Test Equipment Anonymous (TEA) group therapy thread

[xrunner]

Out of the "because I have way too much free time on my hands" dept.   

Was interested in amplitude stability of the 437B power meter cal source. I let the spectrum analyzer warm up for an hour (Rigol DSA815) and plotted the power output of the cal source of the power meter from a cold start for about an hour. Trace was Max Hold. You can see it drifted in frequency ~28 kHz but the power was very stable (0.1 dB/Div). The frequency started off at the right side (higher F) and got lower.

I now knew the power meter cal source had a stable power output from a cold start. Then I let both the power meter and the DSA815 cool down for an hour, and repeated the test. You can see the results. The frequency drift is due to the power meter warming up and the amplitude changes are due to the spectrum analyzer warming up. But it's tenths of a dB until warmed up. Is Siglent better in this regard I wonder ...

 

[Carl_Smith]

Question: Tek Scopemeter THS 720A

any good ? Fair price ? Seller is asking 270€

These Tek handheld scopes have one feature that makes them very useful in certain situations.  The two channels are completely isolated from each other and since it's battery powered they are not grounded.   This lets you do things you can't do with a normal scope, like connect one channel to a motor being driven by an H bridge, and connect the other channel to the logic signals driving the H bridge, without shorting anything out through the grounds.

But I have seen issues with them, like sometimes the LCDs have a problem where the contrast goes all funny.  So I don't know if I would get one unless I needed it for a situation like I described above.

It does seem like a good price it it is in working order with battery and probes.

[vk6zgo]

Question: Tek Scopemeter THS 720A

any good ? Fair price ? Seller is asking 270€

Back in the day, It was about the only early DSO that I found useful for TV pix monitor repair work.

At my work, you had to move fast to get your hands on a 'scope (we had a lot of them, but a lot of Techs, too!).

I found I had missed out on grabbing an analog 'scope, so "liberated" the THS720A from the office cupboard.
(It had been purchased for its isolated inputs to use looking at our studio power conditioner, & the EE & Electrician "sort of" hid it away after that, but I knew where it was!)

It wasn't ideal for what I was doing, but "did the job", so I could be productive.
That said, when a daggy old Tek485 with one dead channel became available, I happily returned the THS720A!

It struck me as being a nice, solid unit that did all that it purported to do.
That was, of course, with a near new 'scope many years ago.
Others with experience with them as they have aged, have mentioned battery issues.

[capt bullshot]

Question: Tek Scopemeter THS 720A

any good ? Fair price ? Seller is asking 270€

Looks like most important topics were mentioned:

- UI is lame, and it's no fun having to use it
- Waveform update rate is lame, very small memory depth
+ At least it works without the battery (most probably the battery will be dead), battery can be replaced by homemade bodges (they use NiCd cells). Works with 15V/1A DC wallwart or power brick.
++ Isolated inputs (these come in handy sometimes)
- isolated inputs can be confusing sometimes, too
- Built-in multimeter is solala at best
- They tend to be overpriced on the bay
+ One can easily mod the 720A to make it believe it's a 720P (you get very lame power analysis) or 730B (you get 1GSample/s but not the 200MHz BW)
- I've seen aged units show some mysterious ripple on their traces (maybe / probably internal power supply involved)

270 EUR is on the lower end of price span I've seen
If you want isolated inputs and battery operation, lurk for a TPS20xx series model (beware these often are over 1000 EUR at the bay)
If you don't need isolated inputs, get a cheaper TDS220 or similar.
If you want it now, get it

Personal experience is involved.

[ch_scr]

Question: Tek Scopemeter THS 720A

any good ? Fair price ? Seller is asking 270€

For comparison, a modern 4-ch handheld scope in "tablet" form factor (avaivable 2ch/4ch with/without knobs) is around 600€.
Review form mikeselectricstuff:

Sure its "double the price", but it's also no comparison otherwise

[Saskia]

Everybody, thanks for the feedback. Use case would be working on Pinball machines, arcade machines, etc where you do not necessarily want to use your bench scope due to space and portability constraints.

I'll think about it.

