JRC NDH 518 memory unit Service instructions
Below you will find brief information for memory unit NDH 518. The memory unit NDH 518 is designed to store up to 96 frequencies, with 24 channels per channel switch. This allows the user to easily access and recall their favorite frequencies. The memory unit also offers the option of installing a backup battery to prevent data loss in the event of a power outage. This is an important feature for users who need to rely on their radio for critical communications.
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SERVICE INSTRUCTIONS : NDH518 MEMORY UNIT GENERAL The block diagram and schematic for the memory unit are shown in the appendix. The unit is made up of a memory circuit utilising six integrated circuits type HPDS5IDILC. These IC are 1K CMOS static RAM (256 x 4) where the FF is used to store data, clocks are not needed, and the information stays in storage as long as power is supplied. It should be noted that an optional battery(s) can be installed to back up data stored. Important - Alkaline batteries should be used as commonly used manganese types will possibly leak when they become exhausted. Any consequent damage is not covered by warranty. Frequency data is transferred from the receiver via the three state buffers (IC 9, 10, 11, 12, 13, 14). Data input and memory output is via the cable terminated with the plug PL. 96 frequencies can be put in memory (24 channels per channel switch x 4 = A, B, C, D, selected by the push button switches). The channel is designated by specifyino the address of the RAM's by the channel switches and this informat. n is simultaneously sent to the channel display circuit, IC7 and IL. The power source voltage detecting circuit controls the chip enable terminal of the RAM's in order to protect the memory frequency data from being lost when the power switch is turned off. The power detecting circuit is TR2/1C16. POWER Since CMOS is used, power supply requirements are low. 10-11V from the receiver is supplied through P4 and P7/J7 pin 2,3 and regulated to 5V through IC17. DATA - TESTING The table below shows the INPUT state of data from the receiver for each of the digits that are capable of being displayed on the receiver, Levels for all digits representing 100Hz, 1KHz, etc. are similar, the exception being the digits representing tens of MHz and the 20MHz digit. IF incorrect levels are being returned from the memory resulting in an incorrect display, isolation of the faulty digit(s) may be made by comparing actual level on the apropriate pins of J7. PROCEDURE 1. Set the receiver in manual. 2, Check with logic tester to see if the levels are according to the following table as each digit is selected. Increment the tuning knob or band switch as required to access the digits corresponding to their place in the dialled up frequency, e.g. 12,345. 6_KHz MHz nm digits digit digit digits digits J7 PINS 100Hz UNITS = о пог | er EE rrr on гого ооо ооо ог ог" |-- a EE EEE ho бо A Un Eh PY E H = HIGH =5YV Similar levels will be evident for KHz, tens KHz, and 100KHz digits. 1KHz Pins are on J7 Pins 9 and 10, J6 Pins 1 and 2 10KHz Pins are on J6 Pins 3,4,5 and 6 100KHz Pins are on Jb Pins 7,8,9 and 10 Levels for 1MHz are on J5 Pins 1,2,3 and 4 Note: Levels will be same as in 100Hz sample chart as above, with pins taken in sequence listed. For tens of MHz, J5 pin 9 is "High" for a reading of "1", and pin 8 is "High" for a reading of "2". MEMORY IC Levels noted on all pins including the supply rail for IC 1,2,3,4,5 and 6 are shown in the table below. TEST CONDITIONS 1. Dial up a frequency of 12,345.6 MHz on the receiver, with memory unit connected. 