Recently I picked up this wee gadget, figured it was useful for parts. Then I discovered the power supply had died, and chances are that it would actually fire up once it was repaired. Its a 1980s spectrum analyser, 100 kc all the way to 22 gigs!! It would have cost an absolute fortune in the day. Before dismantling it, decided to have a quick fault find.
First problem was the voltage regulator chips, the 5 volt at 8 amp section was faulty, as is the -18 volt. The supply is current limited via 2milliohm shunts, and overvoltage protected via SCR crowbars. These are vicious, in that when the voltage rises over a set amount, the SCRs literally will short the supply to ground, blowing all the fuses. Anyways, the supply is faulty. The 723 regulators, 4 of them are the older round can type packages with 10 leads, so nothing else will fit. I did consider building a new supply using the existing huge and heavy transformer, but its a lot of work if the thing is truly knackered. As luck would have it, Alibaba has these old chip in stock, they are on the way to me as I speak!! Thought Id post this, as I am quite excited to see if it is repairable.
If anyone has any data on this thing, Its proudly made in the US, and seems to use a lot of Hewlet Packard microwave bits, a Motorola CRT display module, these were a generic thing fitted to many devices of the era. Its a real hodgepodge of different modules. Its branded as an Eaton 757, thats whats written on the service manual I found on the internet, the brand on the SA is ETN advanced electronics.
Here are some pics in case it activates anyones memory. I have no use for it, but its a waste to dump it without trying.