Test Equipment Anonymous (TEA) group therapy thread

[wkb]

That looks really neat.......

[m k]

I'm using the old faceplates for now. I haven't found a place that can do printed anodizing (but I haven't looked too hard...)

Vinyl cutters can print, or vice versa.

Sticker on sticker is easier than self made sticker, means underside printing and glue-on-glue stuff.

[m k]

the level of TE drought is terrible,

Berești-Bistrița is a county in Romania.

[M0HZH]

..
Berești-Bistrița is a county in Romania.

Actually it's more like a small township, but how did that come about?

[Ice-Tea]

For those experiencing TE drought. If it's not about owning stuff but rather play or tinker with it:you can always get an item of my repair list and fix it for free. 

[tggzzz]

For those experiencing TE drought. If it's not about owning stuff but rather play or tinker with it:you can always get an item of my repair list and fix it for free. 

"Get" would be just fine. "Borrow" would be less attractive

[TERRA Operative]

For those experiencing TE drought. If it's not about owning stuff but rather play or tinker with it:you can always get an item of my repair list and fix it for free. 

Sure thing, I'll take something off your hands to repair. 


I can't guarantee you'll ever get it back though!........

[Zucca]

Interesting

https://github.com/Qw3rtzuiop/DS1245Y_FRAM

[Ice-Tea]

See, that's the problem with dealing with you lot.

If you guys don't want it for cheap, you want it for free. 

[m k]

..
Berești-Bistrița is a county in Romania.

Actually it's more like a small township, but how did that come about?

It's just one of those zone things of TEA.

[Vince]

Say hi to my new friend ! 

He popped up on Leboncoin.fr a few days ago, just received it this evening.

Another Rochar Nixie meter, my 5th one now, this time it's a type A.1613

SPECS

Unlike my other Rochar meters that do just this or just that... this one does it all, a true DMM : does V and A both DC and AC, does resistance and capacitance.

It's also very compact indeed, so all in all it ticks all the boxes to be used often on the bench 

4 digits, 2,000 counts.

Goes up to 1,000V Vdc which will be perfect to check the B+ voltages when fixing my hollow-state Tek scopes.
Can go down to 0.1mV resolution on its 200m range, so it will be able to check ripple voltage as well.

Capacitance range only goes to 1uF but goes down to 200.0pF so 0.1pF resolution which is excellent.
I mean as much as I love my collection of fancy Metrix MX53/54/56 handheld DMM, they couldn't measure anything below 1 or 2nF to save their lives.

It has the printer output option !

Came with the original power cord... that can plug into that long obsolete power socket. Great, ready to go 

Oh, and 100% discrete transistors, zero IC. A mix of Germanium and Silicon trannystors.
I spotted some 2N2905 on the PSU board. I think all the Germanium ones must be on the display boards.

As usual with Rochar, following their take-over by Schlumberger, this meter was also available under the Schlumberger or Solartron badge. Only the colour of the face plate changed. My Rochar is dark grey which I love, but was also apparently available in "chocolate". A different model year / face lift I guess. Schlumberger was purple, and Solartron, the usual beige.

Oh ! One odd thing about this meter... It's got 3 input jacks : a common negative, a positive for V/A/ohms, and the third jack is used solely for capacitance
measurements.  Well, believe it or not, but the common ground is... RED, and the positive jack for V/A/ohms is BLACK ! How twisted is that ! 

No, nobody messed with the jacks... I checked several pictures of that meter on the web, and they were all like that !

COSMETICS

Overall like new inside out, like fresh from the factory. Only problem is the enclosure. It's a one piece plastic part, Bakelite. Up close it does not look nor feel as"cheap" as I feared it might, so I am good with that. Problem is that it's brittle of course, and the top left rear corner is broken, a good chunk parted with the instrument. Also, there are paint chips all over the edges. Paint is also impossible to clean because the Bakelite is textured.
The display bezel = same causes same consequences...

So at some point I will reconstruct the broken corner, strip the paint (with chemicals not by sanding, to conserve the texture/grain...), fill all the dents/nicks that need filling, and repaint it... maybe satin black, or pink with yellow and lime green stripes, no sure.

