Dead flash. What happened?

Discussion in 'Lighting Equipment' started by Fiodor, Oct 28, 2020.

  1. It’s a Sunpak PZ42X. It was in a cabinet for months without being used. Now it doesn’t turn on.

    I changed the batteries, to no avail.

    What could be the problem?
  2. SCL


    Check the flash's battery connectors for corrosion or oxidation. Best to not store your equipment with batteries installed.
    Fiodor likes this.
  3. Especially if those batteries are advertised by an annoying toy rabbit. They're the only brand of battery that I've had leak (several times) and ruin a few bits of kit.

    Anyway, +1 to cleaning the battery contacts. Maybe work the on/off switch a few times as well, if it's mechanical and not a rubber press-button.

    BTW. The tiniest spot of green corrosion on the battery contacts can cause an open-circuit, but a cotton-bud (Q-tip) dipped in vinegar will usually removed it.
    Fiodor likes this.
  4. Thank you for the messages.

    I found out that my Nikon SB-23 didn’t turn on either, but I cleaned a bit the contacts with a cotton bud moistened with apple vinegar. And apparently this is what made the flash work again.

    But I still haven’t had luck with my Sunpak. I cleaned the contacts with vinegar and also with a pencil rubber (and by the way, the inner contacts are tiny springs, difficult to clean, and it is impossible to rub them with a pencil rubber without damaging them).

    I also tried with a new set of non-rechargeable batteries.

    And I turned the flash on and off for some minutes. I don’t know how much time I should do this routine, which implies that I spend time doing this and have my hands occupied with this task.
  5. I have isopropyl alcohol and a contact cleaner (and lubricant). Could I clean the contacts with one of these products?

    Here are some photos.



    Look that there is a bit of green in some borders. It is subtle, and I don’t know if that is just the glue or something which is not wrong. It is a relatively new flash, bought like 10 years ago. And yes, last years it hasn’t been used (I don’t remember when was the last time I fired it).
  6. Those top contacts look clean enough.
    IME spring contacts are the most vulnerable to corrosion and the most stubborn to clean. I've had to resort to scraping them with a metal screwdriver sometimes. (Disclaimer. I'm not recommending that..... but as a last resort....)
    Fiodor likes this.
  7. Tony Parsons

    Tony Parsons Norfolk and Good

    Suggestions :

    1) Never store flashguns (or other equipment) unused for long periods with batteries in.

    2) Use rechargeable batteries, not alkaline (if the flash will take them - my Vivitar 283 and Canon ring flash won't, so I keep unused alkaline ones in the appropriate (Pentax or Nikon) bag). Good luck with cleaning the contacts.

    One final point - a 'new' flash, bought ten years ago ? Maybe the internal components have deteriorated over time.
    Fiodor likes this.
  8. Sandy Vongries

    Sandy Vongries Administrator Staff Member

    There are stories of capacitor failure in flashes stored unused for long periods.
    Fiodor and Charles_Webster like this.
  9. Nyaaah, maybe.
    Personally I have an unhealthy attraction to electronic flash equipment, and I have far too wide and numerous a collection of used speedlights, hammerheads and their battery packs. Far more than I could reasonably need.

    OK, I'm a hoarder of old electronic flash equipment. There, I admit it!

    Anyway. Out of all those dozens of flashes that have passed through my hands, precisely none have had a failed capacitor.

    I have one Sunpak AZ 3600 with a weakened capacitor that quickly loses charge and gives a below-par light output, but that's not an outright failure. And I'd consider my sample size to be fairly indicative of the general state of health of old and underused flashes in general.
    Fiodor likes this.
  10. A few decades back I worked with some non-photo electronic gear that had DC to DC converters to step up the power supply voltage. Many such circuits used feedback from a winding on the converter transformer to maintain oscillation (transformers don't work on DC). Some relatively simple circuits of that sort will not start with a heavy load on the output. The high energy density electrolytic capacitors used in electronic flashes are prone to increased electrical leakage if they spend a lot of time without a charge. Once that leakage gets too high, the converter won't start. Probably in some such cases if one could get to the capacitor and slowly ramp up a charge on it and hold said charge for a while, it might start to work better (IIRC the process is called "forming"). As with many things, avoiding the problem is the best approach, load up batteries and charge up the flash and let it sit charged for a while periodically.

