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Reducing audio hum on BK2K

  • Thread starter Thread starter Guddler
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G

Guddler

Ok, probably going to be posting about BK2K quite a bit as I start to give it it's second clean up and restore since I've had it - surprising how cruddy these things can get when you move house a lot and neglect them!



At the moment, I'm on a mission to remove as much of the speaker hum as possible as it's really bad.



Are there any tips specific to System 11B / BK2000? I've just pulled the audio, power and aux power boards and was going to replace all of the electrolytics that I have replacements for (and source those that I don't). Is this likely to help. I know it would with early Atari video games!



Mostly, this isn't noise from the lamps. Sure there is some noise that varies as the light effects change, but the worst noise is a constant low hum that is still there even if I disconnect all the power inputs from the interconnect PCB. I'm guessing that's general transformer / power noise. That's the only thing that makes me hesitate and ask about the electrolytics. I probably have replacements for all but the big caps in my parts bins already but I don't want to just waste them if it's not going to make the blindest bit of difference!



The manual also shows a mains line filter. I think I've got a spare one of them, is it worth replacing that? Again, don't want to waste it as my DE Star Wars needs all this too.



Thanks,

Martin.

[EDIT]PS: Game is otherwise fully working - no resets for instance.
 
I've found that the most improtant thing is to maximise grounding of circuit boards. Ensure the brounding tabs are clean where they meet the back plane, and that all the screws are present and tight.
 
Cheers for the tip. What size are the screws and do you sell them? There are 5 missing from the interconnect PCB - though none of those are grounding screws so shouldn't have any impact. There are 4 missing from the aux power board though and they probably are.



What about caps? As it happens, I've looked and am missing about half of what I would need to replace them all. I'm quite surprised given how many I have here but vids and pins are, at the end of the day very different
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The biggest of which are the 18,000uF and 30,000uF big ones.
 
I had a Jokerz years ago that developed a REALLY loud, throbbing hum.

After trying a few things without success I posted the problem on RGP.

A guy replied and said to change one of the bridge rectifiers on the main board (I can't remember which one but presumeably the one that deals with sound board power. Andy N might be able to help).

I changed it and the sound was crystal clear with no hum afterwards.



Might not be your problem but worth bearing in mind.
 
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Thanks for the heads up, I'll have a nose at that when I get a moment.



I haven't been able to do anything on this yet as no-one I've asked seems to be able to tell me what size / thread the screws are that I need for the back-box, or where I can buy them which I find a little odd!
 
Guddler' date=' post: 1683925 said:
Thanks for the heads up, I'll have a nose at that when I get a moment.



I haven't been able to do anything on this yet as no-one I've asked seems to be able to tell me what size / thread the screws are that I need for the back-box, or where I can buy them which I find a little odd!
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Martin - I might have some in my box of bits/scrapped parts. I'll have a look
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OK Martin I have laid my hands on 6 :cool: I might have more somewhere, but I think I gave a bunch to someone else a while back maybe.



Just to check these are the ones that screw into metal standoffs yes ? These came from a Sys 11 game so should do the job - round philips head, machine screw, 1/2" length.



PM me yr address or I could leave em with Rav ...but prob quicker to chuck in post.
 
Freespawn said:
Ohh 😲🤣😂
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Lol - there is a big notice above the text box on old posts you know....
Thread Status: Hello User,
There has been no response in this thread for more than 365 days.
Unless your response is directly related to the original post contents, it is suggested to create a new post.
Original posters may not be present any more, or may not respond to your message.
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:)
 
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