Wells-Gardner Vector Monitor 6100 Faq And Guide Version

							Wells-Garnder Color Vector Monitor Guide Page 21 of 75 HV Board Notes. 
On the HV circuit board there are two diodes, which the Atari TM-183 manual does not identify. 
They are just referred to as silicon diodes. Apparently the replacement for these is NTE558. 
Also be careful installing the zener diode ZD902. Apparently some people mistakenly install this 
at D902 instead of ZD902. The monitor will not work if you make this mistake! 
 
Please be careful if you decide to replace R918 (25K potentiometer) in the HV unit. R918 needs 
to start out adjusted to an in-circuit resistance of 5.5K when testing the upper two contacts of the 
three. This is the average of the normal adjustment range, which is always between 5K and 6K. 
If you have the potentiometer maxed out you will probably damage your unit when you turn it 
on. 
  
NECK BOARD 
 
The Neck Board is the PCB attached to the neck of the monitor tube.  
 
Zanen Neck Board Parts Location Part Number C503 33 mfd 250v axial capacitor  
  
						

							Wells-Garnder Color Vector Monitor Guide Page 22 of 75  
CAP KIT SUMMARY: 
 
Parts you need to buy in addition to the Zanen cap kit.  
 
Summary: Parts you need to buy in addition to the Zanen cap kit Quantity Description Location (1) LV2000 board (http://www.diac.com/~jeffh/lv2000/)   (1)* NTE50 (do not buy if you are installing an LV2000) Q101 (2) NTE49 (or MPSU07 (NTE188) if the heavier duty NTE49 can not 
be found) Q604, Q704 (1) 3.9 ohm ½ watt resistor R903 (2) 3.9 ohm 3 watt resistor R901, R907 (1) 22 ohm 3 watt resistor R106 (1) 1.3k ohm 5 watt resistor R701 (1) 2.2 ohm 3 watt resistor R926 (1) 4.7k ohm ¼ watt resistor R911 (1) 6.8k ohm ¼ watt resistor R910 (2)* 5.6k ohm ¼ watt resistor (only needed for revision P327 or P339 
Deflection board; not needed if you have revision P314) R812, R813 (4) 1 mfd 50v axial capacitor C800-C803 (2) 220 uF 50v axial capacitor C901, C902 (2) 4700 uF 50v axial capacitor C100, C101 (4) 1N4007 (NTE125) rectifier diode D100-D103 (2) 6.25 amp slo-blo fuse F100, F101 * these parts may be optional for your monitor.  
 
 
Here are some good parts places to get the big transistors (and other things): 
· Allied Electronics; +1.800.433.5700; www.alliedelec.com 
· Digi-Key; +1.800.344.4539; www.digikey.com 
· Mouser Electronics; +1.800.346.6873; www.mouser.com 
· Newark Electronics; +1.708.495.7740; www.newark.com 
· Circuit Specialists; +1.800.528.1417; www.web-tronics.com 
 
Here are a few surplus type places that have great prices on things like electrolytic capacitors:  
· All Electronics; +1.818.904.0524; www.allelectronics.com 
· BG Micro; +1.972.205.9447; www.bgmicro.com 
· Marlin P. Jones; +1.407.848.8236; www.mpja.com 
· HSC Electronic Supply; +1.408.732.1573; www.halted.com  
						

							Wells-Garnder Color Vector Monitor Guide Page 23 of 75  
TESTING YOUR WORK 
 
Test the Game Board Outputs before Turning the Monitor On. 
Make sure the game board is outputting correct voltages before you power the monitor 
on! Otherwise you can waste the monitor and all the above work. To test the outputs, set 
your meter on DC volts and measure the leads of R600 and R700 (fuses) of the deflection 
board. These are connected to the plug with wire colors yellow (R600) and orange 
(R700). The correct voltage should be in the +0.5 to -0.5 volt range (basically zero volts). 
The voltage will fluctuate because of changing deflection signals. If the measured voltage 
is between 5 and 15 volts (positive or negative), then check the X and Y amplifiers on the 
GAME board. Also check for broken potentiometers on the game board.  
 
Spot Killer On. 
If the spot killer LED lights on the monitors deflection board, this indicates there is a 
problem. First test the voltages going to the large chassis-mounted transistors (2N3716 
and 2N3792). Set your meter on DC volts. With the monitor powered on, put the black 
lead on ground (the metal monitor chassis), and put the red lead on the metal case of each 
of the chassis-mounted transistors. You should get either +30 or -30 volts DC. If you do 
not, theres a good chance one of those chassis-mounted transistors is bad. With the 
monitor off, use your meter (set to continuity ohms) and make sure the metal monitor 
chassis is not shorted to the metal case of each chassis mounted transistor. If it is, the 
mica insulator is probably damaged (and the transistor is probably blown). 
 
