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POLYGRAPH WORK SHOP

Article 1: GSR Pen whipping problems

Article 2: Repairing pneumo tube assembly

Article 3: Scratchy Thermal Pens

Article 4: Inking Capillary Pens

More articles and Helpful Tips coming soon, so please visit us again. 

If you have a helpful Tip or Hint on Polygraph instrument operation or maintenance you wish to share please pass it along. I will be happy  to post your suggestions here for all to take advantage of.  You may email your Tips and Hints to Spectrum_dynamics@yahoo.com

Article 1:

Are you experiencing any of the following GSR malfunctions?

1. Your GSR pen whips.

2. Your GSR will not balance in manual mode.

3. Your GSR is not responsive in the Auto mode.

Prior to Beginning:

1. Make certain all clothing is protected from ink sprays.

2. Check to make sure finger plates are making proper contact with the GSR cables

Step 1

Plug cable into GSR input of the storage door and place the finger plates in the calibrator. Do not short finger plates together.

A. Turn the GSR sensitivity up to 10.

B. Center pen

C. Shake GSR cable all over to find ant intermittent shorts. Note: Small deflections of the   GSR pen is normal at this sensitivity setting. A problem would be indicated if violent whipping of the GSR pen occurs.

D. If the problem is present, continue with step 2.

E. If no problem is evident, continue running test as normal, noting if any unusual problems occur and call a qualified polygraph service technician.

Step 2

A. Unplug the cable from the door, unplug the interconnecting cable ( gray wire coming from the underside of the door to the module) and plug the GSR cable directly into the GSR module.

B. Again, shake the cable all over.

C. If violent pen whipping is noted, proceed to step 3

D. If problem is gone, the cable from the door to the module is defective and must be replaced. Lafayette Instruments has field replaceable GSR cables. Just call Lafayette Instruments and request a prewired GSR jack/cable assembly. This will enable you to replace the defective GSR interconnecting cable yourself, or if you prefer, send your instrument to us and we can repair it for you.

Step 3

A. Unplug GSR cable from module.

Check to see if the pen whipping is still present; if is is, the malfunction is in the GSR module and repair or replacement of the defective module is necessary.

B. If the pen whipping has stopped, then the GSR cable is defective and replacement is necessary

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