Hey everyone, I have a combination wattmeter and freq. counter here for repair
and am having trouble crossing the IC's. This was made back in 1977 so it uses
some of the older stuff. The mfg. scraped the numbers off the chips and there's
4 of them. Now, 3 of them look to be the same used in a counter made by Conar
and there part numbers given were 7207 cmos, 7208 cmos, and a 74176. Now this
unit here has another chip, 14 dip, which takes the place of a transistor
preamp on the Conar model. This looked to be maybe assembled from a kit by the
mfg. It is one of the old Wawasee Electronics JB 1002 FC/M. I doubt they
designed it but copied something or a kit for the counter. The 7208 cmos is the
readout driver. The 7207 cmos is the oscillator circuit and uses a 5.24288 MHz
xtal.. The 74176 looks like it might be a presettable counter/latch. This from
the NTE cross reference. The two cmos chips dont show up in an online search
just using those numbers. They also dont cross right in
the NTE book. It seems to me like these numbers are maybe short part of a
number. Back in the 70's they did use these numbers but it's been so long I
cant remember what they may be lacking. Does anyone have any info on a 50 MHz
counter like this with schematic and part numbers? Also, any help with figuring
out these chips would be a blessing. Without knowiing them, it may have to be
junked. I have the original schematic of the meter/counter but its part numbers
are only in-house ones. I need to know for sure what the two cmos chips are,
check to see if the 74176 is a correct cross, and find what the input IC is.
Any help will be appreciated.
Thanks,
Will
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