1. Completely dead game. If the game shows some sign of life then Go to (2).

A) Before you start, check for the obvious. Check plug wiring and fuse. If there is plug to the game, is it properly seated? Are all plugs seated in the game? Is there a power switch on the cabinet that has been switched off? If there is a door operated switch, push in the button by hand to see if game comes on. Sometimes the door wont push this in far enough.

B) Next look for burnt plugs or dry solder joints especially where plugs are soldered directly on to the boards. If the solder has dried or cracked around power plugs on the boards, the game will not power up. Re-solder these and any other suspect joints.

C) If the main fuse keeps blowing in the plug, check the suppressor hasn't shorted out by unplugging the game, disconnecting the wires and checking with a meter across live and earth and live and neutral. The suppressor is usually a small aluminium can screwed the cabinet

D) The only other things to check on the power side is the fluorescent lamp and possibly the isolation transformer for the monitor. Disconnect the lamp power and try the game. Isolate the monitor transformer power and switch on. The monitor should have its own fuse, but you can try disconnecting the power plug from the monitor to see if this helps. If the game still refuses so show any signs of life, check the cabinet wiring diagram for anything unusual and use a meter to see how far the power gets to try and isolate the fault.

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2. Fluorescent light is on or power present, but no picture.

If there is no light or obvious signs of life, you will need to determine that the mains is at least reaching the power supply or monitor transformer using a volt meter. If it is not go back to Section 1.
Put a credit on the game and press the start button. Can the game sounds be heard? If the answer is yes, then the power supply and the game board are functioning which points to faulty monitor. Go to (E). If the answer is no, this points to either the power supply or the game board. Go to (F).

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E)This now looks like a monitor fault. You should not proceed unless you are familiar with monitor safety procedures. There can be up to 25,000 volts present and messing around even with the power off can be fatal. YOU HAVE BEEN WARNED! See top of page for more information. If you have a Hantarex MTC9000 monitor, a more detailed fault list can be found at Hantarex.htm. If you have something obvious like a horizontal line or a missing colour you can start there although specific faults like this wont be covered here. Use the circuit diagram or seek the services of a repair man. A dead monitor is not so clear cut. First increase the screen brightness. Can you see a grey/white screen (raster). If the answer is yes then the monitor is working and we have to suspect the logic board. Go to (K). Look at the neck of the tube. Is there a faint orange glow from the heaters? If the answer is yes then the monitor is receiving power. Can you hear a high pitched noise and the build up of static on the tube when you switch on? Take a mains testing screwdriver. Hold the bladed end and hold the neon lamp end near to the EHT transformer. Does the lamp glow? If the answer to any one of these is yes, this shows that the monitor is receiving power and the EHT is working. Go to (G). If not we have to look at the power section. Go to (H).

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F) Using a meter check power supply for +5V, +12V and -5V where used. If this a newer game, you will only need the +5V to get a picture on the screen. +12V usually just powers the sound amplifier. If you have all the correct voltages present at the input and output of the power supply, the the logic board is most likely at fault. Go to (K). If you have no +5V or other voltages are missing you can suspect the power supply. Go to (J).

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G)We have heaters and EHT but no raster. If you have another working logic board, then try it. If the screen still refuses to show anything, this could be any number of awkward faults. It would be better to get the monitor looked at by a engineer.

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H) Use a meter to check that power is reaching the monitor power plug. Check the monitor fuse. Remove or lift up the chassis and look for dry joints especially around the power plugs, other connectors and the base of the line output transformer. Re-solder any dry joints. If you have a circuit diagram, check the power supply on the chassis. You should find a value around 120V. If there is no voltage check the power regulator and the large shunt resistor if used. If you still have problems Go to (L).

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J) If you have got here I assume that main voltage is present 120/240V, but some or all of the output voltages are missing. There could be high voltages present, BE CAREFUL! Switch mode power supplies are beyond the scope of this article, but you could check the components up to the bridge rectifier that may have short circuited. If the fuse has gone with a bang, you will need to find the problem before you replace it. The easiest and cheapest option is to replace the faulty unit. Other power supplies can be easier to fix depending on their complexity. Check all the fuses one by one. Often a bridge rectifier or power regulator is all that needs replacing. Use the circuit diagram to try and locate the fault. Any further help is beyond the scope of this article.

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K) Suspected game logic board. First things first, make sure 5V is set correctly and present on the board, not at the connector. If it is missing, check the wiring between the power supply and the board. Check any plugs between boards by removing and replacing them. Check all socketed ICs' are properly seated by pushing down on them. Use the boards self test facility if there is one to help try and identify any failed components. This is about as far as you can go unless you can repair logic boards, in which case I doubt if you need this article!

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L) Two other main failures are the LOPT and vertical output transistor. The monitor hand book and circuit diagram will be useful here. We can supply manuals for many monitors. Check the vertical output transistor to see if it has shorted. Other low resistance components can be connected across it, so remove it before checking with a meter. If the LOPT has blown, the casing may often be cracked , swollen or melted. These have a tendency to fail in Hantarex monitors. From here you are on your own, and may need the services of your local TV repair centre or send the chassis away for repair.

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3. Game OK, but no sound.

Check +12V on PSU and at the main board. This voltage is responsible for running the audio amplifier.

Check wiring to speaker using a meter and any volume control used in line with the speaker. You can check the speaker with a meter, it should read between 4 and 8 ohms.

Check to see if there is any sound output from logic board. Use voltmeter set to 20V. It should move like a level meter on a tape recorder. If there is no sound output, and the 12V is present, the audio amplifier on the main board should be suspected.

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4. Controls not working.

If some or no controls are working, check ground continuity between logic board and panel. This is the common wire that links all the switches together. There should be no breaks in the line and it should be connected to Ground. 0V.

For individual controls, check switches with a meter and the individual wires back to the PCB.

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