Honeywell Strobonar 770 Questions

Discussion in 'Lighting Equipment' started by henry_finley|1, Oct 20, 2021.

  1. I have a Strobonar 770 here that has a bad battery pack. Referring to the attached photos, the pack appears to be made up of 4 sub C cells. But look at the charger. It says 14.2 VDC. Four sub C rechargeables = 4.8V. So it would be obvious that the cells would have to contain 3- 1/3 sub C cells for a total of 14.4 volts. 1/3 sub C's do not exist that I can find. Although 1/2 Sub C does exist. That would be a total of 9.6V. Still well under the 14.2V printed on the charger.
    I have studied other Srobonar models where people have been happy with new battery packs made up of 4-Sub C batteries. Obviously those Strobonar models were made for a 4.8V supply.
    Can anybody shed light on what I have here, and how to get some batteries in it? Thank you.

    bat 1.jpg

  2. Assuming it's not a typo, the charger says the output is 14.2 Volts AC, not DC. I'm no battery expert so I can only guess that this is compatible with charging 4.8V batteries...
  3. The AC from the mains power is converted to DC in the charger, if I'm not mistaken. The batteries are DC, so they need DC trickle charge. Low power solar cells can be used also for a DC charge when there's no mains power around.

    First up the batteries will need to be identified as NiCad, I'm sure that's what they were in early rechargeable devices ..... Yes they were NiCad, I just researched that flash
    Link ...

    Here's what you can do - You can find out if you can get NiCad cordless power tool battery cells, combined together to make up 14.2V or near enough to it. Cordless power tool batteries are full of smaller rechargeable cells, just like a Tesla home battery. You may be lucky to get some cells that fit into the flash and be a very similar voltage to 14.2V at the same time.

    Or you can make an external battery holder to take 4off 3.7V Lithium rechargeable batteries such as these ...

    Link ....

    But they'll need a different charger, one for lithium batteries, probably a wall charger. The external battery holder you make could be attached to the flash handle but then, the wires will need to be extended from inside the flash to the outside and either soldered or plugged to the terminals on the holder in their right polarity, very important.

    I would exhaust all avenues finding the right NiCad batteries first though for a simpler repair, but if you fail at that, the external battery idea is the best, you get to easily change batteries when needed, they are readily available and you avoid any future dismantling of the flash, messing around with old technology NiCads. I did the external conversion with a Metz and never regretted it, but with four plain AA 1.5V batteries, just a little more voltage than original, but it's fine.

    Metz Conversion.JPG
  4. I think it's just 4 NiCad cells. So the voltage is around 4.8-5V. Don't use 14V battery it would kill your flash.
  5. I didn't even notice the 14.2 volts being in AC. I stupidly assumed it was DC and didn't look more closely. Since there is a transformer with several secondaries in the unit, I'm willing to bet that one of the secondaries supplies the voltage for rectification into the 3.8V needed to charge the 4 batteries. I cut the paper covering off one of them hoping to see something printed on the metal case inside. But there was nothing there. I suppose the only real was to know that the 4 cells have inside is to cut the metal case of one.
  6. My guess is if you removed the wrapper and saw one cell, it's one cell. I've never seen multiple cells in a single metal can. Shouldn't be much trouble to replace them with like.
    Gary Naka likes this.
  7. OK, I am satisfied that I am indeed dealing with sub-C NiCd batteries. Actually a sub C from my RC airplane glow-plug battery is about 3/32 longer than what the Srobonar has. But the diameter is the same. And the flash has 2 layers of chipboard spacer which I could just leave out. So the next question is where I can get some NiCd's online that are not cheap worthless Chinese crap. I've already discovered more times than once that the ratings specified are outright lies and the batteries are WORTHLESS.
  8. I'm a dumpster diver. I grab a non-Li power tool pack from the recycle bin at the dump. Usually a couple cells have shorted out with whiskers and the rest charge up fine. If you want new, there are still good ones made. Maybe here-
  9. Tenergy's rating for NiMH stinks. NONE of 20+ AA and sub-C cell came anywhere near 80% of the rated capacity. That was an expensive lesson.
    On the other hand, their NiCd AA batteries did meet the rated capacity.
  10. Make sure you get the tabbed cells, so that you can solder them together.
    Do NOT attempt to solder onto the battery itself. It is very easy to overheat the cell, and damage it.
  11. As an aside, I wonder how to get the bottom end cap off of the case to extract the big capacitor. As long as I'm in the neighborhood, I'll bet there's a way to replace that thing.
  12. End caps are usually screwed in, clipped in, or tightly pressed in, or even pinned in. I doubt there's an easy way to remove it because capacitors are dangerous things and they can hold a charge for years. By sheer coincidence, two days ago I removed the capacitor and battery from one of those old folding fan type flashes that uses blue bulbs. I know for sure that that flash hasn't been used for many years, possibly decades. I wasn't even cautious when I removed the capacitor thinking that both the battery and the capacitor would be dead flat, not so, the battery, being a standard non-rechargeable 15V battery for that flash, still had 7.7V in it ... and the capacitor, 12.9V ... I needn't have worried about those low voltages, but in a shorter time span of sitting around, the capacitor may have had 100s of nasty volts.