Screen Glitters After the Game Warms Up. 
The small XY adjustment trim pots on the game boardset are probably at fault. These 
trim pots are factory adjusted and sealed with some hot-melt glue. As the board warms 
up, the expansion rate of the trim pots and the hot-melt glue is different. The glue can 
expand enough to separate and damage the small plastic pots! You can try removing the 
glue, but often you will have to replace the small trim pots (10k, 2k, 200 ohms). The only 
hard value to find is the 200-ohm pot (the 10k trim pots you can get at Radio Shack). You 
can get the 2k and 200-ohm trim pots from Mouser Electronics, or other electronic parts 
houses. 
  
						

							Wells-Garnder Color Vector Monitor Guide Page 24 of 75 DIAGNOSING YOUR WELLS-GARDNER MONITOR  
 
All the documentation and boards for the Wells-Gardner 6100 monitors refer to X as the longer 
axis and Y as the shorter axis, independent of how the monitor is oriented in your game. 
Confusion arises because the game PCB will refer to X as the axis parallel to the floor and Y 
as the axis perpendicular to the floor and this is dependent on how your monitor is oriented. Why 
is this important to distinguish? Well if you notice that there is a horizontal line on your Tempest 
screen and you go to figure out why you are not getting any Y deflection, you must check the 
Y portions of the vector generator circuitry on your game PCB but you need to check the X 
portions of your monitor deflection board! 
 
If your monitor is not working, the very first thing you should do is check all the fuses in the 
machine with a meter. There are four on the deflection board and most Atari machines have 
seven more in the power supply at the bottom of the machine (six in a fuse block on the left, and 
one under a black cap on the right). Remember to check resistance on the fuse HOLDER not on 
the fuse itself. Many times a fuse will meter out OK but it is not making good contact with the 
fuse holder so it is not conducting. If you always put your probes on the fuse holder, a bad 
contact will never trick you. Many times fuses that are not conducting can be made to do so 
merely by reseating them after pinching the fuse holder clips tighter. Sometimes the clips are 
corroded and need to be cleaned first. The wire contacts connecting to the fuse holders may also 
not be conducting properly so you may want to move your leads and test there to cover all your 
bases. This rule applies to fuses in general anywhere you find them. 
 
Before you begin work on your monitor, you must discharge the CRT - even if you are just going 
to be unplugging the socket from the neck of the CRT (i.e., to gain access to another part). A 
tube that has some air in it can deliver a nasty shock back out of the neck pins. It is extremely 
inadvisable to work on the HV section while the machine is turned on or even plugged in; 
always unplug the game before you work on the HV section. 
 
I would recommend using a High Voltage Probe to discharge the monitor. This is the safest 
method, as the probe is designed to withstand extremely high voltages (hence the name, right?).  
 
Lacking an HV probe, you can use this tried and true method, be it a little more dangerous. Use a 
plastic handled screwdriver; connect one end of a wire with an alligator clip at each end to 
chassis ground and the other end to the metal shaft of the screwdriver. Be certain you have a 1 
Meg ohm resistor somewhere in your connection. Using ONE HAND ONLY (put the other in 
your pocket) and touching ONLY the plastic handle of the screwdriver (DO NOT TOUCH THE 
METAL SHAFT) work the end of the screwdriver under the big suction cup on the top of the 
tube until you hit metal. Be prepared for a fairly loud pop and a flash. The longer the monitor has 
been turned off, the smaller the pop and dimmer the flash. But BE CAREFUL, picture tubes will 
hold a very healthy charge for at least a week if not longer. Even after you’ve discharged it once, 
it may still carry a residual charge. It’s better to be too careful than dead, which is why electronic 
equipment always carries stickers referring servicing to qualified personnel. Handle the side with 
the viewing screen against your chest when changing it. ALWAYS wear safety goggles when 
handling the picture tube.  
						

							Wells-Garnder Color Vector Monitor Guide Page 25 of 75  
You may want to leave the game plugged in BUT TURNED OFF for this step so that you can 
ground to the earth instead of just the chassis. If you plan to remove the HV unit, you must 
disconnect the secondary anode from the tube, which is a little tricky if you have never done it. 
Under that suction cup is a double-barb connector. The barbs extend perpendicular to the wire as 
it enters the suction cup. Simply pinch the suction cup as best as you can and wiggle it back and 
forth while pushing in at the edges and pulling out at the center. It will eventually come off. Here 
is a cut-away depiction of the anode; the wire will run perpendicular to this view (i.e., 
towards/away from the reader): 
 
                         |    /\   /\    | 
                          \     \ /     / 
                           \____|_|____/ 
 
 
WARNING: That picture tube is a bomb!  When it breaks, first it implodes, then it explodes. Large pieces of glass have been known to fly in excess of 20 feet in all directions. DO NOT carry it by the long, thin neck. Discharge its voltage to ground by shorting the anode hole to ground.  
 
