Opened up my SDS100

Azgunguy

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So I recently sent in my SDS100 for a volume knob repair. It came back receiving absolute garbage for transmissions. Thought it was a corrupted SD card. Rubber duck antennas won't pick up much of anything. A mobile antenna will pick up some stuff. So it being out of warranty already I decided to crack it open and see if anything looks out of the ordinary. Take a look for yourself and tell me what you all see. I'm not an electronics wizard by any means either. Also I messaged @UnidenSupport about this and got no response at all. They had my scanner for a month just to repair the volume knob and I've since become disappointed with the company.
 

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jonwienke

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It doesn't look that much different than the other SDS100s I've been inside. What do you think is the issue?
 

Azgunguy

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It doesn't look that much different than the other SDS100s I've been inside. What do you think is the issue?
No idea. Thankfully uniden support reached out and offered to pay for my shipping label, so I'm going to dig into that and maybe go that route.
 

Azgunguy

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So uniden got back to me. Offered to pay for my shipping label so I packed it up and sent it off Friday the 13th. They received it on the 17th, and I got it back from fedex yesterday Dec. 21. Their estimated ship date was Jan. 14 2020. Since it was in the repair warranty window it got fixed up and the rssi went from about -115dBm to a consistent -50 to -60 dBm. Super happy about it.
 

jonwienke

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That's a pretty significant signal difference.
 

Azgunguy

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That's a pretty significant signal difference.
Its huge. I knew something wasn't right. The first time I sent it back for the broken volume knob, and I was living in an apartment and when I got it back I had moved into my new house. So I thought maybe my new location is causing the signal degradation. But my 536HP was working like a champ so it had to be something with the scanner.
 

N9JIG

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Did they mention on the repair sheet what they did?

One of my 436's had a cracked solder joint for the antenna center pin a few years back that I resoldered and that improved my reception many times over. It was likely caused by drops, being lifted by the antenna or being slammed into a console multiple times as the reception had been much better when new. Of course 2 weeks later I dropped it and snapped off the SMA connector and had to replace it but at least my solder job held up!
 

Azgunguy

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Did they mention on the repair sheet what they did?

One of my 436's had a cracked solder joint for the antenna center pin a few years back that I resoldered and that improved my reception many times over. It was likely caused by drops, being lifted by the antenna or being slammed into a console multiple times as the reception had been much better when new. Of course 2 weeks later I dropped it and snapped off the SMA connector and had to replace it but at least my solder job held up!
They said they replaced Q1 and Q2. So not really descriptive at all lol. Sounds like your 436 has been through hell!
 

Azgunguy

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Did they mention on the repair sheet what they did?

One of my 436's had a cracked solder joint for the antenna center pin a few years back that I resoldered and that improved my reception many times over. It was likely caused by drops, being lifted by the antenna or being slammed into a console multiple times as the reception had been much better when new. Of course 2 weeks later I dropped it and snapped off the SMA connector and had to replace it but at least my solder job held up!
They said they replaced Q1 and Q2. So not really descriptive at all lol. Sounds like your 436 has been through hell!
 

SteveSimpkin

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They said they replaced Q1 and Q2. So not really descriptive at all lol. Sounds like your 436 has been through hell!
Here is a description of what that may have been caused by.
 

Azgunguy

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Here is a description of what that may have been caused by.
Interesting. So if I transmit on my 60 watt vhf radio should I keep my SDS away from the antenna?
 

SteveSimpkin

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Interesting. So if I transmit on my 60 watt vhf radio should I keep my SDS away from the antenna?
Definitely. From a reply further down the thread.
"Can confirm — I needed Q1 & Q2 to get replaced on my HP-1 by putting 50w into it from 10ft away at VHF. "

That's not to say you can easily predict what power level and distance are safe.
 

Azgunguy

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Definitely. From a reply further down the thread.
"Can confirm — I needed Q1 & Q2 to get replaced on my HP-1 by putting 50w into it from 10ft away at VHF. "

That's not to say you can easily predict what power level and distance are safe.
Wow. That's unsettling.
 

jonwienke

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If you have a question whether something is safe RF-wise, get a watt meter and a dummy load. Connect your scanner antenna to the meter input and the dummy load to the output, key up the high-powered radio, and see what kind of reading you get on the meter. The 436 and SDS100 can handle 250mW of RF input, but I wouldn't try anything more than that. That will at least give you a rough idea of the "unsafe zone" around the TX antenna.
 

Azgunguy

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If you have a question whether something is safe RF-wise, get a watt meter and a dummy load. Connect your scanner antenna to the meter input and the dummy load to the output, key up the high-powered radio, and see what kind of reading you get on the meter. The 436 and SDS100 can handle 250mW of RF input, but I wouldn't try anything more than that. That will at least give you a rough idea of the "unsafe zone" around the TX antenna.
It's just kind of unsettling that I have to do that lol. I'd say the closest my sds gets to a TXing antenna would be while it's in my vehicle, and my antennas are NMO mounts on my roof. Otherwise I'm not sure what would have burned them up.
 

jonwienke

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The problem isn't unique to Uniden scanners. Most scanners and radio receivers are susceptible to damage if you get them too close to a high-powered TX antenna. Transceivers are typically protected a little better so they don't fry themselves when you key up, but even so, every radio has a limit to the amount of incoming RF it can handle before damage occurs.
 

Azgunguy

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The problem isn't unique to Uniden scanners. Most scanners and radio receivers are susceptible to damage if you get them too close to a high-powered TX antenna. Transceivers are typically protected a little better so they don't fry themselves when you key up, but even so, every radio has a limit to the amount of incoming RF it can handle before damage occurs.
Right. I wasn't saying it was unique to uniden. I know radios can fry eachother but I didnt think the sds100 was this sensitive.
 
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