Test Equipment Anonymous (TEA) group therapy thread

[Zucca]

Okay I got this one.



That hole on the handle inspired me. 

The china boat arrived today here in Germany, surprise suprise!
Now I understand that hole in the handle is not to put a finger in it, but is a sort of spring STOPPER so you don't cut into the copper.
Actually clever made, when you are close to the copper the resistance increase (the hole squeezes) and you have a fine control...

It's time now to use it and see how it goes in real life.

[bd139]

Right got to play around with the spectrum analyser for a bit. Started with power supply by hooking it up to the 6205B. No problems there. Ramp coming out of X, nothing on Y at all. Hmm. Followed the alignment instructions in the article and found that the internal reference marker generator was dead as a dodo. Pulled out the 74LS90 divider and it started oscillating. Fortunately I have a whole bunch of 74LS90's so I stuffed a new one in and confirmed that were the correct signals at the output. And guess what? Well it only bloody works!

Debugging session:



Yep definitely works:

[med6753]

Good day here as well. The PSU re-cap on the HP 5248L is done and it's currently warming up.


I was able to drill out 2 rivets without any excess drama and got all the chips/shavings. Here are 2 terminal strips mounted. Yes, it's very tight in there.



And two pix from opposite angles all wired and caps installed. One 1500uf/16V and two 22uf/200V. 




This one is a wrap. 

[med6753]

Right got to play around with the spectrum analyser for a bit. Started with power supply by hooking it up to the 6205B. No problems there. Ramp coming out of X, nothing on Y at all. Hmm. Followed the alignment instructions in the article and found that the internal reference marker generator was dead as a dodo. Pulled out the 74LS90 divider and it started oscillating. Fortunately I have a whole bunch of 74LS90's so I stuffed a new one in and confirmed that were the correct signals at the output. And guess what? Well it only bloody works!

Debugging session:



Yep definitely works:

That is cool. 

[bd139]

Nice one with the recap med. What's next? Blue 

(I'm liking blue  )

[Neomys Sapiens]

Item number two. This was the £30 spectrum analyser gamble which appears to have paid off so far despite being 100% untested.





Very nicely constructed. This is a house clearance item so RIP to the engineer who this came from. It will be looked after and not bounced.

After doing some digging it appears to be a very faithful build of the Radcom 1989 simple spectrum analyser: http://archive.retro.co.za/archive/amateur/SimpleSpectrumAnalyser-Radcom-Nov1989.pdf

I am suspicious about the mains filter so will bring it up on a bench power supply when I get some time and check it out thoroughly.

Huh. It is some time ago that even a Ham would have considered those attenuator switches as fit for RF.
Or are they DC command only for PIN diode attenuators?

[Neomys Sapiens]

@bitseeker @McBryce @Terra Operative @TorinoFermic:
Now you've done it. I'm sitting here and look at my 3478 suspiciously all the time, but I have no time to spare. Aaaaah!

[bd139]

Huh. It is some time ago that even a Ham would have considered those attenuator switches as fit for RF.
Or are they DC command only for PIN diode attenuators?

This is ~1989. They're just crap I think. The dynamic range, sensitivity and filter bandwidth isn't great for this SA but it's enough for casual harmonic measurements and looking at mixer products etc.

[med6753]

Nice one with the recap med. What's next? Blue 

(I'm liking blue  )

Next project is pull down the Pioneer amp and find out what's up. But that may get put on hold. Late yesterday got a phone call from one of the owners of the PC's I maintain. 6 year old Dell tower went tits up. Completely dead, no power. Probably just the PSU but given it's age and it's Win7 told them they would be better off purchasing new. And they need one ASAP and have no backup. So once they purchase one I get the job of setting it up for them and I'll also pull the old hard drive and move their files over. A back up? Surely you jest.   

[tautech]

The dynamic range, sensitivity and filter bandwidth isn't great for this SA but it's enough for casual harmonic measurements and looking at mixer products etc.

And the SDS1202X-E inbuilt 1 MPts FFT isn't ? 

[Specmaster]

Huh. It is some time ago that even a Ham would have considered those attenuator switches as fit for RF.
Or are they DC command only for PIN diode attenuators?