 CHASSIS TRANSISTORS 
 
There are two types of the large chassis deflection transistors on the Wells-Gardner 6100. They 
are the six large TO-3 package transistors mounted to the chassis (package refers to the 
physical description of the transistor, NOT the electrical characteristics). The three NPNs are 
2N3716s and the three PNPs are 2N3792s, which are all in the final stages of the deflection 
amplifiers or the power supplies. The deflection amps are like an audio push-pull amplifier and 
to power these amps the monitor takes AC in and produces plus and minus DC voltages. 
 
· 2N3716 (NPN); widely available replacement is NTE284 
Q705: +X (right) for horizontal; +Y (top) for vertical 
Q605: +Y (top) for horizontal; -X (left) for vertical 
Q102: output positive (+) power supply 
 
· 2N3792 (PNP); widely available replacement is NTE285 
Q706: -X (left) for horizontal; -Y (bottom) for vertical 
Q606: -Y (bottom) for horizontal; +X (right) for vertical 
Q103: output negative (-) power supply 
 
SPECIAL NOTE: Q705 and Q102 lie in such close proximity that it is not uncommon for their 
respective transistor sockets to be switched at some point, which obviously swaps the 
corresponding functionalities (symptoms). 
  
						

							Wells-Garnder Color Vector Monitor Guide Page 26 of 75 This gives reference frames for when the monitor is mounted horizontally (for games like Space 
Duel and Major Havoc conversions) and vertically (for games like Tempest). 
 
An easy way to remember which kind of transistor goes where is to know that each connector 
has one of each kind; the 2N3716s are on pins 1, 3, and 4 (key at pin 2) and the 2N3792s are on 
pins 5, 6, and 7. If the wiring has not been altered, all 2N3716s are connected to the yellow, 
green, and red wires and all 2N3792s are connected to the purple, blue, and white wires. Here are 
2 diagrams of the layout as viewed from the top:  
 
 
   +---------------------------------------+---------------------+ 
   |          (front; Picture Tube)        |                    / 
   |               2   _                   |  2   _            / 
   |               N  / \                  9  N  / \          / 
   |               3 / Q \                 0  3 / Q \        / 
   |               7| 705 |                |  7| 605 |      / 
   |               1 \   /                 d  1 \   /      / 
   |               6  \_/                  e  6  \_/      / 
   |   2   _                    2   _      g 2   _       / 
   |   N  / \                   N  / \     r N  / \     / 
   |   3 / Q \                  3 / Q \    e 3 / Q \   / 
   |   7| 706 |                 7| 103 |   e 7| 606 | / 
   |   9 \   /                  9 \   /    | 9 \   / / 
   |   2  \_/                   2  \_/     b 2  \_/ / 
   |               2   _                   e       / 
   |               N  / \                  n      / 
   |               3 / Q \                 d     / 
   |               7| 102 |                |    / 
   |               1 \   /                 u   / 
   |               6  \_/                  p  / 
   |                                       | / 
   |                (back)                 |/ 
   +---------------------------------------+ 
 
 
    or, more simply (where 2 = 2N3792 and 6 = 2N3716):  
 
                  _________________ 
                 /      FRONT      \ 
                |   Picture Tube    | 
                |-------------------| 
                +-----+   6  +-----+6 
                |HV   | 2    |Def.2|| 
                |Cage |   6  |PCB  |2 
                +-----+------+-----+- 
 
  
						

							Wells-Garnder Color Vector Monitor Guide Page 27 of 75 These transistors often go bad and here is a quick lesson on how to check a transistor with a 
meter. Unplug the red plugs from the deflection board to isolate the transistor from the circuit. 
From the bottom of the transistor, the configuration is:  
 
                    _ 
                   / \ 
          base -> /o o\ 
						

							Wells-Garnder Color Vector Monitor Guide Page 28 of 75 Deflection Board 
 
On the deflection board, the most common failures are Q100 and Q101 and when these fail they 
take R100 and R101 (respectively) with them. These transistors are part of the + & - power 
supply circuit and are often bad when the resistors are really burnt. To properly test these 
transistors, they should be desoldered and removed from the PCB. Even in-circuit and not 
isolated from other components you can still get a pretty good idea with a multi-meter (analog 
meters work best since digital meters show infinite resistance most of the time) if the transistors 
are bad as transistors tend to fail catastrophically. In other words, they usually completely short 
(0 Ohms) or open. If you see 0 Ohms where there should be an open circuit or 2.5K Ohms, then 
the transistor is probably shorted. If you see greater than 2.5K Ohms when the reading should be 
in that range the transistor is probably open. When these transistors are bad, they usually show a 
large crack in the case if you look closely at them. 
 
