[volt-nuts] Anyone have a manual for an Eico 235 VTVM?

[Charles Steinmetz]

I wrote:

>I have both versions of the 232/249 manual, as well as a 232 in the 
>flesh, and the 235 is obviously different.  It is said to have 25 
>Mohm DC input resistance rather than the usual 11 Mohm, and it has a 
>0.5v DC range.  The switch decks are considerably different from the 232.

Thanks to a kind list member, we have an original manual for the 235 
on the way.  (Thanks!)

Contrary to some information floating around on the web, the 235 does 
NOT have a 25 Mohm DC input resistance -- it uses the traditional 10 
Mohm architecture (7M, 2M, 700k...) with an added 0.5v 
range.  However, Eico put the meter in the plate circuit rather than 
the cathode circuit as in the 232/249 (and the other Eicos and the 
Heathkits).  As the RCA VoltOhmyst series demonstrates, this tends to 
make a VTVM considerably less stable (i.e., to drift considerably 
more) than the cathode connection.

It will be good to get this one going again -- it was bequeathed to 
my friend by her Elmer (now SK), and will be a tangible reminder of 
his help and guidance as she advances in the hobby (and perhaps 
pursues an engineering career later on).

Best regards,

Charles