2. Select CH1, depress button "A" and "preset'' button. 3. Check levels per table below. PINS LL. 3 XT 56 2.8 3 101147232 14 45 16 17 10113 20 2 22 Cl L LLALHAHHLAHHLLEHAHHAHHHLO LHHIZHS IC2 LL LLHLHHHLLLHAHLELLLHHLELEHAEELH IC3 LLLAHLHHHHLEOHGHHLLLLEHKHK.LLHELH ich LI L:t-® LH HEL LLLHASLLELLHTLMH C5 LLLUHLHHLHHLLHHLLHLLH LH C6 LL HU HH LL LL EU HU H LL EL LH EN - 3 = Levels for the three state buffer IC's, IC 9,10,11,12,13 and 14 are shown on the table below. Frequency reading on the receiver is 12,345.6 MHz. PINS 1. 2 3 & 5 E 5 ËE 4 Ш он т в ICS H H H H L L L H H H H H H IC10 H L L H H H L L L H L L H IC11 H H 0 H H H L L L H L L H IC12 H L L H L L L H H H L L H IC13 H H H H H L L H H H L L H 1C14 H L L H H H L H H H L L H COMPONENTS 1. Parts list for the NDH518 is appended. 2. Schematic diagram. 3. Block diagram. IC's specifications of the major IC used in the memory unit are also appended. — „= EEE | | CHANNEL SW | | ADDRESS(2bit ) +5V—REGULATOR A~D | | —_ | 1-24 | | | | | i | ! CMOS RAM | BACK UP |— | | EE Е | DATA (22bit) NL ME M “FROM NRD-515 Fig. 1 Block diagram of NDH-518 Memory Unit В] 1 NDH-518-2€x)J2=-7 | — gl e. 1K CMOS Static RAM(256 X 4) 5101 НЙ +70 77 2101 EEE, AMAIA TTL 224470, т FIFE EE. 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MEMORY CDD-206 DISPLAY CDE-162 PARTS LIST MEMCRY UNIT MODEL NDH-518 % The table lista parts in alphanumeric order of their reference designations "NO." (see abbreviations below), and provides the following information on each part: A. JRC code number. : B. Type. C. Description of part. Ordering information To obtain replacement rta, address order or inqui to our Sales Offices. Identity parts by their JRC Sods Genus, To dan aa is not listed, included: A. Equipment model number. B. Equipment serial number, C. Description of the part, D. Function and location of the part. ABBREN [AT IONS A | Assembly [Hic | Microphone a т ANT Antenna | | MG “| Meter Etbérator ] CT | blanes bases mr AT Attenuator MR Shunt, multiplier B | Rotary machine a a MT Centering magnet [BEL | Bell т P | Plug BT | Battery -— = a M - Printed circuit BZ | Buzzer tT | Leap — ic | Fined capacitor 15 | Lamp socket CH | Circuit breaker | FU Pick-up a ET гр Г Recta [rer detector disde, varistor {A Fized resistor; thermistor су | Variable capacitor | RS Lead selector © NE Uynamotor a EE a |RY | Variable resistor LM” Directional coupler a | 5 | Switch, key, thermostat, interlock BL | Delay dame se | speaker | E Earth, ground IT | Trans former FF | ue OO Th | Terminal board “NN | FL Filter | = TT Theruncomaler a e Fs | Fuse holder [TF | Tuning fork 6 Generator, vibrator Tr — Testpoint 7 We. “Hybrid circuit IB - о : TH Transistor a IR Thermostalic oven, healer u 8 | TRS Transistor socket Hs Handart — En E —Eliectran tube a | : | HT Telephone receiver | ув Voltage regulator daa HY | Hybrid coil [vs Electron tube socket - _ a ii Je E Integrated circuit Gi | “Mire, cable, vave guide a J Jack IX Crystal В | к | Relay о ~ |x» | Discriminater KS | Relay socket | X3 | Cryatal socket L | Inductor, coil XU Crystal oscillator | M Meter 2 | Tuned cavity, pulse forming network, 3a5 TS LIST — Es — TITLE a ETST ET, ¡Sari My | | MEMORY CND-206 l PART NC, | DAFT NAME | TYPE | DE SCAT REMAIKS | CONF _ | _ LE a TAN cd Lo — BTS1 ВТ HOLDER 67706801965 ATS? 