Replace Q100 with the same type transistor, but if Q101 is bad (and even if it is not), you are 
STRONGLY suggested to upgrade it to a larger transistor that will handle more current. 
ALWAYS replace Q101 with a TO-202 package instead of the much smaller TO-92 package 
that the board comes with. In fact, the P327, and P339 versions of the deflection board were 
manufactured with this upgrade. Use an NTE50 or equivalent. 
 
Even though these transistors (and resistors) are the most common failures on the deflection 
board, you will most likely NEVER see them go bad after Q101 is upgraded to a NTE50. If you 
cannot find the generic parts, a common modern day replacement for MPSA06 (Q100) is 
NTE287 and a common modern day replacement for MPSA56 (Q101) is NTE159 (but I cannot 
stress enough the utility of going with the larger replacement for Q101). Upgrading Q101 should 
always be the first thing you do to any deflection board; replacing it before it fails will save you 
from having to replace the other parts that go bad when it does fail. 
 
It is unusual, but sometimes some of the four heat sinked transistors on the deflection board will 
die (Q603; Q604; Q703; Q704). If any of these transistors are bad, you will usually get no 
picture at all, but you will see background brightness that lets you know some electrons are 
being thrown at the tube. Be sure to check the resistors and diodes around any bad transistors you 
find. 
 
Very infrequently, you may have problems with some other transistors in the X/Y amp section of 
the board. Most of the other transistors that populate the deflection board (Q600-602, 700-702) 
are type TPS98 and are not easily found anymore. The good news is that TPS98 is equivalent to 
the PN3569 and the ECG or NTE 194. All Electronics (800-826-5432) usually has PN3569 
transistors in stock. 
 
Once in a while you will see D104 or D105 open or shorted as well. 
 
  
						

							Wells-Garnder Color Vector Monitor Guide Page 29 of 75 Neck Board 
 
The neck board very seldom has problems. Occasional faults will be caused from mishandling 
where someone has broken some of the pots that control the RGB drives. Check the pots if you 
are missing a color. If you are blowing your 5A fuses and your other boards are OK, check C503 
(33 uF @ 250V). If this is open, shorted or cold soldered, it will cause the 5A (or 6.25A 
depending on your board) fuses to blow. 
 
 
HV Supply 
 
Last is the HV supply. The HV transformer (or flyback) is fairly robust, and does not fail very 
often. Normally, HV failures are due to a semiconductor or capacitor failure. Unfortunately, 
replacement HV transformers are unavailable, although the Atari-designed Disco raster monitor 
contains an identical HV transformer. The Disco monitors are very difficult to find as well. 
 
You will frequently see HV units with the protective metal shield removed from the case and 
discarded in attempt to keep it cooler. The shield reduces the EMF emissions and the picture 
distortions that go along with it. If your picture is slightly distorted, this may be the cause. If you 
upgrade the HV section as outlined in this document, your monitor should run much cooler and 
removing the metal shield should be unnecessary. However, it is always a good idea to run your 
games with the back door removed to allow for proper airflow. 
 
 
Solder Joints 
 
Also watch for broken solder joints at the base of the connector pins for all the major connectors. 
You tend to rock the plugs back and forth when you pull the connectors off and this often cracks 
the solder joints to the circuit boards, which were poorly soldered to begin with. You may also 
want to check each pin for continuity with the next component on its trace line (and also with 
adjacent pins), and remove and resolder any dubious connections. While you are at it, resolder 
the three pins of the PTC thermistor (in the middle, along the left edge of the deflection board) as 
they are almost always loose for some reason. 
 
 
  
						

							Wells-Garnder Color Vector Monitor Guide Page 30 of 75 TEMPEST DISPLAY TROUBLESHOOTING (FLOWCHART)  
 
The following flowchart is excerpted from the Star*Tech Journal, which means it was 
originally in an Atari Field Service Bulletin. 
 
Most problems in the Tempest display can be found by following the procedure shown in the 
chart below. 
 
                          No picture and... 
         +--------YES---- 5 amp fuse (F100 or F101)----NO-------+ 
         |                on Deflection PCB blows?              | 
        \|/                                                    \|/ 
Cannot get/keep +/- 28 Volts.           Turn up brightness and contrast controls 
Disconnect P600, P700, andR101, R102, and R103       |          | 
         |                              for open circuits.         |          | 
     YES |                                      |                  |          | 
        \|/                        +------------+                  |          | 
Replace the following components   |                              \|/         | 
if defective: Q603, Q605, Q606,appear as though being viewed through 
Check remaining transistors        |    a magnifying glass)?         | 
in the X and Y amplifiers.         |         |                       | 
Then make sure the following-------+      NO |                   YES | 
resistors are not open: R702,               \|/                     \|/ 
R703, R711, R712, R602, R603,              >END