URC-7540 One For All Not Responding To JP1 Simple Interface

Tiku · Post by **Tiku** » Tue Apr 15, 2014 5:10 am

Hi All, i have already upgraded my URC-7541/44 Many times but now i have got another one URC-7540 Which is not communicating with IR804, after clicking check interface i get this message 'No response from interface,Make sure the interface is connected to PC.and that you've specified the correct port",where as there is no problem with URC-9541/44, Can anybody help me out. Here's the inside pics,Thanks.

PIN 4&6 are connected to processor and also to the pads of U2 IC.

mdavej · Post by **mdavej** » Thu Apr 17, 2014 7:39 am

I'm no expert on these, but it looks like your new remote has no EEPROM (U2). The blob is the processor, not the EEPROM. Perhaps you can add one as we do on the 6131.

https://www.hifi-remote.com/forums/viewtopic.php?t=2590

Post by **The Robman** » Thu Apr 17, 2014 8:10 pm

You definitely need to add the missing EEPROM chip (in the U2 spot) and a capacitor in the C11 spot. I see that the C6 spot is also vacant and I can't tell if there's anything in the C2 spot, but I don't know if those need to be filled, but the C11 for sure needs a capacitor.

Tiku · Post by **Tiku** » Fri Apr 18, 2014 12:33 am

Ok, Thanks Robman you made it quite clear, now i would like to know about the value of C11 Capacitor. what should be the value of C11?,also what about C6? its also empty, does it also need a capacitor? if yes, than how much V & uF required.
Thanks.
Here's More Detailed Picture Of
URC-7540(Black)

Post by **The Robman** » Fri Apr 18, 2014 8:43 pm

Sorry Tiku, I don't remember. You could try searching for URC-8011 or URC-6011 as those remotes were also missing a few capacitors and a resistor if I recall correctly.

Post by **The Robman** » Fri Apr 18, 2014 9:08 pm

ok, I found it, C11 is 0.1 uF and I think C6 is the same. You should use a 24C16 chip for the U2 EEPROM chip.

Tiku · Post by **Tiku** » Fri Apr 18, 2014 11:34 pm

Rob. you have not mention the voltage,what voltage is required also are you talking about the ceramic capacitors like the one s in the pic.

or this will also work? Its 50v.
https://www.sparkfun.com/products/8375

Post by **The Robman** » Sat Apr 19, 2014 2:07 pm

I'm really hoping that someone with a more current memory will jump in here and provide some answers as I haven't done anything with remotes in years. I only knew about this thread because you sent me a few PMs on it.

The one thing I can tell you is that you need surface mount parts, not the feed through types that you posted pics of. And making a guess about voltage, a 4 battery remote starts off with 6v and a 2 battery remote starts off with 3v, so you would be looking for something in that range.

This is purely a guess, and you would need to check the physical size, but I would think you need something like this...
http://www.digikey.com/product-detail/e ... ND/2050319

Tiku · Post by **Tiku** » Sun Apr 20, 2014 9:27 am

Both my remotes are 2 batteries, that means i have to look for 3v Capacitor Right? Please see the pic of URC-7541 & the chip marked, i would like to know Is it C11? if yes then i guess i need same value for my URC-7540, can you or anybody tell me how to test its value with voltmeter so that i can try to find same value chip from the Scrape of PC Motherboards or satellite receivers PCB as its not possible to find these type of chips in our local market.
Thanks.
URC-7541

Just for the info the size of C6(6mm) and C11((5mm),from the pads of URC-7540.

3FG · Post by **3FG** » Sun Apr 20, 2014 11:40 am

The voltage rating of a capacitor is the maximum voltage it can tolerate. It's perfectly fine to use a capacitor with a higher voltage rating, and nearly any capacitor that you'll find on a circuit board will be able to tolerate the 3 volts from the batteries. To measure the capacitance value, you need a capacitance meter. If your meter has a scale for nano or micro Farads, you can measure the capacitance. If you find capacitors with markings (but UEI generally uses no markings on the capacitors), then use this converter to find the capacitance value. UEI generally does mark resistors, so don't confuse the two kinds of parts.

Tiku · Post by **Tiku** » Mon Apr 21, 2014 11:17 am

OK, I Got 24LC16B Chip in my local market but the vendor told me that i have to get it programmed according to my device as these chips are used in many different devices,
No one in the forum took bother to inform me that these chips comes blank and i have to programme before soldering it, now please i request forum friends to guide me to the file section of this chip so that i can get it programmed over here. one more thing i want to know is that, the file of this chip is common for all the remotes or i have to look for specific model file, Thanks.

3FG · Post by **3FG** » Mon Apr 21, 2014 1:50 pm

For JP1 remotes, the chip is supposed to be soldered in blank. You should know this if you have "bothered" to read the threads on adding EEPROMS to JP1 remotes. After the chip is soldered in, then RMIR or IR is used to program the EEPROM.

This thread from the stickies is a good place to start, and there are others if you use the search function.

Tiku · Post by **Tiku** » Mon Apr 21, 2014 11:00 pm

Rob, do i have to initialize the chip after soldering in URC-7540 Like explained in the text "Adding an EEPROM chip to the URC-6012w, URC-6011 and URC-8011 remotes".

3FG · Post by **3FG** » Mon Apr 21, 2014 11:34 pm

Yes, you do need to do the 981 reset, and see the 4 flashes.

Also see this thread (found by searching on 7540 EEPROM) which says you need to solder a shorting wire across "J12", which I think means J2.

Tiku · Post by **Tiku** » Mon May 05, 2014 12:08 pm

Ok,3FG, I bought Atmel 24C16N Chip Today, can you please mark on my pic which side of the pad should be pin1 of the chip.
URC-7540 (Black)

shorting wire across "J12", which I think means J2.

there is neither J12 nor J2 on the PCB, I have only J9 & J10 and both
are having their chips already soldered see the top full size pic.