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LEO en 20109E10235592V02 30V 109099 5609144792701 E MEE 10 = En PROYED DARTS LIST = NENES| TITLE | _ 'SH=FT FC. | MEMORY CNN-296 2 PART MC AE NAVE | wee | A REMARKS | E c33 CARL FXO EL ECE-ALESIOO 25V19UF SCEAAOQ 1348 C24 CAR FXD EL FCE-ALES101 25V100UF SCEAANI34€ C35 CAC, EXA NDL125L102J50V02 52V 1030PF SCAAAJILI? C36 Cap, FXD DO1125L102J50V02 50V 1990PF SCAAZOLTI? C37 САР FAN NOLIZSLINZJSOVO? 50v LONOPF 5САЛАО! 112 Cos ol ODE 1902 200V 1 А 5TXAGOJ0N] CDS NTE 151539LB8B-10 STXANNN247 C Dé NIODE 151539LB8-10 S5TX4N09249 CD? ITODE HZI3HC1 STXAENOI1A Cos ОТООЕ 1798 STXAGOODNO? ICI IC UPDSIOILC 350"àä(09)15! [C2 IC UPDS101LC 5IDACIONS1 [C3 IC UPDSLIILC SDRACONLS1 IC4 IC UPDSIOILC 539AÇ09151 ICS IC UPDS101LC 5SIACIOLS1 [C6 Ic UPNSIONLC - SINACIO!51 ICT IC HDT74L 5477 5°04F0936S0 Ica IC HDT&4LS4TP STNAFNI3GO CS ГС SMT&LS126AN SC BL +27 ICIO IC SNT&LS126aAN STTAL329422 [CI] IC SMT&LS1254NM SALA? ICl2 [С SMT&LS12648N 97I72L)04622 [C13 IC SNT4LS12564N SIZAL 99422 [C14 IC SNT4LSIZ26A4N 5004L.20+27 1С15 IC TC4049Ap 5904697944 [C16 Ir 1040490? 5071590746 1C17 EE, HA17305P 8241509567 J 1 LENYELTOS PCM6-20P4-2.575 275 5J°4A0004< J5 COMNECTO: HMC2-2_ 50-1718 1970 JAE TE J A LONMECTOS HHNC?2-2.5P-132758 175 534144330275 J 7 CONYECTO HM 2-2 .5P=1775 179 > JARED TIS « 1 TELAY ME—HND=-5V S¥LANNAN3C un: Cr IL LF1-100K LAUH 5LCA302771 D 4 CONMECTOC = H-67CJN07012 éZCJNVIN17 55 CC'IMECTZZ HNC2-2.55-10 109 SJ744 39277 E 10 15 ch 'FROYED JECKED | DALT LIST a... 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SHEET Ar. 1 DISPLAY CnE=167 | 1 PART NM, PAPT NAVE TYPE ies | REWADKS | CONE NE a - — 1 TION — col LEN TLR313 5T7A000003 Сп2 LEN TLR313 ST7ANN02N3 CD3 LEN TLG103 GREEN 5774793923 Pl CONNECTCS PCN6-205-2.505 508495080 PLE PCA MPOCOT9A7 MIPLITGAT 10 15 20 23 PROVED] 35 да] En = [MEMORY OUTPUT | 12 11 2531 207 16 17 66155 - 0000 871-3 OPTION MBELWO2033 MPFC 08758 + сэ eo 1 тя! 250 1815-7 A [manna | 28 1) MEET FhODAMRILIIÆTOBHEL NAN E TE 8 pFEM 7. [aon 2). EPI RAR TRE NOTES |. UNLESS OTHERWISE INDICATED RESISTANCES ARE IN OHMS CAPACITANCES ARE IN MICRO-MICRO FRAE 7. 4 YALUES SELECTED IN MANUFACTURE, OUTPUT 11 IN AT A FU 11 999 77 M1 5 0000 ae 7 100K тя # 25C1B15-Y R23 33 ARE IH MICRO-MICRO FRADS, C1-E23.035-C37: Goo — [icy — 106 | wPDSIOILE — R1- R6, R73, AM * AJiad тет. ICH SHTALSATH RT — RID “ 4704 ICT ~ ICIá SH 74L5126AM |IC15, IC!6 | TC4049 BP der. cOn * HA313 FE} = z ICI7 — HA 17805 P coa * тб ЮЗ PRESET C30 ICT ~~ ICH == ICH CS IC l6 16 4 Bod jug pa Г в а т т т т от от Те! NOH- 518 м Е Ч IL. + 6 E LE Sl =e 11111 aot | 22 22 27 72 72 it a #8 89 84 8 8 E ca * ca STE ICE IC16 Y 13 EJ 1 APPENDIX 1 LA MEMORY UNIT SCHEMATIC DIAGRAM ">

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Key features
- Stores up to 96 frequencies
- 24 channels per channel switch
- Optional battery backup
- CMOS static RAM
- Three-state buffers
- Power source voltage detecting circuit
- Low power consumption
Frequently asked questions
Alkaline batteries are recommended for backup as manganese type batteries could leak and cause damage which is not covered by warranty.
Set the receiver in manual mode. Dial the frequency you want to store. Select the desired channel and press the preset button.
Select the channel with the stored frequency and press the button corresponding to the stored frequency.