Hello,
I just got a Romisen RC-T6 off ebay today, and I haven't found a really detailed tear-down or mod of it yet. So I thought I'd drop one, as this thing seems really cheap!
As a sidenote: if you are getting this off ebay, don't get the one with the charger included ("SINCE SE-H001"). The charger is absolute garbage.
I've tried to avoid duplicating anything that's in the other threads!!
Obviously do anything in here at your own risk - there's a very good chance of damaging your flashlight, or running your batteries at too high a drain current, which could cause fires.
Construction
The flashlight is constructed pretty well! As other people have mentioned, the wiring is pretty crappy...
I was interested in the o-rings, as I'm hoping to make this waterproof for a dive light.
There is double o-rings on the extension tube / battery end, with lots of grease:
However the two seals closer to the head have a single o-ring, but they do still have the o-ring at least!
And the glass does have an o-ring pushed against it:
Tear-Down
Taking the flashlight apart is a little tricky, you've got to do it in the right order! Don't just twist or you might rip all the wiring out (see other threads):
You MUST unscrew the very front part of the flashlight first. Wack it on the table if needed to break the seal...
With the front off, you should be able to twist at "3", make sure the six LEDs are twisting with the main body.
When you take the reflector out, you should see the heatsink the LEDs are mounted on. Note that when putting the reflector back in, it is NOT perfectly symmetrical. You'll have to rotate it until the LEDs line up perfectly, which they will.
Here's a picture of the heatsink:
And here's how it looks with the reflector out:
Finally you have to remove the LED driver. To do this use pliers, and unscrew the aluminum part carefully:
Then the driver should slide out. There you go, that's it!
LED Driver
The box on the Romisen said it would work from 6V to 16V input. The driver itself is based around a PT4105 (see http://www.zhaoming.com/bbs/u/2008/08/22/13021219393302.pdf), of which there are three exact copies. Each driver drives two LEDs.
The switch just mechanically selects if 1, 2, or 3 drivers are powered. There is no intelligence to it, no memory. The order is 1,2,3 driver for low/med/high.
The Mod
The feedback resistor can be adjusted to adjust current. Before the mod each LED had 0.389A* going through it. I only modified two of the drivers in the end, leaving two LEDs with 0.389 and four with 0.505A*. This was done for two reasons: (1) to have a "not suicidal bright" setting, and (2) to avoid having too high a drain on the battery (it's still pretty high!).
*measured with DC ammeter, won't capture peak.
I added a 1-ohm resistor in parallel with the on-board 0.27 ohm resistor:
In my case I only did that to two of the .27 ohm resistors. In fact in the final version the resistor shown in this picture isn't mounted, this is the only .27 ohm that wasn't modified!
The inductors for the driver are on the other side, they are 22 uH. I noticed some stability / start-up problems with the driver, since you are now running it will above the designed current! But it seemed to work most of the time!
Here's the unmodified one:
There's a snowstorm outside right now, so can't get any outdoor beam shots sorry.
Hope someone finds this useful / interesting!
Regards,
-Colin
I just got a Romisen RC-T6 off ebay today, and I haven't found a really detailed tear-down or mod of it yet. So I thought I'd drop one, as this thing seems really cheap!
As a sidenote: if you are getting this off ebay, don't get the one with the charger included ("SINCE SE-H001"). The charger is absolute garbage.
I've tried to avoid duplicating anything that's in the other threads!!
Obviously do anything in here at your own risk - there's a very good chance of damaging your flashlight, or running your batteries at too high a drain current, which could cause fires.
Construction
The flashlight is constructed pretty well! As other people have mentioned, the wiring is pretty crappy...
I was interested in the o-rings, as I'm hoping to make this waterproof for a dive light.
There is double o-rings on the extension tube / battery end, with lots of grease:
However the two seals closer to the head have a single o-ring, but they do still have the o-ring at least!
And the glass does have an o-ring pushed against it:
Tear-Down
Taking the flashlight apart is a little tricky, you've got to do it in the right order! Don't just twist or you might rip all the wiring out (see other threads):
You MUST unscrew the very front part of the flashlight first. Wack it on the table if needed to break the seal...
With the front off, you should be able to twist at "3", make sure the six LEDs are twisting with the main body.
When you take the reflector out, you should see the heatsink the LEDs are mounted on. Note that when putting the reflector back in, it is NOT perfectly symmetrical. You'll have to rotate it until the LEDs line up perfectly, which they will.
Here's a picture of the heatsink:
And here's how it looks with the reflector out:
Finally you have to remove the LED driver. To do this use pliers, and unscrew the aluminum part carefully:
Then the driver should slide out. There you go, that's it!
LED Driver
The box on the Romisen said it would work from 6V to 16V input. The driver itself is based around a PT4105 (see http://www.zhaoming.com/bbs/u/2008/08/22/13021219393302.pdf), of which there are three exact copies. Each driver drives two LEDs.
The switch just mechanically selects if 1, 2, or 3 drivers are powered. There is no intelligence to it, no memory. The order is 1,2,3 driver for low/med/high.
The Mod
The feedback resistor can be adjusted to adjust current. Before the mod each LED had 0.389A* going through it. I only modified two of the drivers in the end, leaving two LEDs with 0.389 and four with 0.505A*. This was done for two reasons: (1) to have a "not suicidal bright" setting, and (2) to avoid having too high a drain on the battery (it's still pretty high!).
*measured with DC ammeter, won't capture peak.
I added a 1-ohm resistor in parallel with the on-board 0.27 ohm resistor:
In my case I only did that to two of the .27 ohm resistors. In fact in the final version the resistor shown in this picture isn't mounted, this is the only .27 ohm that wasn't modified!
The inductors for the driver are on the other side, they are 22 uH. I noticed some stability / start-up problems with the driver, since you are now running it will above the designed current! But it seemed to work most of the time!
Here's the unmodified one:
There's a snowstorm outside right now, so can't get any outdoor beam shots sorry.
Hope someone finds this useful / interesting!
Regards,
-Colin