Also, the 5 tiny Philips self taper screws that hold the face plate to the Bakelite case... one of them jumped under the bench, it's gone for good. 2 other screws are turning round and round... stripped "thread". The last 2 screws are good for now but for how long.
All my Rochar TE have these crappy screws that drive me nuts and cause nothing but problems.
So I need to come up with something... maybe enlarge the holes in the Bakelite, fit metal thread inserts and use machine screws instead. They actually did jsut that for the 2 bottoms screws at the rear of the unit, that secure the chassis to the enclosure. That would solve the "reliability" issue, as well as give me a lot of choice regarding the style of head, and finish.

ELECTRICALS

As I said it's like new in there, but it has issues nonetheless.
It mostly "works", but needs fixing. Unusable as is. It's got an unacceptable zero offset issue, plus the measurements are very unstable, never twice the same reading. If you average the values in your head, and take into account the offset, I would say that it basically works in all functions and ranges, and the average value is not far off the expected value, say -10% off max, and it jumps around this value by maybe +/- 5% or something.

Problem is that I can't find a service manual for this particular meter. If you find one... I mean for free or not, gimme a call...

"Luckily" Rochar was short lived, I mean design-wise all their meters were roughly from the same technological era, so same engineering solutions across their TE. Just looking at it I can see that the guts / core of the instrument are similar to my other Rochar TE.  So I have some idea of what might be wrong, but still, without a manual, I could be working on this thing for 25 years.


CONCLUSION

Overall, extremely happy with my purchase (60 Euros, the top end of my "impulse buy budget"....).
Featureful yet compact meter, looks super cute, excellent nick inside out, mostly works... it sure is well worth fixing the electrical issues and refurbishing the Bakelite enclosure / display bezel.

So I have now 5 Rochar TE, one counter that's like new and works perfectly without me even opening it.... the remaining 4 are all voltmeters or volts/am-meters that need electrical troubleshooting... but they are resisting me big time.

The good news is that I actually have a hope of fixing them... because I took the decision for the next 12 months to take it easy on the construction of the garage/workshop, for money reasons. Instead, I have decided to work on the lab : downsize, make room, keep only the old TE that I really value most, and freaking FIX THEM so I can actually put them back together and USE them at long last, have some fun with them.

[Vince]

Oh ! One odd thing about this meter... It's got 3 input jacks : a common negative, a positive for V/A/ohms, and the third jack is used solely for capacitance
measurements.  Well, believe it or not, but the common ground is... RED, and the positive jack for V/A/ohms is BLACK ! How twisted is that ! 

No, nobody messed with the jacks... I checked several pictures of that meter on the web, and they were all like that !

Sussed it... I was mistaken. In the photo above I measured +10V from my Chinese Vref box, and no polarity symbol showed up, so assumed it meant it was positive... but it was not.
It's just that symbol failed to show up...  after playing some more with the meter, the symbol thing works more reliably and I do get a '+' symbol for positive voltages, rather than nothing.

Anyway, so in the end the black and red jacks are not reversed, black is indeed negative as you would expect, phew ! 

[TERRA Operative]

For Bakelite repairs, check out what the tube radio guys do. It does look like pretty repairable stuff.


Also, I have found that the dishwasher is good for cleaning textured stuff, when the wife isn't looking!

[med6753]

For those interested I have posted a new check point on the ongoing experiment to develop a process for repair of the known Tek Type 547 HV transformer issue that doesn't resort to break down and rewinding of the transformer.

https://teanonymous.com/f1/viewtopic.php?t=34

[Carl_Smith]

Whoops, I did it again baby.

Just bought a Tek THS720P scope, paid roughly US$120 for it, screen looks good but no accessories (I already have a bag and charger from my THS720STD anyway)

I'm jealous.  Where do you find these for that price?  Yahoo Auctions in Japan?

I've been trying to find one for like a year in the US, and the only place I find them is on eBay.  They fall into one of two categories.  They are either in great condition but sell for $300.  Or they sell for $200 and have toasted LCDs, no accessories, and BNC connectors that look like they were chewed on by an animal.

[Black Phoenix]

Whoops, I did it again baby.

