Simple Solution (verified) for SDS-200 Speaker Noise Issue

[escortz28]

First of all, credit goes to tkowalik for their effort and multiple posts documenting the debug and general solution set. I simply built upon this work and their observations. https://forums.radioreference.com/threads/sds-200-speaker-noise-again-like-the-536hp.383186/page-18

I have two SDS-200's each of which exhibited the speaker noise out of the box (reported in this thread: https://forums.radioreference.com/threads/sds-200-speaker-noise-again-like-the-536hp.383186/page-17). The following is the solution that worked on my two units.

Steps:
1. Remove the four (4) screws rear panel that secure the outer black casing.
2. Slide the outer black casing back approximately two (2) inches.
3. Using Scotch 3M double-sided tape (UPC 051131769960; https://www.amazon.com/3M-311DC-Mou...1769960&qid=1550011316&s=gateway&sr=8-1-fkmr0) I took one square (each 'sheet' in the Scotch package has four pre-cut squares) and cut it in half. Approximate dimensions of 1" by 0.5 ".
3. On the shield on the top side of the unit I attached the two cut square pieces. I only peeled off the tape on the side mounted to the shield. Note: see attached photo for placement on the shield. I found the best results were achieved when the attachments were made closer to the center versus near the outer edges.
4. I placed a piece of black electrical vinyl tape over the top of the front panel (to protect it from getting scratched in the Step 6.).
5. Slide the outer black casing forward to near the edge of the attached double sided tape.
6. I used a plastic flat tool (used for tuning RF circuits like slugs and coils), carefully inserted under the lip of the outer black casing, gently prying up enough to start over the two attached double sided tapes, then gently slide the outer black casing completely forward into its original position.
7. Reverse Step 1.
8. Reverse Step 4.

After the above, both units were noise free and I am once again a happy camper after a $1400 investment.

On the first unit, I did a lot of testing and attempted other solutions - as well as attempted to debug the source. I will share this information in a post later this evening.

Once again THANK YOU to tkowalik for identifying this solution.

 

[DataSquid]

Do the shims of the foam tape help with pressing forward the inner shield so it seats better in that direction as well? If so, I imagine you won't want to "pry" the outer case up too much when fitting it back in place, otherwise you'd not get as much forward "push" as you may need.

ps. you have two step #3s.

 

[KR7CQ]

Thanks much for posting this. I had a sneaky feeling a DIY solution was coming, and here we are. Nice. I'll have my tape ready for the arrival of my SDS200.

 

[KevinC]

I'll try this on my 536 and see what happens.

First it's foil tape, now foam tape.

And thanks for the effort.

 

[ansky]

So is the actual source of the noise some type of vibration coming from the outer case of the scanner? I can't imagine it's any type of circuitry problem if the noise is resolved by tape.

 

[escortz28]

Do the shims of the foam tape help with pressing forward the inner shield so it seats better in that direction as well? If so, I imagine you won't want to "pry" the outer case up too much when fitting it back in place, otherwise you'd not get as much forward "push" as you may need.

ps. you have two step #3s.

Yes, the intent of the shims is to apply constant pressure on the top shield when the outer casing is in place. The purpose is to maintain an adequate contact with the metal frame that the digital logic board and front panel are attached to. For some reason, the product design has felt tape between the top shield and the remainder of the metal frame (btw, same design on the bottom shield). I theorize that the tolerance stack-up (e.g. mounting locations of the top & bottom shields to the frame, tape thickness/location on the metal frame, etc) on some units is such that an adequate ground is not achieved or maintained leading to improper shielding.

Sorry about two Step 3's - the post was between the RR Community and my dinner.

 

[tkowalik]

Thank you escortz28 for elaborating and providing more detail! Excellent work!

 

[n2pqq]

After the procedure did you still get a
hum when plugging in a external speaker ?

 

[trentbob]

escortz28- congratulations man. When I saw those posts from tkowalik earlier when he took the cover off while the radio was on and reduced the hum the wheels in my head were turning.

I was thinking felt or cloth and even thought of lens cleaning cloths folded in the same shape the double-sided tape is in... The whole time I was doing this I had a roll of the double-sided tape right in front of me on the desk LOL... I use it all the time just like a lot of us do and have been using it for years and it never hit me.

