Super Graphic Battery Conversion?

[E. von Hoegh]

I haven't got it figured out THAT well. Here is the circuit diagram. Note the diode in it. I wondered yesterday why there would have to be a diode, till it occurred to me it must be to protect against insertion of the batteries backwards. Now it occurs to me to wonder if it would be a simple enough test of the operation to just hook up 90 volts AC straight off thee 90 volt tap of my isolation transformer, let the camera's own diode provide rectification to 45 volts, and fire the shutter switch to see if it works. If someone can point out something wrong in my thinking, I'd sure like to hear it. Attachment 103831

You're way too full of... yourself.

[HT Finley]

You're way too full of... yourself.

That's too bad. I've come to respect your expertise, but somehow I've managed to get on your bad side.

[dsphotog]

If I remember correctly the Super or TRF Crown also have an illuminated rangefinder focus system. Is that right?

[HT Finley]

The TRF Speeds and Crowns did, but I don't think the Super had it, which defies understanding. I'll see when it gets here tomorrow. If it does not, you can bet I'll dream up a way to retrofit one somehow.

[Jac@stafford.net]

The main reason they used a 22.5V battery with a capacitor was due to the poor retention of voltage compared to today's batteries. Flashes of sizes including the monsters F-33 and Mazda 75 would trip with a minimum of 4.5 volts, but nobody wanted to risk a shot with a poor battery. I do not know if today's replicas are better. Shame if they are not. Perhaps someone could inform us.

If I remember correctly the Super or TRF Crown also have an illuminated rangefinder focus system. Is that right?

That was a variant of the Focuspot and worked with 3V to 4.5V. More to 22.5V plus didn't hurt with the proper bulb.

[gleaf]

Fast electronics 101. Diode is an on off switch. Reverse direction it is a open until you exceed the prv. At that point it becomes a carbon short then burns open if your lucky. In the forward direction the on state voltage drop is approx. half a volt. 90 - 0. 5=89.5 volts to the circuit. E=I *R or in this case I=E/R. E=90 ... everything was designed
for battery voltage that dropped over time. I know you want to try it. Variable transformer to drop active to 45 vac or two Door bell type 24 volt (hardware store should have them, used in heating cooling for thermostats control voltage) transformers would be much less of a Smoke Test situation. If I get a chance tonight I will check the ohms of my Crowns solenoid. Trouble with smoke tests is the release of smoke from micro parts burning is nearly instant. Enjoy your learning experience.

[BrianShaw]

The main reason they used a 22.5V battery with a capacitor was due to the poor retention of voltage compared to today's batteries. Flashes of sizes including the monsters F-33 and Mazda 75 would trip with a minimum of 4.5 volts, but nobody wanted to risk a shot with a poor battery. I do not know if today's replicas are better. Shame if they are not. Perhaps someone could inform us.

Jac... That may be true of many flash units of the 50s and 60s, but the battery on a SuperGraphic does not trip the flashbulb... it only operates the shutter solenoid. The 2 or 3 D-cell batteries in the battery case trip the bulb.

Re: focuspot... it really is too bad that the Super never offered that!

[Jac@stafford.net]

Jac... That may be true of many flash units of the 50s and 60s, but the battery on a SuperGraphic does not trip the flashbulb... it only operates the shutter solenoid. The 2 or 3 D-cell batteries in the battery case trip the bulb.

Thanks for the information. My ignorance is bottomless. I had no idea.

Re: focuspot... it really is too bad that the Super never offered that!

Wasn't there something like the focuspot built into the RF?

[HT Finley]

Fast electronics 101. Diode is an on off switch. Reverse direction it is a open until you exceed the prv. At that point it becomes a carbon short then burns open if your lucky. In the forward direction the on state voltage drop is approx. half a volt. 90 - 0. 5=89.5 volts to the circuit. E=I *R or in this case I=E/R. E=90 ... everything was designed
for battery voltage that dropped over time. I know you want to try it. Variable transformer to drop active to 45 vac or two Door bell type 24 volt (hardware store should have them, used in heating cooling for thermostats control voltage) transformers would be much less of a Smoke Test situation. If I get a chance tonight I will check the ohms of my Crowns solenoid. Trouble with smoke tests is the release of smoke from micro parts burning is nearly instant. Enjoy your learning experience.

Thanks gleaf. I've been restoring and working on radios, TV's tape recorders, test equipment--most everything for years, but I seriously doubt I'd pass Electronics 101. I get the part about PRV, but I just did not follow what you said. The mail lady will be showing up with my Super any minute, and it will be some time before I could have any batteries shipped in for it. I'm itching to find a way to hook up my tapped isolation xformer to it, but not entirely sure what I need to do. I can tap off anywhere between 25-125VAC. And I have a leftover diode I bought to experiment with a wave-clipping experiment for my soldering iron to run it at half voltage when I wasn't using it immediately. (The idea was to keep it warm when idling, and flip a toggle switch to give it full wave 117 when I pick it up to solder something). Thanks.

[Tin Can]

Before you hot wire that solenoid, why not find out if it's rare and expensive.

Just a thought.

Thanks gleaf. I've been restoring and working on radios, TV's tape recorders, test equipment--most everything for years, but I seriously doubt I'd pass Electronics 101. I get the part about PRV, but I just did not follow what you said. The mail lady will be showing up with my Super any minute, and it will be some time before I could have any batteries shipped in for it. I'm itching to find a way to hook up my tapped isolation xformer to it, but not entirely sure what I need to do. I can tap off anywhere between 25-125VAC. And I have a leftover diode I bought to experiment with a wave-clipping experiment for my soldering iron to run it at half voltage when I wasn't using it immediately. (The idea was to keep it warm when idling, and flip a toggle switch to give it full wave 117 when I pick it up to solder something). Thanks.