Heath Company Heathkit H8 Manual Download Page 63

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Summary of Contents for Heathkit H8

Page 1: ...eathkit Manual for the DIGITAL COMPUTER Model H8 ASSEMBLY 595 2013 01 HEATH COMPANY BENTON HARBOR MICHIGAN 49022 Copyright 1977 Heath Company All Rights Reserved Printed in the United States of Americ...

Page 2: ...EMBLY NOTES 4 Circuit Board Installation 55 Circuit Board Checks 56 CHASSIS ASSEMBLY Parts List 7 Step by Step Assembly 9 CPU CIRCUIT BOARD Replacement Parts List 59 Circuit Board Installation 61 Moth...

Page 3: ...e 3 Each assembly section of this Manual contains its own Parts List and Step by Step Assembly in structions At the beginning of each Parts List you will be instructed which parts pack to locate and u...

Page 4: ...trations in the Manual are called Pictorials and Details Pictorials show the over all operation for a group of assembly steps Details generally illustrate a single step When you are directed to refer...

Page 5: ...5 SOLDERING Soldering is one ofthe most important operations you will perform while assembling your kit A good sol der connection will form an electrical connection be tween two parts such as a compon...

Page 6: ...00 BLUE 6 6 1 000 000 VIOLET 7 7 10 000 000 GRAY 8 8 100 000 000 WH IT 9 q 1 000 000 000 GOLD 1 S I L VE R 01 Capacitors will be called out by their capacitance value in F microfarads or pF picofarads...

Page 7: ...T1 A9 60 54 120 240 slide switch SW2 A10 60 608 NOR LOW slide switch SW3 A11 60 619 Rocker switch SW1 A12 401 163 Speaker SP1 A13 421 23 1 ampere slow blow fuse F1 maining parts not called for in this...

Page 8: ...1357 Model label 390 1415 Instruction card F2 390 926 Warning label F3 391 34 Blue and white label F4 391 611 Nameplate F5 390 1371 Keyboard label set 597 260 Parts Order Form 597 1656 Heath User s Gr...

Page 9: ...ightly to hold the re sistor in place PART NUMBER 1 I IDENTIFICATION DRAWING PICTORIAL 1 1 CONTI NUEv Solder the resistor leads to the circuit board as follows 1 Push the soldering iron tip against bo...

Page 10: ...to obtain a good connec 1 L connection tion I SOLDER BRIDG S A solder bridge between two adjacent foils is shown in photograph A Photograph B shows how the con nection should appear A solder bridge ma...

Page 11: ...f f i B fj Install two 25 pin plugs at each of the following locations Pl0 P9 P8 P7 P6 P5 P4 P3 P2 P1 Visually check each plug for solder bridges Page 11 PICTORIAL 1 2...

Page 12: ...8 I I I I I I I I 0 5 eM 2 3 4 2 I I 5 I i Ii I i 6 PICTORIAL 1 3 3 4 I I I i I II I I I I I I I II I 8 9 10 2 CONTINUE 0 I NOTE As you wire this kit you will be instructed to prepare lengths of wire...

Page 13: ...citor C3 Use an ohmmeter to check for unwanted shorts between each adjacent pin at any of the 50 pin plugs two 25 pin plugs NOTE Pins 0 and 1 and pins 48 and 49 are connected together these should sho...

Page 14: ...dware_ Similarly mount rubber feet on the bottom of the chassis at AB AC and AD Use 8 32 x 1 2 hardware Scrape or sand any excess paint from around holes AE and AF on the inside of the chassis Detail...

Page 15: ...ng nuts in five of the remaining holes in the side panel marked with arrows Do not install a nut at BE at this time Refer again to Detail 2 1D and mount a circuit board mounting bracket to the left si...

