Electrohome G08 Manual

G08 Vector Monitor FAQ & Guide Page 21 of 39    
Assuming you are using your G08 monitor with the Sega G-80 vector game boards, you will need 
to add the following two capacitors to the X-Y Timing board on the G-80 game boardset. Install 
two 100pF, 50V ceramic capacitors in locations C32 and C33. Install C32 between pin 2 and pin 6 
of U2. Install C33 between pin 2 and pin 6 of U3. 
 Symptom: Blowing Main Fuses 
 
If a monitor is blowing main fuses, check the deflection amp power transistors Q605, Q606,...

G08 Vector Monitor FAQ & Guide Page 22 of 39   Voltages 
 
The following G08-003 voltages are measured during running of the monitor (taken from the 
Zektor manual): 
 
 All Readings are DC Level Voltages 
 
                
 
 B=BASE E=EMITTER C=COLLECTOR AN=ANODE CA=CATHODE 
 
                
 
                                    D401 CA 63.0  D403 CA 63.0  D400 AN -63.0  D402 AN -63.0                        ZD400   59.0  ZD401   9.0  ZD402   -9.1                            Q400 B 59.0      Q401 B 9.7...

G08 Vector Monitor FAQ & Guide Page 23 of 39   INSTALLING A CAP KIT  
 
Zanen Electronics 
5023 52nd Street 
Lubbock TX 79414 
806-793-6337 
Fax: 806-793-9136 
Zanen Kit #110 Bob Roberts also sells cap kits. Bob provides a 
kit for the G08 Vector Monitor. 
 
[email protected] 
http://www.therealbobroberts.com 
 
Key: 
· Q = Transistor  
· R = Resistor  
· C = Capacitor (all polarized electrolytic)  
· F = Fuse  
· D = Diode  
· ZD = Zener Diode  
 
Note that the capacitors come in two types:...

G08 Vector Monitor FAQ & Guide Page 24 of 39   
CAP KIT SUMMARY: 
 
There are some known problems with Zanen and Bob Roberts G08 cap kits. Below is a 
recommended list of parts. Almost all of the suggested replacement capacitors are upgraded in 
terms of voltage rating and should make your G08 monitor last longer and run cooler. 
 
G08-003 Cap Kit Parts List PCB Location Part Description Upgrade Notes      Deflection C401 1000uf 160V Radial Capacitor Yes Original was 80V Deflection C405 10uf 50V Radial...

G08 Vector Monitor FAQ & Guide Page 25 of 39   
CHASSIS TRANSISTORS 
 
All the monitor chassis transistors are mounted in a socket with two machine screws. No soldering 
is necessary; just unscrew the old one and replace. You cannot put these chassis transistors in 
backwards; the leads are offset so they will only fit into the chassis and screw down in one 
direction. If you put the transistors in backwards, the screw holes will not line up.  
 
Make sure you install a new clear plastic Mica insulator...

G08 Vector Monitor FAQ & Guide Page 26 of 39   
G08-003 DEFLECTION BOARD 
 
Not all of these parts are necessary for a monitor rebuild, but are good to have on hand. For 
capacitors, see “Cap Kit Summary” section above. 
 
NON-Zanen Deflection PCB Parts Location Part Description Upgrade Notes     F400 5 amp Slo-Blo Fuse  Replacing these is a good idea F401 5 amp Slo-Blo Fuse  Replacing these is a good idea F600 4 amp Slo-Blo Fuse  Replacing these is a good idea F700 4 amp 125V Slo-Blo Fuse  Replacing...

G08 Vector Monitor FAQ & Guide Page 27 of 39   
G08-003 HIGH VOLTAGE UNIT 
 
Not all of these parts are necessary for a monitor rebuild, but are good to have on hand. For 
capacitors, see “Cap Kit Summary” section above. 
 
NON-Zanen HV PCB Parts Location Part Description 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 uH on G08-001 D901...

G08 Vector Monitor FAQ & Guide Page 28 of 39   MAKING THE MONITOR MORE RELIABLE  
 
Ok, so now you have a working G08 monitor (hopefully). Here are just a few things you can do to 
the monitor to prolong its life just a bit longer. 
 
 Input Clamp Board Modification 
 
Replace the tape on the back of the input protection board with a strip of electrical tape or other 
non-conductive material to prevent it from shorting to the metal bar it is typically mounted on. 
 Deflection Board Modification 
 
For...

G08 Vector Monitor FAQ & Guide Page 29 of 39   The 0.39-ohm resistor allows the transistors to be hooked in parallel without one transistor going 
into thermal runaway and trying to drive the whole load itself. (A good place to find out more 
about hooking transistors in parallel is a Voltage Regulator handbook of some kind) 
 Heat Sink Modification 
 
From anonymous:  
 
“The deflection transistors mounted on the heat sink can be more efficiently cooled (and therefore 
will last longer) if you place...

G08 Vector Monitor FAQ & Guide Page 30 of 39    
TUBE REPLACEMENT  
If you are unfortunate enough to come across a G08 with a bad tube, there is still something you 
can do about it. 
 
You can replace the tube. As mentioned before, the tube is the same as the one used in the Wells-
Gardner 6100 series color XY monitors. You can also buy a brand new color vector tube 
(19VLUP22) from Richardson Electronics (1-800-222-2787) for around $165. It will not come 
with the tinted gel, nor a deflection yoke or...