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The Evil, Infamous, Unreliable, Flaming... 

Electrohome

 

 

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               |   ___   | |   ____   | |   ____   | 
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                \_______/   \________/   \________/ 

 
 

FAQ version 1.1 

Oct 7th, 2002 

 
 
 
 

Table of Contents 

 
INTRODUCTION .............................................................................................................................. 2 
MONITOR HISTORY........................................................................................................................ 3 
PART DESCRIPTIONS ..................................................................................................................... 5 
HOW IT ALL WORKS .................................................................................................................... 14 
REPAIR PREPARATION................................................................................................................ 15 
DEBUGGING THE MONITOR ...................................................................................................... 19 
INSTALLING A CAP KIT .............................................................................................................. 26 
MAKING THE MONITOR MORE RELIABLE............................................................................. 31 
TUBE REPLACEMENT .................................................................................................................. 33 
USING A G08-003 WITH COSMIC CHASM ................................................................................ 34 
Appendix A: Common Ground Connections.................................................................................... 36 
Appendix B: Testing Transistors ...................................................................................................... 37 
Appendix C: Parts Lists .................................................................................................................... 39 
REFERENCES ................................................................................................................................. 41 
DOCUMENT HISTORY.................................................................................................................. 41 
 
 

 

CAUTION: The Electrohome G08 monitor is extremely flammable. Do not operate around 

combustible liquids or materials. This document should not be used to put out any flames caused by 

the monitor.

 

Summary of Contents for G08 Series

Page 1: ...IR PREPARATION 15 DEBUGGING THE MONITOR 19 INSTALLING A CAP KIT 26 MAKING THE MONITOR MORE RELIABLE 31 TUBE REPLACEMENT 33 USING A G08 003 WITH COSMIC CHASM 34 Appendix A Common Ground Connections 36...

Page 2: ...BLE FOR ANY DAMAGES THAT MAY OCCUR TO YOUR PERSON OR PROPERTY The Electrohome G08 is the monitor that was used in the Sega Gremlin color vector games Space Fury Eliminator Zektor Tac Scan and Star Tre...

Page 3: ...rsion of the monitor specifically for Cinematronics The G08 105 was manufactured in October of 1982 and it uses SDT 1064 s for deflection transistors A special transformer s used for this game outputs...

Page 4: ...omething that would fit into the G 80 setup this was a must they were really in love with it and eliminate the massive board they were using in the lab I was initially going to try to do this on one b...

Page 5: ...nput Clamp board The c denotes the most complete information on the G08 003 monitor Manual Schematics Parts List Sega Drawing Number Eliminator none none 200 0025 Space Fury Preliminary none none none...

Page 6: ...nt that something went wrong with the deflection circuitry The deflection board creates a low voltage power supply for the HV board and controls the X and Y video amplifiers Looking at the board with...

Page 7: ...the board match the schematics in the Tac Scan or Star Trek manuals If they do not modify the deflection board accordingly The input amplifier IC600 and surrounding circuitry on the deflection board...

Page 8: ...pot killer 9 1 VDC to the IC s 126 VDC to the EHT oscillator When you look at your deflection board and your schematics you may notice some discrepancies and ask Where is part x R636 R637 R736 and R73...

Page 9: ...he PCB as usually seen on most deflection boards I think when this hack is used the bottom of the PCBs did not have to be cut Defection Transistors And Heat Sink When looking at the back of the monito...

Page 10: ...for Are there any of you with only 110 volts coming out of the wall More like 120 to 130 isn t it THAT is why I keep saying the game needs to be re strapped to match the power line Either buck out th...

Page 11: ...ide of the metal cage is a voltage regulator which regulates the input between 100VDC and 126VDC IC900 on the HV unit is a high voltage oscillator This is Electrohome part number 14 002155 01 EHT Cont...

Page 12: ...Most of the neck PCBs will have different Issues numbers screen into the top of the board and the bottom of the board It is unknown if there are any different revisions of the neck board However this...

Page 13: ...01 Deflection Amp PCB Assembly G08 001 02 170005 01 CRT Socket PCB Assembly G08 001 02 170006 01 Heat Sink Assembly G08 001 02 170004 01 G08 003 Preliminary Manual EHT Supply Assembly G08 003 02 17000...

Page 14: ...picture tube and the AC to the heater The deflection board then feeds the color signals to the neck board and controls their position with the deflection yoke The G 08 monitor has a unique spot kille...

Page 15: ...e cup it is the suction cup thingy attached to the tube that has a red wire coming out of it A few inches from it there is a metal shield that surrounds the back of the tube We will be discharging the...

Page 16: ...2 Get out your multimeter and do a resistance test between the following pins using the red and black probes indicating and common ground respectively Example 1Red means you are touching pin 1 with t...

Page 17: ...ns that accept connectors Check all the header pin joints on the bottom of the deflection board the current limiting boards if present the input protection board and the HV unit Do not just reflow the...

Page 18: ...f the combinations should look like a short Test the fuses A visual inspection may not catch a blown fuse Use the ohmmeter across the fuse holder not just the fuse itself 6 Reassemble Reconnect and sc...

Page 19: ...center of t he monitor Do not test like this for a long period of time because it may damage the phosphors However this is normally not a problem because it should take less than 30 seconds to determi...