Page 16: ...r away from the fuseholder body as shown in the Picto rial o l4 h 3 1 INCHES l 8 I 3 8 I 5 8 I 7 8 I I I I I I 2 I I I I I I I Ii II i i i i o 5 1 CM 2 3 4 5 6 8 9 FUSEHOLDER LOCKWASHER Detail2 1G NUT...

Page 17: ...IN THE SLOT SQUEEZE THE TWO SEGMENTS TOGETHER Detail 2 2B Page 17 INSERT THE REAR HALF I NTO THE HOLE Connect the white line cord lead to AC socket Sllug 2 NS Make a mechanically secure con nection I...

Page 18: ...e other end will be connected later Locate the power transformer Then slide a rub ber grommet over the black black red black green black yellow black white and black gray transformer leads Connect the...

Page 19: ...POW ER TRANSFORMER PICTORIAL 2 3 INS f I B Page 19...

Page 20: ...C shield with the flat side as shown at CA and CB on the Pictorial Refer to Detail 2 4B and mount the 120 240 slide switch SW2 onto the AC shield at CC and CD Use two 6 32 x 1 4 screws Detail2 4B Simi...

Page 21: ...the backing paper from the caution label Then press the label on top of the AC shield as shown in the Pictorial NOTE When you perform the next step do not use the brass washer Refer to Detail 2 5A an...

Page 22: ...screw driver to push the nut into the panel until the top of the nut is flush with the flat washer 4 Turn a 6 32 x 1 4 screw all the way into the nut Then remove the screw and flat washer and set them...

Page 23: ...on each wire at one end of the twisted pair 8et this twisted pair aside tem porarily Locate the mother circuit board and position it inside the chassis Twist together the two green and the green yell...

Page 24: ...ht side panel Use six 6 32 x 1 411 screws Position the green and green yellow trans former wires along the rear edge of the chassis as shown in the Pictorial Prepare a 3 3 411 large black wire Refer t...

Page 25: ...ight traces of CO2 Refer to the inset drawing on the Pictorial and cut open the thermal compound container Then spread a thin layer of the compound onto the mounting flange of the diode assembly NOTE...

Page 26: ...transformer lead to the positive or dot marked terminal of the capacitor Use a 10 32 x 1 4 screw and a 10 lockwasher Position the solder lugs as shown in the Pictorial Connect the free end of the bla...

Page 27: ...the capacitor mounting strap Do not however allow any wires to become pinched be tween the capacitor and the chassis or the strap and the chassis Refer to Detail 2 7H and loosely mount capacitor C2 t...

Page 28: ...and EB r SP1 Refer to Detail2 8A and mount the speaker to the capacitor shield with three shoulder spacers and three 6 32 x 1 4 screws Be sure to position the lugs on the speaker as shown in the Picto...

Page 29: ...nst the bottom of the chassis re move the shield and reform it as necessary until it does Position the excess twisted pair inside the capacitor shield Check the wires near the diode assembly If necess...

Page 30: ...touching adjacent terminals or the chassis Then proceed to Secondary Wiring Tests Ifyou have an ohmmeter perform the following resis tance measurements NOTE You will be instructed to connect one of th...

Page 31: ...out properly the first time PROBLEM 1 Low reading 2 High reading Page 31 Connect the common or ground lead of your meter to plug Pi pin O Be sureyour ohmmeter is in the R x 10 position Touch the othe...

Page 32: ...ge the power supply in your Computer Remove two 3 8 pieces of insulation from an orange wire Use these pieces of insulation in the next two steps Slide one piece of insulation over plug Pi pin 1 Slide...

Page 33: ...g A Transformer T1 wiring B Capacitor C2 C Switch SW2 or SW3 2 High reading A Transformer T1 wiring B Switch SW2 or SW3 C Resistor R1 Push the POWER switch to OFF Unplug the line cord Disconnect the m...

Page 34: ...ted by a fourth color band of gold A1 1 56 12 8 15 n brown green black R123 R124 R125 R126 R127 R128 R129 R131 A1 1 103 12 150 n brown green brown R154 A1 1 105 12 200 n red black brown R104 A1 1 121...

