Re: [volt-nuts] Anyone have a manual for an Eico 235 VTVM?
David wrote:
An Eico 235 is the as a 232... differing metre style is the only
difference. IIRC
No, the 249 is the same as the 232 but with a larger meter. 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.
So no, I'm pretty sure it is not the same as (or even very similar
to) the 232/249, but rather is a significantly different design.
To anticipate another possible response: Yes, I know one on-line
vendor claims to have manuals available, but I had a most unpleasant
experience with them in the past and won't repeat that mistake.
So, back to the original question: Does anyone have a manual (or at
least a schematic) for the Model 235?
Thanks,
Charles
Your right, I was thinking of the 249.
I don't know which online vendor you've had problems with, but I did
find references to both Surplus Sales (of Nebraska) having it, as well
as ManualMan, I can say I've bought at least one manual from
ManualMan w/ no issues.
But I'm afraid I don't have anything to help you.
David
On Thu, Jul 31, 2014 at 9:17 PM, Charles Steinmetz
csteinmetz@yandex.com wrote:
David wrote:
An Eico 235 is the as a 232... differing metre style is the only
difference. IIRC
No, the 249 is the same as the 232 but with a larger meter. 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.
So no, I'm pretty sure it is not the same as (or even very similar to) the
232/249, but rather is a significantly different design.
To anticipate another possible response: Yes, I know one on-line vendor
claims to have manuals available, but I had a most unpleasant experience
with them in the past and won't repeat that mistake.
So, back to the original question: Does anyone have a manual (or at least a
schematic) for the Model 235?
Thanks,
Charles
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
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