Page 20: ...input hooked to pin 10 via 22pf capacitor and 30k resistor in parallel Pin 17 wiper for vertical center Other inputs to pot are 9 1VDC and 9 1VDC Pin 18 output that drives Y circuit If you are getting...

Page 21: ...oblem in your deflection circuitry If the heater is not glowing most likely you have no HV Check for the presence of HV by inserting an HV probe under the anode cup You should read about 19 5 KV If th...

Page 22: ...ard Sometimes the solder joints for this pot and the nearby resistor break and can cause the brightness to shoot up too high If the dot is still present try adjusting R933 on the HV unit Symptom The n...

Page 23: ...ing fed into the coil To do such instead of the coil take a multimeter and measure the voltage across the X coil or Y coil whichever you are having trouble with When powered normal readings will fall...

Page 24: ...from power supply to the game boardset Bad connections of XY pair with card cage in G 80 game boardset Bad connections of ribbon cables between XY pair in G 80 game boardset Bad connections to HV unit...

Page 25: ...0 5 Q603 C 63 5 Q604 C 63 9 Q605 C 63 9 Q606 C 63 9 B 0 1 B 0 1 E 0 1 E 0 1 Q702 C 0 8 Q703 C 63 5 Q704 C 63 5 Q705 C 63 9 Q706 C 63 9 B 0 1 B 0 1 E 0 1 E 0 1 Q901 E 8 0 Q902 E 0 0 Q903 E 0 0 B 7 5 B...

Page 26: ...electrolytic F Fuse D Diode ZD Zener Diode Note that the capacitors come in two types _____ _____ radial lead axial lead Note if you cannot find an exact replacement for one of the capacitors you may...

Page 27: ...Capacitor Yes Original was 16V Input C801 10uf 50V Radial Capacitor Yes Original was 16V Input C802 10uf 50V Radial Capacitor Yes Original was 16V Input C803 10uf 50V Radial Capacitor Yes Original wa...

Page 28: ...istors Location Part Number Notes Q605 2N6259 Substitute is MJ15024 Q606 2N6259 Substitute is MJ15024 Q705 2N6259 Substitute is MJ15024 Q706 2N6259 Substitute is MJ15024 Important after replacing the...

Page 29: ...s 3 amp ZD400 1N5263B 9 1V 1 2W 5 Zener Diode ZD401 1N5239B 9 1V 1 2W 5 Zener Diode ZD402 1N4739 9 1V 1W 5 Zener Diode Yes Replace with a Motorola part Q201 Q251 2N3904 Current Limiting Board Q202 Q25...

Page 30: ...Upgrade Notes ZD903 1N751 Zener Diode ZD904 1N751 Zener Diode Q900 Power transistor 5A 1400V Hitachi 14 601 36 Q901 2N3906 Q902 MPSU07 Q903 2N3904 Found on back of PCB L900 12 uH Horiz Delay Choke 8...

Page 31: ...ion For capacitors see Installing A Cap Kit section of this document Deflection Transistors Modification From Zonn Moore The biggest problem with the Sega G08 is the underrated Deflection Transistors...

Page 32: ...Unscrew the deflection transistors from the heat sinks 4 Place the transistor sockets on the outside of the heatsink and then mount the transistors on the inside of the heat sink Make sure to reinsta...

Page 33: ...or around 165 It will not come with the tinted gel nor a deflection yoke or convergence rings so you will have to transfer those from the broken tube and reconverge the monitor colors From Mark Jeniso...

Page 34: ...e the Cosmic Chasm RGB outputs are designed to be compatible with a Wells Gardner 19K6401 or Electrohome G08 105 which are 1V BLACK level to 3 6V 4 0V full ON The color levels of the more common Wells...

Page 35: ...l ODD numbered pins are GND Adjust the pot attached to U29 so that the signal level swings between 0 volts and 4 volts Repeat the adjustment for GREEN U14 and BLUE U15 Modification complete CAVEAT I h...

Page 36: ...ings happen I first discovered this on Gottlieb pinballs over ten years ago the ground for the regulator would overheat the pin wiper contact which would become a small resistor and thus the ground of...

Page 37: ...around 0 4 0 7 volts depending upon what they are made of and a lot of other stuff In a way diode junctions are similar to neon light bulbs they act like open circuits until the right voltage is reach...

Page 38: ...leads in your hands and repeat the test This time connect the black meter lead to the base of the transistor Connect the red meter lead to the emitter A good PNP transistor will read a JUNCTION DROP v...

Page 39: ...ts List Location Part Description Upgrade Notes D800 1N914 D801 1N914 D802 1N914 D803 1N914 D804 1N914 D805 1N914 D806 1N914 D808 1N914 Q800 2N3904 Q801 2N3906 Q802 2N3904 Q803 2N3906 R800 10K W Resis...

Page 40: ...zontal Current Limiter Vertical Current Limiter Location Description Location Description D200 1N914 D250 1N914 D201 1N914 D251 1N914 D202 1N4935 D252 1N4935 D203 1N4935 D253 1N4935 Q201 2N3904 Q251 2...

Page 41: ...001 future G08 003 5 Preliminary Service Data G08 003 004 X Y Color monitor www arcademonitors com DOCUMENT HISTORY Version 0 1 Looking for contributors Version 0 2 David Shuman s additions Version 0...

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