[med6753]

Woke up early to find that notifications is working finally. Got over 100 of them in my in box. 

[tautech]

Woke up early to find that notifications is working finally. Got over 100 of them in my in box. 

Just 2 arrived here and good luck remembering what they were about if they didn't add a topic or quote a previous PM. 
We still running on the substitute server according to Dave but it's been pretty good today.

[med6753]

Woke up early to find that notifications is working finally. Got over 100 of them in my in box. 

Just 2 arrived here and good luck remembering what they were about if they didn't add a topic or quote a previous PM. 
We still running on the substitute server according to Dave but it's been pretty good today.

This isn't PM's. I have notify turned on for this thread. Every time someone posts to this thread I get an e-mail notification. Is a big help to keeping up. Apparently the server was storing them and then blasted them all out at once. 

But I cleaned up the mess. 

[Ice-Tea]

Re. 720A and on top of what others said: accessories matter. I sold a number with case, new home made battery pack and probes for 400-500€. Without the proper probes the isolation means little so whether they are included or not matters a lot.

[bd139]

Woohoo decided to small claims packlink for the £185 they owe me. I’ve sent a copy of the form to their CEO first to see if he wants to avoid it. Turns out after looking at it, the company’s registered office is in the UK so
I only have to file here albeit their contact address is in the EU.

[med6753]

It appears that Mouser USA is now on a consistent 2 day turnaround. They used to be typically one day. I find 2 day acceptable. But UPS is turning into a giant fail. The parts shipped on Friday. I paid for UPS 2nd day. As of this morning the parts are in Philly. Projected delivery Tuesday. So 4 days when I paid for 2 day because UPS doesn't work weekends. That's ridiculous. FedEx 2 day is a shipping alternative for the same price. And guess what? They deliver on Saturday and turns out on Sunday too. But I can never predict when FedEx will show up but given I'll get it within 2 days I think from now on I'm going with them.

Brown can go suck it.   

[wkb]

400+ notifications for this subject wow..    But the forum is getting back full steam   

Picked up a very clean HP 3325A synthesizer last friday. It is now living with its family as shown on the pic.

Back to working condition is now also my HP 5342A 18GHz microwave counter. Bought two parts units to fix it, during the fixing process on of the parts units was the first one to work again  . The 2nd unit once repaired I gave on permanent loan to a ham radio friend of mine.  All in all I now am running out of space   

Hmm.. could this be TEA? 

Wilko

[Robert763]

Everybody, thanks for the feedback. Use case would be working on Pinball machines, arcade machines, etc where you do not necessarily want to use your bench scope due to space and portability constraints.

I'll think about it.

The isolated input can be useful on pinball machines. You can look at logic and solenoid drive at the same time without risk of blowing anything up. I've had a 720 before and would certainly consider another at that price if there were funds in the TEA kitty.
My first full time job was repairing arcade video games and pinballs straight out of school in 1978.

[Saskia]

comes complete with probes, power brick and manual. I think I'm gonna drop him a note ...
Thanks guys.

[Specmaster]

Everybody, thanks for the feedback. Use case would be working on Pinball machines, arcade machines, etc where you do not necessarily want to use your bench scope due to space and portability constraints.

I'll think about it.

I thought that you was getting rid of your pinball machines as part of your thinning out of stuff?

[Specmaster]

Woohoo decided to small claims packlink for the £185 they owe me. I’ve sent a copy of the form to their CEO first to see if he wants to avoid it. Turns out after looking at it, the company’s registered office is in the UK so
I only have to file here albeit their contact address is in the EU.

PackLink are IMHO a steaming great pile of dog poo, I will not use them again.

[Saskia]

@Specmaster got defrauded and decided to keep my stuff for now.

Will clean out as much as I can, but will keep other stuff that is of high value.

[med6753]

400+ notifications for this subject wow..    But the forum is getting back full steam   

Picked up a very clean HP 3325A synthesizer last friday. It is now living with its family as shown on the pic.

Back to working condition is now also my HP 5342A 18GHz microwave counter. Bought two parts units to fix it, during the fixing process on of the parts units was the first one to work again  . The 2nd unit once repaired I gave on permanent loan to a ham radio friend of mine.  All in all I now am running out of space   

Hmm.. could this be TEA? 

