MTX Service Manual
MTX 500/512 SERVICE MANUAL & TECHNICAL INFORMATION Memotech Limited Witney Oxon OX8 6BX Tel: (0993) 2997 Tlx: UK83372 MEMTEC G MTX Service Manual
CONTENTS Page Overall Description...................................1 Internal Expansions compatibility.....................4 Z80 CPU...............................................6 Z80 Pin Description.................................7 Z80 CTC..............................................10 Z80 CTC Pin Description............................11 Z80 DART.............................................13 Z80 DART Pin Description...........................14 TMS 9929 VDP.........................................
Timing Chain.........................................46 Rear Plastic moulding................................48 PARTS LIST...........................................49 MTX500/512....................................50 PAL Video Board...............................54 Keyboard/Keytops..............................56 Power Supply..................................59 Plastic Rear Panel............................60 Packing.......................................60 RS232 Board...................................
1 INTRODUCTION Overall Description The MTX Series personal computer systems are high performance 8-bit computers uniquely designed to operate in memory intensive ROM-based or DISCbased environments.
2 CPU Board Mounted in accommodates: the lower chassis, the CPU board Z80A CPU operating at 4Mhz. 24K of ROM which contains: MTX BASIC - incorporating sophisticated MTX graphics commands. LOGO-type MTX NODDY - Interactive screen manipulation routines. FRONT PANEL DISPLAY incorporating Assembler/Disassembler plus Z80 Register, Memory Program display and manipulation routines. Z80 and VIDEO DISPLAY PROCESSOR - with 16K dedicated video-RAM. USER-RAM - 32K on the MTX500 and 64K on the MTX512.
3 Graphics Facilities Up to 32 independently controllable user definable sprites, plus pattern plane and backdrop plane. High level sprite-orientated graphics commands. Input/Output Provided as standard: 1. CASSETTE PORT (variable rate, up to 2 400 baud) 2. UNCOMMITTED PARALLEL INPUT/OUTPUT PORT 3. TWO JOYSTICK PORTS with industry standard pinouts 4. FOUR CHANNEL SOUND UNDER SOFTWARE CONTROL three independent voices plus pink noise output through TV speaker, or through separate Hi-Fi output 5.
4 NODE/RING SYSTEM Communications software and interfacing enabling construction of MTX Ring Systems. The system is interrupt driven and runs in conjunction with the twin RS232 Communications Board. Compatibility of the memory boards and Board is given below.
5 mouldings are incorporated in the PSU casing to support the input and output cables. The output cable terminates in a 240 degree, six pin DIN connector. The PSU is supplied as a sealed unit.
6 Z80 CPU The instruction set contains 158 instructions. The 78 instructions of the 8080A are included as a subset; 8080A software compatibility is maintained. Eight MHz, 6 MHz, 4MHz and 2.5 MHz clocks for the Z80H, Z80B, Z80A and Z80 CPU result in rapid instruction execution with consequent high data throughput. The extensive instruction set includes string, bit, byte and word operations.
7 Pin description A0-A15. Address Bus (output, active High,·3-state). A0A15 form a 16-bit address bus. The Address Bus provides the address for memory data bus exchanges (up to 64K bytes) and for I/O device exchanges. BUSACK. Bus Acknowledge (output, active Low). Bus Acknowledge indicates to the requesting device that the CPU address bus, data bus and control Signals MREQ, IORQ, RD and WR have entered their high-impedance states. The external circuitry can now control these lines. BUSREQ.
8 IORQ. Input/Output Request (output, active Low, 3state). IORQ indicates that the lower half of the address bus holds a valid I/O address for an I/O read or write operation. IORQ is also generated concurrently with M1 during an interrupt acknowledge cycle to indicate that an interrupt response vector can be placed on the data bus. M1. Machine Cycle One (output, active Low). M1, together with MREQ, indicates that the current machine cycle is the opcode fetch cycle of an instruction execution.
9 RFSH. Refresh (output, active Low). RFSH, together with MREQ, indicates that the lower seven bits of the system's address bus can be used as a refresh address to the system's dynamic memories. WAIT. Wait (input, active Low). WAIT indicates to the CPU that the addressed memory or I/O devices are not ready for a data transfer. The CPU continues to enter a Wait state as long as this signal is active. Extended WAIT periods can prevent the CPU from refreshing dynamic memory properly. WR.