    Do you suspect that your capacitor may be faulty?. Give it a test, capacitors last a hell of a long time barring catastrophic events. The other six flashes I have here, all from the 60s and 70s, are still charging their capacitors up quickly and working normally after their fifty year life span so far. To test the capacitor, you'll need the new batteries installed, don't try to test it any other way for the time being.

    With a new battery installed, this flash would be up and running again I'd say.
    I'm not sure why these capacitors were so accessible, perhaps another member could explain it,
    but fully charged with high voltage, seems they'd shock you pretty well.
    Capacitor charge.jpg
  13. I thank you for the caution, but I am also a radio man. I've dealt with capacitors that hold enough juice to kill King Kong. And you're right. They can be very nasty little things. I've got a buddy that had a Kenwood 1000W linear. I refused to work on it and finally convinced him to sell it rather than trying to mess with it. The flash actually seems to work with the Honeywell charger. But I've only had it a couple days. And I figured if there was a secret to getting the end cap off the case, as long as I was in the neighborhood, I'd give it a look-see. I have no idea what the ratings are, but figured new caps might be smaller and I could find a new one to go it, just to put that issue to rest.
  14. Not sure how available big photoflash caps are these days, as demand is near zero.
  15. Install new batteries and see how it goes, chances are the original capacitor will be ok. After sitting idle for years on end, the capacitor could take anywhere up to 10 minutes to fully charge, but if the ready light fails to come on at all, then perhaps the old capacitor really does need replacing. But first try it. The best sign that the capacitor is working well, without removing it from the flash, is if the recycle time is no more than approx 6sec. If it's taking 30sec or more with fully charged batteries, the capacitor is probably on it's way out, and then will need to be replaced.
  16. I ordered some sub c cells today for this 770, since it seems to be in working order. The reason I bought it was to replace my 682S, which has more features including thyristor operation. But the 682 developed a curious problem, and I think it has something to do with the electronics and not the capacitor. On that one, the green light comes on as soon as you turn it on, and stays on. I can hear the whine, but the orange ready light will not come on. And the flash flickers sometimes, and even sets itself off. Strange problem. I fear a transistor or SCR has gone bad, but I can't find a schematic on it so I can troubleshoot it. So I guess it's toast. It will flash when you push the test button, but the orange ready light won't light. I know it's not a bad bulb, because it HAS lit a couple times. The reason I want a Strobonar is because the Graflex flash holder rings fit them. It's for my Super Graphic.

    Gary Naka likes this.
  17. Well at least you have a chance to resurect the Strobonar.
    I have an 800. I need the long obsolete 510v battery pack to use it.
  18. I think you'll find that the original cells are full C sized ones. Sub Cs are a comparatively recent 'invention'.
    All old (pre-1980ish) Metz and similar hammerhead design flashes used either AA or C size NiCd cells in their battery packs. A modern C cell has a capacity of 4000 mAH, whereas Sub-C cells top out at a claimed 3300 mAH - and in practise a fair bit less.

    As for the charger voltage: NiCd and NiMH cells need a constant-current charge, and the easiest way to acheive that is to feed a high(er) voltage through a resistor. So 14.2 volts rectified and fed through, say 100 ohms, gives you an RMS current of about 100mA into a 4.5v battery. Enough to trickle charge those old NiCds to their pathetic 1500 mAH capacity in about 24 hours. While only wasting 24 Watt-hours of energy in the process!

    Of course, you'll sit twiddling your thumbs for 3 or 4 days to get new C size NiMH cells up to full capacity with the original charger. :confused:
  19. In those old circuits the ready-light neon sometimes acted as a switch to regulate the inverter voltage. Neon strikes, current flows, inverter circuit is switched off or moderated. So something as simple as a dry joint or other intermittent contact in the neon indicator chain could b*gger up the entire voltage regulation circuit and cause the symptoms you've described.

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