Model 35P Troubleshooting

The first thing the 35P attempts to do when first powered on is synchronize with the printing mechanism. If the printer is jammed the chronograph will not power on. Test this by turning DIP switch #7 to the OFF position to disable the printer. Restart the chronograph by plugging in a Skyscreen and check the LCD display. If the display reads “- – -0” you will need to un-jam or replace the printer. If the display is still blank with switch #7 in OFF position, replace the battery and check battery leads for broken connection.

Several different issues can be caused by damaged Skyscreens. Each Skyscreen should be tested individually by plugging it into the “Start” jack on your chronograph. There should be only one Skyscreen plugged in to the chronograph at any time during this test. Proceed to fire over each screen individually; an air-gun, .22 rimfire, or even a slingshot is fine for test purposes. One of three things should happen:

I) The chronograph prints one line of data, and/or the display changes/ flashes: This indicates the chronograph received a trigger and the Skyscreen is functioning correctly. Repeat the test with the next screen.

II) Nothing happened: The Skyscreen did not trigger the chronograph. There is probably a short in the Skyscreen circuit and it will need to be repaired or replaced.

III) The chronograph started printing or triggering as soon as the Skyscreen was plugged in: The chronograph is “False Triggering”. If only one of your Skyscreens exhibits this behavior, it will need to be repaired or replaced. If more than one Skyscreen causes this problem, it is unlikely multiple screens are damaged in the same way, see “35P prints or displays data when I have not shot over it” below.

There is a rubber roller inside the printing mechanism that deteriorates with age. It may be time to replace the printer mechanism. You may either send your chronograph in for repair or we can mail you the replacement mechanism.

One of the black push button switches is probably stuck. Massage each of the buttons until printer stops running. If problems persist buttons will need to be replaced by Oehler.

The source of “False triggers” can be difficult to identify. Some common causes are:

  • Corrosion or oxidation of the Skyscreen plugs: Use a Scotchbrite pad (not steel wool) and rag with rubbing alcohol to lightly polish the plugs. Once they are clean insert them into the chronograph. Gently rotate the plugs back and forth in the jack to further clean/polish the electrical contact area.
  • Insufficient light level: The Skyscreens must have open sky above them; they will not work under trees or structures. The orange diffusers are for use under bright/sunny conditions, they should be removed when it is overcast or the sun is low on the horizon.
  • Electrical interference: Radar towers, electric fences, air compressors etc. have all been known to produce high levels of electrical noise. These items should be turned off if possible; if not possible the light level entering the Skyscreen sensor should be increased. The quickest way to do so is by removing the Orange Diffusers.

If the 35P is to be used indoors proper incandescent lighting must be used. Oehler Skyscreens will not function under fluorescent lights.