10 Z80 CTC The Z-80 CTC four-channel counter/timer can be programmed by system software for a broad range of counting and timing applications. The four independently programmable channels of the Z-80 CTC satisfy common microcomputer system requirements for event counting, interrupt and interval timing, and general clock rate generation. System design is simplified because the CTC connects directly to both the Z-80 CPU and the Z-80 SIO with no additional logic.
11 Pin Description CE. Chip Enable (input, active Low). When enabled the CTC accepts control words, interrupt vectors, or time constant data words from the data bus during an I/O write cycle; or transmits the contents of the down-counter to the CPU during an I/O read cycle. In most applications this signal is decoded from the eight least significant-bits of the address bus for any of the four I/O port addresses that are mapped to the four countertimer channels. CLK. System Clock (input). system clock.
12 INT. Interrupt Request (output, open drain, active Low). Low when any Z-80 CTC channel that has been programmed to enable interrupts has a zero-count condition in its down-counter. IORQ. Input/Output Request (input from CPU, active Low). Used with CE and RD to transfer data and channel control words between the Z-80 CPU and the Z-80 CTC. During a write cycle, IORQ and CE are active and RD inactive.
13 Z80 DART The Z-80 DART (Dual-Channel Asynchronous Receiver/Transmitter) is a dual-channel multi-function peripheral component that satisfies a wide variety of asynchronous serial data communications requirements in micro-computer systems. The Z-80 DART is used as a serial-to-parallel, parallel-to-serial converter / controller in asynchronous applications. In addition, the device also provides modem controls for both channels.
14 Pin Description B/A. Channel A Or B Select (input, High selects channel B). This input defines which channel is accessed during a data transfer between the CPU and the Z80 DART. C/D. Control Or Data Select (input, High selects Control). This input specifies the type of information (control or data) transferred on the data bus between the CPU and the Z-SO DART. CE. Chip Enable(input, active Low).
15 IEI. Interrupt Enable In (input, active High) is used with IEO to form a priority daisy chain when there is more than one interrupt-driven device. A High on this line indicates that no other device of higher priority is being serviced by a CPU interrupt service routine. IEO. Interrupt Enable Out (output, active High). IEO is High only if IEI is High and the CPU is not servicing an interrupt from this Z-80 DART.
16 RxDA, RxDB. Receive Data (inputs, active High). RESET. Reset (input, active Low). Disables receivers and transmitters, forces TxDA and marking, forces the modem controls High disables all interrupts. both TxDB and RIA, RIB. Ring Indicator (inputs, Active Low). These inputs are similar to CTS and DCD. The Z-80 DART detects both logic level transitions and interrupts the CPU. When not used in switched-line applications, these inputs can be used as general-purpose inputs. RTSA, RTSB.
17 TMS 9929 VDP (Video Display Processor) Introduction This Preliminary Specification of the TMS 9929 is to be considered as an "ADD ON" to the basic TMS 9918 specification. The TMS 9929 is effectively identical to the TMS 9918 functionally and only has the color video section that is different. The TMS 9918 provides a composite color video signal output that if driven by a suitable amplifier can go directly into any color video monitor.
18 4116 VRAM PIN NAMES A0-A6 Address Inputs CAS Column Address Strobe DIN Data Input DOUT Data Output RAS Row Address Strobe WRITE Read/Write Input VBB -5V Power Supply VCC +5V Power Supply VDD +12V Power Supply VSS Ground 19 MTX Service Manual
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20 MTX SERIES BUS The system Bus comprises the full Z80 A bus, power supply rails, ROMpak enable (GROM), ROM page ports R0 to R2, RAM page ports P0 to P3 and serial clock lines 01 and 02. All lines are externally available on J1, which is a 60 way (30 + 30) 0.1" card edge plug, or internally on J0 which is also a 0.1" 60 way card edge plug.
21 System Block Diagram MTX Service Manual
22 DISASSEMBLY INSTRUCTIONS 1. Using an Allen key, remove the three dome head screws from the right & left hand ends of the MTX. 2. Lift the MTX keyboard at the rear just above plastic panel. Be careful not to damage keyboard interconnecting cable. 3. Gently ease the KBD (keyboard) interconnecting cable from the mother board and slide the top KBD to the left or right until detached. 4. Remove the video monitor cable (fig 3) and tape it to the plastic panel to prevent any unnecessary damage.
