Bowens Illumitran 3S

wschraml · Jun 9, 2016

Hello,

Trying to rig up an older Illumitran 3S for slide digitizing. It switches on and charges but then makes a "clicking" noise about once a second. The neon ready light is also slightly changing intensity at the same rate.
I have a schematic for an Illumitran 3 but the 3S has an additional circuit board that is not covered there. That's where the clicking seems to originate.
I connected an oscilloscope parallel to the flash bulb to observe the high voltage and sure enough, it goes down and up about every second in a range of approx. 20V.
- Wanted to verify - is this behavior normal?
- Does anyone have service info/schematic for a 3S?

If the behavior is not normal, I suspect one or both of the capacitors (trigger and main photoflash) need replacement.
Any thoughts?

Thank you.

wschraml · Jun 9, 2016

Thanks ... that gives me a starting point.
I did run a first test and the flash fires. The constant clicking is just annoying ... will probably replace the main cap first.

Old-N-Feeble · Jun 9, 2016

Probably a faulty (leaky) capacitor.

wschraml · Jun 19, 2016

After countless hours of troubleshooting, reverse engineering (I even redrew the schematic as best as I could), I came to the conclusion that the "clicking" of the relay may actually be normal. I tried a new main capacitor, replaced several other components I suspected to no avail.
My specific unit also seem to have received a factory modification for the relay used. It has a small Omron relay on a separate PCB that looks like it was created to take the place for an older, larger model.
The way I interpret the schematic:
- Initially, the relay is set to charge the main capacitor
- Once the capacitor is charged, the MOSFET will switch on the relay which in turn now switches off the main capacitor charging path and instead activates the trigger circuit
- Once the flash has been triggered, the MOSFET shuts the relay down which starts the cycle all over again

The clicking comes from the relay switching back and forth between the two main states aforementioned before the flash is triggered. The main capacitor loses enough charge once disconnected from power (probably through the relay coil itself) after approx. 1.5 seconds to make the MOSFET block and thus top of its charge again. So the two states toggle every 1.5 seconds.

Since I had the unit open and disassembled, I replaced the main capacitor with newer photoflash caps of only 375 uF in total. Hope this will reduce the flash output enough so I won't need as many opal glasses to reduce the light output enough for use of my Sony NEX-7. Haven't fully reassembled and tested it yet.

Attached a copy of my redrawn schematic and a few pics of the main PCBA and the relay modification (without the spark quenchers) that my specific unit received.

Old-N-Feeble · Jun 19, 2016

I don't know enough to help other than to tell you I used a Bowens Illumitran for 3-4 years and it didn't inadvertently click any relays as you describe. Maybe a bad solder joint?

wschraml · Jun 19, 2016

Was that a "3" or a "3S"? I also have a "3" and it doesn't have the PCBA with the enhanced electronics and the relay. Thus no clicking. The main capacitor remains always connected to the charging circuit in the "3".

Old-N-Feeble · Jun 19, 2016

I don't remember but it was an all black model, not an older gray/silver one.

owenyzone · May 16, 2020

wschraml said:
After countless hours of troubleshooting, reverse engineering (I even redrew the schematic as best as I could), I came to the conclusion that the "clicking" of the relay may actually be normal. I tried a new main capacitor, replaced several other components I suspected to no avail.
My specific unit also seem to have received a factory modification for the relay used. It has a small Omron relay on a separate PCB that looks like it was created to take the place for an older, larger model.
The way I interpret the schematic:
- Initially, the relay is set to charge the main capacitor
- Once the capacitor is charged, the MOSFET will switch on the relay which in turn now switches off the main capacitor charging path and instead activates the trigger circuit
- Once the flash has been triggered, the MOSFET shuts the relay down which starts the cycle all over again

The clicking comes from the relay switching back and forth between the two main states aforementioned before the flash is triggered. The main capacitor loses enough charge once disconnected from power (probably through the relay coil itself) after approx. 1.5 seconds to make the MOSFET block and thus top of its charge again. So the two states toggle every 1.5 seconds.

Since I had the unit open and disassembled, I replaced the main capacitor with newer photoflash caps of only 375 uF in total. Hope this will reduce the flash output enough so I won't need as many opal glasses to reduce the light output enough for use of my Sony NEX-7. Haven't fully reassembled and tested it yet.

Attached a copy of my redrawn schematic and a few pics of the main PCBA and the relay modification (without the spark quenchers) that my specific unit received.

View attachment 159263 View attachment 159264 View attachment 159265 View attachment 159266 View attachment 159267

owenyzone · May 16, 2020

Whoops, didn't mean to post the above!

wschrami, did you ever get to the bottom of the endless clicking? I have bought an illumitran with exactly the same problem. It all works ok, just the recycling and clicking shouldn't be happening. I know it's been quite a while since your original post, but was hoping you ( or someone else ) could shed some light.

