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"Potato-Masher" Strobonar help?

 
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ImageMaker



Joined: 20 Jun 2006
Posts: 93
Location: North Carolina

PostPosted: Sun Aug 06, 2006 10:59 pm    Post subject: Reply with quote

I've got a couple of the old "potato-masher" Strobonar flashes, which I recall as being *extremely* bright compared to most modern electronic flash units. One has a clip-on mount that fits an under-camera bracket I got with the flashes. I also have one (long dead) 510V battery and the connection unit and cord for it, and can pretty readily build a replacement battery to use the cheap alkaline button cells I can buy locally at 10/$1 (340 cells will cost a good bit less than this dead 510 V unit did when it was new).

However, given these units are at least 35 years old, I expect to need to replace the flash capacitors. I know enough about this to do the job safely, but I'm not sure how to proceed in opening the plastic Strobonar handle unit's case without damaging anything. Can anyone point to photos, diagrams, or instructions for opening one of these to replace the capacitor (assuming it doesn't reform after I apply voltage)?

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RichS



Joined: 18 Oct 2001
Posts: 1467
Location: South of Rochester, NY

PostPosted: Mon Aug 07, 2006 4:34 am    Post subject: Reply with quote

It would help if you mentioned a model number...

If you're talking about the 6xx, 7xx and 8xx models, you've got some work cut out. I've taken a couple apart (and back together) but never to replace the capacitors. I don't think I'd want to?

The front bezel is held on by snap clips and not too difficult to remove once you know where to press and which directions. Sorry, I don't remember...

The top circuit board comes loos with the screws visible from the battery compartment.

I vaguely remember another board inside sitting on top of the capacitors? May be a different flash?

To completely remove everything is tedious and the wiring is a pain. The slide switch isn't difficult to get out but another pain to get back in.

I _think_ I have a service manual from possibly the 770 series which may help. I don't have a pdf version and getting it scanned might take a while. The computer connected to the scanner seems to be fairly full at the moment... And I'd have to locate the manual. But it could be done within the week or so, hopefully?

I don't think the handle slipts for capaitor access. I believe they come out the top which is yet another pain...

And I could be wrong, but I thought the high voltage units with the 510v batteries didn't use the capacitors? I don't own one so I never bothered to check into...

Let me know if you need the manual or pages from it...


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ImageMaker



Joined: 20 Jun 2006
Posts: 93
Location: North Carolina

PostPosted: Tue Aug 08, 2006 9:23 pm    Post subject: Reply with quote

Thanks, I didn't even realize there were different models; one of these is an 800, the other a Pressmaster 800.

My understanding is that the 510V battery supply is just connected directly to the capacitor (no need for an oscillator circuit to step up the voltage), which gives *awesome* fast recycles (like around 5 seconds) even in absence of a thyristor. Looking more closely, there is another set of holes just forward of the 510V connector, though I don't know if that's for an external head, multi-flash synch cord, external low-voltage power supply, or what. I also see that there's a battery tray inside the head that comes out by squeezing a couple tabs, looks like it would take 4xC cells, but has no contacts (easily corrected, I'd think, but polarity could be an issue -- I see contacts inside the head, so if I can power the unit from the extrnal battery I might be able to put a meter on those contacts and see which way the C cells should connect, if these models are actually capable of running on those).

With that tray removed, I see three screws holding a panel at the front of the cavity (or holding the reflector/lens in place), and two more holding a molded panel that fits the bottom of the battery tray, with the neon ready light between them.

Given no contacts on the battery trays, I don't know if these units even have the oscillator step-up supply that most of us are used to in "modern" strobes, though I think I'll be able to tell if/when I get the panel under the tray out.

Under the principle that someone had to assemble this thing, the capacitor pretty much has to come out through the head, unless the bottom plate comes out -- I see a couple little indents in the sides of that bottom plate, might be worth looking more closely there.

When you can get to it, I'd greatly appreciate seeing a PDF (or even just raw scans) of the manual you have -- it should give me a start. Making a 510V battery is trivial -- handling a large flash capacitor is not...

