Battery hungry remote control for JVC Radio

[Jimbo]

Moderators, please relocate this enquiry to 'Modern Technology' if it is more appropriate there.

Our kitchen radio is a JVC 'Flat Panel' DAB/FM receiver with a front loading CD player, model RD-D227B. Other than simple on-off / volume / waveband / up-down stations buttons, all of the controls, [tone equalisation / scanning / CD track selection / timer / Bluetooth / USB] are accessible only from the separate remote control handset, model RM-SRDD227.

Unfortunately the remote control handset has developed an appetite for its CR2025 batteries, and destroys them at the rate of about one every 10 days!

Without the remote control, the tone equalisation defaults to 'pop' settings with added bass boost which makes listening to any speech programmes very unpleasant.

I have checked [with the camera on a mobile phone] that the remote control is only producing an infra-red pulse when one or other of the buttons is pressed, so there must be another current drain on the battery as well.

So far I have not been successful in trying to open the case of the remote control, -and I don't know if opening it up will reveal anything useful.

Replacement remote controls do seem to be available, but before I give up and part with the cash I would be grateful for any advice that others may have.


Thank you. Jim M0GJD

[60 oldjohn]

Hi Jim, Is there a capacitor across the battery that has failed causing a high drain on the battery when a button is pushed, or a corrosive path that is draining the battery?

How fresh are the batteries? reputable make? not fakes?


John.

[Herald1360]

A couple of thoughts....

Are you using known branded cells or "ten for a quid" cheapies?

Has anything ever been spilled on the remote or a cell leaked in it?

Do you have enough access to measure any idle current? (Perhaps some mileage in a couple of foil tails with insulation between to get into a series connection between cell and remote?)

[paulsherwin]

'Ten for a quid cheapies' should last a lot longer than 10 days, especially in a remote control which won't see heavy use. There's something else going on here.

[Tractionist]

I've had this with motor vehicle Plibs too ...... obviously a short, probably a tiny SMD cap - I just changed the board.

[SiriusHardware]

If you have a bench power supply with current indication, try running the remote on that and seeing what the 'idle' current is (when the remote is doing nothing and there are no keys pressed).

If you don't have a bench supply but you do have a meter with a mA / uA range try breaking into the battery connection path and measuring the standing current that way.

One homebrew tool I find helpful for this is a narrow (~1cm wide) strip of cardboard with two bits of copper foil stuck on either side of it near one end - solder wires to the foil 'pads', take the two wires to the mA / uA terminals of your meter and shove the end of the cardboard strip between two of the battery contacts so the current is forced to flow from one foil pad, up to and through the the meter and back down the other wire to the foil pad on the opposite side of the card strip.

The copper foil pads of course should not touch each other, so ideally make them a little bit less wide than the cardboard strip.

[Jimbo]

Thank you all for your helpful replies and thoughts.

I was not able to use the 'contact sandwich' method to measure the current consumption as [I discovered later] the JVC remote control uses a contact on one face of the CR2025 cell for the -ve terminal, and a spring a bit like a safety pin that makes contact on the far edge of the cell for the +ve terminal. Unfortunately the plastic battery carrier prevents access to the -ve side of the cell so no luck!

However I did manage to prise the case apart and managed to measure the current consumption with the battery connected by clip-leads to the pcb.

The stand-by consumption is just under 60 micro-Amps, suggesting a 50kOhm load on the 3V cell, which is greater than the 15kOhm load that the 'Energiser Battery' data sheet suggests would give about 750 hours [a month] of usage to draw the terminal p.d. down to about 2.8 Volts.

When I have changed batteries in the past, [and I have been using reputable manufacturers], the off load p.d. has been about 2.85 Volts

I have noted that cells that fail to make the remote control work still have enough energy to pulse the infra-red LED, so I can only imagine that the integrated circuit that modulates the LED signal is particularly fussy about the supply voltage and is not sending data correctly to the LED. [There are only three components on the PCB....the LED, the integrated circuit, and one other tiny surface mounted item with no visible markings].

With nothing else that I can get-at to test, I think I am resigned to buying a replacement remote control, -readily available on the Internet. In this respect I am surprised at the number of identical remote control handsets are available as 'used' on Internet auction sites! What have the vendors done with the rest of the set?

Thanks again.

Jimbo M0GJD

[Mooly]

If I was faced with this I would probably give the remote a good wash in hot water using detergent on the PCB. Just be sure to dry thoroughly afterwards using a paper towel initially to wick up water from under any components. Then dry on a radiator. Make sure battery contacts are clean. Use ISO or similar.

Also have a look at page 6 here titled 'Passivation'. This is something I have encountered with key fob coin cells where they seem to just stop working if left unused for a long period and yet the battery is ultimately OK.

https://data.energizer.com/pdfs/lithiumcoin_appman.pdf

http://www.michaelshell.org/gadgetsa...liconeoil.html

Me washing a remote: