Help Identifying Receiver Component
03-31-2003, 12:33 AM
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Help Identifying Receiver Component
Maybe someone could help me identify a part that is in my receiver. It is rectangular, made of orangey yellow plastic, and has these marking on it.
D455
C 7
M X
The M is circled, I am assuming Motorola. I am looking for a source for one of these (Mouser or Digi Key part #). Any help would be appreciated.
Thanks
Alan Angus
D455
C 7
M X
The M is circled, I am assuming Motorola. I am looking for a source for one of these (Mouser or Digi Key part #). Any help would be appreciated.
Thanks
Alan Angus
03-31-2003, 01:25 AM
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Help Identifying Receiver Component
It sounds like a 455KHz ceramic filter -- a component that helps filter out adjacent frequencies.
The M may indicate that it's manufactured by Murata.
The M may indicate that it's manufactured by Murata.
03-31-2003, 06:53 AM
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Help Identifying Receiver Component
What you have is a two pin 455khz Ceramic Resonator. It replaces the Quad Coil used in miniature receivers.
Would be interested to know if you are intending to replace one ?
Would be interested to know if you are intending to replace one ?
03-31-2003, 06:06 PM
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Help Identifying Receiver Component
Alan,
Out of all the Japanese manufacturers, Futaba prefer to use these rather than the standard 455khz coil - I assume it is a Futaba receiver.
These devices tend to be fairly robust and rarely need replacing. What evidence do you have that it is unserviceable ?
Out of all the Japanese manufacturers, Futaba prefer to use these rather than the standard 455khz coil - I assume it is a Futaba receiver.
These devices tend to be fairly robust and rarely need replacing. What evidence do you have that it is unserviceable ?
03-31-2003, 11:55 PM
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Help Identifying Receiver Component
David:
It is in an Airtronics 92185 PCM receiver. I know that the resonator is not serviceable anymore because I broke it! I got this receiver used and for a good price. It is in very good shape and works fine, but appears to be on the older side. When I opened it up to see what it looked like inside, I found that the potting adhesive that was used had reacted with something (flux I am assuming) in a number of areas. The adhesive had turned from yellow to brownish black and had broken down. I was cleaning these areas when I inadvertantly pushed the wrong way on the resonator and broke it. I just wanted to clean away the worst of whatever this is and then repot with electronics grade silicone. I did find the resonator at Mouser. Cost is 67 cents. Do you know if replacing this resonator will necessitate a retune? I was just going to range check and then go accordingly. Oh, and do you think it would be worthwhile to replace the 3 electrolytic caps that are in this receiver? I have heard that the insulator material in them deteriorates with time.
Thanks
Alan
It is in an Airtronics 92185 PCM receiver. I know that the resonator is not serviceable anymore because I broke it! I got this receiver used and for a good price. It is in very good shape and works fine, but appears to be on the older side. When I opened it up to see what it looked like inside, I found that the potting adhesive that was used had reacted with something (flux I am assuming) in a number of areas. The adhesive had turned from yellow to brownish black and had broken down. I was cleaning these areas when I inadvertantly pushed the wrong way on the resonator and broke it. I just wanted to clean away the worst of whatever this is and then repot with electronics grade silicone. I did find the resonator at Mouser. Cost is 67 cents. Do you know if replacing this resonator will necessitate a retune? I was just going to range check and then go accordingly. Oh, and do you think it would be worthwhile to replace the 3 electrolytic caps that are in this receiver? I have heard that the insulator material in them deteriorates with time.
Thanks
Alan
04-01-2003, 09:39 AM
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Alan,
A good description of your receiver condition.
The corrosion concerns me a little. If only light pressure was applied to the Resonator it should not have fractured. It's worth removing the potting adhesive and surveying the condition of all soldered joints - these should be bright and clear.
Some people spead Household Silicone over the components. NEVER USE HOUSEHOLD SILICONE WINDOW SEALANT ON ELECTRONIC COMPONENTS - the vapours given off in drying are highly acidic and corrosive. Within a matter of weeks your receiver will be totally useless.
ONLY USE NEUTRAL CURE, NON-CORROSIVE ELECTRICAL SILICONE ADHESIVE SEALANT. The brand I use is Servisol.
Let's assume the receiver shows no sign of corrosion. Soldering a new resonator into position is a straightforward procedure. In removing the old pins be very careful that you don't disturb any surface mount components in the vicinity. Retuning of the whole receiver is not be necessary. The resonator plays a large part in tuning the final part of the receiver. If it were a 455khz coil then a small rotation of the core would be all that it required to bring it on tune. Being fixed at 455khz, you are entirely dependant on the manufacturers accuracy. There are ways and methods of determining this accuracy but you will not detect any difference in overall receiver performance.
Old type electrolytics used a paper insulator which dried out over time. Modern Aluminium Electrolytics don't exhibit these characteristics as they use more modern materials. No harm in replacing them, they cost very little.
David.
A good description of your receiver condition.
The corrosion concerns me a little. If only light pressure was applied to the Resonator it should not have fractured. It's worth removing the potting adhesive and surveying the condition of all soldered joints - these should be bright and clear.
Some people spead Household Silicone over the components. NEVER USE HOUSEHOLD SILICONE WINDOW SEALANT ON ELECTRONIC COMPONENTS - the vapours given off in drying are highly acidic and corrosive. Within a matter of weeks your receiver will be totally useless.
ONLY USE NEUTRAL CURE, NON-CORROSIVE ELECTRICAL SILICONE ADHESIVE SEALANT. The brand I use is Servisol.
Let's assume the receiver shows no sign of corrosion. Soldering a new resonator into position is a straightforward procedure. In removing the old pins be very careful that you don't disturb any surface mount components in the vicinity. Retuning of the whole receiver is not be necessary. The resonator plays a large part in tuning the final part of the receiver. If it were a 455khz coil then a small rotation of the core would be all that it required to bring it on tune. Being fixed at 455khz, you are entirely dependant on the manufacturers accuracy. There are ways and methods of determining this accuracy but you will not detect any difference in overall receiver performance.
Old type electrolytics used a paper insulator which dried out over time. Modern Aluminium Electrolytics don't exhibit these characteristics as they use more modern materials. No harm in replacing them, they cost very little.
David.
04-01-2003, 06:33 PM
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Help Identifying Receiver Component
Thanks for all your help David. The potting adhesive appears to be factory applied. It is the same yellow stuff that you see on most r/c electronics. It was applied to the component side of the board to hold the larger components together. The adhesive broke down primarily where the component meets the board. This is why I thought that it had reacted with flux. The good news is that it did not react at all with the components. They are bright and shiny underneath. I did not crack the resonator, I pushed sideways on it, pulling one of the leads out. I am well aware of the differences in silicones. Regular silicone gives off acetic acid when curing, electronics grade silicone gives off metahanol. (my brother is a chemical engineer)
Thanks Again
Alan
Thanks Again
Alan