23 The under side of the MTX reveals a single screw which secures the MTX mother board to the bottom chassis. By removing the main screw and earth strap the MTX Mother Board and Rear Plug panel will slide from the case bottom. Faults are rarely complained about but nonetheless faults, include I/O ports that are insecurely soldered or not 'flush' with the main P.C.B. i.e. Power Supply socket, Printer port, cassette ear and mic and joy stick ports.
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25 Introduction To Trouble Shooting Guide Memotech products are all given a vigorous series of tests before despatch to the end user. These tests include:- Loading and saving functions, sound channel checks, compatibility with printers and other add ons, etc etc. Once the units have passed this stage of tests they are given 24 hour soak test, (burning in process). Any component that is faulty is generally weeded out at this stage.
26 SYMPTOM 1 On power up:display. No display or only a black and white a) Cause of Trouble Black and White output. Check Point Video Board Oscillation IC47. of Xtal 4.433619Mhz or pin 17 of LM1889 Repair Method 1 If pulse is present on P17 of LM1889 until oscillation is at its optimum peek to peek. See fig no 1. 2 If pulse is absent LM1889 associated circuitry. is turn CVI pitch 3v faulty - or b) Cause of Trouble Rapid Fading of colours.
27 3 If still faulty replace the Modulator. c) Cause of Trouble No video output, i.e. 'fuzzy screen' Check Point Pal board J11 and or Modulator Repair Method 1 Check for Modulator. pulse on pin 3 of J11 or Pin 3 2 Check for short to 3 Check +12v - if absent replace 12v Regulator. of 5v...or replace Modulator. d) Cause of Trouble Monitor display faulty Check Point Pal board monitor connection cable Repair Method NB: 1 Check for pulse on Q6 - (2N3906 transistor) absent Q6 is faulty.
28 SYMPTOM 2 When power is switched on: sound. Blank screen - no humming a) Cause of Trouble Faulty video board Check Point Check to see if you have control G note Repair Method 1 If control G note is present video faulty-Replace video board. board is b) Cause of Trouble Blank screen with no control G sound Check Point Check +5v -5v +12v 0v Repair Method 1 If the +5 voltage is absent, fuse has blown. 2nd stage 2 If +12v and +5v are absent check regulators and associated circuitry.
29 Repair Method 1 If pulse is absent on 4Mhz Xtal - follow associated circuitry until fault is apparent. 2 If RESET is held low- follow associated apparent. circuitry until fault is Also - see page 33. d) Cause of Trouble Blank screen with no control G sound Check Point If above Xtal checks are o.k. check the 10.6875 ;hz Repair Method 1 If pulse is absent Xtal is likely to be faulty. 2 If pulse is present processor is faulty.
30 SYMPTOM 3 Corrupt video display or characters a) Cause of Trouble - 5v absent Check Point 1 If -5v is absent - check for short at J12 (monitor o/p) of video board - or repair open circuit. The -5v is generally shorted to 0v at this point. b) Cause of Trouble Faulty Video Ram Check Point Check for pulse on pin 2 of Video Ram. Check for signal on P14 of any Video Ram. Repair Method 1 Systematically disable the Video Rams by earthing pin 14. Continue with this process until corruption has reduced.
31 may pick out the faulty component. c) Cause of Trouble Faulty TMS 9929 Check Point Check pins 3 to 10 and pins 25 to 32 Repair Method 1 If signal processor. is absent replace TMS 9929 video WARNING:When you earth the Video Rams - make sure earth them via a 10 OHM - 15 OHM Resistor. not earth them directly as this may damage components. you Do the SYMPTOM 4 When power is switched on: corruption of display. Very bad hum bars causing a) Cause of Trouble Faulty P.S.U.
32 b) Cause of Trouble Faulty Bridge Rectifier Check Point Check your +5v and +12v Repair Method 1 If signal is poor trace fault from either the 7805 or 7812 Regulators to faulty component. SYMPTOM 5 When power is switched on:- Green screen noise. and humming Whilst testing the MTX during Manufacture the most common fault we find is:- On fire up - Blank screen and humming sound.
