Frequency Counter IB-1100 Rebuild

[Scott Roberts]

Hi- I just thought I'd share my latest rebuilding
project, a change from my usual Philcos, rebuilds
which my Heathkit test equipment usually support.

I just received my IB-1100 iI bought on e-bay. While
it is in generally decent shape, it bears the
hallmarks of an abused machine. A coating of gunk on
the circuit board, and everything there-on, prompted
me to start a complete overhaul. Currently, I am
removing everything form the board, so it may be
properly cleaned, and the minor corrosion issues
addressed. One of the ZM-1000 tubes was replaced with
a miniature version! I have no idea if it worked
properly: only the remaining 4 original tubes came on,
and the last one read "8" rather than "0" as it should
have. However, this may be because one of the pins on
one of the ICs had literally rusted off...

I am not sure how to check out the IC's, but they are
inexpensive enough, I may just replace them all, as I
am going to try to do with the transistors, which were
hurting as well. Restistors are also iffy. Basically,
I am putting together all new hardware, and will,
presumably, end up with a new machine. 

One thing the previous owner had done, was to modify
the circuit: there was a switch added at the back, and
a small sub board installed. The switch is labelled
"Prescaler on-Prescaler off" I have no idea what this
did, or why it was added to the circuit. Can anyone
tell me, and would it be in my best interest to keep
this modification? And would anyone have the
particular schematic for this mod? I am not sure what
was done intentionally to accomodate the mod, and what
was just plain damage to an old unit inside. As I
understand it, this unit was part of a ham radio
setup.

Thanks!
Scott

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com 

-----------------------------------------------------------
Products bought, sold or traded here is the responsibility of the
parties involved.  This list and the City of Tempe are not responsible
for losses or misrepresentations of any kind.  Buyer beware!

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://listserv.tempe.gov/archives/HEATH.html