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clnfrd



Joined: 26 Mar 2002
Posts: 616
Location: Western Kentucky Lakes Area

PostPosted: Wed Aug 09, 2006 9:34 pm    Post subject: Reply with quote

If your Strobonar has the capacitor in the handle, similar to my Auto 770's, the bottom with the two little indentations is easily popped off with a couple of screwdrivers. It's glued or plasti-welded on. Once removed you then can shove the capacitor up through the top with a little coaxing. I like to attach a clip lead to the terminals of the cap to make sure it stays discharged. Caps have been known to take a partial charge from solar, cosmic, or whatever, radiation.
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C. Henry



Joined: 13 Dec 2005
Posts: 360
Location: North East Georgia, USA

PostPosted: Thu Aug 17, 2006 2:59 am    Post subject: Reply with quote

If your 800s are the same as my 770 & 780 units the battery tray takes "sub C" nicad cells which are charged by a plug in AC power pack. My units have the plus contact to the right and the polarity of each cell is moulded in to the tray under the batterys.

C. Henry
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ImageMaker



Joined: 20 Jun 2006
Posts: 93
Location: North Carolina

PostPosted: Sat Aug 19, 2006 9:26 pm    Post subject: Reply with quote

Aaah. Okay, these might well be sub-C, I haven't checked them. Given there are no straps or contacts, I don't know that I'd expect to find the oscillator supply on the flash circuit board; OTOH, the self-contained battery unit might have been sold separately, and wouldn't have been first choice for those who could use the 510V belt battery, since the big one would give both longer life and much faster recycle. Either way, I'll have to take it apart a bit after getting the necessary bits together to extract the capacitors and ensure they're safely discharged.

I also note there's no synch cord with this set, and it's not no-brain obvious where to plug it in -- I see some holes just behind the bezel on the bottom of the head, with a red button that looks like a "test" button; is that the synch connector? If so, I might have to fabricate something to adapt a household cord (since I have a couple household-to-PC extensions around).

However, I think I'll start by building a battery unit and putting 340 of these little LR44 alkalines in it, to see if the capacitors will reform. I've got a much smaller "consumer" strobe, probably 10 years newer thans these Strobonar units, that reformed pretty nicely (though the original NiCd cells in that are completely shot, it charges and fires nicely on the 120V supply cord).

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Murray@uptowngallery.org



Joined: 03 Apr 2002
Posts: 164
Location: Holland MI

PostPosted: Fri Aug 25, 2006 6:41 pm    Post subject: Reply with quote

Did you say 340 LR44 batteries? Did they cost more than the flash?

I wonder if you could stack them in shrink tubing ...

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ImageMaker



Joined: 20 Jun 2006
Posts: 93
Location: North Carolina

PostPosted: Sat Aug 26, 2006 11:56 pm    Post subject: Reply with quote

Well, given the flash units cost, IIRC, ten bucks at a yard sale 10-15 years ago, yeah, I guess $34 worth of batteries would be more than the flash -- but at 10/$1, the 340 LR44 cells aren't all that painful; the original 510V carbon-zinc stacks cost close to that price in the 1960s.

I was thinking of Lucite or polystyrene tube to carry the cells; shrink tube is too flexible. I'm intending for this to allow for replacement of the cells when they run down, as I hope to use the flash semi-regularly once I get it back up to snuff.

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Thomas Evans



Joined: 05 Jul 2004
Posts: 10
Location: Northern California

PostPosted: Fri Oct 06, 2006 10:23 pm    Post subject: Reply with quote

I have a Strobonar 880 that was intended to be used with the Eveready 497 510 volt battery, or with an AC adapter, and not with the four Sub-C NiCads in the battery compartment. In fact, the manual describes the battery tray as a handy storage tray for the sync cord. If the 800 is the same, you should find three rectangular holes underneith and just behind the bezel. and two small round holes. The rectangular holes are for a sync cord with household plug, inserted either way with one prong in the center. the two small holes are for plugging in a Prox-o-light (flash ring around the lens).
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