Just bought a Tek THS720P scope, paid roughly US$120 for it, screen looks good but no accessories (I already have a bag and charger from my THS720STD anyway)

I'm jealous.  Where do you find these for that price?  Yahoo Auctions in Japan?

I've been trying to find one for like a year in the US, and the only place I find them is on eBay.  They fall into one of two categories.  They are either in great condition but sell for $300.  Or they sell for $200 and have toasted LCDs, no accessories, and BNC connectors that look like they were chewed on by an animal.

Most used markets in Japan things are took care and in good condition. It is totally different of what we are used to. Most of my best finds in terms of price and condition was from Japan, being old games or recent ones, Audio equipment, old books or CDS and even test equipment.

And the prices are fair, not like some sellers who think they have gold on their hands when in reality is a pile of crap no one would give more than enough to be DESTROYED!

/RANT OFF

[TERRA Operative]

Whoops, I did it again baby.

Just bought a Tek THS720P scope, paid roughly US$120 for it, screen looks good but no accessories (I already have a bag and charger from my THS720STD anyway)

I'm jealous.  Where do you find these for that price?  Yahoo Auctions in Japan?

I've been trying to find one for like a year in the US, and the only place I find them is on eBay.  They fall into one of two categories.  They are either in great condition but sell for $300.  Or they sell for $200 and have toasted LCDs, no accessories, and BNC connectors that look like they were chewed on by an animal.

Yeah, on Yahoo Auctions.

I did get lucky though, they are often exactly the same here as you find over there. This one was sold as "Unable to test, we don't know how so try your luck" which is perfectly fine by me.
They also has the listing for 'buy it now' rather than an auction, so I snapped it up before I had time to think about it.

It does indeed work well (I'm currently fixing the usual broken battery door), passes SPC and self tests, has almost immaculate BNC's and a good screen and the multimeter mode says 10.00V against my Fluke 731B.

Sometimes you get lucky.

[m k]

For those interested I have posted a new check point on the ongoing experiment to develop a process for repair of the known Tek Type 547 HV transformer issue that doesn't resort to break down and rewinding of the transformer.

https://teanonymous.com/f1/viewtopic.php?t=34

So battery backed, hermetically sealed and heated known volume thing with humidity meter and moist summer air.
HV transformer there for half a year.
Then swap the air to dry winter air.
Then measure the next half a year.

If process is speeded up by moisture and pressure where is the curve how time should be multiplied.

[m k]

I'm using the old faceplates for now. I haven't found a place that can do printed anodizing (but I haven't looked too hard...)

Vinyl cutters can print, or vice versa.

Sticker on sticker is easier than self made sticker, means underside printing and glue-on-glue stuff.

Some cutters are auto positioning, means that an eye is searching the place.
There a sheet of printed plastic and sheet of glue is a sticker to cut.

Number one bad rap with stickers is static electricity.
Particles in between are pretty permanent.

But even quite big bubbles can disappear by them selves.
To speed that up slice a small, sticker lateral, cut to the side of a bubble.
If slice is vertical the nasty light will reflect.
Slice here is not the actual slice but a hole made by something not round, scalpel is good, quality box cutter can also do, like maybe a skin needle.

[factory]

Say hi to my new friend ! 

He popped up on Leboncoin.fr a few days ago, just received it this evening.

Another Rochar Nixie meter, my 5th one now, this time it's a type A.1613

SPECS

Unlike my other Rochar meters that do just this or just that... this one does it all, a true DMM : does V and A both DC and AC, does resistance and capacitance.

It's also very compact indeed, so all in all it ticks all the boxes to be used often on the bench 

4 digits, 2,000 counts.

Goes up to 1,000V Vdc which will be perfect to check the B+ voltages when fixing my hollow-state Tek scopes.
Can go down to 0.1mV resolution on its 200m range, so it will be able to check ripple voltage as well.

Capacitance range only goes to 1uF but goes down to 200.0pF so 0.1pF resolution which is excellent.
I mean as much as I love my collection of fancy Metrix MX53/54/56 handheld DMM, they couldn't measure anything below 1 or 2nF to save their lives.

It has the printer output option !

Came with the original power cord... that can plug into that long obsolete power socket. Great, ready to go 

...snip...