Wilko

I don't know how warm that HP unit below it gets but if you want that 2465 CTS to live a happy life you should not stack it above other equipment. Or at the very least raise it up a few cm to allow maximum airflow to the bottom vents. The unobtainum U800 IC will thank you.

[BU508A]

Question: Tek Scopemeter THS 720A

any good ? Fair price ? Seller is asking 270€

I'm having a THS 720A as well. I've bought it some years back at the HAM Radio in Friedrichshafen for around 250 Euro.
It came with two Tek probes, a new battery, the charger and a suitcase for all the stuff.

If you are interested in, check the BNC connectors. They tend to wear out and changing them is a pita. If you'll get replacements.

[1Ghz]

Recently I'm suffering from TEAS. Especially Spectrum Analyzer Acquisition Syndrome.
I also bought 26.5GHz RF Counter, 26.5GHz RF Power Meter, 26.5GHz RF Power Divider, RF adapters, RF attenuators and much more accessories ... for my precious Spectrum Analyzers.
I need therapy... 

[Peter_O]

Speaking of desoldering, I have bench-news regarding soldering.   

A while ago I acquired a JBC HD-2B soldering station with T470A handle, some tips and original JBC stand for a half-decent price (270€) -given the corona-driven somewhat higher price level.

The station was delivered last week and today I had the time to modify it to accept C470 cartridges (JBC-tips, 48V) as well as C245 cartridges (24V). Nice thing is that the T470 handle accepts both types of cartridges.
After a little bodging and adding a 2pole DPDT switch I now have a manually switchable HD-2B soldering station I can use all types of C470 and C245 cartridges for soldering jobs demanding high and higher power/heat*. 

New topic: https://www.eevblog.com/forum/reviews/modification-of-the-jbc-hd-2b-soldering-station-to-work-with-24v-and-48v-tips/

HD-2B heating a C245 cartridge:


HD-2B heating a C470 cartridge:


I put the switch on the back right above the power inlet:


The modification I made:


edit: There's a third connection involved with the 12V supply, that i didn't show: It might be a NTC sharing one connection with the 12V supply. Didn't modify.

edit²: *-compared to my T12 KSGER OLED-soldering stations with self-assembled alternative power supply.
The T12s have become my daily driver and have pushed out my Wellers completely.

I'm using a Weller WS81 and have been thinking about a TS12 or JBC CD-2BQF.

Is it just a reflex of an TAE addict, or are there substancial differences in performance?

Let's say, a Weller Magnastat kind of very old shool soldering system is 20 points on a scale and the WS81 is 100.  What would a TS12 score, what a JBC?

[beanflying]

My Brain is hurting. Chinese made version of a fully open sourced project and the Muppets subbed in 100k 7 bit Digital Pots instead of the specced 50k 8 bit ones Wonder why my Smoothieboard isn't talking to the steppers    Midnight here so a double Scotch and Chocolate for the brain.....

mnem
*distraction-ily*

Sub $3 worth for the two Digital Quad pots but I think a few kicks in the balls might be preferable to reworking the 20 pin TSOP packages by hand 

LOL... My intent was to provide a momentary amusing diversion from your misery, not to cast it in such sharp contrast. 

The parts are at least pin-compatible, I hope...? 

mnem
 

Yep several alternates with the 'correct' spec  Ordered 2 for a few pesos and another $100USD+ of 'bits' from Digikey because - reasons

[wkb]

The HP3325 below the Tek 2465 is a  "cool dude", at 60VA.  So that should not be a problem, its Pabst fan keeps the case nicely cooled.

That said: thanks for your hint! I am aware of the unobtainiums in my beloved 2465.

Wilko

[wkb]

Recently I'm suffering from TEAS. Especially Spectrum Analyzer Acquisition Syndrome.
I also bought 26.5GHz RF Counter, 26.5GHz RF Power Meter, 26.5GHz RF Power Divider, RF adapters, RF attenuators and much more accessories ... for my precious Spectrum Analyzers.
I need therapy... 

*drool*