Test Equipment Anonymous (TEA) group therapy thread

[med6753]

First test of Type 1A1 in the Type 547. Needs an extensive amount of troubleshooting. Both channels extremely unstable. Channel 2 spends most of it's time off screen. Gain on both channels wacky. And if you bring either trace towards the bottom of the screen the waveform horribly distorts.

But surprisingly at first glance compensation doesn't look bad if the trace is towards center of the screen. And at least it didn't blow up the Type 547. 

[mnementh]

...And at least it didn't blow up the Type 547. 

That's okay, med, we know you'll get there. Take your time; we've got all weekend.

mnem

[Vince]

Frequency counter : an "interesting" / unusual one just popped up here :

https://www.leboncoin.fr/sports_hobbies/2077524690.htm

It's an old looking Thandar counter, model PFM200A it looks like.... What's interesting to me are the specs, an incredible 200MHz for such an old and basic looking counter + the fact it does so in a tiny package + it's portable/handheld ?! Not sure why one would want a handheld 200MHz counter ?!
Also, even though it's got 2 inputs, it's not the usual " one LF 1M input and HF input is 50ohms only ". No, look, here both inputs are 1Meg ?!
But of course, what makes this thing even more cute is... its display ! Doesn't it look like it's got these famous early calculator / ancient microscopic/bubble LED displays with lenses on top of them ?!

So the combination of all these points in a single device caught my attention, thought it was worthy of eating some B/W on TEA before going to bed ! 

[TERRA Operative]

Hmmm, so the TDS620B black-and-white screen 2-channel scope can apparently be upgraded to a TDS684B colour 4-channel, with the addition of a couple chips, and the deletion of a couple caps and resistors. (And a colour LCD, which I am working on an aliexpress source).

I also noticed only half the acquisition memory is populated, so while I can enable the 1M memory option, 2M is beyond reach.
However, a USA seller of new-in-packaging memory chips accepted my offer so I'll slap the extra memory in and see if 'it just works' to get full memory depth.

First thing first, a local seller (well, way down in Osaka) had the relays that often go bad on the input hybrids in these units in stock for a better price than Mouser/Digikey, so a full set should arrive today. That'll fix the calibration/SPC error hopefully.

[bitseeker]

Cool. Looking forward to seeing it renewed and improved!

[Cerebus]

Frequency counter : an "interesting" / unusual one just popped up here :

https://www.leboncoin.fr/sports_hobbies/2077524690.htm

It's an old looking Thandar counter, model PFM200A it looks like.... What's interesting to me are the specs, an incredible 200MHz for such an old and basic looking counter + the fact it does so in a tiny package + it's portable/handheld ?! Not sure why one would want a handheld 200MHz counter ?!
Also, even though it's got 2 inputs, it's not the usual " one LF 1M input and HF input is 50ohms only ". No, look, here both inputs are 1Meg ?!
But of course, what makes this thing even more cute is... its display ! Doesn't it look like it's got these famous early calculator / ancient microscopic/bubble LED displays with lenses on top of them ?!

So the combination of all these points in a single device caught my attention, thought it was worthy of eating some B/W on TEA before going to bed ! 

Well I suspect someone had a large stock of displays to use up when they designed it. The resemblance with the below is, I suspect, no accident.

[mnementh]

Currently watching the DRL World Championships Level 10. So far being dominated by rookie ALEXFPV, and the only names I recognize are actually doing commentary. 

I suddenly feel so very old...

EDIT: Oh, there's NUBB and GAB in the 2nd half. Now I don't feel quite so bad.

mnem

[Specmaster]

Frequency counter : an "interesting" / unusual one just popped up here :

https://www.leboncoin.fr/sports_hobbies/2077524690.htm

It's an old looking Thandar counter, model PFM200A it looks like.... What's interesting to me are the specs, an incredible 200MHz for such an old and basic looking counter + the fact it does so in a tiny package + it's portable/handheld ?! Not sure why one would want a handheld 200MHz counter ?!
Also, even though it's got 2 inputs, it's not the usual " one LF 1M input and HF input is 50ohms only ". No, look, here both inputs are 1Meg ?!
But of course, what makes this thing even more cute is... its display ! Doesn't it look like it's got these famous early calculator / ancient microscopic/bubble LED displays with lenses on top of them ?!

So the combination of all these points in a single device caught my attention, thought it was worthy of eating some B/W on TEA before going to bed ! 

Well I suspect someone had a large stock of displays to use up when they designed it. The resemblance with the below is, I suspect, no accident.

Probably not, wasn't Thandar something to do with Sinclair, starting out as Sinclair Instruments I think?

[cyclin_al]

And I see you have a secret stash of those little Tek toggle-switch caps. More than a few in here gonn' be a little jelly o' dat. 

