UK Vintage Radio Repair and Restoration Discussion Forum

UK Vintage Radio Repair and Restoration Discussion Forum (https://www.vintage-radio.net/forum/index.php)
-   Vintage Computers (https://www.vintage-radio.net/forum/forumdisplay.php?f=16)
-   -   Power supply QRM shielding (https://www.vintage-radio.net/forum/showthread.php?t=166198)

Malcolm T 29th Apr 2020 2:10 pm

Power supply QRM shielding
 
I have a very nasty qrm coming from my psu inside the computer . Does anyone have any suggestions as to how to tackle this please . I have not had it apart yet so dont know if there are some critical filtering components missing !.

Thank you.

Guest 29th Apr 2020 4:41 pm

Re: Power supply QRM shielding
 
I think you are right about missing filter components, all too prevalent today. A portable radio waved around the mains cable will find out.

Andrew2 29th Apr 2020 5:22 pm

Re: Power supply QRM shielding
 
1 Attachment(s)
I found our previous PC was putting a lot of noise onto the mains lead and it was radiating all over the house.
So I made a short flylead which plugged into the PC's IEC socket and was fitted with a filtered IEC socket, see picture. This socket was mounted in a small plastic box for safety. Once fitted, peace & quiet reigned again!
The filtered socket came from Surplectronics. https://www.surplectronics.com/ It's listed under capacitors.

Malcolm T 29th Apr 2020 6:14 pm

Re: Power supply QRM shielding
 
Thanks for replies. Looks like i,m going to have the lid off and take a look see first then maybe even roll my own filter , its very noisy its unreal on the s meter.

Radio Wrangler 29th Apr 2020 6:39 pm

Re: Power supply QRM shielding
 
You'll probably find a nice virgin area on the PCB ready for X and Y capacitors, and a pair of links where a common mode choke ought to have been. Probably was on the one sent for testing. Fitting these ought to be a start. Adding a big ferrite on the output wires might help as well. 1 per connector.

David

Malcolm T 29th Apr 2020 8:39 pm

Re: Power supply QRM shielding
 
Yep, that's got me curious now as to missing stuff!!!. We shall see.


All times are GMT. The time now is 8:26 am.

Powered by vBulletin®
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.