This is ~1989. They're just crap I think. The dynamic range, sensitivity and filter bandwidth isn't great for this SA but it's enough for casual harmonic measurements and looking at mixer products etc.

At only £30, it was well worth the punt and if it covers the ranges of interest, considerably, considerably easier on the old pocket to boot, well done. 

[bd139]

The dynamic range, sensitivity and filter bandwidth isn't great for this SA but it's enough for casual harmonic measurements and looking at mixer products etc.

And the SDS1202X-E inbuilt 1 MPts FFT isn't ? 

I was getting there. Give me a few minutes to catch up 



Edit: To be clear I couldn't resist the homebrew one. Someone put a lot of time and effort into it and it ended up in a generic house sale at £30. The probability is that the thing was going to get bought by someone who couldn't repair it or didn't know how to use it and either bounced around on ebay or stripped for parts. Didn't want to see that happen.

I've had a "build a spectrum analyser" on the bucket list for a few years but I just don't have the time to do it. So I'd like to revel in someone else's success at least and give it a good home rather than consign it to some twat with a weller soldering gun 

[tautech]

The dynamic range, sensitivity and filter bandwidth isn't great for this SA but it's enough for casual harmonic measurements and looking at mixer products etc.

And the SDS1202X-E inbuilt 1 MPts FFT isn't ? 

I was getting there. Give me a few minutes to catch up 

They do take a bit of driving but work just fine. Previous SA experience helps but you're sharp enough to work it out. As you already know they are a good little DSO.
Enjoy. 

[bd139]

The SDS requires considerably less driving required than the Rigol brick. That was horrible on the FFT side of things. I did get some mixer products out of it after arguing for nearly 20 minutes.

[tautech]

The SDS requires considerably less driving required than the Rigol brick. That was horrible on the FFT side of things. I did get some mixer products out of it after arguing for nearly 20 minutes.

All FFT results vary with timebase settings as you probably already know and SDS give better with slower settings as they have more data points to work with.
Don’t forget a 50 ohm terminator for when accuracy is required.

[bd139]

Cheeky fucker who sold me that E3630A is trying to screw me. The auction just changed to “for parts or not working” 

https://www.ebay.co.uk/itm/392920926783

I don’t think the numpty realises that eBay takes a snapshot at purchase time  . As yet no reply to the return request. If he doesn’t reply by 28th then escalated to eBay 

[bitseeker]

LOL! Plus eBay customer service likely has full view of the change history on the listing (of which we only see a very high-level view).

[bitseeker]

Public Service Announcement

All HP 3478A owners:

• Clean your front/rear switch
• Replace your RIFA caps
• Back up your cal data
• Check your SRAM battery voltage (replace as needed; see also #3)

Everyone else: Don't forget when the next item on your auction watchlist ends. 

Is there any easy way of backing up the cal data? I replaced the battery last year (without losing the cal data), but it would be nice to have it stored safely somewhere else.

McBryce.

There have been several threads on it. This is one I had handy: https://www.eevblog.com/forum/repair/hp-3478a-how-to-readwrite-cal-sram/

Also, I've seen at least a couple of programs folks have written to download and restore the cal data.

[bitseeker]

@bitseeker @McBryce @Terra Operative @TorinoFermic:
Now you've done it. I'm sitting here and look at my 3478 suspiciously all the time, but I have no time to spare. Aaaaah!

I know the feeling. I have some in my repair queue daily reminding me that they're running on old batteries. But I have to get them working to pull their data.

[bitseeker]

3. is a problem, i have that keysight adapter..installed 1,5 GB of keysight crap...on the adress of the DMM (11 in my case) only one meter connected, i see lot of devices?? but none is detected..
anyone a tip how to do this?

Screenshots?

Screenshots and steps to reproduce would be helpful. If you're using BenchView for the first time, it can be a bit confusing.

I recently upgraded the SSD in my laptop and don't have all the GPIB stuff installed, yet. But seeing what you're doing should refresh my recollection.

