Need Schematic for an Exact 7030

It's been 10 years since I've ask, so here it is again, has anyone come across a manual for an Exact 7030 signal generator? It has an output above the 100kHz setting, no output below

100kHz. Mikek
Reply to
amdx
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None that I could find for free. Here's one for $20. There was a 7030 that sold on Ebay in Australia last week for $20, so buying the manual for the same price doesn't seem very profitable.

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Jeff Liebermann     jeffl@cruzio.com 
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Jeff Liebermann

Found it!

The first thing I found was part 1 of the instruction manual, but with no schematics:

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Google linked directly to that PDF. A little more Googling gives the forum post, in French, where that attachment was made

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and part 2 of the manual at

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. With schematics and parts list. :)

If you have difficulty with those links, Googling for GBF_exact7030_p1.pdf and GBF_exact7030_p2.pdf may help; those were the original filenames used by the uploader at arduino.cc .

If I believe Google Translate, the person that posted it a couple of weeks ago had just scanned it, so perhaps that why it was unfindable until now.

If you get it going, it might be an idea to sign up for that forum and shoot the person who posted it a "merci". (Even if you don't speak French, write a simple English message and put it through Google Translate to get close.)

Some other stuff I found before I found the above:

Here's a guy fixing one, but in Dutch:

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There is an ended listing for one on Ebay US; the seller claimed "Operator and service manual, including schematics supplied on CD."

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This site

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claims that Exact Electronics was a tentacle of Tek.

The second post in this thread

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has a link to a manual for a 7271, which the poster claimed "might work" for a 7060. Your 7030 is probably even more different, but maybe it would help.

Matt Roberds

Reply to
mroberds

Those links worked just fine, a quick look at the board and the faceplate tells me it is the right one. This thing died about 16 years ago, I looked for info then and didn't find it. I looked again about 10 years ago.

This is great, I appreciate your effort to find it. Thank you.

I found a dried out filter cap and bad bridge, I replaced those and it still didn't work, further testing showed the -24v supply was 0v. I found a bad predriver transistor in the -24 regulator. After replacing that I thought I had it done. Nope, it has output from the 100kHz and up setting but not below, but even the upper frequency setting have some large amplitude changes between settings. So now with a schematic, I have a better chance of fixing it. I hope the parts are available and cheap enough to make it worth fixing. So far just parts I had on hand, haven't had to order anything. Thank you again, Mikek

Reply to
amdx

Ya, I won't spend a lot, so far I replaced a bridge, filter cap and predriver in the -24v regulator with parts on hand. Mikek

Reply to
amdx

My guess(tm) is the range switch, or one of the components attached to the range switch, is the problem. If there's a string of resistors daisy chained around the rotary switch wafer, one of the resistors attached to the 100K range position is open.

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Jeff Liebermann     jeffl@cruzio.com 
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Jeff Liebermann

Possibly, It is set up two sided, the wafer switch has double of all the resistor in two sections of the wafer switch. My early teats say one side has the problem.

btw, don't connect the scope ground to these units. (At least mine) It shuts down the power indicator light. I don't know what else, it didn't blow a fuse are make any sparks and nothing changed after doing that. It will get set aside this week, got to organize my tax paperwork by Saturday. Really fun stuff :-( Mikek

Reply to
amdx

Exact made about the best of the old-time analogue pulsers and function generators. They even made an arb that multiplexed between like 40 panel pots to set the voltage at each point in the waveform.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
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Phil Hobbs

Wein bridge oscillator. The corresponding resistors on each wafer should be identical. Dig out the ohms-guesser and look for mismatched values.

Incidentally, some days I almost wish I didn't have a schematic. I'm working on four Wavetek/CT/SSI 3000 and 3000b service monitors. I have two printed manuals (one original from the factory), and 3 different scans that I downloaded or purchased. All are different and none of them match any of the 4 units exactly. I've spent more time reconciling discrepancies and dealing with errors (no errata included) than I have actually fixing them.

I also had a related problem when I was doing marine radios. The very last thing to get shipped was the service manual. Typically, the service manual would be ready 6 months after the first radios went to the customers. For those 6 months, there would be few field failures and no tech oddities that bordered on supernatural phenomenon. Then, the manuals and schematics were shipped, and radios were returned mistuned, miswired, burned up, broken, and with associated mysterious problems. Once the dealers got the schematics and were able to do real damage, there was no end to the problems. Much as I detest not having schematics to fix things, I can see the point of hiding them from the other side of the fence.

Incidentally, California has Civil Code Section 1793.03 which proclaims that repair facilities are entitled to schematics, parts, and info for 3 years. ...shall make available to service and repair facilities sufficient service literature and functional parts to effect the repair of a product for at least three years after the date a product model or type was manufactured... The responses I've received from manufacturers over this law are not suitable for a general audience.

Ummm... Please remember that you have but one life to give. Premature death is natures way of telling you that you screwed up. I have an isolation xformer on my bench for working on dubious devices and switching power supplies. I suspect it has saved my life at least once.

I prefer to procrastinate to the last moment. It makes no sense to give the government my money 1 msec early. Lie, cheat, steal, fabricate... whatever works best.

