UPL with Option B1 - Enabling Cuts Audio Output

I've just purchased a second UPL, this one with the Low Dist Gen option (3 years searching for one!) and am in the process of checking it out. Seller is ATE Test Equip.

I noticed there is no output from the generator unless I turn off the Low Dist option.

Is there something else that must be set up for this to work? I'm testing with the THD setup. The normal (non Low Dist Gen) seems to work, although the Ch1 voltage level reading is not 1.000V as with Ch2 (both are 1.000V on my other UPL). Maybe the calibration is off, too.

Anyway, just wondering if something's wrong with this unit.
After several hours of letting the UPL run, the Low Dist oscillator began working, but intermittently. With the monitor speaker on, it is audibly sounding like a bad connection, getting louder and softer and crackling sounds. Distortion levels were around 8%. Without the Low Dist Osc engaged, distortion in Gen Crossed mode is .004%. Still way higher than most of the amplifiers I test on my other UPL, so no use to me. Gradually, the Low Dist Osc improved, but the best it is doing now is around the same as the internal generator.
I know it is operating because I can turn the freq up to 110KHz.
Other issues, I'm noting is the readout of levels is not matching between left and right channels and the frequency reading is not exactly on 1.00000KHz when the generator is set to 1KHz, unlike my other UPL. The display is also very dim and hard to see even in low lighting and the fan seems to have a bad bearing. So it's got some issues.

Seems that R&S doesn't service this model anymore. They said there are no replacement parts now.
Seller sent an RMA and will take the unit back. Given R&S told me that it will cost $705 just to evaluate if it can be repaired, plus roughly $200 round trip freight, that's too many thousands wrapped up in this.

The current issues are the high distortion in ch 1 readout and the fact that the Low Dist Osc failed calibration, but after 24 hours, started to work intermittently and then improved over time from 8% THD down to .00006% THD in ch 2 and an order of magnitude worse in ch 1.

Other issues are failing fan bearings/noise and a display so dim you have to turn out the lights to see it.

I think I'll wait til a UPV goes on sale for a price I can finance next year.
I don't have any advice to offer you, but as a UPV user since 2014, there are a couple of things that you may or may not realise:

There is a UPV on Ebay at the moment which was repaired to a pretty deep level, where he fitted a new CPU board and had to remap all the keys as a result. If you search Eevblog you will see his tear down. He got it booting off an SSD as well. It doesn't have a B1.

This leads into another question: if someone managed to fix numerous faults in a UPV, just how difficult is it? (Too difficult for an analogue dog such as myself - I know that!).

Considering R+S's rates, being able to repair it yourself is somewhat of a dream. I guess the question is whether it's a shrewd use of your time. His faults seemed to mainly pertain to the CPU and firmware side of things. Had the B1 or B3 stopped working I guess it could have been a different story.

I am tempted by his one on Ebay, but worried that R+S wouldn't touch it. Whoever buys it might have to be an obligate self-servicer.

When my UPV needed fixing I opted for their fixed price repair, as it included a year warranty and calibration. In 2014 this was a little over £2k GBP. I worry it would be quite a bit more now.

Anyway - please excuse my rambling thoughts. I do worry a little about keeping the UPV going long term (and also have a 2nd that needs repair....). It gets a lot more use than the 2722 - I can tell you that (or the Dscope - am tempted to sell that).
The problem is likely on the analog board. Tracing why a component has .0003% THD vs .00003% THD is not for the casual repairer. But I've narrowed it down to the analyzer ch1 section.

The seller isn't willing to offer enough of a refund to make this worthwhile, so I'm returning it.

I know of the UPV you are talking about. I chatted with the guy, but he cannot guarantee calibration. I'm a bit concerned about the noise figures with the replacement board because R&S software nulls out known EMI and without reprogramming, it may have degraded performance.

Calibration of a UPL (and I would estimate UPV similar) is $1200, according to Greg Stewart at R&S.

I'm in negotiations with the seller of the UPV. I'm just a little leery of paying that asking price, plus shipping, plus the new sales tax on used items that have already been taxed. I know the UPV should do around .0001% in GEN CROSSED mode. His is a little higher, maybe .0002%.

My main concern is not to pay more than I would regret getting a year or two of use out of it before it craps out and is deemed unrepairable.
Was going back and forth with the seller on eBay. I showed the link to an engineer friend of mine who said he "wouldn't touch it with a ten foot pole" and I asked him why and he said because it has a non conforming motherboard and relies on the macro software to translate the keys so that they work at all.