That reminds me that I need to find some of those ... more time acquiring stuff instead of doing stuff 

And now for an ad from our sponsors me: https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg3484004/#msg3484004

Thanks for offering that design!

Well, to be honest, I have been intentionally trying to avoid 3DP stuff.  It is easier on the pocketbook that way, plus my backlog of honey-do's is already long.
The list is so long, SWMBO and I started using Microsoft ToDo, before it was taken over by microsoft... (sigh)
Is it time to cave in and order one?  Dang, BlackFriday may be dangerous...

[mnementh]

Sorry buddy, I can't help you with a freebie to salvage; I actually packed both mine down and in storage stateside. 

mnem
But yeah, BF Deals is def the time to jump on a 3DP...

[cyclin_al]

Sorry buddy, I can't help you with a freebie to salvage; I actually packed both mine down and in storage stateside. 

mnem
But yeah, BF Deals is def the time to jump on a 3DP...

Nah, I never had any thoughts of salvaging pillaging from a friend!

-- who me?

[mnementh]

What pillaging? If I'd left one behind, I'd mail you the key myself.

mnem
 

[med6753]

Deoxit, deoxit, and more deoxit. And persistence. Getting years of crud off those precision attenuator wafer decks. And it's paying off. Stable displays but still a little switching noise between ranges. Have to keep working the switches. Despite the initial instability the gain is perfect, the compensation looks real good and even the DC balance is acceptable with just a few tweaks.

My Type 1A1 is an older S/N with nuvistors in the pre-amp. This Type 1A1 is newer with the FET pre-amps. Those first generation FET pre-amps tend to be rather fragile but apparently are working fine. 

 

[Zucca]

med how many scope have you repaired?

My best guess 4/month, 12*4=48 year. 10 years retirement so about 500 scopes, and counting up.

[med6753]

Not that many.   

In January will be 3 years retired.

If I look at just scopes of all makes probably about 25 or so. Plug-in's probably close to same amount.

But then there's DMM's, Frequency counters. etc. Lost count. 

[mansaxel]

Frequency counter : an "interesting" / unusual one just popped up here :

They still make an updated version, which goes to 3GHz. 

While they're very cute, they don't attract me, because reference input is missing, and that's a must for what I'm after.

[vk6zgo]

shit I need one now... Stark VT-9 

You might have better luck finding the Hickok 209A version of this.  Stark built a lot of Hickok designs under license in Canada which meant they were made in low numbers and only sold here so they're not all that common, even here.

One of the oddities about mine and you can see this in the picture I posted is that it's from the old dual frequency era when there was a good chunk of Ontario still on 25 Hz power and it's got 25/60 stamped in the frequency box.  I didn't notice from Mr. Carlson's video if his is the same.  Frequency standardization was still a work in progress then.  Mine still needs restoration too.  It's in the lineup but there's only so many hours in a day...

Back in the day, West Oz had 40Hz mains frequency, compared to 50Hz in other States.

For most things, it didn't matter, but for record players, it did.

The stepped piece attached to the motor shaft that allows speed selection needed to be replaced to get the correct speeds, so local electronics retailers outsourced the manufacture of "40 cycle" replacements for the standard part to small machine shops, adding a premium to the price of the record player to cover costs.

They also kept all the "redundant" 50 Hz parts.

In due course, WA changed to 50Hz, & customers needed "new" replacement "50 cycle" parts.
The old box of 50Hz bits was unearthed & they were sold at "a small premium"----business doesn't get much sweeter than that!

[med6753]

When the New Haven RR electrified in the early 1900's it was overhead 25Hz. Those rail lines still exist and are now owned by Metro-North RR but I don't know if they are still 25Hz or have been converted to 60Hz.

[Andrew_Debbie]

It's an old looking Thandar counter, model PFM200A it looks like.... What's interesting to me are the specs, an incredible 200MHz for such an old and basic looking counter + the fact it does so in a tiny package + it's portable/handheld ?! Not sure why one would want a handheld 200MHz counter ?!

Sniffing for low cost bugs?   The PFM 200A dates from the late 1970s. 


Checking 2m band mobile radios?   Checking aircraft radios?

[dl6lr]

And now for an ad from our sponsors me: https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg3484004/#msg3484004

Thanks for offering that design!

You can use the STL to have them printed at a makerspace or by an online printing service.

[Specmaster]

It's an old looking Thandar counter, model PFM200A it looks like.... What's interesting to me are the specs, an incredible 200MHz for such an old and basic looking counter + the fact it does so in a tiny package + it's portable/handheld ?! Not sure why one would want a handheld 200MHz counter ?!

Sniffing for low cost bugs?   The PFM 200A dates from the late 1970s. 


Checking 2m band mobile radios?   Checking aircraft radios?

I know that Radiocruncher uses one on his YT channel.