    I admit I don't follow my own advice, and I have a couple of flash units, decades old, that lay there and do nothing. I haven't thus far bothered to attempt to open them and diagnose the internal workings, but I wouldn't be at all surprised to find a leaky cap (as in electrically leaky). Although in 30 or 40 year old electronic gear, especially the sort with two or three hundred volts running around inside, there are plenty of other possible failure scenarios.
    Fiodor likes this.
  11. As I said, in dozens of cases of trying old flashes - some of which haven't been used in a decade or more - none have failed to have the inverter whine into life and eventually charge the main storage capacitor.

    Plenty have refused to work because power wasn't getting from the battery to the inverter circuit through corroded or broken contacts, but once that was sorted, they've all whistled into life.

    Musing on what might go wrong isn't the same as having years of hands on experience with the gear in question.
    Fiodor likes this.
  12. Failing to hold and deliver its nominal capacity is failing, failure. That is indeed not uncommon.

    I propably have just a fraction of your number of flash units, but i have experienced local thunder claps quite a few times: capacitors blowing with a very loud bang. It happens. Nasty stuff, electricity.
    Interestingly, perhaps, without also displaying the expected flash.

    Neither loss of capacity (not in a few months) nor blown capacitors will have caused the OP's flash to die.
    Fiodor likes this.
  13. AJG


    I still remember quite vividly when I had a capacitor blow in one of my White Lightning monolights in my studio 25 years ago--I thought a gun had been fired!
    Fiodor likes this.
  14. A loud bang is caused by the discharge of a large amount of energy stored in the capacitor. That's a sudden and catastrophic failure.
    That's not the same as an un-formed or leaky capacitor not taking a charge in the first place. The worst you'll usually get with a leaky capacitor trying to charge is a hissing sound as its electrolyte boils out through a purpose-made vent. Often accompanied by an unpleasant smell.
    Fiodor likes this.
  15. Hey, how are you?

    Thank you for sharing your knowledge.

    I cleaned a bit more the contacts with isopropyl alcohol but I haven’t been able to turn on my Sunpak flash.

    So, maybe I will ask a repair service if it is possible to fix it. Why do you think a dead capacitor means the end of the flash? Because repairing it is as expensive as buying a new flash?
  16. Almost certainly, even if you can find a repairer. And you would still have a used flashgun, whereas a new one should be guaranteed.
  17. Why is there this fixation with the main capacitor being at fault? It's almost the last thing to suspect.

    If there's no sign of the LCD display turning on, nor any sound, nor any indicator lamp lighting, then chances are it's not the storage capacitor at fault. It's still most likely a bad connection between the batteries and the rest of the circuitry.

    Corrosion is a good insulator and can be very stubborn. A dab of alcohol won't shift it. It's more water or acid soluble.

    IMO the bottom spring contacts need acid or mechanical cleaning - i.e. abrasion or scraping.
    However, removal of the chrome or nickel plating, while allowing temporary electrical contact, will make those spring contacts susceptible to oxidation from air. Meaning that they'll need regular additional cleaning ever after.

    Corrosion might even have eaten through the wiring between the battery and the circuit of the flash. In which case it'll need dismantling to repair it.

    Whatever the cause, the chances are that the cost of professional repair will be more than the thing's worth. Especially since a new one is on sale here at only 50 quid.
    Last edited: Nov 10, 2020
  18. I had all sort of flash units fail on me, mostly because they sat around too long, or were DOA after purchasing them online. This is why I never buy used flash online anymore because you are essentially playing Russian Roulette. Sometimes you might get lucky, sometimes not.

    I had to bring back a couple of my Vivitar 283's by using the Q-tip dipped in vinegar method, which to me works better that the erasure method.

    I had a Metz hammer head blow up on me after it sat in storage for 5 years and that was the latest Metz hammer-head model. My older Metz hammer heads worked fine after I "slowly" re-formed their capacitors.

    One flash unit that got me totally puzzled and is still in my bag is an old(30+ years old !) ZAKAR 27MD speed light. This was my first flash unit and it is totally manual although I think it uses Thyristor technology ? This flash unit has been sitting around at the bottom of my bag totally ignored, got knocked around more times that I can remember, had liquids spilled on it, has sat in a dusty environments for years, yet when I put in a new set of batteries it works like brand new !
    Last edited: Nov 11, 2020

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