Vivitar 2000 Flash Modification (DF500 board version), (Simple and Low Power) Options

[dkirk]

As a continuation of my Vivitar 2000 work, I have developed a new modification for the DF500 board that incorporates the previous Low Power Modification as well as the elimination of the second board (DF-501) including the elimination of the large yellow capactior (3.3 ufd) that is located on the DF-501 board.

I have attached a picture showing the DF500 board along with notes on my modification.

Modification Steps :
1) Unsolder all of the wires on the DF500 board that go to the DF-501 board.
2) Remove Resistor R16 (10K ohm resistor).
3) Remove the Neon Bulb (ready light).
4) Remove Resistor R15 (22K ohm resisotr).
5) Jumpered pins 1 and 2 together on SCR (CR5CS) that is labeled T2

(Note : steps 2 and 3 above duplicate the previous Low Power Mod for the Vivitar 2000 DF500 board)

 Vivitar_2000_DF500_Board_Modifications.jpg ( 110.34K ) Number of downloads: 150


Additional recommendations (applies to Vivitar 2000 units that have 800 ufd capacitor and DF500 board):
1) Install a 0.47 ohm resistor (2 watt or greater) in series with your battery if using 4 NiMH batteries.
2) Install a 2.5 ohm resistor (10 watt or greater) in series with your battery if using a 6 Volt SLA battery.

(Note : the above 2 recommendations limit the in rush current which will help protect transistor T5 (C2500) which is the inverter transistor that has a continuous current rating of 2 amps and a peak rating of 5 amps. The peak is broad, so I opted to limit the current to the continuous rating value.)

I have analyzed the Low Power Mod and its impact on charging current and capacitor voltage, and find no evidence that this modification has a large impact on on the chrarging current or capacitor voltage (see my previous posting on this subject). Therefore the Low Power Mod does not appear to be related to the failures noted with the Vivitar 2000 flash units that have DF500 boards.

The Low Power Mod does an amazing job of minimizing capacitor discharge, and closely approaches what would be acheived if the capacitor were totally isolated.

I ran across a posting this morning that shows a schematic for a Vivitar 2000b flash unit. Turns out that my modifications basically duplicate the original Vivitar 2000b design except I also removed the ready light. The Vivitar 2000b does not have the bounce back feature, and my modification totally bypasses the components used in the bounce back feature of the Vivitar 2000. It does not appear anyone was taking advantage of the bounce back feature of the Vivitar 2000 in their trail camera builds, so elimination of the bounce back components should help clean up future builds for those using the Vivitar 2000 that has the DF500 board.

(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 Kirk

This post has been edited by dkirk: Aug 11 2006, 08:54 AM

[treetop]

Thanks thats some great information I just got done mounting a older 2000 flash last night it is a older 31057a board and doesnt seem to have the components on this one. It does have the yellow capacitor though is there something to gain by eliminating that?? Once again a big thanks for your effort and sharing with us. HAGS Member of the week award to you !!!

This post has been edited by treetop: Aug 2 2006, 08:37 AM

[212]

dkirk, thank you very much for all the work here, even though it is fun work it still takes a lot of time. I wonder what the capacitor voltage goes to when using the 6 Volt SLA battery?

Many of our members here live where it gets colder then a.......so I suggest you try to simulate real world conditions also. I don't have any fancy equipment, but I know when I do the "freezer test" the charging slows considerably and the transistor really gets loud.

I respect a man that is so much willing to help others, thanks again

[dkirk]

Hello 212,

When using a 6 Volt SLA, the capacitor will go over the rated working voltage of the capacitor (goes up to around 355 Vdc) if you let it charge continuous for a long time. It pretty much tops off around 355 volts after 2 continuous minutes of charging (using 2.47 ohm series resistor).

I really don't like the fact that the capacitor voltage can run above its rated working voltage (depending on the charge and refresh cycles), and therefore would like to address this issue (long term). I don't like it above the working voltage for a couple of reasons (potential failure of the cap, and also concerned about reduced strobe tube life due to running it so hard (high energy discharge)). A co-worker of mine who is an avid trail camera builder uses SLA batteries to run his Vivitar slave flash units, and has yet to have a Vivitar flash unit failure.

I personally am running my Vivitar 2000 flash with 4 NiMH batteries, and the Vivitar 2000 capacitor voltage tops off around 330 Vdc if allowed to charge for a long period, and this is right at the working voltage rating of the cap.

Placing a resistor in series with the battery really does not alter the final steady state capacitor voltage much(just a few volts), but it does slow down how fast it charges up.

I will be posting charge curves for both the NiMH and SLA batteries using various series resistors within a few days.

Thanks for the heads up on cold weather operation. This is something I have not yet looked at.

Don

[Matt in MO]

When using a 6 Volt SLA, the capacitor will go over the rated working voltage of the capacitor (goes up to around 355 Vdc) if you let it charge continuous for a long time. It pretty much tops off around 355 volts after 2 continuous minutes of charging (using 2.47 ohm series resistor).

Brian has the BG2 programmed to only charge a slave for 10 seconds in an effort to prevent overcharging.

[jcosmo]

On T2 which ones are pin 1 & 2? With the way the board is shown in the picture I'm guessing its the top and middle pins, but that is only a guess.

[Acrowe]

Looking at it from the picture it is 1,2,3 top to bottom.

[dkirk]

jcosmo,

Another way to identify the correct pins is by looking at the face of T2 that has writing and with the pins (legs) of T2 pointing down the pins are 1,2,3 from left to right.

Don

[busman]

Where are you getting the .47 ohm resistor? Local radio shack doesnt carry one.

[Acrowe]

I get mine from Mouser.

[busman]

Thanks Acrowe

[dkirk]

Radio Shack should carry the 0.47 ohm resistor.

The Radio Shack part number is 271-130 and they sell for $1.59. They are 0.47ohm 5 watt resistors.

They are nomally located in the component cabinet drawers.

Don

[jcosmo]

Thanks guys!

[irbowhntr]

DO these mods help when using alkiline batteries also..Or is this just for using rechargeable nimh's?

[boman49]

dkirk,
I am about to start to convert two BG1's & P41 to "IR" with a slave. Where do you recommend I get the Vivitars?
Thanks,
Boman49