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Jeff Liebermann     jeffl@cruzio.com 
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Jeff Liebermann

Well, the only one I consider suitable for public consumption was that one I received from Best Buy when they informed me that they could not obtain the parts needed to fix a fridge that they sold me and that I will need to purchase a new fridge. The warranty did not include replacement if unrepairable. Their answer was "sue us". So, I did, or rather I went through the motions of preparing a small claims lawsuit[1]. I'll spare you the details, but Best Buy caved in immediately when I shoved the letter of the law in their face and gave me a brand new fridge, which so far has survived for about 5 years.

Incidentally, 1793.03(b) is why Apple assassinates old products after

7 years in California, but after 5 years everywhere else: Every manufacturer making an express warranty with respect to an electronic or appliance product (...) shall make available to service and repair facilities sufficient service literature and functional parts to effect the repair of a product for at least seven years...

Most of the other undiplomatic responses came from various vendors and manufacturers when I pressed them on behalf of a customer. I do that quite often, where I represent the customer in dealings over a defective product. I usually can reach a suitable compromise or deal. However, a small number suggest that I do a physical impossibility to myself, which I believe is unsuitable for a general audience.

[1] It was actually more complexicated. The warranty was serviced by a company in Texas(?). In theory, I would need to sue them in Texas. Best Buy probably knew this, but to their credit assumed full responsibility.
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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

Oh come on, we are all men aren't we? Well most of us here, that is!)

Jamie

Reply to
Maynard A. Philbrook Jr.

Got tired of tax paperwork.

Set the Exact on the bench removed the ground connection from the isolation transformer. Then I noticed everything is working. I'm driving the scope and a frequency counter. So I removed the isolation transformer with power cable ground pin still open, works fine, inserted ground and then it has a problem. There is a link to connect earth/chassis ground to the power supply common, that is open.

This ground problem seems wrong, I have an HP651B on my bench and never had any ground issues, what good is the Exact if I have disconnect the ground to use it.

There is 7.5 kohms of resistance between the earth ground and power supply common. I see nothing on the schematic to cause this. I think this is a defect but I don't want to chase it, if it is normal.

Any thoughts?

Mikek

Reply to
amdx

I found it! one of the case mounted regulator transistors had found a way to leak through the insulator. Put in a small piece of Sil-Pad and the ground problem is fixed.

Thanks all, Mikek

Reply to
amdx

Maybe you should meg your transformer?

If you find that it may have a short to one of the leads, you can install a 1:1 transformer and then isolate the existing transformer from the chassis. Connect primary leads to the newly installed 1:1, which can be grounded.

Jamie

Reply to
Maynard A. Philbrook Jr.

I had an exact problem with a HP 1 Ghz signal generator, a power transistor in the back cause intermittent start up problems. I got this from Ebay and I went inside one day to clean up a knob and noticed the screws were just a little loose on this one transistor, so I commenced to tighten it. Things seem to be find but I noticed there afterwards that I was getting intermittent start up problems where I would have to restart it a couple of times. I went back in there and fired it up when it was cold and probe back to the same transistor, I replaced the insulator..

Apparently this happens from heat contraction/expantion over time of start ups and it got thin, I put a mica type in.

Jamie

Reply to
Maynard A. Philbrook Jr.

Nicely done. Kinda sounds like this Exact 7030 might have been previously repaired. Sil-Pads don't cold flow unless you radically overtighten the 4-40 mouting screw. The usual culprit is a cracked insulating shoulder washer caused by an over tightened 4-40 screw. If you didn't replace the shoulder washer, you're going to experiencing that shorted feeling again.

Remember, you have but one life to give for your hobby.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Jeff Liebermann

Sorry the silpad didn't fail, I replaced a Mica that failed with Silpad, cause that's what I have. Odd that I had 7.5 Kohm of resistance ground to common, hmm, maybe not, it was the +24v supply shorted to case/earth ground, so makes some sense. Yes, this unit has obviously been repaired before, it looks looks like some of the caps came from Radio Shack. At least one of the regulator transistors is an ECG sub. I don't know what else has been replaced. It has some kinda neat functions, you can change the symmetry of the triangle wave, so it can be ramp up then straight down or straight up then ramp down or a triangle. The same symmetry adjust when in square wave mode sets the duty cycle. I don't like the fact that it doesn't have a detent at the 50/50 point. The adjustments ask for a 1000 megaohm meter. I'm in no hurry to start an alignment. I'm not sure 10 meg is going to affect most adjustments, but some of the frequency setting resistors are 10 megaohms.

Mikek

Reply to
amdx

So much for subtlety. Use an isolation xformer when working on devices with potentially defective power supplies. I used to have a melted scope probe hanging on the wall of my shop as a reminder.

Silpad or mica, it doesn't matter if they're intact. I was worried about the insulating shoulder washer. They're easily cracked or crushed.

Look for the sloppy soldering on foil side of the PCB. Also, check if the values have changed from the original schematic. I sometimes find amazingly creative part substitutions.

I've never seen a 1 gigaohm resistor. Sounds like a misprint.

Wash those down with a brush and alcohol. If the resistors are carbon composition, I would expect some value changes due to aging.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

You can buy them easily. Or buy 10 10G resistors and put them in parallel.

--sp

Reply to
Spehro Pefhany

Yep 100G out of the Farnell catalog IIRR. And there is a 1T in my Keithley electrometer.

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John Devereux
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John Devereux

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