[AVGresponding]

Cheeky fucker who sold me that E3630A is trying to screw me. The auction just changed to “for parts or not working” 

https://www.ebay.co.uk/itm/392920926783

I don’t think the numpty realises that eBay takes a snapshot at purchase time  . As yet no reply to the return request. If he doesn’t reply by 28th then escalated to eBay 

Don't forget to post the seller name on the forum.



Just been watching a bunch of items on fleabay go for silly money (ie TDS210 for £180), but at least I managed to bag a Philips PM6667 counter earlier, despite several people trying to elbow me out at the last second     which caused the price to jump from £20 to £31   

Waiting on my doorstep when I got home was an Atari 2600 (untested), cost thirteen quid shipped. Surprising lack of crustiness inside, I was expecting multiple leaking caps, blown traces, missing ICs etc etc. Seems intact:


With the shield removed:


The soldering on the IC socket is a bit how ya doin' though:


And wtf are these? Caps in glass jackets?!? As if tants aren't bad enough already, they put these ones in shrapnel-generating casings!
 


The one questionable cap could be the main reservoir, the heatshrink label has some holes in it, but whether this is from the factory or evidence of overheating idk. Gave it some limited juice, uses around 10mA @ 8.6V according to the meters on the TTi 354, which seems fine (7805 is the only power regulation). No carts to test it with yet, though I suppose I could probe the CPU clock, and I could plug in a tv to the rf out, though icr if these have a no-cart boot screen.
The reset and select buttons need new sponge/springs, a quick test with a bit of packing foam gave good results.

Looking forward to getting pwnd at asteroids...


@TorinoFermic, glad you found it was a simple solution!

[Robert763]

Huh. It is some time ago that even a Ham would have considered those attenuator switches as fit for RF.
Or are they DC command only for PIN diode attenuators?

This is ~1989. They're just crap I think. The dynamic range, sensitivity and filter bandwidth isn't great for this SA but it's enough for casual harmonic measurements and looking at mixer products etc.

Actually if wired correctly a DPDT slide switch makes a pretty decent PI attenuator switch. Virtually no lead length, flat (low inductance) connections, very low stray capacitance and no joints in contact path.Good to high VHF at least.
From the ARRL Handbook step attenuator project "The switches must have low capacitance between the contacts, and simple slide switches are the best selection."

The RADCOM design was pretty good for the time - as long as you don't have a 2m repeater nearby 

[mnementh]

Nice one with the recap med. What's next? Blue     (I'm liking blue  )

Next project is pull down the Pioneer amp and find out what's up. But that may get put on hold. Late yesterday got a phone call from one of the owners of the PC's I maintain. 6 year old Dell tower went tits up. Completely dead, no power. Probably just the PSU but given it's age and it's Win7 told them they would be better off purchasing new. And they need one ASAP and have no backup. So once they purchase one I get the job of setting it up for them and I'll also pull the old hard drive and move their files over. A back up? Surely you jest. 

Maxim 41. “Do you have a backup?” means “I can’t fix this.”   

mnem
13th Commandment: Thou shalt back it up, lest thine data go to heaven without you.

[med6753]

Nice one with the recap med. What's next? Blue     (I'm liking blue  )

Next project is pull down the Pioneer amp and find out what's up. But that may get put on hold. Late yesterday got a phone call from one of the owners of the PC's I maintain. 6 year old Dell tower went tits up. Completely dead, no power. Probably just the PSU but given it's age and it's Win7 told them they would be better off purchasing new. And they need one ASAP and have no backup. So once they purchase one I get the job of setting it up for them and I'll also pull the old hard drive and move their files over. A back up? Surely you jest. 

Maxim 41. “Do you have a backup?” means “I can’t fix this.”   

mnem
13th Commandment: Thou shalt back it up, lest thine data go to heaven without you.

Just got a text from them. They bought an HP tower and they'll bring it over tomorrow morning along with the dead Dell and I'll set it up for them and transfer their data.

[med6753]

And wtf are these? Caps in glass jackets?!? As if tants aren't bad enough already, they put these ones in shrapnel-generating casings!
 

They are glass encased ceramic bypass caps. Little or no threat of smoke.