User's Manual

1 1 7 B 2 0 W at t V H F H igh Band Transla t or Upconve rt er/ Am plifie r Tray
Det aile d Align m ent Pr oce dur e
- Page 3 of 5 -
THE FOLLOWI NG DETAI LS THE MEANI NG OF EACH LED ON THE ALC/ AGC BOARD WHEN
I LLUMI NATED.
DS2 - Abnorm ally low or no I F signal is present at the I F input connect or J1.
DS3 - I ndicates that t he ALC circuit is unable t o m aintain the signal level request ed by the ALC
reference. Usually caused by excessive att enuat ion in t he Linearity Correct or pat h or
Switch S1 is in Manual ALC.
DS4 - I ndicates that t he AGC circuit is unable t o m aintain the signal level request ed by the AGC
reference. Usually caused by excessive att enuat ion in t he Am plifier Circuit s or Switch S2 is
in Manual AGC.
DS5 - A Mut e com m and is present. Typically generat ed when t he Translat or is in St andby.
( A16- A1) FI LTER/ MI XER BOARD (1150-1102)
The L.O. signal and t he I F signal are m ixed to produce t he desired channel frequency which is t he
difference product of the t wo signals. The out put of the Mixer at J6 (- 14 dBm ) is j um pered to J1
the input to a bandpass filt er located on the Board. This filt er has been fact ory swept and
adj ust ed for a 6 MHz bandwidt h and should not be t uned wit hout proper equipm ent .
The out put of the Filt er is am plified by U1 to (- 2 dBm ) and is fed to the Filt er/ Am plifier Board.
( A16- A2) FI LTER/ AMPLI FI ER BOARD (1150-1101)
The Filt er/ Am plifier Board has been fact ory swept and adj ust ed for a 6 MHz bandwidt h and should
not be t uned without proper equipm ent.
The filtered out put connects t o J1 of the board and is am plified by U1 to + 8 dBm Visual and - 2 dBm
Aural in level. Adj ust R9 for a Nom inal output of + 8 dBm Visual - 2 dBm Aural. The out put is fed to
the VHF High Band Driver Board (A17- A1) .
( A17- A1) VHF HI GH BAND DRI VER BOARD (1174-1107)
This am plifier has a gain of about 18 dB and is tuned with C15 for m axim um out put at t he VHF
Channel Frequency. The RF output ( + 26 dBm Visual and + 16 dBm Aural) is fed t o the VHF High
Band Am plifier Board ( A17-A2) .
1. Adj ust the operat ing st atic current to .6 Am ps with R4 located on the Board. This is
accom plished by adj ust ing R4 for 600 m A, .06 Volts across R6, a .1 Ohm / 3 Wat t Resist or.
The RF out put ( + 44 dBm Visual and + 34 dBm Aural) is fed t o the Am plifier Board.
( A17- A2) VHF HI GH BAND AMPLI FI ER BOARD (1174-1101)
The am plifier has a nom inal gain of 18 dB and is t uned wit h C9 & C19 for m axim um out put .
1. Adj ust the operat ing st atic currents for Q1 to 2 Am ps for each half of the device, 4 Am ps
total. This is accom plished by presetting Pot s R5 and R9 full CCW then adj ust ing R5 for a .2
Volt, 200m V, drop across R21, a .1W/ 5W Resist or, locat ed on t he Am plifier Board. Next
adj ust R9 for .4 Volt , 400m V, drop across R21. This gives the desired 4 Am ps of St atic
Current for t he Q1 Device.