chuck wrote in message
...
On Sun, 05 May 2013 15:53:24 -0400, Archon
wrote:

On 5/5/2013 3:21 AM, N_Cook wrote:
With about half mains voltage , for a bit of personal safety. About 20V
over
C-E of one driver Q and 120V over C-E of the other, whenever powered
up.
Plan of campaign will be to try biasing on the off one and see what
happens.
Could a leaky driver transistor be the most likely cause of
non-oscillation?
one sliver-mica cap could have metal migration , others are polyester
and
ceramic. Otherwise loads of diodes and coils.


Just scanning the info on Yahoo Tek scopes, the batteries need to be in
situ as part of the regulation on these, bad things may happen
otherwise? (so they say, no experience with them myself) JC


The batteries do need to be in the circuit and they can't be
completely dead, or the scope won't function, even when hooked up to
AC. Chuck


The batteries are modern replacements and good order, the scope works well
on battery power but cuts out , as it should, when the batteries run down.
Although this range of scopes started in the mid70s , the one I have here
seems to be made in 1989 with the later protection against self-imolatation.
Try-out replacement Qs in there , but will be tomorrow before I power up
again