33 a) Cause of Trouble Faulty voltages Check Point Check all your voltages 0v, 5v, 12v, -5v, -12v Repair Method 1 If any signal is absent follow circuitry from source and repair. offending b) Cause of Trouble Faulty RESET circuit - also see page 29. Check Point Check Points are:- Pin 3 of IC18 BCN4070 CMOS Pin 26 of C.P.U. Pin 34 of V.D.P. NB. 1 If signal is low - trace fault back from Pin 3 of IC18 4070CMOS (pay particular attention to C11 10uf cap). 2 If signal is high RESET circuitry is o.k.
34 Repair Method 1 If any address signal is absent - Reset MTX whilst probing. If signal is still absent start by replacing C.P.U. 2 Check both 74LS157's (PCB Location 6C and to see if they are multiplexing. 3 If 74LS157 pin 1 pulse is absent, check pin 14 of PAL14L4 and follow circuitry through pins 3,4,5 and 6 of the 74LS04 (PCB Location 2B) to REF points MPX. faulty.
35 NB: We find it helpful to replace all the socketed IC's with a known good set before attempting to rectify this fault. * The fact that a signal is absent from the system data bus does not necessarily mean that there is a fault in Ram. It is very difficult to determine Ram faults with an oscilloscope alone. You really do need the Memotech Ram Rig Tester.
36 Check Point By typing LO."" (RET) and loading in a long playing cassette tape start probing at J2 CSST out. Repair Method 1 You can easily follow the signals from J2 through opamp 10E 314. (Remember pin 6 is normally -12v) and in to 4070 CMOS out at pin 4. - Replace faulty component. 2 If no fault found change CPU or CTC.
37 d) Cause of Trouble MTX 512 with internal expansions only Check Point Check right hand bus connector Repair Method 1 NB: Either make sure the bus connector is clean or...ideally hard solder the expansion board to the mother board. Before these tests are carried out always check that you have a good tape recorder that is set at the correct volume (between level 7 and 10). Check your cassette leads (remember ear to ear and mic to mic). Check that the cassette tape itself is working - and not damaged.
38 4 If pulse is present on both 4E (374) and (SN76489AN) check for pulse on pin 1 of J13 pal board and pin 3 of J11 on pal board. either are absent check for open circuit replace pal board. 5 If pulse is present on J11 and J13 check tuning of modulator. See ref Page 42. 5E on If or the b) Cause of Trouble Faulty SN76489AN or 74LS374N Check Point As above Repair Method 1 NB: Often the sound channels become the components have reached temperature.
39 Repair Method Generally key bounce is caused by faulty key board switches. Simply de-solder and replace the offending key(s). b) Cause of Trouble Key(s) u/s Check Point J1-keyboard interconnection header plug Repair Method 1 Check that the keyboard interconnection is secure and not torn. cable 2 Check that the offending keys work by buzzing across the terminals whilst depressing the switch. 3 Check for pulses on diodes DR0-DR7 (4148) Anode -> 74LS273N (3A) -> LCD lines.
40 SYMPTOM 9 Add on faults - e.g. Memory expansions, RS232, Printers etc. Rom boards, a) Cause of Trouble Memory upgrade not obtaining Ram top Check Point Check for correct prom coding, see page 45, check rams in sockets (if any) for poor connection Repair Method 1 If prom is o.k. make sure that both connector and upgrade connector is clean. are edge 2 Check links on the upgrade soldered in the LO position. correctly 3 R1 = 330 OHM. 4 R2 = 680 OHM.
41 4 Check links 6 and 7 on MTX. 5 Look closely at the 273 (5A) on and associated circuitry. mother board c) Cause of Trouble RS232 Check Points As above. Repair Methods As above -> 1 If intermittent fire up modify timing chain see page 46. -> d) Cause of Trouble Printer Check Point J6 Printer o/p Repair Method 1 Be sure that the fault is not itself or the interface cable. the printer 2 STROBE should be Hi. 3 Check Printer data lines (PRD0-PRD7) 374 and on J6. 4 Also check 74LS244.
42 Further information on the UM 1286 Modulator. The Pal-Modulator is used to encode the R-Y, B-Y and Y signals from the MTX home computer and to modulate them together with the sound signal to a high frequency (591.250 MHz). R-Y and B-Y are called the Chrominance signals. All the information about the brightness is in signal called the Luminance signal. the Y The Pal Encoder is built up around the LM 1889 and the UM1286.
