My wireless radio flash trigger modification

[OlyFlyer]

I just received my first radio trigger which I bought via eBay. It is a 4 channel type, called YONGNUO. It seems to work fine for what I intend to do, except for one thing. I have many old flashes, and since I have been around using SLRs for about 35 years, I have several old, fully functional, which are of high trigger voltage type. I haven’t checked before hitting the “Buy now” button and I missed the information about the trigger only supporting low trigger voltage type of flashes. Anyway, as soon as I realized that, I tried out a mod, which works fine, so I made a permanent modification to make sure it can be used with any flash.

The mod is a very simple one. I started by measuring the output pulse.



It gives a 700mV 120ms long pulse, so I figured it will work just fine for triggering a triac.

I de-soldered the centre contact and in between the GND and the centre pin contact I added a triac and connected the gate to the circuit board contact where the centre contact was before. The triac is an L401E5 type, I chose this one because I had one on my desk, but almost any one would work as long as it can stand the current and the voltage. The one I used is a 400V 1A type.



Triacs are supposed to be insensitive of polarity, but for some reason this one is not, which I found out quickly. On the test bench I connected the triac via some lose jumpers with clips. When I tested it that way it worked fine. Then I soldered permanently and closed the box. After doing this, the trigger did not work, and I actually thought I fried it or the triac.



Of course, I de-soldered and put it back the other way, just in case…

As a result, it seems to work fine now with my old flash with the highest trigger voltage.



End of part 1.

[OlyFlyer]

Part 2.

In case anyone plans to buy this trigger, there are some things to be warned about. Some flashes have other than centre contacts as well, like all the TTL flashes, old and new. The T32 has for example two extra contacts and a little plastic tab.



The plastic tab normally lifts up the extra contacts, into the shoe. That is, with every other trigger I have seen, except this one. The reason is that the plastic tab falls into the screw hole in the middle, which is too bad.



The only way to avoid that is by adding a plastic strip which prevents the contacts to touch the base, the GND part of the trigger. If you are not doing this the flash will always fire at full power, regardless of the settings you select.

In a way, the FL flashes are even worse because they have even more contacts and no plastic tab to lift the electric contacts.



The metal pin which locks the flash is of no use since the flash trigger has no hole for it. I decided never to use this trigger with my FL-50. I just don’t want to risk the flash getting stuck on the trigger or falling off of it.

Another nice feature is that the actual transmitter has also a PC cable, so I can connect the trigger transmitter and at the same time use the pop-up flash, or another one, for example the FL-50 on top of the camera.

BTW, I just ordered two more radio triggers.

[Mikefellh]

This came just in time for me...I bought a Sankyo wireless remote that was designed to trigger when an 8mm video camera would turn on and off, and it was my intention to use it to trigger flashes manually remotely. I was going to get a relay to do this, but now I'll just use this idea.

[OlyFlyer]

Mike, I am glad you find my idea useful but before you start, wait for part 3. I will post as soon as I can upload my images to Photobucket.

[OlyFlyer]

Today I decided to continue, since there was some space left in the box. I thought I better add a more powerful triac and a second output. I pulled out of my desk drawer a BT136, which is a 600V 25A non repetitive peak, or 4A RMS current type and I connected it. GND to common (T2 on the triac), Gate to the trigger output and T1 to the tip contact of the 2.5mm connector.



To fit the connector, I used the screw hole, since I will not use the ‘L’ shaped attachment anyway. That is in my opinion too weak to use as fixing, I am afraid the flash will fall, since all my old ones are quite heavy.



I figure this one can now handle every flash. The plastic box is now full and I can close the lid.



When All that was done, I decided to test in case I can trigger the camera with it as well. I pulled out my JJC eBay RM-CB1 clone which also has a 2.5mm external connector and interconnected this with my new Wireless radio trigger.



Voila. No problem, the flash trigger triggers the camera as I suspected. There is an occasional refusal of triggering the camera, which I suspect is due to the fact that I just picked a piece of cord with two 2.5mm mono male connector at each end, and the connector is not connecting to the right contacts. I used this piece of cord back in the OM days to connect my flash grip to the winder which was used on my OM cameras. I will buy a stereo plug as soon as possible to make a proper connector to solve this tiny final step in making my US$23 Wireless radio flash trigger into a high quality, high voltage universal dual output trigger.

[splim]

Do you know if this works on FL36(R) ?

My other brand pt-04 has a Thyristors MCR 100-6 can handle 400V 0.8A but doesn't trigger FL36R

I measure the DC voltage of the flash:
FL36R=4.53v
FL50R=4.55v

[OlyFlyer]

I don't think there is any difference between the FL-36 and the FL-50 in this regard. The shoe is similar, the contacts and the communication is the same.

I don't know about the older triggers, but there is a slight possibility that your old one needs some power from the flash as well. I know the old one could not trigger Canon flashes, or were unreliable. Maybe you have the same problem.

Please note, if you think of using this trigger on an FL-flash, I advice you to read my warning about TTL flashes. That includes the FL-36 as well. You simply MUST make sure only the centre and the side contacts of the flash are connected to the trigger, all the other MUST be isolated. I don't know what will happen with the flash if you don't do that, if you are lucky then nothing, if you are less lucky you get some uncontrolled flashes and if you have real bad luck you will fry your flash. Personally, I will not use this trigger on my FL-50. I have enough flashes, so I don't feel I have to take any chances.

[Mikefellh]

Just as an example, my Vivitar optical slave requires a trigger voltage between 30v and 350v, so obviously they couldn't be used with the Olympus flashes.

Actually I've had monolight strobes damaged because people insisted on using a Safesync when it wasn't needed (something about damaging their camera)...the Safesync draws a certain amount of power from the device to operated, and it was too much for the diode that was used in the strobes.

[Blu-By-U]

Since this wireless trigger would render the FL flash's TTL interoperable, it makes no sense to use those FL with it. A brandless cheap manual flash should be sufficient for most needs.

[OlyFlyer]

I agree in a way, but if I had no other options I'd still use this. Just that one must cover the TTL contacts and allow only the centre contact to touch the trigger. I am not sure if it would do any damage to the FL flashes, but it is better to be careful. I have many other alternatives, sine I have quite a few other flashes as well.

[Blu-By-U]

I ordered a similar wireless trigger.. I notice that the raised plastic in the middle would isolate the 3 data pins from the metal bracket.

[OlyFlyer]

If you mean that regarding the FLflashes, yes that may be the case, I have not checked it because my intention was not to use them on the FL-50. Using it on the T32 it causes some issues unless additional protection is added, like a small strip of plastic.

I'll check tonight and update the thread if needed regarding the FL. I hate to spread false information and warnings, there is enough of that around on the Internet.

[OlyFlyer]

Originally Posted by Blu-By-U I ordered a similar wireless trigger.. I notice that the raised plastic in the middle would isolate the 3 data pins from the metal bracket.

Hi Blu,

I remember now, after having had a look at the FL-50 and the trigger that the reason I decided not to use with the FL-50 the first place was the fact that there is no hole for the locking pin. Be careful so that your flash won't get stuck on the trigger or won't fall off. The "L" metal bracket seems to be quite weak considering the size of the FL-50, but the electrical contacts are no problem.

The fact remains the same, if used on a TTL type of flash, careful attention must be taken prior using the trigger. The TXX flashes are definitely of concern.