Need some help with my nikon sb-15 flash

[CrazyCockatoo]

i've got an old nikon sb15 flash. It works well in the first like 10-20 times but after that the flash ready light isn't going on anymore. i leave it for 30 minutes and it's still not on. After pressing test button there's only some red light coming from the tube. Anyone know how to fix this?

 

[koraks]

Fresh batteries?

 

[BradS]

... and, clean battery contacts?

 

[Chan Tran]

Looks like batteries.

 

[Andreas Thaler]

The thing with the red light is interesting. Obviously the voltage on the flash tube is not enough to cause a discharge. But there must still be voltage.

I suspect a fault in the electronics.

Without specialist knowledge, I advise against opening the flash because of the danger of high voltage.

 

[foc]

Are you using alkaline/lithium or carbon zinc type AA batteries?

Sounds like it might be carbon zinc batteries being used. They are not strong enough to use in a flash and they will leak and cause damage.

I suggest alkaline or lithium AA like Energizer Ultimate and see how you get on.

 

[Chan Tran]

I have 2 of those SB-15. Good luck on taking it apart. I tried and I couldn't.

 

[Andreas Thaler]

I have 2 of those SB-15. Good luck on taking it apart. I tried and I couldn't.

And once the flash is open, how would troubleshooting proceed? What would be said about security?

 

[Chan Tran]

And once the flash is open, how would troubleshooting proceed? What would be said about security?

For me personally I don't worry about that. I know about high voltage and how to deal with it. I worked on high voltage high power stuff in my job. But the problem I have with my SB-15 is that one has a broken foot, and even a broken battery holder (but this can be swapped) and the other one has a little piece of the dial chipped off. This doesn't affect its operation but I like to swap it with the one from the broken unit. I couldn't figure out how to take it apart.

 

[Chan Tran]

And once the flash is open, how would troubleshooting proceed? What would be said about security?

Now for the case of the OP the first troubleshooting is to ensure to have good batteries. The OP didn't get back to us whether he tried it. Sure there is voltage at the capacitor but it's low and it can very well be low battery power. So my troubleshooting is first to replace the batteries with known good ones. The after that I would try to power the flash unit with external power by using clips to clip to the battery terminal inside the battery compartment. I would monitor the voltage and current draw while doing this.

 

[Chan Tran]

Actually I just power my SB-15 up with external power and simulate bad batteries. The symptom isn't the same as the OP found. I powered it up with 3.5V and limit the current to 100mA (normally the flash could draw more than 3A when it started up) and while it the ready light never come on I could fire the flash after a minute of so and the LED's that indicate the mode would light up just fine. I can never get it to flash red light like the OP saw.
So the problem isn't batteries.