BCD436HP/BCD536HP: Looking for advice - Scanner got zapped by static discharge

[jbmoss]

Living at 6,000 feet elevation has its downside with humidity often in the single digits. A couple of days ago, I reached for my BCD436HP scanner while it was connected to a power supply/charger and a large static spark was generated between my finger and the menu button. The scanner was on at the time and immediately went "dead". Attempts to turn it on failed for about three or four minutes. It finally came back to life and seems to work fine with one exception: when it is turned on, instead of opening in scan mode, it opens with the main menu. Pressing the "SYSTEM" button puts it into scan mode but the Menu button no longer works. The only way to go to the menu is to turn the scanner off and back on again. Everything else seems to work just fine. These symptoms seem to indicate that the static spark fused the contacts in the menu button together (???), putting it into the "on" position permanently. I'm guessing that the only remedy would be to repair(?) or replace the switch.

I'm looking for advice as to the best way to get this fixed. I'm not squeamish about opening the case and digging in ... to a limit. Is the switch reachable and repairable, or can it be replaced without doing more damage? Also, is a replacement switch available for purchase. Alternatively, would it just be more prudent to send it in to Uniden along with a $90 check?

 

[RandyKuff]

It looks the menu switch is shorted... I can duplicate the same problem by holding my menu switch in.
And thats on the SDS100... It does the same thing...
Or somewhere on the circuit board it shorted...

 

[jonwienke]

The keypad contacts are not susceptible to static damage, but dirt or debris can get in and cause trouble. You can clean them easily with a q-tip and isopropyl alcohol. Remove the batteries, then the 6 screws in the back. The front panel will come off, giving access to the keypad. The black circles contact the motherboard traces to register keypresses. If that doesn't solve the problem your only option is Uniden repair.

 

[tvengr]

Disconnect the AC adapter and remove the batteries for several minutes. Sometimes, computers get something stuck in the memory and removing power will clear it. The SD card remembers the state your scanner is in when you turn it off and returns it to that state when you turn it back on. It is possible that the card got corrupted when the scanner took a hit. Try reformatting the card or change to a new one.

 

[RandyKuff]

Disconnect the AC adapter and remove the batteries for several minutes. Sometimes, computers get something stuck in the memory and removing power will clear it. The SD card remembers the state your scanner is in when you turn it off and returns it to that state when you turn it back on. It is possible that the card got corrupted when the scanner took a hit. Try reformatting the card or change to a new one.

Thats true...
But the dead givaway is his menu button does not work now.

 

[kruser]

The keypad contacts are not susceptible to static damage, but dirt or debris can get in and cause trouble. You can clean them easily with a q-tip and isopropyl alcohol. Remove the batteries, then the 6 screws in the back. The front panel will come off, giving access to the keypad. The black circles contact the motherboard traces to register keypresses. If that doesn't solve the problem your only option is Uniden repair.

The 436 has a mechanical tactile type switch on the side for the Menu key Jon.
I guess you have not done any GPS mods in a while and that one slipped by ya! Either way, that type switch should not be susceptible to static damage like you said.

 

[jonwienke]

Oops I missed that, brain fart. That's going to require a trip to Uniden. Its probably not the switch, but the chip that reads it having a fried input.

 

[RandyKuff]

Oops I missed that, brain fart. That's going to require a trip to Uniden. Its probably not the switch, but the chip that reads it having a fried input.

I dought it's the switch too...
Either zapped across a trace or fried an IC's input...

 

[kruser]

Oops I missed that, brain fart. That's going to require a trip to Uniden. Its probably not the switch, but the chip that reads it having a fried input.

That's my thinking as well unless the static zap scared the bejesus out of him and caused him to push the key extremely hard damaging the switch! Yes, I've seen that happen before!

 

[WB9YBM]

It looks the menu switch is shorted... I can duplicate the same problem by holding my menu switch in.
And thats on the SDS100... It does the same thing...
Or somewhere on the circuit board it shorted...

or alternately/additionally the microprocessor got zapped into partial failure mode or (if so equipped) a "reset" button may need to get pressed...

 

[RandyKuff]

That's funny Kruser...
To the"OP"... Does the switch still have a mechanical click to it?

 

[RandyKuff]

or alternately/additionally the microprocessor got zapped into partial failure mode or (if so equipped) a "reset" button may need to get pressed...

I don't think the CPU got hit... I Can duplicate the problem on my scanner by holding my menu button in...

 

[WB9YBM]

I don't think the CPU got hit... I Can duplicate the problem on my scanner by holding my menu button in...

correction on my comment: CPU got zapped causing partial failure...

 

[jbmoss]

I've been following all the discussion and I thank you all for taking the time. The switch does still have a mechanical click - I didn't push the key any harder than usual but the mini lightning bolt did take me by surprise. I remove the batteries for external charging every night, which hasn't made a difference. I'll try replacing the SD chip with a reformatted one to see what happens, but I'm convinced that the switch trace is shorted or, as Jon suggested, a partially fried IC. Would opening the case and looking around be a waste of my time? Seems like that $90 might be well spent to get things working properly again.

 

[kruser]

I don't think the CPU got hit... I Can duplicate the problem on my scanner by holding my menu button in...

It could be some type of latching component like a transistor that shorted before the CPU line. That would be best case other than a reset fixing it but without any service manuals, finding and fixing something like that could be tough.
Of course physical damage to the switch should be fairly easy to spot plus check with a meter as well.

That was a good call asking about the mechanical 'click'.
Somebody good could probably find something that would work from Mouser or the likes if the switch is damaged but it would still be a tedious job for someone not skilled with working with these tiny components.
My eyes are bad enough now that I doubt I could do it but I sure would have just a couple years ago!

 

[RandyKuff]

Been so long since I had my 436 apart don't remember what the switch looks like...
Don't have it at the moment... Just sent it out for the RTC and display repair yesterday...

 

[kruser]

Would opening the case and looking around be a waste of my time? Seems like that $90 might be well spent to get things working properly again.

If you are comfortable opening it up and also have a meter, it may be worth a look. I think you may be able to put a meter across the contacts of that switch and test it. I really doubt it shorted though. That would require something more like a lightning strike!

Opening these things up is not really that hard. Pay attention to the battery contacts as they pass through the case when opening it.
The rubber parts around the button you need to look at can also be a bit tricky to get lined back up before closing it back up but it's also not really that hard.

Jonwienke has opened a bunch of these things with all the mods he has done so he may have some advice.

If you are the least bit uncomfortable opening it plus don't have a decent meter for testing, I would just send it in for repair.

 

[ot0tot]

Been so long since I had my 436 apart don't remember what the switch looks like...
Don't have it at the moment... Just sent it out for the RTC and display repair yesterday...

Pictures of the switch here:

Inside look at the BCD436HP

Last week I dropped my BCD436HP and broke the antenna connector. This torqued me off quite a lot since it is my main handheld scanner and I was leaving on a trip that weekend. I was able to buy the…

n9jigblog.wordpress.com

(Credit @N9JIG)

 

[jonwienke]

Getting at the side switches is a lot more involved than the front keypad. They are mechanical, and not likely to be damaged by static discharge. The motherboard is multilayered (6 levels of traces iirc) so if the static damaged the board, its really unlikely you'll be able to fix it.

I recommend sending it in to Uniden.

 

[kruser]

That pic show the switches pretty well. They look like something that DigiKey or Mouser may very well have.

It's funny that Uniden will sell the SMA connector for this radio but they sure as heck won't sell the battery door clip to the SDS100 users who are out of warranty!