Teardown time ...
An Agilent 3324A is ripped apart. The beastie had problems with its power supply. A blown regulator prevented it from starting up. It would go all wonky and sit there flashing its display and clicking its relays. Darn ol lm317 died. For no apparent reason. After replacing it the machine works perfectly fine. This is a kind of an odditiy machine. A direct successor to the 3314A and a crossbreed with the 3325A it sports a mixture of parts making this a funny machine. It has IC's in metal can(TO-100) , Ceramic sidebrazed DIL , Standard plastic dil and SMDA all on the same board. The powerstage is fully descreetly built and even though SMD is employed on the main synthesizer board the controller board is an all thru-hole affair. It almost looks like this thing was slapped together from bits an pieces they had laying around but none of the boards are found in other machines. So it looks like a rewash of some earlier designs. kinda weird machine.
This is a 21MHz sweep generator with a couple of specialties not found in other machines. Besides linear and logarithmic sweeps this thing can Step-sweep. you can program multiple begin and end frequencies and the machine will cascade the programmed settings. it can also step through a list of frequencies. It has all kinds of output signals allowing it to intermesh with external equipment.
The frontpanel :
it shows its selftest screen. This one is kinda funny as well. It will walk the display pixels, then perform a keyboard test where you have to press each button and then it will proceed with a relay test. It says on the display to 'listen for relay clicking' it then proceeds to click each of its internal relays 5 times while showing on the display what relay is switching over. these relays are the mechanical memory type and are high quality RF relays.
The bootscreen
a mixture of fixed texts and alphanumerical dotmatrix
The synthesizer board
at the front middle the TO-99 metal can IC , middle middle the custom ASIC in ceramic sidebraze surrounded with SMD parts. the same ceramic chips are found in the 3314 and 3325a. they form together a DDS ( direct digital synthesizer ). The big guy is the fractional-n divider while the little guy is a sort of PLL linking the fractional-n output to the VCO's in the metal cans. So this machine employs real VCO's that are under control of a DDS.
Different view:
The endstage poweramp and the RF relays
The power supply
THe brains of the outfit : A motorola 68008 based thing
I swapped the battery even though it still read 3 volts.
Running :
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