Graflex.org

[albeatty]

Hi Group,

I just returned from the local camera repair shop where I tried to get one of my 500RG heads repaired. They said the parts were no longer available. Here is what it is doing. It seems to charge to the point I can seen the little charge light on the back flashing indicating it is charged. The problem is it won't discharge either by pressing the button on top or via a camera connection. My other flash head works fine. Any ideas on what needs to be repaired?

By the way, I got some really good advice from all of you regarding the battery pack. The 8 D cells are working great.

Tight Lines - Al Beatty
BT's Fly Fishing Productions

[clnfrd]

Sounds like the xenon flash tube may have sprung a leak and is defective. The fact that the charge light illuminates indicates the electronics and capacitors are probably ok. When you press the test button or trigger the flash with your shutter, a trigger voltage is applied to the tube, causing it to conduct, discharging the capacitors through the xenon-gas-filled tube. If the xenon gas has leaked, it won't flash. Fred.

[albeatty]

Hi Fred,

Thanks for your responce. Any chance I could replace the tube you mentioned in your answer? Thanks again for your comments.

Al Beatty

[Graflite]

Al:

Fred is right, it does appear that the flash tube (FT-1) may be defunct, sometimes it springs a leak and loses the xenon gas and also sometimes the ends of the glass tube might appear blackened indicating a non functioning lamp.

The neon indicator light flickers when the capacitors reach a certain voltage level needed to trigger the flash tube, the trigger levels vary based on the multi level pushbutton switches on the upper capacitor pack which connects to the lower battery pack (AC, HV or RG), so it appears that everything else is working properly.

If you are knowledgeable with electronics and handy with a soldering iron then you might consider replacing the flash tube (FT-1), and what I found interesting from working on these units is that the flash tube (FT-1) for the "older" Strobomatic 500 flash head and the "newer" Strob 500 flash head, while having differences in the parts layout and schematics, both use the same flash tube, and here is where I come to the point about this subject is that the less expensive Strob 250 flash head also uses the same flash tube, which is a Graflex Part Number 40765P1, Lamp, Flash (FT-1).

Now, of course you can no longer order these parts from any appreciable stock, but what I was going to suggest is to keep an eye out for an inexpensive Strob 250 flash head (from various sources) and use the flash tube from it to solder into your Strob 500 flash head.

The flash tube has three leads: anode, cathode and the trigger transformer lead, so one must be careful to align these leads correctly on the printed circuit board.

Hope this helps and good luck.

graflite

[clnfrd]

I replaced the tube in a Heiland 64B Strobonar with a tube from this site: http://www.mouser.com/index.cfm?handler=search.processsearchb
It works.....wasn't a good fit...and, frankly, it hasn't been given much testing, so I don't know how long the tube will last in the long run. I don't necessarily recommend this if you want an exact replacement, but it was cheap and fun to make the repair. I chose a tube that would trigger with the trigger voltage of the 64B. Be advised: the charge on the large capacitors can be lethal. This charge is present at the anode of the xenon tube. The tube conducts and flashes when the trigger voltage is applied to the trigger connection on the tube. The trigger voltage ionizes the gas in the tube, causing it to conduct. Be also advised that the capacitors can hold a charge for quite a while. If you're not familiar with this type of circuitry, be very careful. The charge on the trigger capacitor may also be enough to give you quite a jolt.
Fred.

[albeatty]

Thanks Fred & graflite, what great answers. Replacing the tube is probably a bit over my head as I couldn't get the circuit board apart just now even after removing all the screws. Oh well, any idea where to buy a 500RG flash head or another brand that would work off the cords or battery pack?

Thanks again guys, you've been great!

Tight Lines - Al Beatty
BT's Fly Fishing Productions

[Graflite]

Al:

Fred is right about the capacitors, I'm so used to working with them that I often fail to mention the danger of a charged capacitor to those less familiar with them.

Some people use an insulated (hopefully) screwdriver to discharge the capacitor, which I don't like to do because it can damage the capacitor, the terminals and/or the screwdriver, plus it scares the heck out of my cat, instead I prefer to use a high wattage resistor carefully bridged between the positive and negative terminals and then check the capacitor afterwards with a voltmeter.

The RG that you refer to in your post denotes the lower portion of the battery pack which came in three versions, and not the actual flash head, as the 500 flash head that came with either the Strob 500 (or Strobomatic 500) will work with any of the battery pack's as shown below:

AC battery pack = AC/DC Transformer using an AC line cord.
HV battery pack = 1 Carbon Zinc Battery #496 450 VDC.
RG battery pack = 8 D size Ni-Cad Batteries (total > 9.6 VDC).

The RG base is the best for field shots and is the most versatile of the three bases, while the AC base is good for studio shots, and finally the HV base is pretty much useless now as the #496 battery is not made anymore.

Try e-b*y, as from time to time a 500 flash head will appear, and this seems to be your best bet, but then there is no guarantee that it will work unless the seller is able to test it first with a working battery pack, so with anything you take a chance without a money back guarantee.

graflite

[albeatty]

Hi guys,

I found a gentleman via the internet in Denver who is very proficient in repairing electronic flashes. I sent him the defective flash and less than a week later it was return in working order. His name is Paul at PK Photo & Electronics in Lakewood, CO.

Thanks for all you help and suggestions. Take care & ...

Tight Lines - Al Beatty

[Graflite]

Good information to have if you need an electronic flash repaired, Paul is the only Norman repair representative for Norman flashes in Colorado and is excellent with not only Norman flashes, but as Al pointed out, also with the older Graflex electronic flash units.

The Norman service center web page (at the bottom) has a state by state listing of other repair centers that might be closer or more convenient to you and with a phone call, letter or e-mail could advise you as to whether they can repair the Graflex units also.

Here is the Norman service center listings web page:

www.bookendzdocks.com/norman/service.htm

graflite