Test Equipment Anonymous (TEA) group therapy thread

[med6753]

That's about 45 mins from here. Nope not got the room! 

And you don't want or need the hernia that comes with it, even if it is free 

While it's not as heavy as say a 545 or 547 it is NOT light. 

[bd139]

Edit: considering bagging a Duratool desolder station for this one as I don't fancy having to braid all these displays out https://cpc.farnell.com/duratool/d00672/desoldering-station-uk-eu-plug/dp/SD01384

Yeah, bag one of those desolder stations, you'll wonder why you stuck with braid for so long, honestly it is a good investment.

The Duratool uses the same guts as my Aouyue 2702; tho the handset is different. On the 2702, it is definitely high-maintenance; sometimes requiring disassembly/cleaning after only a couple-three desolderings. We spoke aboot using "alternate" filter materials in the handset and hose a while back... if that one Saskia offered can be had at a price you can live with, I'd think aboot going with it both for you having a better tool and for giving her the business.

mnem
Well, not giving her the business that way.... jeez, you pervs...

Yeah can't be worse than the Weller ones I used to use. I must have spent most of 1996 unblocking the fucking things. Turns out operation and blockage is mostly down to technique apparently although I never mustered it. Alas I don't want to pay for a nice one so I'm going to make do with this I think.

[mnementh]

Found two reasonable "primary" source for info on the dg-mos fet probe:
T. Hirschbüchler Bachelor Thesis on the "Design of a low-cost 1 GHz Active Probe" with "conception, construction and evaluation"
https://content.instructables.com/ORIG/FQZ/1QZP/IPJTFO82/FQZ1QZPIPJTFO82.pdf (SNIP Faulty URL)

...I actually found that article while doing my own research; however I didn't agree with two primary features of his construction technique:

1), his pogo pins are just too long. Everything I've read on the subject aside from his article indicates that ~5mm or less is the ideal length here.

And B) the pin spacing is just ridiculously too wide (yes, I understand the reasons) to actually be a useful probe for most of the kind of stuff you'll use it for.  The really good thing aboot the  60dbmcom probe is the big pads for soldering pins to; you can easily reconfigure to match almost any needed pin spacing.   

   https://www.ebay.com/itm/174764316127

There's also this one; it supposedly has specs from the actual device (not just copied from the Elektor article), and I like that the total signal path is as short as possible; however, it was 2x the price and completely unreasonable delivery time. Also it does not use the gimmick capacitor and no pad for GND pin, which is part of the reason the Elektor design uses a dual-gate FET.

mnem
 

Surely such a probe should be in a shielded body of some sort?

One would think so... but after reading the discussions here:

https://www.eevblog.com/forum/rf-microwave/response-of-cheap-rf-active-probe-from-ebay/

https://www.eevblog.com/forum/testgear/hi-z-probe-for-50-ohm-spectrum-analyzer/50/

my takeaway was that it should in principle, but unless you figure up the resonant frequency of both the circuit and the shielding solution, in practice it makes little difference as long as you aren't touching anything active. It could actually make it perform worse if the shielding acts as a antenna for common-mode noise; we're in that area where such black magic becomes a problem.

The 60dbm probe is mostly GND fill on the back; I suspect that is a large part of why it seemed to be pretty indifferent to how it was handled in my testing, even before I put the shell on it. 

Honestly, the printed shell was as much aboot being clever with a built-in battery as it was making a cover for the tool; tho the discussion suggested that covering in heat-shrink actually could improve flatness.

Here's that ELEKTOR article again to pull it all together in one place for those playing along at home:

https://www.eevblog.com/forum/testgear/hi-z-probe-for-50-ohm-spectrum-analyzer/?action=dlattach;attach=1060862

and the PDF of the original PCB:

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1243238

mnem

[bd139]

Non scientific option: Keep your fingers away from the Hi-Z bit at the end and it'll probably be fine 

Edit: ordered - new toy to play with at least this month 

[mnementh]

" ...in practice it makes little difference as long as you aren't touching anything active."

mnem

[mnementh]

Well I can't see the fluff with a tester like this, especially with the price and UI 
The TL866II Pro "eeprom" programmer that also does flash, bios, etc. also has a chip tester as well for 300 different logic IC.