43 Test and setting procedure of UM 1286 and video board 1 Be sure that your TV set, MTX computer and any other test equipment is switched on at least half an hour before beginning the test. 2 Connect the MTX computer to the TV aerial cable. 3 Set the TV set to channel 36 of the 1V band (UHF) to obtain the best combination of sound and colour. 4 With the aid of a frequency meter, check the audio carrier; if (for PAL A units) it is not 6 MHz (values allowed: 5.99 - 6.
44 Link arrangements and PAL colour coding 1. MTX 500 - 4000/04 with 32k H Ram chips. 2. MTX 500 4000/04 with 32k L Ram chips 3. MTX 500 4000/05 with 32k H Ram chips. Links 6 and 7 as point 1. 4. MTX 500 4000/05 with 32k L Ram chips. Links 6 and 7 as point 2. 5. MTX 512 4000/04 - 64k 6. MTX 512 4000/05. 7. MTX 500 4000/06 - 32k. 3 and 4. Links 6 and 7 as points 8. MTX 512 4000/06 - 64k. Links 6 and 7 as point 6.
45 PROM CODE FOR MEMORY EXPANSION BOARDS MTX 500 CODE DESCRIPTION OLL (MAX 96K) 1 ROW OF 32K L OR 2 ROWS OF 32K L OLH (MAX 96K) 1 ROW OF 32K L 1 ROW OF 32K L AND 1 ROW OF 32K H OHH (MAX 96K) 1 ROW OF 32K H OR 2 ROWS OF 32K H OL64 (MAX 128K) 1 ROW 32K L AND 1 ROW 64K 00128 (MAX 160K) 2 ROWS OF 64K 04128 (MAX 288K) TO RUN IN CONJUNCTION WITH 00128 2 ROWS OF 64K 08128 (MAX 416K) TO RUN IN CONJUNCTION WITH 00128 AND 04128 2 ROWS 64K MTX 512 CODE DESCRIPTION 1LL (MAX 128K) 1 ROW OF 32K L OR 2
46 Timing chain modification In October 1984 Memotech altered the timing chain circuitry due to occasional faults occurring after about 2 hours of use - and poor fire up response. (esp; when running in conjunction with F.D.X.) We have since up-dated all our units to incorporate this 'modification'. MTX 4000/06 P.C.B.'s are exempt from this modification due to the fact that multilayered boards are generally not affected.
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48 Plastic back panel. You will find that your TV/Monitor picture will tear or wobble if your plastic back panel does not have: a b Earth straps 47pf capacitor Illustration of assembly of power transistor.
49 PARTS LIST FOR THE: MTX 512 04 RS232 I/F 32K MEMORY EXPANSION ROM EXPANSION MTX Service Manual
50 MTX LOADING STAGE 1. MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO.
51 CAPC NF0047 47pf Ceramic Disc Cap 1 C14 CAPE A470016 4700uf 16v Axial Cap 1 C56 CAPE R001016 10uf 16v Radial Cap 6 CAPE R010025 100uf 25v Radial Cap 1 C11,C38-C40, C49,C57 C53 CAPE R470016 4700uf 16v Radial Cap 10mm 1 C51 CAPP NF0100 100nf Polyester Cap 8 CAPS NF0047 47nf Sibitat Cap 4 C17,C52,C54,C55, C58-C61 C7-C10 CAPS NF0100 100nf Sibitat Cap 15 CAPT UF2216 22uf Tantalum 16v Cap C?????,+MOD 17,MOD21 3 CONL SHUNT02 2 Way Shunt (Jumper) 1 CONL WIRE Wire Link 39/24 SWG
52 CRXL 4.000 4.
53 MDOR UM1286 UM1286 Modulator 1 MODULATOR RES 033R 33 OHM 1/4W C/FILM RES 1 R17 RES 330R 330 OHM 1/4W C/FILM RES 2 R14,R15 RES 560R 560 OHM 1/4W C/FILM RES 2 R34,R40 RES K001 1K OHM 1/4W C/FILM RES 6 RES K002.2 2K2 OHM 1/4W C/FILM RES 1 R10,R11,R19,R20, R21,R60 R41 RES K003.3 3K3 OHM 1/4W C/FILM RES 2 R32,R33 RES K004.
54 ICMO Z80ACTC Z80A CTC 1 IC6 ICPA 14L4 PAL 14L4-2CN 1 IC4 ICRO 38128A ROM 16B MSM38128A 1 IC46 ICRO 3864 ROM 8B MSM3864 1 IC45 MTX PAL VIDEO BOARD MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO.
