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dkirk

Promaster FM600 Slave Flash

5 posts in this topic

I have seen mention that removal of the LED is suggested to save power, but I have a different recommendation. Today I tested the FM600 for peak current, capacitor discharge versus time, and idle current when fully charged under the following 3 configurations.

 

1) Virgin (tested right out of the box with no modifications)

2) LED (D1) removed

3) 1 Meg Ohm resistor removed (R1)

 

I removed R1 since it fed some low voltage components that are not critical to the basic flash operation (including the LED) and it therefore causes some drain on the flash capacitor when in the circuit. I don't know if removal of R1 has previously been mentioned in other postings (I did not run across it), but it sure looks like removal of it does a wonderful job at reducing the flash capacitor discharge rate. Based on my data I would suggest removal of R1 and nothing else (note that removal of R1 disables the LED, so it kills two birds with one stone so to speak).

 

post-2799-1168060186_thumb.jpg

 

Note : The peak current for all 3 configurations using 2 NiMH batteries was approximately 1.7 amps, and the idle current at full capacitor charge for all 3 configurations was approximately 70mA to 100mA (depending on which meter I used).

 

post-2799-1168090901_thumb.jpg

 

(As always modification of commerical products is done at your own risk. Use extreme caution since high voltage exists within flash units. Take proper steps to assure all energy has been discharged (from the capactiors, etc.), before touching any component within the flash unit.)

 

Don

Edited by dkirk

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I always remove R1-- dkirk on the promaster 600-------Used the FM 600 over a year ago on a D380 and the batteries last over a month using 2 C-cells

 

Good info and work though

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ltrangerbob,

 

I have added a picture above showing R1. You can just cut one leg (or both), or just unsolder it from the board.

 

Vic,

 

Good to know that removal of R1 has been working for you for over a year. I did a quick search and only found info on removing the LED, but as usual there are so many postings that I must have missed the old info regarding R1.

 

Don

Edited by dkirk

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