Totally different devices to support different use cases. For example, the first thing I looked up after reading your post were the RAM chips for a Tandy/Radio Shack Color Computer 1: 2104 (4Kx1) and 4116 (16Kx1). Both are supported by the Retro Chip Tester, neither by the TL866II Pro. I'm sure there will be other examples, because the focus of the products is different.

Yes, the UI leaves a lot to be desired, as I eluded to previously. Had I the free time available, I'd probably just make my own retro chip tester. It's not like I have that many retro computers, thankfully.

It can't test DRAM in general, yes. It can test some SRAM. You are right, how often do you need that depends on use case.
I thought more along the lines of testing logic IC's. But if that's your only concern, there are a lot of Arduino DRAM / SRAM testers out there, building one you still might end up at 100€ total for the TL866 and that, but IMHO that would be more favorable still than the other tester 

The Retro Chip Tester was developed to test "old" memory chips from the 1970s and 1980s, which are often no longer recognized by today's programming devices. It is often recommended to use chips in the same device to test the functionality. It is forgotten that the rest of the hardware is also correspondingly old and frequent switching on and off can provoke further errors.

I still see it as having value as a TEA accessory tool; given that we hoard a lot of these same obsolete parts which are used in our boat anchors. Not saying the TL866 isn't a better deal for what it's made for... just not for what the RCT is made for.

Also, this is TEAnonymous... the obvious answer is that you need both!!!

As for the UI... I know that libraries exist for rotary encoder on the Atmega2560; we have used them for our hacking of the FlySky 9x and Taranis RC transmitters. On this project it may be that there aren't enough appropriate pins left to do it.

Or it may be the same as happens to me all the time... you get development to the state of something you can use, and then lose interest as there is so much else you want to do with the results of a project. Or you decide that it is polished enough for something you'll use infrequently.

mnem

[Saskia]

I think I got one of those old tester kits sitting here as well as that TL866.
Never gotten around to unpacking it, other stuff on my mind right now ...

[bitseeker]

...
Arriving today was one HP 5328A counter - ex eBay.  While I would normally prefer picking such items up, the current Covid restrictions forbid such a trip - so Australia Post it was.  I sent the seller a message asking for it to be packed well ... and I must say, it was.  There was a piece of foam carved out to cradle the knobs on the front panel - a nice attention to detail.  All in all, it survived the journey totally unscathed.

Front panel looks pretty good (and it came with the rack ears) but there's a lot of blank space in the middle that's just begging to be populated.  The gauntlet is at your feet, Bean.  (This could be a dangerous challenge.)



SO ... true to the tradition of the EEVblog, I didn't turn it on, I took it apart!
...

Wow, that one looks great. Added a link to this in the POI as we haven't had one, yet (or I missed an earlier post if someone did tear one down before).

[bitseeker]

Edit: considering bagging a Duratool desolder station for this one as I don't fancy having to braid all these displays out https://cpc.farnell.com/duratool/d00672/desoldering-station-uk-eu-plug/dp/SD01384

Yeah, bag one of those desolder stations, you'll wonder why you stuck with braid for so long, honestly it is a good investment.

Indeed. After buying a desoldering station for the first time many moons ago, I had the same revelation. It's definitely a good investment when you're surrounded by aging test equipment!

[Specmaster]

Non scientific option: Keep your fingers away from the Hi-Z bit at the end and it'll probably be fine 

Edit: ordered - new toy to play with at least this month 

Wow, you went for the glass tube, why? I have my original one still, and I've had it now over 4 years, and it's not actual glass but some form of high temperature plastic    You're right, it is about how you use it, to keep it from clogging up, the trick is to when you suck the solder up, keep the pump running while you withdraw the gun from the thing being unsoldered. This then allows the suction to suck the solder all the way out of the nozzle and impact the filter in the "glass" tube, so you are ready for the next job, next time. Just don't suck up too much solder at each session so that the tube gets more than about 10 to 15 mm of solder otherwise you will struggle to separate the spring from the solder. 

[bitseeker]

Well I can't see the fluff with a tester like this, especially with the price and UI 
The TL866II Pro "eeprom" programmer that also does flash, bios, etc. also has a chip tester as well for 300 different logic IC.