[Vince]

Frequency counter : an "interesting" / unusual one just popped up here :

They still make an updated version, which goes to 3GHz. 

Wow, that's one hell of a long product life ! 
Checked their site and datasheet... neither give any clue as to what the use cases / intended audience for this type of counter, might be....

While they're very cute, they don't attract me, because reference input is missing, and that's a must for what I'm after.

Well it's a portable handheld, having an, external ref input doesn't quite make sense ? 
First why wold be the point of handheld if you have to stick a ref to it, not practical.. plus a ref is not meant or designed to be portable for field use... it's supposed to stay plugged in 24/7 and kept warm and safe, left alone, in the lab, comfy, at a stable temperature.
All you can do is make the onboard time base of the counter as good as you can, which is what they did from the datasheet.


EDIT : oh, looks like this little counter has already found a new home ! Ad posted 19H00 yesterday, now 10H00 next day, am checking the web site again and it says someone has clicked the "Buy" button.....
At only 35 Euros it was indeed tempting, but I have no use for portable instruments, other than a decent handheld scope one day... so I tried to be reasonable.. need to refrain my GAS, it's getting out of hand. House is small... storage capability is very limited.

I am progressively getting used to the idea that it's time to stop collecting scopes, 35 of them is a bit much. So am considering getting rid of a few of them and replacing them with a few frequency counters. Once I am done with that, will buy only gear that add functionality to the lab, so as to enable me, and will try to avoid boat anchors as shelf space is limited and they aren't heavy duty enough to support too much weight.

Basically trying to switch from gathering gear to actually DOING something in the lab ! 
I guess it's a fine line that's hard to ride without falling one side or the other, wish me luck...

[beanflying]

Not that many.   

In January will be 3 years retired.

If I look at just scopes of all makes probably about 25 or so. Plug-in's probably close to same amount.

But then there's DMM's, Frequency counters. etc. Lost count. 

Slacker! Get to 'work' you are falling behind the expectations of some 

[Robert763]

I wouldn't touch it either... just in case it's been fuckerized by a gorilla and full of cesium dust and make you glow in the dark.

Even 60 years old that would still gonna be dangerous.

mnem
"...Must be these strangers that come every night;
Their saucer-shaped eyes put people uptight!
Leave little green footprints that glow in the dark;
I hope they get home all right. "

The Caesium in frequency stands is not radioactive. (Some Rb standards do use a radioactive isotope of Rb as an optical filter).
You are more likely to find radioactive material in a regular vacuum tube. Many have thorum in the heaters or cathodes. A lot of Voltage regulator tubes contain radioactive material this can be gas, metal or plating internally or even a piece of material on the outside of the envelope.
Many spark gaps and microwave switch or limiter devices are also coantain radioactive material.

[Specmaster]

Frequency counter : an "interesting" / unusual one just popped up here :

They still make an updated version, which goes to 3GHz. 

Wow, that's one hell of a long product life ! 
Checked their site and datasheet... neither give any clue as to what the use cases / intended audience for this type of counter, might be....

While they're very cute, they don't attract me, because reference input is missing, and that's a must for what I'm after.

Well it's a portable handheld, having an, external ref input doesn't quite make sense ? 
First why wold be the point of handheld if you have to stick a ref to it, not practical.. plus a ref is not meant or designed to be portable for field use... it's supposed to stay plugged in 24/7 and kept warm and safe, left alone, in the lab, comfy, at a stable temperature.
All you can do is make the onboard time base of the counter as good as you can, which is what they did from the datasheet.


EDIT : oh, looks like this little counter has already found a new home ! Ad posted 19H00 yesterday, now 10H00 next day, am checking the web site again and it says someone has clicked the "Buy" button.....
At only 35 Euros it was indeed tempting, but I have no use for portable instruments, other than a decent handheld scope one day... so I tried to be reasonable.. need to refrain my GAS, it's getting out of hand. House is small... storage capability is very limited.

I am progressively getting used to the idea that it's time to stop collecting scopes, 35 of them is a bit much. So am considering getting rid of a few of them and replacing them with a few frequency counters. Once I am done with that, will buy only gear that add functionality to the lab, so as to enable me, and will try to avoid boat anchors as shelf space is limited and they aren't heavy duty enough to support too much weight.

Basically trying to switch from gathering gear to actually DOING something in the lab ! 
I guess it's a fine line that's hard to ride without falling one side or the other, wish me luck...

I'm not surprised that the counter found a home, even with its little bubble LED's. TTI gear is pretty well respected worldwide and doesn't tend to hang around for long once listed for sale, even very early items such as that. I'm in the same boat as you regarding acquiring new gear, I'm looking to add functionality as well, I have too many meters, about 10 analogue and about 14 digital and 5 scopes.