Page 35: ...d IMPORTANT If any components are missing from the sealed IC package return the unopened package for replace ment Claims for missing Ie s will not be honored If you locate damaged or defective IC s or...

Page 36: ...34 311 20 pin IC socket 0 4 Y2 1 INCHES 2 I 8 I 3 8 I I i Ii Ii 5 B 7 8 I I I I I I I I I I I I I I I 0 5 1 eM 2 3 4 5 6 CIRCUIT Compo No 3 I II 8 9 KEY HEATH QTY DESCRIPTION No Part No MISCELLANEOUS...

Page 37: ...pin IC socket at ICI07 14 pin IC socket at ICI0B 14 pin IC socket at ICI09 14 pin IC socket at ICII0 14 pin IC socket at ICll1 14 pin IC socket at IC112 20 pin IC socket at ICl13 16 pin IC socket at I...

Page 38: ...y Solder the pins to the foil as you install each socket 5 pin socket 5 pin socket 5 pin socket 5 pin socket 5 pin socket 5 pin socket 5 pin socket 5 pin socket 5 pin socket 0000 000 0 5 pin socket 5...

Page 39: ...on the diode with the band mark on the cir cuit board D101 1N4149 diode 56 56 Solder the leads to the foil and cut off the excess lead lengths INCHES lifljiili i I o 5 1 eM 2 3 4 5 I 6 o PICTORIAL 3 3...

Page 40: ...1 F ceramic Solder the leads to the foil and cut off the excess lead lengths CJC D O D r r ODC C DDC PICfORIAL 3 4 Cl05 680 pF mica Solder the leads to the foil and cut off the excess lead lengths Ql1...

Page 41: ...black resistors at R127 R128 Rl 31 R129 Solder the leads to the foil and cut off the excess lead lengths 0000 PICfORIAL 3 5 Page 41 RI04 200 n red black brown Install nine 560 n green blue brown resis...

Page 42: ...the circuit board Then solder the leads to the foil and cut off the excess lead lengths LED111 LEDl12 LEDl13 LEDl14 jD 00 00 00 0000 0000 PICfORIAL 3 6 CONTINUE 0 NOTE Use the following procedure whe...

Page 43: ...0 n green blue brown resistors at Rl05 Rl08 Rl09 Rl13 1 114 R117 1 118 R122 Solder the leads to the foil and cut off the excess lead lengths IDENTIFICATION DRAWING The steps performed in this area of...

Page 44: ...Q113 Q114 Q115 Q116 Q117 Q118 The steps performed in this Pictorial are in this area of the circuit board PART NUMBER IDENTIFICATION DRAWING PICTORIAL 3 8 CONTINUEQ NOTE When you install electrolytic...

Page 45: ...t labeled on the circuit board Position the top of the loop 1 4 above the top of the circuit board Then solder the wire to the foil and cut off any excess wire end Yo Yo 3 4 1 INCHES 1 8 3 8 I 5 8 7 8...

Page 46: ...ither way 2 Solder the two lugs of the switch to the foil 3 Check the switch to make sure it is still flat against the circuit board If necessary reheat the lugs and reposition the switch PUSHBUTTON S...

Page 47: ...NTIFICATION DRAWING 8 9 LOAD DUMP I PC 5 6 IN OUT BC 2 3 REG RTMI0 PICfORIAL 3 11 Page 47 ___ The steps performed in this Pictorial are I CANCEL I ALTER R5TII l I r in this area of the circuit board C...

Page 48: ...spring con nector on the brown wire into hole 11 of a 2S hale connector shell 11 1 INCHES 2 3 I f8 I 3 8 I ri 7i iill i 5 8 I I 7i8I I I I I I I I I I I I I I I II I I I I I I I 0 5 eM 2 3 4 5 6 B I...

