Need some help with Exact 7060 function generator

[david77]

I recently scored this nice function generator off Ebay. It was sold as "for spares" and the seller claimed it wasn't working. Even though I couldn't find a manual for it I took the gamble and bid on it.



And surely when I got it in the lab and turned it on it didn't work, instead it filled the room with the familiar smells off cooking electronics - burning resistors and burning FR4.

The problem turned out to be the totally blown output amplifier, blown output transistors and their associated emitter and collector resistors. I replaced all the carbonated remains of these things, turned out it still got very hot very fast, so there was obviously another problem.



The thing's littered with these green 6,8µf tantalums. Every time I see such old equipment filled with these little time bombs I'm instantly suspicious, we all know how notorious they can be. After a bit of probing around with the ESR meter I found a few suspicious tants and replaced them with aluminium electrolytics.
That did the trick. The generator is back in business, clean output signal and no more cooking electrons.
The people at Exact were very nice in printing all component values on the boards, otherwise replacing the charred resistors would've been very hard indeed.

Now there are three problems still remaining and they may be harder to solve without the schematic.

1. I can select sine, square and triangle waveforms but not the 180° phase shifted equivalents. The phase just stays the same.

2. The saw tooth waveform doesn't work properly. I can not adjudst it's frequency and there's only any output when the genny is in sweep mode, but even then the frequency is fixed.

3. The sweep mode works but it behaves a bit odd. It might be user error but I don't think so.
A short example:
Start frequency set to 1kHz, stop set to 2kHz. Everything works fine.
Now when I increase the sto frequ. to say 3kHz it sweeps up to a few 100kHz.
So I figure there's clearly something wrong there.

I think what I really need is the manual. Does anybody here have it? Even one for a different model with sweep function might be enough as I guess there will be similarities. Similar models seem to be the 7059 and the newer 7260.
Other ideas are also much apreciated.

[sitongia]

I was a test technician at Exact a long time ago. I bought a dead Model 7260 on Ebay. It had a shorted +15V power rail and a few burned resistors. I replaced a tantalum drop capacitor, and then found another shorted supply rail. So I bought a bag of 50 tantalum on Ebay and replaced them all. That fixed it. It now has one more problem that requires a schematic. I searched around again for a manual and just found your post. I kept looking and I found that you can buy a manual on http://www.manualsplus.com but I don't know what the codes mean and which come with schematics.

Alternatively I found a pdf manual http://roundhousekick.net/bastelei/Exact7271Generator.pdf

In the model number the '2' means 20 mHz option I believe. The 7271 is a linear/log sweep generator. Otherwise the front panels look the same. So this manual schematic might work for you. For your Model 7060 just ignore the 20 mHz option and the log sweep option in the schematic.