Message 23472 in TECH.WW
From: G8MNY
Date: Wed, 03 Jun 26 07:57:00 Z
Newsgroups: TECH.WW
Subject: Old Venner Counter Type TSA3334
Message-ID: <61398_GB7CIP>
Path: N2NOV|VE2PKT|VE3KPG|N9PMO|CX2SA|GB7CIP
R:260603/0805z @:N2NOV.#RICH.NY.USA.NOAM $:61398_GB7CIP
R:260603/0804Z 9990@VE2PKT.#TRV.QC.CAN.NOAM LinBPQ6.0.25
R:260603/0804Z 23558@VE3KPG.#ECON.ON.CAN.NOAM BPQ6.0.25
R:260603/0804Z 7265@N9PMO.N9PMO.#SEWI.WI.USA.NA BPQ6.0.25
R:260603/0802Z @:CX2SA.SAL.URY.SOAM #:251 [Salto] FBB7.00e $:61398_GB7CIP
R:260603/0757Z @:GB7CIP.#32.GBR.EURO #:61398 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (Updated Feb 11)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
I have been investigating how this very old 1MHz Frequency Counter/Timer works.
It is all done with Germanium PNPs & no ICs! And it uses 4x 2.5cm tall
projected moving number displays, as it was made before Nixi tubes or LEDs!
SCHEMATIC
HOW IT WORKS
The large MODE SWITCH can rearrange the units to COUNT continuously, Gated with
a TimeBase for FREQUENCY, or count a TimeBase gated with the input for PERIODS.
The display timer (Manual or about 2 seconds) starts the process off, clears
down the counters & enables the timer gate.
Each counter & divider circuit uses 8 transistor in 4 bistables as binary
ripple counters they are wired to reset @ 10 & overflow to the next counter or
divider.
Each display digit consists of a meter with 0-9 number shadow mask & lamp. The
DC drive for these uses 4 resistor (72k 36k 18k & 9k) from each binary stage of
the BCD counter output, such that the meter current represents the number 0-9.
_ Continiously
External presets are used to calibrate scale & zero each meter (0 & 9 test
buttons provided).
For PERIOD measurement, it rewires the units, to counts the 100kHz & uses the
or 100x that period. This results in measurements of 10x 1x 0.1x in uS.
PSU
This is -7.5V for the electronics & a raw -10V regulated for the 4 lamps.
IN USE
Despite being very old it still all works & is very easy to read. The 4 digit
readout might seem to be a limitation, but overflow counting is possible. So to
measure say 1.250895MHz you 1st read the 1250kHz & then alter the range to see
the 0895Hz.
For low frequencies like CTCSS tones, where 1/10 of Hz resolution is needed,
then Period measurement & a calculator comes into its own.
See other tech buls "Watson 'Hunter' Counter Mods", "PIC Freq Counter Mods",
"Marconi Counter Type 2434A", "198kHz Off Air Standard", "Off Air Lock for Ref
Osc." & "Calibrating Frequency".
Why Don't U send an interesting bul?
73 De John, G8MNY @ GB7CIP
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