Totally different devices to support different use cases. For example, the first thing I looked up after reading your post were the RAM chips for a Tandy/Radio Shack Color Computer 1: 2104 (4Kx1) and 4116 (16Kx1). Both are supported by the Retro Chip Tester, neither by the TL866II Pro. I'm sure there will be other examples, because the focus of the products is different.

Yes, the UI leaves a lot to be desired, as I eluded to previously. Had I the free time available, I'd probably just make my own retro chip tester. It's not like I have that many retro computers, thankfully.

It can't test DRAM in general, yes. It can test some SRAM. You are right, how often do you need that depends on use case.
I thought more along the lines of testing logic IC's. But if that's your only concern, there are a lot of Arduino DRAM / SRAM testers out there, building one you still might end up at 100€ total for the TL866 and that, but IMHO that would be more favorable still than the other tester 

Yep, all depends what you're in need of. Fortunately, I have the first gen TL866 already. So, I'll likely make a little tester for RAM, memory controllers, etc. for my vintage computing fleet. I actually wrote one in assembly language back in university. It was handy for debugging not only the ICs, but also the crappy wiring we had for our microprocessor lab projects. Cracked wires lead to all kinds of fun intermittent hardware problems.

[Specmaster]

Where have all the bidders gone on eBay then, nobody was there to save me from bidding on and winning yet another DMM  Like I really need another, oh yeah?

I thought, I'd just slap a low bid on gixen, like I have on others before and been beaten each and every time, and then today Shazam, I win one  What did I win, only this little beauty here.

   

[bitseeker]

Oh and what's that lurking on top? A 475 and an E3630A. Deja Vu here 

So totalling it up, did you make or loose money buying and selling the same gear over and over again? 
Also  on getting a desoldering station.

There's a nice story behind this. If I go back to 2015 when I started this again, I was actually financially completely up shit creek. Buying and selling TE was a good way of making low investments with good returns to keep me afloat while I sorted everything out and it was something I found interesting at the same time. It took through to 2018 to get properly sorted and I was running on a 200% profit overall on arbitrage and value-add repairs which is a pretty amazing ROI. Quite frankly TE saved my ass for about 3 years of my life. I do this for love now not for survival, plus if I don't do it the devil might make use of my idle hands 

Yep, definitely better to have you here, running up the post count.

Thanks for the storytime, bd. That is a pretty amazing ROI. Glad you made it through and have been having fun since.

[bitseeker]

Well I can't see the fluff with a tester like this, especially with the price and UI 
The TL866II Pro "eeprom" programmer that also does flash, bios, etc. also has a chip tester as well for 300 different logic IC.

Totally different devices to support different use cases. For example, the first thing I looked up after reading your post were the RAM chips for a Tandy/Radio Shack Color Computer 1: 2104 (4Kx1) and 4116 (16Kx1). Both are supported by the Retro Chip Tester, neither by the TL866II Pro. I'm sure there will be other examples, because the focus of the products is different.

Yes, the UI leaves a lot to be desired, as I eluded to previously. Had I the free time available, I'd probably just make my own retro chip tester. It's not like I have that many retro computers, thankfully.

It can't test DRAM in general, yes. It can test some SRAM. You are right, how often do you need that depends on use case.
I thought more along the lines of testing logic IC's. But if that's your only concern, there are a lot of Arduino DRAM / SRAM testers out there, building one you still might end up at 100€ total for the TL866 and that, but IMHO that would be more favorable still than the other tester 

The Retro Chip Tester was developed to test "old" memory chips from the 1970s and 1980s, which are often no longer recognized by today's programming devices. It is often recommended to use chips in the same device to test the functionality. It is forgotten that the rest of the hardware is also correspondingly old and frequent switching on and off can provoke further errors.

I still see it as having value as a TEA accessory tool; given that we hoard a lot of these same obsolete parts which are used in our boat anchors. Not saying the TL866 isn't a better deal for what it's made for... just not for what the RCT is made for.

Also, this is TEAnonymous... the obvious answer is that you need both!!!

Indeed!