Gerlo · Oct 12, 2020

Same problem here. A clicking machine. the 3S
Hopefully someone found the solution?

owenyzone · Oct 14, 2020

Gerlo said:
Same problem here. A clicking machine. the 3S
Hopefully someone found the solution?

Perhaps the clicking is normal. Is there someone out there with a 3S who could confirm whether it should click or not?

Kino · Oct 14, 2020

Has anyone ever turned off the lights and looked for a arc or discharge to ground from some electrical component? Wonder if some insulation in the flash circuit has a break and is arcing to the cabinet?

owenyzone · Oct 14, 2020

Hi Kino,

It's nothing like that, the unit just clicks when it reaches full charge. The clicking is repetitive though, every few seconds. It may actually be normal - just need someone who has one which doesnt click to say so!

Kino · Oct 14, 2020

OK. What about contacting the person who runs this web page? If anyone would know, it would likely be him...

Tom Martin

http://members.bitstream.net/tlmartin/copiers.html

Chan Tran · Oct 14, 2020

owenyzone said:
Hi Kino,

It's nothing like that, the unit just clicks when it reaches full charge. The clicking is repetitive though, every few seconds. It may actually be normal - just need someone who has one which doesnt click to say so!

Perhaps all of them click but good ones don't click as often? Your unit may have some leakage somewhere that causes the capacitor to discharge rather quickly without firing the flash?

Philippe-Georges · Nov 2, 2020

Are you talking about this?

lion · Dec 6, 2022

wschraml said:
After countless hours of troubleshooting, reverse engineering (I even redrew the schematic as best as I could), I came to the conclusion that the "clicking" of the relay may actually be normal. I tried a new main capacitor, replaced several other components I suspected to no avail.
My specific unit also seem to have received a factory modification for the relay used. It has a small Omron relay on a separate PCB that looks like it was created to take the place for an older, larger model.
The way I interpret the schematic:
- Initially, the relay is set to charge the main capacitor
- Once the capacitor is charged, the MOSFET will switch on the relay which in turn now switches off the main capacitor charging path and instead activates the trigger circuit
- Once the flash has been triggered, the MOSFET shuts the relay down which starts the cycle all over again

The clicking comes from the relay switching back and forth between the two main states aforementioned before the flash is triggered. The main capacitor loses enough charge once disconnected from power (probably through the relay coil itself) after approx. 1.5 seconds to make the MOSFET block and thus top of its charge again. So the two states toggle every 1.5 seconds.

Since I had the unit open and disassembled, I replaced the main capacitor with newer photoflash caps of only 375 uF in total. Hope this will reduce the flash output enough so I won't need as many opal glasses to reduce the light output enough for use of my Sony NEX-7. Haven't fully reassembled and tested it yet.

Attached a copy of my redrawn schematic and a few pics of the main PCBA and the relay modification (without the spark quenchers) that my specific unit received.

View attachment 159263 View attachment 159264 View attachment 159265 View attachment 159266 View attachment 159267

Sorry to revive this dead thread but I would really like to know how your modifications turned out for you? Especially how satisfied were you with the power of the flash with the 375uF Capacitor? I want to build a custom xenon flash unit for digitising and I am trying to figure out how much power I need.

presch · Oct 1, 2023

wschraml said:
After countless hours of troubleshooting, reverse engineering (I even redrew the schematic as best as I could), I came to the conclusion that the "clicking" of the relay may actually be normal. I tried a new main capacitor, replaced several other components I suspected to no avail.
My specific unit also seem to have received a factory modification for the relay used. It has a small Omron relay on a separate PCB that looks like it was created to take the place for an older, larger model.
The way I interpret the schematic:
- Initially, the relay is set to charge the main capacitor
- Once the capacitor is charged, the MOSFET will switch on the relay which in turn now switches off the main capacitor charging path and instead activates the trigger circuit
- Once the flash has been triggered, the MOSFET shuts the relay down which starts the cycle all over again

The clicking comes from the relay switching back and forth between the two main states aforementioned before the flash is triggered. The main capacitor loses enough charge once disconnected from power (probably through the relay coil itself) after approx. 1.5 seconds to make the MOSFET block and thus top of its charge again. So the two states toggle every 1.5 seconds.

Since I had the unit open and disassembled, I replaced the main capacitor with newer photoflash caps of only 375 uF in total. Hope this will reduce the flash output enough so I won't need as many opal glasses to reduce the light output enough for use of my Sony NEX-7. Haven't fully reassembled and tested it yet.

Attached a copy of my redrawn schematic and a few pics of the main PCBA and the relay modification (without the spark quenchers) that my specific unit received.

View attachment 159263 View attachment 159264 View attachment 159265 View attachment 159266 View attachment 159267

Electrolytic capacitors leak slightly, usually getting worse as they age.
Adding resistors as shown helps balance out unequal voltages across the capacitors preventing the voltages across them possibly exceeding their maximum voltage rating when one or more leak more than the others.

Bowens Illumitran 3S

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