Signal generator recommendation please

[peter-h]

I have an old HP 3314A from the 1980s and it needs regular repair. It has a load of reed relays and the switches need replacing. I have the service manual for it but... It cost about 5k-10k way back then.

Now the market is full of them; all of them seem to be Chinese and some look like they are junk. I tend to think that when the on-screen text is not even lined up properly the rest of it must be junk.

I don't want to pay more than say $300 or so. I can get the old HP 4-digit priced ones on Ebay for that much. Don't need arbitrary waveforms. Do need a reasonable amount of output, say 10V. Don't need more than 10MHz; have a Marconi 2024 to go high up.

Which make is of reasonable quality?

Thank you in advance.

[nctnico]

Yeah... I have replaced all the reed relays in the 3314A I used to own a decade ago. What are your requirements in terms of THD? If you just need some signals to tests with then I think one of the newer Feeltech units (FY6900 for example) is good enough. If I where to replace a HP 3314A that one would be at the top of my list. Much more convenient compared to some old boat anchor from HP. If the Feeltech unit breaks you just buy another one and still come out on top.

[peter-h]

No special THD requirements.

FWIW I thought the Banggood stuff did look extra cheap... But I guess they do work well. I would probably go 2x up the price range from that.

[tautech]

Have a look at SDG1032X....top end of your budget I know however I've had a good run with dozens I've sold.

[nctnico]

No special THD requirements.

FWIW I thought the Banggood stuff did look extra cheap... But I guess they do work well. I would probably go 2x up the price range from that.

Yup and you won't gain much in terms of features.

[graybeard]

I am very happy with my Siglent function generator.  However this UNI-T UTG932E is well within your budget and may meet your needs.

[peter-h]

The Siglent SDG1032X looks fine actually.

Is there anything in the HP3314A which makes it worth repairing? Does it have low THD or something like that?

The engineering inside is amazing

[graybeard]

The Siglent SDG1032X looks fine actually.

If you have a Bode Plot capable Siglent scope the SDG1032X should work with it.

[tautech]

The Siglent SDG1032X looks fine actually.

If you have a Bode Plot capable Siglent scope the SDG1032X should will work with it.

^^^
 

[nctnico]

However this UNI-T UTG932E is well within your budget and may meet your needs.

That looks nice. And it seems to be fanless as well.

[peter-h]

I normally open up anything with a fan and either replace the fan with a silent one or (if it is say a 5V DC one) put a couple of diodes in series with it

Most equipment designers throw in fans without any thought for how much airflow is actually needed, and in most cases where forced cooling is needed the airflow actually needed to remove the pool of warm air is tiny.

[Martin72]

I like my SDG-1062X, but:

UNI-T UTG932E

30Mhz, 2-channel, 14bit, 200MSa/s....Not the worsest one.

[Hexley]

The Siglent SDG1032X looks fine actually.

Is there anything in the HP3314A which makes it worth repairing? Does it have low THD or something like that?

The engineering inside is amazing

One unusual capability of the HP3314 is its ability to phase-lock to an input signal and either multiply or divide the frequency by N. The phase of the output may be adjusted with respect to the input up to +/- 180 degrees or so.

Handy for some timing needs, even if not something one uses every day.

I also like the design of the output attenuator, in which a single button click can change the output by an order of magnitude. Surprisingly handy when checking the dynamic range of circuits like amplifiers or filters.

[Doddy883]

+1 for the Uni-T UTG932/962. Very pleased with mine. It's compact and performs well - I watched a Youtube video comparing the THD to other (more expensive) generators and it was decent, beating some of them. Unfortunately I can't find the video now!

There is a thread going on here though, https://www.eevblog.com/forum/testgear/uni-t-utg932utg962-200msas-function-arbitrary-waveform-generator-220394/

[peter-h]

I repaired the HP3314 yet again, using up my stock of reed switches, so the main thing I would get with one of the chinese boxes would be the nice scope-like display. And they are much more portable.

How can these reed switches fail, when they are supposed to do, what, 100M operations?

[joseph nicholas]

The fans inside these units are like the warning on your mustard jar telling you to keep it refrigerated.  Useless.

[SilverSolder]

I repaired the HP3314 yet again, using up my stock of reed switches, so the main thing I would get with one of the chinese boxes would be the nice scope-like display. And they are much more portable.

How can these reed switches fail, when they are supposed to do, what, 100M operations?

If they are what I think they are, they are not really reed switches...  they are leaf-spring key switches, known within HP as the “Bill West switch” after its inventor.

They don't age gracefully in all examples.  I have some that work smoothly, and some that are in need of help...

You can fix the ones you have, usually without buying parts.  Search for 'Bill West Switch" even here on this forum, lots of advice...

[nctnico]

I repaired the HP3314 yet again, using up my stock of reed switches, so the main thing I would get with one of the chinese boxes would be the nice scope-like display. And they are much more portable.

How can these reed switches fail, when they are supposed to do, what, 100M operations?

If they are what I think they are, they are not really reed switches...  they are leaf-spring key switches, known within HP as the “Bill West switch” after its inventor.

No. There is a whole bunch of reed switches inside the HP3314A. I had one too and in mine the reed switches stopped working after the unit had been running for a while. I never quite understood the failure mode. Maybe the contacts got magnetised over time and became sticky.

I owned a later model 3314A with rubber keys. The leaf-spring switches are awfull to use and in general I avoid HP equipment which has those. I hope Bill West didn't invent anything else to cause inconvenience to humankind.

[peter-h]

I've just done ALL the reed switches I can find in the HP3314A. About 10 of them. Now it works find without any error codes. Yes I agree it must be magnetisation, because reed switches have an incredibly long life.

They were spot-welded, not soldered, so one has to cut them out and solder in the replacements.

I will get the SDG1032X - thanks for the tips. It looks like a nice unit.