Here's a question for you. Can we use the roll type double tape and lay one-piece continuously across the top from about 2 to 3 inches from the end of each side without interruption or should it be cut in the same sizes and placed in the same place you put your tape? You did say it works better towards the middle than the sides. Will The Continuous piece make for a poor fit or over compress? Man you are a genius. I have to admit it's been quite disturbing to see some of the responses here not owning up to what is obviously a problem for a number of users. Instead of insulting our intelligence and quibbling over how many feet from the radio is a problem somebody put their thinking cap on and worked on the problem. Thanks for your reply to the question ahead of time. Way to go brother and thank you tkowalik.

 

[escortz28]

After the procedure did you still get a
hum when plugging in a external speaker ?

The hum is still present albeit greatly attenuated. Before the procedure I could clearly hear at three (3) feet from the speaker (my sitting position). What I also heard before the procedure was the switching digital noise when loading the full data base or a Favorites list, and a few other select times. Now I have to be within an inch or two of the speaker to hear a hum, and there is no digital switching noise.

 

[escortz28]

escortz28- congratulations man. When I saw those posts from tkowalik earlier when he took the cover off while the radio was on and reduced the hum the wheels in my head were turning.

I was thinking felt or cloth and even thought of lens cleaning cloths folded in the same shape the double-sided tape is in... The whole time I was doing this I had a roll of the double-sided tape right in front of me on the desk LOL... I use it all the time just like a lot of us do and have been using it for years and it never hit me.

Here's a question for you. Can we use the roll type double tape and lay one-piece continuously across the top from about 2 to 3 inches from the end of each side without interruption or should it be cut in the same sizes and placed in the same place you put your tape? You did say it works better towards the middle than the sides. Will The Continuous piece make for a poor fit or over compress? Man you are a genius. I have to admit it's been quite disturbing to see some of the responses here not owning up to what is obviously a problem for a number of users. Instead of insulting our intelligence and quibbling over how many feet from the radio is a problem somebody put their thinking cap on and worked on the problem. Thanks for your reply to the question ahead of time. Way to go brother and thank you tkowalik.

I did not try the full length, certainly would provide more contact surface area. Only potential challenge I can foresee is getting the lip of the outer case over the length of the tape. If someone tries, please share your results with the community.

 

[trentbob]

I did not try the full length, certainly would provide more contact surface area. Only potential challenge I can foresee is getting the lip of the outer case over the length of the tape. If someone tries, please share your results with the community.

Yes I can see it being more difficult getting the case over the tape and I don't think it would work any better as the mission is accomplished either way. Maybe some kind of compromise towards the middle. I have the half-inch tape, the one inch tape and the squares. Your way is probably the best. Thanks for getting back to me. You da man. LOL... Bob.

 

[mikewazowski]

Gents, let's try and keep this thread focused on the technical aspects of the fix without derailing it with comments on Uniden's quality control or lack thereof. There are plenty of threads in the Tavern which would be more suited to that discussion.

It would be nice to be able to read the thread without having to sort through a bunch of off-topic crap.

Thanks.

 

[ColdnFrosty]

Shimming the case does not resolve the underlying engineering flaw. Hopefully, Uniden will share their findings with us and offer a proper fix!

 

[allend]

I made some modifications along the line from the OP. It has helped a bit. I can tell if I push on the plastic top on top of the radio into the top of the display the noise gets worse. I put a shim in between and its helped a bit and that's it. Its still noticeable on the external speaker but a bit less on the internal speaker.

 

[tkowalik]

I think I found the root cause. I’ll test more tonight. So far I’ve elimated the problem, just want to be sure it’s not affecting anything else.

 

[maus92]

More pictures please.

 

[KevinC]

It made no difference on my 536 (unless I did it completely wrong ), but I suspect the 536 isn't as bad as the SDS200 is. I can only hear the what I call "processor noise" if my fan, computer and everything else is off, then I can hear it about 2 feet away.

 

[allend]

It made no difference on my 536 (unless I did it completely wrong ), but I suspect the 536 isn't as bad as the SDS200 is. I can only hear the what I call "processor noise" if my fan, computer and everything else is off, then I can hear it about 2 feet away.

Yes the 536 did have less noise

 

[tkowalik]

I think I found the root cause. I’ll test more tonight. So far I’ve elimated the problem, just want to be sure it’s not affecting anything else.

What I thought isn’t a fix. I’m in the right church but wrong pew. Going to continue testing as I am getting braver.