It appears the remote for my camera broke the other day, the remote is a Vivitar RC-200. Both pieces work; LED's light up and the receiver can trip the camera with it's on-board shutter release. I'd typically buy another one but I think they increased from $17 to $35 since I last bought one. I think. So, I'm going to attempt a repair. Some research brought to my attention that I can resync the two back together by performing the following:

Quote:
To synchronize the transmitter and the receiver of the Shutter Release, please follow the steps given below:

1. Turn on the receiver by holding down the Set/Power button for about 3 seconds until a red LED light comes on.
2. Repeatedly press the Set/Power button 5 times until the other LED light begins flashing red.
3. Press the shutter button on the transmitter.
4. The flashing red LED on the receiver will stop flashing and your unit is now synchronized.

To check this, press the shutter button on the transmitter half way down. The LED lights on the transmitter and receiver turn green if it is synchronized.


I got the same instructions from Vivitar support. I have two of the transmitters and one receiver from when I lost my first receiver. I tried syncing both transmitters to the receiver with out success. So, I took apart the receiver.

I can't find the antenna. It's got to have one. It must be pretty inconspicuous. I have one hunch and I worked on that for a bit with no luck.



This picture would be viewing from the bottom of the receiver, closest to the camera. I think the towery screw thing in the middle right with the red wax is the antenna. I unscrewed it completely and screwed it back in a bit tighter. No luck. There's a redding brown resistor(?) in the lower center that looks like it split towards the left side.

I don't think there's anything worthwhile on the top side, but I'll include it because one thing peaks my interest.



The top metal square is the shutter release, the rectangle one in the lower left is the On/Off button and the switch on the right is the mode: Hold & On. The beige square module below C2 in the middle right alludes me, it might be an antenna too, but I'm not 100% positive as I still have my money on the screwy thing.

Any other guess as to what the antenna might be, so I can try and repair this? After awhile of no success I will go out and buy another, and take it apart just to see if the reddish brown thing is suppose to have the split.
I don't see any particular indication that this thing is actually RF. What makes you think it is? These things are usually IR.

comicIDIOT wrote:
This picture would be viewing from the bottom of the receiver, closest to the camera. I think the towery screw thing in the middle right with the red wax is the antenna. I unscrewed it completely and screwed it back in a bit tighter.
Looks like a trimpot to me. If this device is really RF, you probably totally screwed the calibration.

comicIDIOT wrote:
No luck. There's a redding brown resistor(?) in the lower center that looks like it split towards the left side.
Things that look mechanically broken often are, but I can't tell from that photo.

comicIDIOT wrote:
The beige square module below C2 in the middle right alludes me, it might be an antenna too,
It's a capacitor.

comicIDIOT wrote:
Any other guess as to what the antenna might be, so I can try and repair this?
There's no obvious antenna, so if this is indeed an RF device, the antenna's probably a simple trace antenna. Whatever the case, the antenna would likely not be the problem, since it's a very simple passive component. Finding the problem would probably require a full-scale teardown and functional analysis, so I'm going to say you're screwed (and likely borked the calibration by messing with that trimpot).
The thing in the middle with a screwdriver is likely a tuneable inductor, either for a receiver LO or a bandpass filter. This seems like an RF remote, if it were IR you'd have to point the remote at the receiver.

I suspect that the top picture, the part down towards the battery is a banded RF module that receives at specific bands that would be country specific. U2, on the back side, it probably a cheap remote control IC. If I had to guess, I suspect that the antenna is between the two boards (RF module, and main remote board). The Reddish brown thing that's cracked may be a dipped tantalum cap.

C2 is a tantalum cap for sure.
It is indeed RF, it also as 160,000 frequency combinations if I recall correctly. Bah, no fun that I may have screwed the calibration. What exactly is there to calibrate in an RF device? Just the frequency?

rfdave, a lot of the circuitry in the top picture is on a secondary board that's raised a millimeter or three from the main board. Is that where you suspect the antenna might be?
Quote:
It is indeed RF, it also as 160,000 frequency combinations if I recall correctly. Bah, no fun that I may have screwed the calibration. What exactly is there to calibrate in an RF device? Just the frequency?

It could be a couple of things.

- Oscillator Frequency. There's probably a local oscillator generating a signal to feed into a mixer, using that to downconvert the incoming RF signal to a lower frequency that can be demodulated.
- FM demodulator. Look http://www.radio-electronics.com/info/rf-technology-design/fm-reception/fm-demodulation-detection-overview.php for some details.

Quote:
rfdave, a lot of the circuitry in the top picture is on a secondary board that's raised a millimeter or three from the main board. Is that where you suspect the antenna might be?

Yes, I suspect that it's in there, on the bottom of that secondary board. It looks like there's some tape between the two, possibly as an insulator.
  
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