Chico Flash - need help please!!

[romualdo]

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I've just acquired a Chico Flash Unit (type for IIIf models) - I'm having trouble removing the internals so I can change the battery - there is still one in the unit - visible (original red Eveready Photoflash 505) when the side panel is removed. The instructions that accompanied it describe "To open your Chico, just grasp the foot on the bottom of the unit (or the adjustable holder) with one hand, while holding the body of the unit in the other. Pull down firmly & smoothly & the working parts will slide out of the case". I've attempted this & the internals only move  half to one millimeter - there is significant resistance & I'm frightened that I may break/damage something.

An article I have found online describes removing a hexagonal screw??

https://www.photo.net/discuss/threads/leica-chico-flash-fixed-and-how-to-fix.465274/

Any help would be greatly appreciated

[alan mcfall]

The link article is correct. Bend up the thin metal positive  battery tab at the top of the battery chamber, and you wil see the hex screw. The hex is 4.5mm, but can be easily removed with small needle nose pliers. Then the unit slides out easily, the battery tab is now loose and must be reinserted during assembly. This will give you access to the capacitor which can be bad after so many years.

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[romualdo]

Thanks Alan - the design on my Chico is slightly different - there is no tab but only a hex head screw with what appears to be solder like material covering it - that's probably why I didn't understand the initial description in that link. All worked well & managed to slide the cartridge out. Next step, how to test the capacitor? I'll need a new battery - ordering one (Exell 505) from B&H (can't get these in Australia).

https://www.bhphotovideo.com/c/product/1062351-REG/exell_battery_a221_505a_a220_504a_22_5v_alkaline_battery.html

I presume that with a new battery & the the test bulb lights up once a bulb is inserted, that indicates the capacitor is functioning?

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[Pecole]

Nothing to say about the "technical" problem, but, knowing that I had and used several "CHICO's", I went to my collection's archives and found these two images. The first is just illustrates the DEOOC flash with the reflector still "closed" and the DFOOB pivoted holder (same as DFHOO, but without the wiring). The second shows two CHICO, one complete in its DHMOO plastic box, with the DFOOB holder and a bulb.

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[romualdo]

This also came in my "Chico" case - i don't think it's a Leica part as it has the General Electric logo engraved into that protruding arm.

Is this an adapter to enable other bulbs - maybe bayonet to M2, 3, 5, 25 (mini bayonet/miniature base)

 

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Edited October 28, 2019 by romualdo

[jc_braconi]

Yes I have it also with my chico box

[masjah]

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I know nothing of this particular flash unit, but if it is the usual battery/capacitor gun, then, as a schoolboy,  I used similar ones from Agfa, and I think Ilford. The capacitor was a physically quite small electrolytic, and such capacitors definitely do degrade over the years. My inclination would be to renew it as a matter of course. You ought to be able to find one with a similar capacitance and voltage rating which will fit in (these components have got physically smaller over the years).

[romualdo]

16 hours ago, masjah said:

I know nothing of this particular flash unit, but if it is the usual battery/capacitor gun, then, as a schoolboy,  I used similar ones from Agfa, and I think Ilford. The capacitor was a physically quite small electrolytic, and such capacitors definitely do degrade over the years. My inclination would be to renew it as a matter of course. You ought to be able to find one with a similar capacitance and voltage rating which will fit in (these components have got physically smaller over the years).

I've managed to track down a contemporary equivalent/replacement capacitor (25V 100µ F) - look at the difference in size

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[masjah]

Romualdo, I'm sure you are aware of this, but polarity is important with electrolytics. I mention this because on older types, there may not be a polarity marking, because it was aways understood that the can itself was the negative terminal,  and the other connection (often a solder tag at the end, but maybe a wire) is the positive. The modern replacements will have one or both wires explicitly marked.

[romualdo]

16 hours ago, masjah said:

Romualdo, I'm sure you are aware of this, but polarity is important with electrolytics. I mention this because on older types, there may not be a polarity marking, because it was aways understood that the can itself was the negative terminal,  and the other connection (often a solder tag at the end, but maybe a wire) is the positive. The modern replacements will have one or both wires explicitly marked.

John, your comments regarding polarity are definitely a concern to me - I've added more pics after removing the capacitor from the unit

1. top view showing terminals - from your description I presume the wire to the left will be the positive terminal & the central connection is negative?

2. comparison of both capacitors - I've read that one of the easy ways of determining polarity with modern capacitors is the length of the terminal wires ie positive is always the longer one - is that correct & definitive?

Many thanks for your helpful input John

Cheers Stephen

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[masjah]

Stephen, with regard to the old capacitor, I suspect that both of the connections at the top relate to the positive terminal. It looks as if the wire is soldered on to a tag which is in contact with the screw like object. The can will be negative, and must somehow be clamped to something metallic connected to the rest of the circuit. (There's something at the other end of the capacitor which I can't quite make out, but which may relate to this.)

So far as the modern capacitor is concerned, the long white stripe along the length of the body, with a minus sign and an arrow indicator, points to the negative wire.

[romualdo]

14 hours ago, masjah said:

Stephen, with regard to the old capacitor, I suspect that both of the connections at the top relate to the positive terminal. It looks as if the wire is soldered on to a tag which is in contact with the screw like object. The can will be negative, and must somehow be clamped to something metallic connected to the rest of the circuit. (There's something at the other end of the capacitor which I can't quite make out, but which may relate to this.)

So far as the modern capacitor is concerned, the long white stripe along the length of the body, with a minus sign and an arrow indicator, points to the negative wire.

John, I've removed the capacitor from the casing/cartridge to give you a better view - I presume that elongated metallic strip is the contact point for the capacitor (negative), it's also attached at the base with a screw point (all of which is part of the metallic strip). The hollow cylindrical object on top (positive terminal) fits into the casing (see small hole above) - this then (once the capacitor is in place) becomes a contact point (male/female connection) - see second picture - fits into lowermost pin when the capacitor/battery casing slides into the outer unit. How do I go about soldering/attaching the new capacitor? I'll have to try & remove the cylindrical contact from the old capacitor or try & retain the top of the capacitor to maintain this contact.

Cheers, Stephen

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[masjah]

Stephen, what a bodge this design seems to be! If I understand things correctly, the positive capacitor connection is connected to the rest of the circuitry in two ways: one via the wire, and the other by the hollow cylindrical object which in turn goes through the hole of the capacitor holder and connects with the male connector of the outer case.

I would be tempted to have a go by sawing off the top of the old capacitor and glueing it into its original position (keeping the wire attached). The pare back the wire insulation somewhere along its length, solder the new capacitor positive wire to it, and tape it to insulate the solder join. Then I'd  solder the negative terminal of the new capacitor to a solder tag, and use the original bottom screw mounting point to attach it. There should be plenty of room to put the new capacitor where the main body of the old capacitor was. Hope I've understood this correctly! Good luck!

PS: Be careful with the stuff inside the old capacitor - it may not be pleasant.

 

[romualdo]

3 hours ago, masjah said:

Stephen, what a bodge this design seems to be! If I understand things correctly, the positive capacitor connection is connected to the rest of the circuitry in two ways: one via the wire, and the other by the hollow cylindrical object which in turn goes through the hole of the capacitor holder and connects with the male connector of the outer case.

I would be tempted to have a go by sawing off the top of the old capacitor and glueing it into its original position (keeping the wire attached). The pare back the wire insulation somewhere along its length, solder the new capacitor positive wire to it, and tape it to insulate the solder join. Then I'd  solder the negative terminal of the new capacitor to a solder tag, and use the original bottom screw mounting point to attach it. There should be plenty of room to put the new capacitor where the main body of the old capacitor was. Hope I've understood this correctly! Good luck!

PS: Be careful with the stuff inside the old capacitor - it may not be pleasant.

 

Many thanks again John - I get the gist of your attachment/soldering recommendations. What unpleasant material may emerge from the capacitor when I attempt to saw the top part off?

Also I'm wondering if the old capacitor still has function - I tested it today with a multimeter (resistance only & not capacitance - my meter cannot perform the second function). 

I set my analog multimeter at the x1K ohm

1. old capacitor - connected leads to terminals (Red +ve & black -ve) -> needle went right across to right (0 ohm) then gradually moved to the left until reaching approx 25 ohms

2. new capacitor - connected leads to terminals (Red +ve & black -ve) -> needle went right across to right (0 ohm) then gradually moved to the left until reaching approx 80 ohms

does that comparison tell you anything? The old capacitor is still functional but failing???? ie it only goes to 25 ohms while the new one reaches 80 ohms

Cheers, Stephen

Edited November 5, 2019 by romualdo

[masjah]

Stephen, I'm not exactly sure what is used as an electrolyte in these old capacitors, but it may be a bit unpleasant on the skin. I'd use some thin disposable gloves to handle it, and be sure to dispose of it safely.

It's very difficult trying to test electrolytics with just a DC multimeter. I can never remember the polarity of a multimeter meter when set to ohms, but it does apply a voltage to the device under test; I would also try it with the leads reversed. It's the applied voltage that polarises an electrolytic so that it works as a capacitor, so if it's the wrong way round, you would tend to depolarise the capacitor. At the low voltages of the meter, this wouldn't damage things  - it would still simply repolarise when a positive voltage was applied to its positive connection relative to tis negative one. When properly polarised a genuine leakage resistance of 80 ohms would not be acceptable, but that doesn't mean the capacitor is faulty. But also, a good result doesn't necessarily mean the capacitor is OK at a higher voltage. In short, I would still change the old capacitor anyway! Hope this helps!

[romualdo]

On 11/5/2019 at 7:49 PM, masjah said:

Stephen, what a bodge this design seems to be! If I understand things correctly, the positive capacitor connection is connected to the rest of the circuitry in two ways: one via the wire, and the other by the hollow cylindrical object which in turn goes through the hole of the capacitor holder and connects with the male connector of the outer case.

I would be tempted to have a go by sawing off the top of the old capacitor and glueing it into its original position (keeping the wire attached). The pare back the wire insulation somewhere along its length, solder the new capacitor positive wire to it, and tape it to insulate the solder join. Then I'd  solder the negative terminal of the new capacitor to a solder tag, and use the original bottom screw mounting point to attach it. There should be plenty of room to put the new capacitor where the main body of the old capacitor was. Hope I've understood this correctly! Good luck!

PS: Be careful with the stuff inside the old capacitor - it may not be pleasant.

 

thanks again John

[romualdo]

Update on my Chico flash - it's now working on my IIIf BD

Sourced the correct/appropriate battery (21V) late last year

Had the capacitor tested yesterday at an electronics workshop & it's working fine (not bad for a piece of early electronics that is 60-65 years old)

Just needed some cleaning of the connections (there are a few as this has the specific lower attachment that is compatible with the IIIf only - no cords required) plus making sure the bulb is functional & presto - successful (from the point of view of the flash actually discharging on depression of the shutter button) pics taken with the combination - we'll see once the film is processed

I still can't believe the capacitor is functioning after this time

Edited May 3, 2020 by romualdo