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« on: September 11, 2016, 04:24:35 PM »
Kris this might help you
I found this from Jim StJohn (owner/designer for Sandevices). Sadly it is not definitive. He says "test" various resistor values and gives the range. I hope we can find more ..
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If you are encountering issues such as pixel flickering when trying to drive pixels over a long cable run (say more than 15-20 feet) with the E682, this can sometimes be cured by replacing the pluggable resistor network that drives that output with a different value.
There are 8 pluggable networks on the E682, each drives the 2 output connectors immediately beneath it. The default value is 270 ohms, indicated by a part number containing "271" 27 followed by 1 zero = 270.
A smaller value can often help when driving long pixel leads. There are a couple of ways to test this without having to have different resistor networks available.
You can use individual 1/4W or 1/8W resistors (say from Radio Shack), or you can use small wire jumpers (effectively 0 ohm resistors).
Remove the resistor pack above the output to be tested. This will leave 8 empty socket holes, 1 thru 8 from left to right. Form the resistor or jumper leads into a "U" shape with the legs equal lengths (about 1/2") and about 1/10" apart.
For 3 wire pixels such as 2811/2812, only one resistor or jumper is needed per output. For the upper jack of the pair, insert the resistor or jumper between contacts 5 and 6, for the lower jack use pins 7 and 8. Power up and test the output.
If you are using resistors, I would try starting at 33 ohms and working up. Go one standard value less than the highest value that works reliably. For example, if 56 ohms works, but 68 ohms appears flaky, go with 47 ohms.
If you are doing the test with jumpers, if the output works properly with the jumper in place, then I would suggest purchasing the Radio Shack resistors to identify the best value.
The resistor networks can be purchased from any electronic supplier. They are "83" series, 8-pin networks containing 4 individual resistors. A typical part number would be: 83S560. The resistance is shown by the 3 digits after the S. 2 significant digits and the 3rd digit represents the number of 0s. So 83S560 is a 56 ohm resistor, "56" followed by no zeroes.
83S101 would be 100 ohms "10" followed by 1 0 = 100.
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Here's a user reply to Jim:
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I have replace all of my resistor packs with 33 ohms. On short or long runs that solved my flickering problems. I have 5 682's.
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