 2^17403 lu^FER 2SC1740S s z i : s 0.R.8 BUFFER TP7003...
  • Page 48 » VIDEO PWB pwc-aaaa SCHEMATIC DIAGRAM 2/2 IC7402 UPC78M12H • C749I I C743a C74J0 .C74as 3 : 470 :z 0.1 z: 0.1 2 E 100 - 16V T asv - 25V REGULATOR 1.84 r^j— -------- OUP^CSO B7201 07201 0. 1 07202 •...
  • Page 49 V-CRT PWB PWC-3834 SCHEMATIC DIAGPAlIl Q901 Q902 Q903 2SC30B3-RL 2SC3063-RL 2SC3063-RL R-OUT G-OUT B-QUT 170V iiff 0.01 0.01 0.01 OINAMIC FOCUS VR901 OINAMIC FOCUS VOLUME 0901 0902 1_(<U 1SS253 ^ C901 ZZ C903 lOOOp lOOOp 0910 0911 1SS83 1/4H C930 0905 1SS253 0912...
  • Page 50 » verAf* TO K-PS PMB V8TATC I18V S> pooi > •fit iSS^ TTlxX Y Y Y Y Y Y Y Y Y Y Y Y Y Y...
  • Page 51 PG-2740 UCOM/V PWB PWC-3B39, TO JIO TO VIDEO I/O Pl« SCHEMATIC DIAGRAM 2/3 mrmm X X X X jAa^AA 9^ [S "1“ A£l SViftAWl vcgoa SEL A-WTECEKTl CVtSAOd RE>«TE DATA aJT COWTWAST —VN>N AjnacowT Riooa igrrnieRKHT IC1006 viocoa —“WS. cviaAoi]...
  • Page 52 PG-2740 IC301 IC302 TAB211AH UPC1406HA AUDIO AMP AUDIO ATTENUATOR i! ; ”■?)» I' X PAMl W- N C30e CS07 A- » vraol IC201 UPC7S15H 15V REGULATOR Sf’; t-(6^ ’ST A >ALB ALPIO 1/91 ,AU4 AUDIO LTft * ^H.P ,AU1 AIOIO .Am Auoio L-xn...

  • Page 53: Schematic Diagram

    PG-274CI WC-3846 TO DC-P9 PW ♦ ♦ DEF/HV PWB 1/2 ^XTXXXX^ 4s 4s »UI £Al ItAa E*aj SCHEMATIC DIAGRAM M.POSI MiVE UAXX. y^-v OHtVE iS^)r « fO e>-^ TP20011 [^_2:Pr 2SA60^. TO V-Cfn PMB li" 't® lOOlM ‘- 05024 2SC1740S C3036 T'‘...
  • Page 54 » DEF/HV PWB PWC-3B46 SCHEMATIC DIAGRAM 2/2 TO FBT ICOCl 12VM 117/ PMAl 1-ee »coc2 1909V IPAfU PAAA2...
  • Page 55 DEF SUB PWB PWC-3B56A ©^rSoTaolSTlaal^oroiT SCHEMATIC DIAGRAM ------- • i > . A4024 }M022 Rg2D? •031 ICOA __ VC* t FFW TTreoi "i i“’ isOO-B metal <K)1 > Op=r <- >tBV o.n.8 ■I 9.« < <—>9iav §ic C4017 0. 1 ’..J- IC9002 vcei...
  • Page 56 PG-2740 » PWC-3856A DEF SUB PWB SCHEMATIC DIAGRAM 9 9 9 I I I KWVE I------ s ^nDyri gs*‘ > >2SV coea: ___ . (nOS6 IC9005 XRA10358 H.WIDTH CTL AND 12V REG sirv toov R3231 Q9062 P0333 --------- > ?7K...
  • Page 57 PG-2740 AC IN 2.SA IKV 0.06a 630V SGK 7W ■pt- ROB I C32 ■'0°'’ 2KV ^^F]D32 ^3—11--- T ¥ 0601 C42 L33i0dH “ : 17 IC31 SI3240C IC32 --O) B2K ^ —IHH 3.3K IC33 SOOP 250V ----IHI SUB01 IC34 C51 r'...
  • Page 58 PG-2740 ----- I 10 R&4 ■» » Y141»1 9A01 < I 330 ro7i o.oir Tlt-i fT 4.7K ^470 I 0.Q1~|~ SUB603 (D3608S3) SUB601 (D3608S1) SUB602 (D3608S2) PWC-3851B PWC-3851 C PWC-3851D...
  • Page 59 PWC-3056B H OUT PWB DIAGRAM SCHEMATIC Q5451 Q5452 2SK1271 2SK1271 H OUT H OUT 56000 05453 2SK2223-01 Q5454 2SC399B H OUT r«...
  • Page 60 PG-2740 SW-LED PWB PWC-3838B SCHEMATIC DIAGRAM RVlOl REMOTE CTL SIGNAL » RECEIVER SlOl MAIN POWER SW fSViBACK UPl 46V(SWITCHg)l uCOH/V PWB +12V(SW1TCHED) •fl2V(BACK UPl DlOl D102 D103 D104 DIOS SEL1320G SEL1820D SEL1820D SEL18200 SEL1820D STAND-BY VIDEO1 VIDE02 RGBl RGB2 VIDE02 LED CTL...
  • Page 61 )■ (■ € C&C for Human Potential...