treetop

Fried Vivitar 2000 fix df500

11 posts in this topic

I have been watching with great interest all of the information that Don Kirk has been providing us with on what the best way to modify the vivitar flash. He seems to have such a great interest in finding how and why these things work.

Well I had one here that I felt I had a df500 slave here that I burned up last fall and put to the side. The cheap :ph34r: in me just wouldnt let me throw away a brand new flash even though I figured I would never mess with it. In one of Dons post he said he would need to look at a df500 vivitar to determine if it was what he thought it was and if he would be able to repair it with the parts available to him. Hmm B) now I felt like a pretty smart/cheap guy B) and sent him a pm I told him I would be happy to send it to him and he could keep it when he was done He said he would send it back if he could fix it He also told me not to even worry about the postage. Now I felt like a really lucky smart cheap guy and was pretty proud of my cheap self and I sent it off last Friday. Well in todays mail (yep 5 days) what do I find but my repaired vivitar df500 slave flash. I beter let Don take it from here but first I need to thank him Don thanks you have been a wonderful assett to Hagshouse since you have joined in with us and not just for fixing my vivitar but in all that you have contributed in such a short time here.

Thanks to Willy Wally He gets a gold star for sucking you in.

 

Thank You Dave

Edited by treetop

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I too would like to thank Don for his patience helping me troubleshoot my DF500 board and I am eagerly waiting to solder in the new part and get it going..

Thanks Don your an asset to Hags :)

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Great to hear :)

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Dave and gang,

 

Summary of findings on Treetops (Dave) failed Vivitar 2000 (DF500 board version)

 

The Inverter transistor (identified on the board as T5) was toast (emitter shorted to collector). The original Inverter transistor part number is C2500 B. The C2500 is an abreviation for 2SC2500, and the B indicates the gain. The transistors I purchased are the A version which have slightly lower gain than the B version (the A version is all that I could find when doing a quick search last week).

 

Transistor Specs (DC current gain) : A = 140 to 240, B= 200 to 330

 

I checked the inverter transformer and inverter diode per my trouble shooting instructions that I recently posted, and they were ok.

 

I replaced the C2500 B transistor with the C2500 A transistor and the unit came back to life, but it looks like the lower gain transistor might cause the flash to not charge as quickly (based on the charge profile data of this repaired unit and charge profiles I have obtained on other Vivitar 2000 (DF500 board version) flash units).

 

I did go ahead and do the full modifcation which I recently posted which involves removing resistor R15 and Resistor R16, as well as shorting pins 1 and 2 on the SCR (T2), and removed the external large yellow capacitor.

 

I measured the inrush current on the repaired unit, and a series resistor is not needed if using a 4 pack of NiMH batteries with this repaired Vivitar 2000 unit. A 1 or 1.47 ohm resistor should be used when using this repaired Vivitar 2000 unit with a 6 volt SLA battery (Note :the inverter transistor is rated for 2 amps continuous current and 5 amps peak).

 

NiMH Data

------------------------------------

Using a freshly charged pack of 4 AA NiMH batteries (Open circuit voltage of 5.70 Vdc) the inrush current was as follows :

 

NiMH inrush current with no resistor = 1.86 amps

NiMH inrush current with 0.47 ohm wirewound resistor = 1.65 amps

------------------------------------

Using 4 AA NiMH batteries with an open circuit voltage of 5.25 Vdc, the inrush current was as follows :

 

NiMH inrush current with no resistor = 1.66 amps

NiMH inrush current with 0.47 ohm wirewound resistor = 1.52 amps

--------------------------------

Charge profile using 4 AA batteries (open circuit voltage = 5.25 Vdc) and 0.47 ohm wirewound resistor

 

0s, 0Vdc

5s, 124 Vdc

10s, 186 Vdc

20s, 248 Vdc

30s, 275 Vdc

--------------------------------

Charge profile using 4 AA batteries (open circuit voltage = 5.70 Vdc) and 0.47 ohm wirewound resistor

 

0s, 0Vdc

5s, 135 Vdc

10s, 202 Vdc

20s, 271 Vdc

30s, 300 Vdc

--------------------------------

Charge profile using 4 AA batteries (open circuit voltage = 5.70 Vdc) and no series resistor.

 

0s, 0Vdc

5s, 147 Vdc

10s, 220 Vdc

20s, 284 Vdc

30s, 306 Vdc

--------------------------------

 

SLA data

--------------------------------

SLA inrush current with 0.47 ohm wirewound reisitor = (over 2 amps)

SLA inrush current with 1 ohm wirewound resistor = 1.98 amps

SLA inrush current with 1.47 ohm wirewound resistor = 1.83 amps

SLA inrush current with 2.47 ohm wirewound resistor = 1.53 amps

(Note : SLA open circuit voltage for above tests was approximately 6.55 Vdc)

--------------------------------

Charge profile with SLA and 1.47 ohm wirewound resistor

 

0s, 0Vdc

5s, 148Vdc

10s, 229Vdc

20s, 302 Vdc

30s, 326 Vdc

--------------------------------

Charge profile with SLA and 1.0 ohm wirewound resistor

 

0s, 0Vdc

5s, 152Vdc

10s, 241Vdc

20s, 319 Vdc

30s, 336 Vdc

--------------------------------

 

Thanks to Dave for letting me look at a failed Vivitar 2000 (DF500 board version), which helped confirm the trouble shooting procedures that I recently posted. Based on the trouble shooting procedure dmach8 has identified a shorted inverter transistor in his Vivitar 2000 (DF500 version), and we will see if the replacement transistor recently sent to him also makes his unit operational.

 

Don

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Umm.....

 

When I stick my finger (espically when wet) on those two shiny things, it hurts.

 

That's how dkirk makes me feel!

 

Nice to have a professional around here to keep all of us rookies in line.

 

Thanks for all the help.

 

-John

:ph34r:

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Great job Dkirk again you have some great info......the only thing though you lost me at Dave and Gang.. :D:D:D:D

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Willraygreen really adores me, but somedays denial sets in.

 

Don

Edited by dkirk

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Dang Don, you beat me to posting the results. I was just getting ready to respond with my tests. Looks like you found what I did.... So no since reposting the results..... 070.gif

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It is what Hags house is all about.

Great work! I love the technical stuff just puts everything into perspective.

 

Nice job Dkirk! :D

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So if I move the gizmo off the #** risistor and move the Rooster tail over to the other side I will be good to go... right??? Don't try to understand that stuff but man it is interesting how you gurus figure this stuff out.

 

Great work dkirk, wish we all knew this stuff as well as some of you. :) This is sure to help a lot of people that used the 500 boards.

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