Econet High Pitched Squeal

discuss both original and modern hardware for the bbc micro/electron
Post Reply
User avatar
KenLowe
Posts: 1173
Joined: Mon Oct 18, 2004 5:35 pm
Location: Scotland
Contact:

Econet High Pitched Squeal

Post by KenLowe » Tue Jun 30, 2020 10:35 am

I went to start up my L3 file server yesterday and when I ran the FS3v125 file I started to hear a very high pitched squeal coming from somewhere around the Econet hardware, and the computer locked up. I've got an IntegraB board installed in the computer which sits over the top of the Econet hardware, so I wasn't sure exactly where it was coming from, but my guess is the 68B54. A reset of the computer stopped the squeal.

I tried it again and got the same result. It then occurred to me that I didn't have my CoPro running, so I set it running, and the file server started up normally with no high pitched squeal. There doesn't seem to have been any lasting damage.

I'm not recommending anyone tries this, but is this a known issue? Anyone else experienced this, or is it just an oddity of my computer?

User avatar
BeebMaster
Posts: 3313
Joined: Sun Aug 02, 2009 5:59 pm
Location: Lost in the BeebVault!
Contact:

Re: Econet High Pitched Squeal

Post by BeebMaster » Wed Jul 08, 2020 2:04 pm

It's possibly random noise coming through the speaker, that happens if you start L3 without the second processor running, because it doesn't check and overwrites the sound workspace! The sort of noise I usually get is like when the Witch appears in Granny's Garden.
Image

User avatar
KenLowe
Posts: 1173
Joined: Mon Oct 18, 2004 5:35 pm
Location: Scotland
Contact:

Re: Econet High Pitched Squeal

Post by KenLowe » Thu Jul 09, 2020 9:25 am

I could have sworn that the sound was coming from rear left of the micro - or even the PSU. However, I think you might be right about the sound coming from the speaker. I tried again yesterday, and didn't get the high pitched squeal. Instead I got odd notes playing out the speaker. It was almost tuneful (is that even a word?)! Makes sense when I'm stupidly trying to load code starting at address &800.

johnkenyon
Posts: 241
Joined: Wed Jul 20, 2011 3:21 pm
Location: Coventry
Contact:

Re: Econet High Pitched Squeal

Post by johnkenyon » Thu Jul 09, 2020 10:53 am

If you want more randomness ;)

Code: Select all

   10 M%=&800
   20 REPEAT
   30 FOR A%=0 TO 47
   40 B%=RND(256)-1  
   50 M%?A%=B%
   60 NEXT
   70 UNTIL FALSE

Post Reply

Return to “8-bit acorn hardware”