Jacuzzi j315 - Manual (Page 11)

11
2.0 Electro Static Discharge
2.1 ESD - What Is It? What Does It Do?
Static electricity is always being generated around us, even at those times
when we no longer get zapped after walking across a rug and touching some-
thing.
Like all state-of-the-art circuit boards, the hot tub’s circuit board can be dam-
aged by unnoticed static electricity. Damaged is the key word. Sometimes a
board which has been subjected to ESD will fail immediately upon being put
back into service. Usually a board will operate for a few days, or months, then fail.
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If the hot tub runs only a few days, the customer thinks you provided poor service.
If the hot tub runs only a few months, the customer thinks the circuit board was a low quality
product.
The customer loses use of the hot tub. You lose money because you must go back to make it
right. Jacuzzi Premium loses its reputation for quality.
2.2 Avoiding ESD Damage
We can’t prevent static charges from building up within us as we go about our jobs, so
we must do three things to protect circuit boards from getting zapped:
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Spa Light
Ozone
Circ Pump
Pump
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Pump
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Red Black Heater In Heater Out
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Never transport or ship circuit boards - good boards or bad boards - except in
the static protective bags.
Never remove the board from the static protective bag unless you are ready to
install it in the hot tub.
After removing the bad board from the hot tub, A) lay it on the ground, B) remove
the replacement board from the static protective bag, C) lay the replacement board
on the ground, D) place the bad board in the bag from which you removed the re-
placement board, E) return bad board(s) to Jacuzzi Premium in undamaged sealed static protective
bags.
2.3 What About Wrist Straps And Special Mats?
The purpose of these devices is to keep the technician, the work surface and the circuit board at the same
electrical potential, and drain into ground any static charges which might build up. Proper use of the wrist
strap and special mat guarantees maximum protection against ESD damage.
2.4 Must Wrist Straps And Mats Be Used When Replacing A Circuit Board?
No, if you keep the spare board in the protective bag during transport and you observe a few simple tech-
niques during replacement.
The possibility of ESD damage to the circuit board during replacement will be minimal because of the hot
tub’s design and the way you normally work on it. Touching the ground lug will drain all built-up static charges
from your body much like a wrist strap would. Laying the bad board on the ground will tend to keep it neutral.
Touching a fi nger to the grounding lug immediately before removing the good board from the bag will drain
charges built up by the rustling of your clothes. Laying the good board on the ground after removing it from
the bag will tend to keep it neutral. Another quick touch of the grounding lug before picking up the bad board
will drain built up charges. Slipping the bad board into the protective bag will allow it to be transported safely.
Another quick touch of the grounding lug before picking up the good board will again drain any charges built
up. In the process of installing the replacement board, you and the board will be grounded to the load box
or grounding lug, draining off charges you may build up during installation.