55 ICMO LM1889 LM1889 1 IC3 IDTA UH004.7 4.
56 MTX KEYBOARD MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO. UNIT / COMMENTS -----------------------------------------------------------------------CONL WIRE Wire Link 39/24 SWG 29 CONP HSILR20 20 Way SIL R/A Header 1 CONS SIL20AS 20 Way SIL KBD Assembly 1 KBNT PNLMTX KBD Switch Mounting Plate 1 PCB MKBD104 KBD 01-04 PCB 1 SWT ML-3-CM ML-3-CM Keyboard Switch 79 MTX KEYBOARD MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO.
57 KYTP 6011F & - 6 1 KYTP 6153F 6 - DEL 1 KYTP 7011F ´ - 7 1 KYTP 7163F 7 - PAGE 1 KYTP 8011F ( - 8 1 KYTP 8163F 8 - EOL 1 KYTP 9012F ) - 9 1 KYTP 9163F 9 - BRK 1 KYTP A000F A 1 KYTP A0033F ALPHA LOCK 1 KYTP AA127F . - ARROW DOWN 1 KYTP B000F B 1 KYTP B033F BS 1 KYTP BB00F > - .
58 KYTP F663F F3 1 KYTP F664F F4 1 KYTP F665F F5 1 KYTP F666F F6 1 KYTP F667F F7 1 KYTP F668F F8 1 KYTP FF00F * - : 1 KYTP G000F G 1 KYTP GG00F ? - / 1 KYTP H000F H 1 KYTP HH000F _ 1 KYTP HH05F = - - 1 KYTP I000F I 1 KYTP J000F J 1 KYTP JJ00F { - [ 1 KYTP JJ03F } - ] 1 KYTP K000F K 1 KYTP KK00F ~ - ^ 1 KYTP KK16F | - \ 1 KYTP L000F L 1 KYTP L054F LINEFEED 1 KYTP LL00F ` - @ 1 KYTP M000F M 1 KYTP N000F N 1 KYTP O000F O 1 KYTP P000F
59 KYTP Q000F Q 1 KYTP R000F R 1 KYTP R031F RET 1 KYTP S000F S 1 KYTP S020F SHIFT 2 KYTP SPACBRF SPACE BAR 1 KYTP T000F T 1 KYTP U000F U 1 KYTP V000F V 1 KYTP W000F W 1 KYTP X000F X 1 KYTP Y000F Y 1 KYTP Z000F Z 1 SBK SPACE BAR KIT 1 GT8C MTX POWER SUPPLY UNIT MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO.
60 MTX REAR PLUG ASSEMBLY MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO. UNIT / COMMENTS -----------------------------------------------------------------------CAP PF0047 47pf Ceramic Plate Cap 1 CONP EYE4BA 4BA Crimped Eyelets 1 CONP BNCONT BNC Chassis MT Socket 1 CONP HIFIC Phono Socket Nut Fixing 1 CONS SIL04AS 4 Way Cable ASSY 1 FACC WIR.5B .
61 BOX MTX512 MTX 512 Box 1 CONP J23.5 23.5 Cable Jack Plug 1 CONP PNOCAX Phono to Coax Cable 1 GUAR 512UK 512 UK Guarantee Card 1 MLD MTXCVR Plastic Cartridge Cover 1 PPK MTX512 MTX 512 Polypack 1 STNP 029 MTX Series Manual 1 STNP 078 MTX 512 Serial No.
62 MTX RS232 I/F MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO.
63 RS232 I/F TESTING MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO. UNIT / COMMENTS -----------------------------------------------------------------------IC 75188 SN75188N 1 IC13 IC 75189 SN75189N 2 IC12,IC14 IC Z80DART Z80A DART 1 IC1 PAL 14L4-2CN 1 IC8 ICPA 14L4 RS232 I/F PACKING MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO.
64 32K MEMORY EXPANSION MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO.
65 TLS ALLK2MM 2MM Allen Key 1 ROM EXPANSION MEMOTECH ITEM DESCRIPTION NO./ PCB COMPONENT LOCATION PART NO.
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71 RING SYSTEM The MTX ring uses channel A of the dart. If the ring is installed, the baud command must not be used for either channel as the dart is initialised differently for the ring. Channel B is not used by the ring and is available as serial I/O port. Node commands are provided to set the baud rate and data format for channel B.
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