From the previous remote control duplicator blog series, you may know that copying position is very important in getting signal successfully copied, and the back to back position usually works the best.
But for customers that haven’t seen the blog post yet, they may use various positions such as place two remotes side by side when using remote control duplicator, and it works sometime, or in some batch, but doesn’t work sometime later, so customer always ask, is there any changes in remotes production process? why remote doesn’t work now, but works before?
The answer is yes and no, no because we didn’t change anything from software to hardware, yes because there is a value range of one important component used by remote control duplicator to detect signal, and it affects the sensitivity of remotes detecting signal.
This one important component is 2SC3356 or R25 by chip marking, it serves as a amplifier to amplify the RC wave that remote control duplicator picked up, there is a parameter called DC current gain or hFE, when hFE is higher, the sensitivity of cloning remote is better, thus easier to copy the signal from a certain position, and vice versa.
From datasheet of R25 from Renesas semiconductor, we can see the normal value of R25 is 125 – 250, sometimes when the value is higher, the remote control duplicator sensitivity is better, and sometimes when value is lower, you will need to put two remotes more closely together.
The datasheet of R25 or 2SC3356 transistor can be found here at website, and the corresponding paragraph can be found on P2, hFE classification.
So it is normal that all cloning remote control duplicators are different in sensitivity, and we recommend our customer using back to back position or refer to our blog post for more details.
Recently we have found another way to improve cloning remotes sensitivity by using another model transistor mark L6 or 2SC1623, the advantage of 2SC1623 over 2SC3356 is the average hFE of 2SC1623 or L6 is around 200 – 400, making it more suitable to use in this cloning signal pickup application.
The datasheet of L6 or 2SC1623 transistor can be found here at Renesas website, check P3, hFE classification for details on this issue.
We will experiment the new model RF transistor at our factory and hopefully the research will improve our cloning remote control quality in future.
Updates – during our research, our engineer find it’s better to keep using original R25 design, since it has better performance, and we will keep using R25 from famous brand to improve quality.