I'm willing to pay $3000 total, including taxes and shipping, if it works for a year, and craps out, I won't feel do bad, but toward 4 grand, delivered, I'd want some sort of garantee that lasts a couple years.

I don't know what the calibration status is, and whether it will hold up over time or develop problems. Apparently the original motherboard died as well as some other components and had to be replaced with substitutes. That worries me. Should I need to send it in to R&S for repair/calibration, whether they'd even touch it after discovering it's not a stock unit, that concerns me.

So I gave my final offer and will have to be willing to walk away. Maybe six months down the road, if it's still unsold, I'll make him another offer.
My colleague raised an interesting question... said some equipment is designed to work with a certain speed of motherboard. Putting in a faster motherboard can cause software to be out of alignment with the expected speeds, resulting in erroneous data.
I recall some years back that some old software would not run on a much newer and faster PC, so maybe a concern?
You have an interesting dilemma for sure.

I see there is another UPV listed that has an error but is only $2k. What's the cost of a flat rate repair? Maybe buy the cheap one and get it repaired plus have R&S add the low distortion option.

That might be a few more $ total but you would wind up with a better unit with fresh calibration and some support.

I understand wanting to upgrade to the newer model. On the other hand, the UPL specs are pretty close to the UPV and with component level service documentation and a spare unit or two you could keep going for years.

You could even spend some time with the UPL schematics and clone the low distortion board. Then you would have complete control over the results but I suppose you want to spend your time fixing customer stuff - not your own stuff!
R&S can't repair a lot of older gear due to lack of boards. They said they don't do component level repairs. And evaluation for a UPL is $705. Calibration is $1200.
If they could add a low dist osc (not likely for UPV, and impossible for the UPL due to no parts available), it would probably be several thousand dollars. Still might be work inquiring though.
I've had to repair my own UPL after an amplifier went into oscillation and took out the generator and attenuators. But I've got so much backlog of work that it's going to take me a month to dig out. I have many pet projects I want to work on, but no time and less energy due to my advanced age.
At this point, I just need test gear that works, saves me time, and provides good printed reports for the customers.
Cloning the low dist board is one thing, but adding the software option and unlocking the software key is another entirely.
R+S added a B1 when my UPV went for a service. I got it at the same time as a fixed price repair and calibration.

I didn't realise the B1 needs a SW key. The option to turn it on is there from standard - no? It just whites out the box if it is not detected (long time ago so memory not reliable on this).
It was £170 to add the B1 in 2014. I could be totally wrong, but I got the impression (don't rely on this) that some people self-install... I did once see some UPV modules on Ebay. Wasn't quick enough to snap them up (I think one was a B2 digi option).

Some other info for you: the 2722 gives approx 2dB lower THD+N when feeding the UPV @ 1KHz / 2V RMS than the B1 (at lower frequencies the B1 has better THD+N than the 2722). If you bear in mind that this proves the UPV's analyser section to be at least 2dB better @ 1KHz than the B1, what's to stop you building one of Viktor's oscillators? (I guess it won't have the output level). Just an idea.
The latest news is the seller accepted my offer. I thought he was going to let it expire, but in the last hour, boom. So I paid and now I'm the "proud" new owner of a UPV.

Somewhere a while back, I had the notion that the Low Dist option for the UPL was around $7,000. I may be completely in error about that, as that was some years back. Nothing comes cheap from R&S.. they charged me $800 for a damned ribbon cable 2 years ago. I doubt they would charge less than that for a low dist osc.

I could build one, but one of the main reasons I needed it was to test amplifiers above 20KHz. The UPV standard oscillators go to 80KHz, so that covers me well. Sometimes I want to check an amplifier to 50KHz.

That vast majority of what I test has an order of magnitude higher distortion than the UPL.
It looks like someone bought the $2000 UPV after my earlier post. The good news is the seller accepted your offer so you should be all set!

Let us know how it works when you get it - maybe even post a picture or two of your test bench with the UPV added.
It's en route via Fedex.

I expect that it will be as advertised and should work trouble free for at least a couple of years.

One of the things I like to do is clone the HDD so I have a backup.

Tomorrow's the expected delivery. The busted UPL should get picked up by the driver at the same time he drops off the UPV.
Did you find the tear down page on eevblog? That is your actual UPV. I think he fitted an SSD - which is a good thing as my UPV is not quick to boot.

I have exchanged a couple of emails with Jonathan re: my spare UPV that needs fixing. He has been really helpful and generous with his time, so I doubt you will have anything to worry about.