Looks much nicer than the Solartron/Rochar version that was advertised over here a few days ago.
https://www.ebay.co.uk/itm/185825559487

My low ball offer wasn't enough, I didn't want to risk more due to the general poor condition, lack of power cable (seller seems to list the connectors separately for more ££), visible rust on the back makes me wonder it the tubes would be any good. 

Knowing it's got a Bakelite case is worse, as some sellers will deliver a box containing the chassis & a Bakelite jigsaw. 

Wonder how easy it is to service those boards behind the range/selector switches, looks tricky from your pictures. I does have some similarities to the A1466 in circuit design & layout, at least for the display counter boards.

Edit: picture added below, as ePay links tend to EOL after a few months.


David

[Neomys Sapiens]

Whoops, I did it again baby.

Just bought a Tek THS720P scope, paid roughly US$120 for it, screen looks good but no accessories (I already have a bag and charger from my THS720STD anyway)

I'm jealous.  Where do you find these for that price?  Yahoo Auctions in Japan?

I've been trying to find one for like a year in the US, and the only place I find them is on eBay.  They fall into one of two categories.  They are either in great condition but sell for $300.  Or they sell for $200 and have toasted LCDs, no accessories, and BNC connectors that look like they were chewed on by an animal.

I'm jealous too. A THS720P in great condition for 300$ would not last a hour over here!

[AVGresponding]

Whoops, I did it again baby.

Just bought a Tek THS720P scope, paid roughly US$120 for it, screen looks good but no accessories (I already have a bag and charger from my THS720STD anyway)

I'm jealous.  Where do you find these for that price?  Yahoo Auctions in Japan?

I've been trying to find one for like a year in the US, and the only place I find them is on eBay.  They fall into one of two categories.  They are either in great condition but sell for $300.  Or they sell for $200 and have toasted LCDs, no accessories, and BNC connectors that look like they were chewed on by an animal.

I'm jealous too. A THS720P in great condition for 300$ would not last a hour over here!

Maybe a 710A or 720A is a cheaper route to a 720P? The last one I bought was roughly £100

[DC1MC]

Whoops, I did it again baby.

Just bought a Tek THS720P scope, paid roughly US$120 for it, screen looks good but no accessories (I already have a bag and charger from my THS720STD anyway)

I'm jealous.  Where do you find these for that price?  Yahoo Auctions in Japan?

I've been trying to find one for like a year in the US, and the only place I find them is on eBay.  They fall into one of two categories.  They are either in great condition but sell for $300.  Or they sell for $200 and have toasted LCDs, no accessories, and BNC connectors that look like they were chewed on by an animal.

I'm jealous too. A THS720P in great condition for 300$ would not last a hour over here!

A THS710A on the other side, is still resisting:

https://www.ebay-kleinanzeigen.de/s-anzeige/oszilloskop-tektronix-mit-multimeter/2399427161-168-1759

[TERRA Operative]

Whoops, I did it again baby.

Just bought a Tek THS720P scope, paid roughly US$120 for it, screen looks good but no accessories (I already have a bag and charger from my THS720STD anyway)

I'm jealous.  Where do you find these for that price?  Yahoo Auctions in Japan?

I've been trying to find one for like a year in the US, and the only place I find them is on eBay.  They fall into one of two categories.  They are either in great condition but sell for $300.  Or they sell for $200 and have toasted LCDs, no accessories, and BNC connectors that look like they were chewed on by an animal.

I'm jealous too. A THS720P in great condition for 300$ would not last a hour over here!

Maybe a 710A or 720A is a cheaper route to a 720P? The last one I bought was roughly £100

Yeah, the ...A and ...P models can be upgraded between each other.
The non suffix (or STD) models can be upgrqded between each other too.

I.e. a THS710 can be upgraded to a THS720, but not to a 720P
However, a THS710A and THS720A can both be upgraded to a THS720P

Apparently the THS730A has different input hybrids or something so it stands alone.
I'll have to try to get one one day to compare it.

[M0HZH]

Not really TE but I sniped this nice and Rohde & Schwarz carry bag off eBay for £6 shipped.

Don't know yet what I'll use it for, but it's really nice quality (should be, R&S carry bags retail for crazy prices, £200+).