As for the UI... I know that libraries exist for rotary encoder on the Atmega2560; we have used them for our hacking of the FlySky 9x and Taranis RC transmitters. On this project it may be that there aren't enough appropriate pins left to do it.

Or it may be the same as happens to me all the time... you get development to the state of something you can use, and then lose interest as there is so much else you want to do with the results of a project. Or you decide that it is polished enough for something you'll use infrequently.

From bits I read, a large part of the current sub-optimal state of the UI may be a simple case of growing pains, feature creep, etc. When the tester only supported a few chips, stepping through them wasn't a big deal. It's just time to stop the evolution and redo it in a fashion that's appropriate for what it has become (and add room for growth). Of course, the next hurdle is when you outgrow (in pins, RAM, storage) the microcontroller. But that's all part of the fun of creating stuff.

[khs]

3)  Defective probe calibrator, shows 300mVdc and no AC.

This seems to be normal. The (or better the calibrator of my 11401) is active during Utility->Probes only.

[DC1MC]

Who wants a crate of LCD displays, cheap 

https://www.ebay.de/itm/373669113603

[Specmaster]

Defective ones at that no thanks 

[mnementh]

Oh, come on... just lookit all that shrapnel for just a EU buck. All it needs is Saskia's favorite 50 gram solution... 

mnem
I prepared Explosive Runes today...

[factory]

Zero feedback (new) seller, nothing but trouble unless you are in the same country. 
Probably not worth the cost of shipping either.

David

[mnementh]

Edit: ordered - new toy to play with at least this month     

Wow, you went for the glass tube, why?

mnem
A ounce of prevention is worth a pound of cure gallon of forget-aboot-it juice...

[Robert763]

Edit: considering bagging a Duratool desolder station for this one as I don't fancy having to braid all these displays out https://cpc.farnell.com/duratool/d00672/desoldering-station-uk-eu-plug/dp/SD01384

Yeah, bag one of those desolder stations, you'll wonder why you stuck with braid for so long, honestly it is a good investment.

The Duratool uses the same guts as my Aouyue 2702; tho the handset is different. On the 2702, it is definitely high-maintenance; sometimes requiring disassembly/cleaning after only a couple-three desolderings. We spoke aboot using "alternate" filter materials in the handset and hose a while back... if that one Saskia offered can be had at a price you can live with, I'd think aboot going with it both for you having a better tool and for giving her the business.

mnem
Well, not giving her the business that way.... jeez, you pervs...

Yeah can't be worse than the Weller ones I used to use. I must have spent most of 1996 unblocking the fucking things. Turns out operation and blockage is mostly down to technique apparently although I never mustered it. Alas I don't want to pay for a nice one so I'm going to make do with this I think.

A couple of tips from years of using Pace, Weller and these desolder tools.
Make sure the whole iron is hot not just the tip.
Give a short suck through before you contact the solder to warm the tube.
Keep the vacuum on after you have removed the tip from the joint for a ouple of seconds to make sure the tube is clear.

[Saskia]

desolder with hot air and a hand pump. fastest way.

[Specmaster]

desolder with hot air and a hand pump. fastest way.

What all the time taken masking every thing else that you don't to remove, or get to hot during the process, I think the Duratool solution wins that one hands down, sorry

[ch_scr]

Ok here comes the comparison: multiple logic gates (74AC04 one ic) either all combined and resistively split to individual outputs or individual gate with series resistor for output. There's a difference but it's not much.
The shape of the histogram is interesting though (just realized it's scaled different  But individual still has a one bin sticking up...). 
Resistive:

Individual:

[Wolfgang]

Ok here comes the comparison: multiple logic gates (74AC04 one ic) either all combined and resistively split to individual outputs or individual gate with series resistor for output. There's a difference but it's not much.
The shape of the histogram is interesting though (just realized it's scaled different  But individual still has a one bin sticking up...). 
Resistive:

Individual:

Not what I suggested. Individual ICs per path please, and their PSUs decoupled by individual RC filters.
And HC instead of AC.

Note: for low phase noise/jitter *everything* must be proper, not just a single trick. The number of relevant dirt effects increases by one order of magnitude for every step in precision required. 
Anyway, small changes give you the chance of learning step by step.