Date   : Thu, 09 Feb 2006 11:49:23 -0000
From   : "David Hunt" <dm.hunt@...>
Subject: Re: BBC B+ LED problem

> Hi,
> 
> I'm currently refurbishing a fairly unmolested BBC B+, however the caps
> lock
> LED fails to light up, despite taking the keyboard out and giving
> everything
> the once over. All the keys work fine and the caps lock button is okay.
> 
> I connected a multimeter up to it last night; the shift lock button when
> turned on gives 1.6V between the two solder points on its LED. On the caps
> lock button it measures 4.8V when caps is selected (but no light). Could
> there be a dry joint somewhere or has the LED failed?
> 
> The keyboard has issue 1 on it.
> 
> Regards
> 
> Aaron

When you mention the CAPS LOCK button, do you mean the LED or the button. If
you are referring to the button I believe the CAPS LOCK LED and CAPS LOCK
button are not connected together on the board, rather, the CAPS LOCK key
sends a signal to the Beeb, which, in turn, illuminates the LED on the
keyboard. It is a very simple process to remove the LED and test it, they
very seldom die, most LED deaths are caused by overheating with a soldering
iron or being over driven. Likely to be a dry solder joint, especially if a
repair has been done by someone lacking soldering experience.

Dave ;)