Page 49: ...Red wire into hole 7 Orange wire into hole 8 Yellow wire into hole 9 Green wire into hole 10 Blue wire into hole 11 Violet wire into hole 12 Gray wire into hole 13 Page 49 Detail 3 12E Locate the key...

Page 50: ...I I I I I I I I I I I I I I I I 0 5 1 eM 2 3 5 6 7 8 I II 9 Connect the wires coming from the 3 hole connector shell to the circuit board at IC10l as follows Solder the wires to the foil as you connec...

Page 51: ...Page 51 I 4 Detail 3 13A Detail 3 13B...

Page 52: ...5 label Remove the label from its protec tive backing and press the label onto the 5 hole connector shell as shown in Detail 3 13D Refer to Detail3 13D and insert the spring con nector on the brown wi...

Page 53: ...as follows 2 3 4 black into hole 1 of the BOT shell g black into hole 2 of the BOT shell 14 orange into hole 24 of the TOP shell 16 orange into hole 25 of the TOP shell Connect the other end of the w...

Page 54: ...it with the metal side toward the heat sink Also be sure to use the correct hole on the heat sink and position the inte grated circuit as shown in the Pictorial APPLY THERiI AL COMPOUND ON METAL S IDE...

Page 55: ...the white wire onto PCB pin E on the back side of the control circuit board Push the PCB connector on the orange wire onto PCB pin F on the back side of the control circuit board Push the BOT bottom c...

Page 56: ...on lead of your VTVM to one of the ground test loops on the control circuit board Do not allow the lead to touch any other part of the circuit board Set your VTVM to read 5 volts DC Touch the probe of...

Page 57: ...u install each IC in the following steps position the pin 1 end of each IC as shown in Part A of the Detail toward the index mark on the circuit board see Part B Then insert the IC leads into the sock...

Page 58: ...ach step without interruption PROBLEM 1 LED111 does not light Push the POWER switch to OFF Unplug the line cord ICl19 Install a 14028 IC 443 713 atICl19 as follows 1 Remove the IC from the conductive...

Page 59: ...rts to do your own service REPLACEMENT PARTS LIST Page 59 The Circuit Component numbers in the following list correspond to the numbers on the X Ray View and Schematic for this circuit board To order...

Page 60: ...CIRCUITS IC s 0201 IC201 IC202 IC203 56 56 442 54 442 617 442 618 1N4149 diode 78051C 78MGT2C IC 79MGT2C IC CIRCUIT HEATH DESCRIPTION Compo No Part No Diodes Integrated Circuits cont d IC204 444 13 MK...

Page 61: ...01 on the circuit board onto the plugs at P2 on the mother circuit board Secure the CPU circuit board to the bottom of the chassis at FA with a 6 32 x 1 4 screw CIRCUIT BOARD CHECK Make sure the POWER...

Page 62: ...g purposes Refer to Pictorial 5 1 Illustration Booklet Page 14 for the following steps o A 1 INCHES I 8 I 318 I 5 8 I 7 18 I I I I I I I I I I I I I i 2 3 I i I I I I I Ii Ii Ii Ii i i i i o 5 CM 2 3...

Page 63: ...s the label onto the nameplate in the area shown Refer to Detail 5 1C and mount the window onto the front panel as follows 1 Wipe off the window with water and deter gent to remove all fingerprints DO...

Page 64: ...acket to the rear panel at FD and the CPU circuit board at FE as shown Use a 6 32 x 1 4 screw at each location Refer to Pictorial 5 3 Illustration Booklet Page 14 for the following steps Install the t...

Page 65: ...Page 65 6 32 x 1 4 SCREW DOD PICTORIAL 5 2...

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Page 68: ...IS FOR U S CUSTOMERS ONLY OVERSEAS CUSTOMERS SEE YOUR DISTRIBUTOR TOTAL PRICE w Z J o w t t o o z o J t J U FOR PARTS REQUESTS ONLY Be sure to follow instructions carefully Use a separate letter for a...

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