Test Equipment Anonymous (TEA) group therapy thread

[Neomys Sapiens]

We won't talk about the pitiful state of my capacitor collection... I just did a massive haul to the dumpster of capacitors I KNOW were at least 10-20 years old. Ashamed I didn't do it 10 years ago.  But I still haven't braved the hallowed halls of Mouser, DigiKey and Newark to find replacements.

mnem

I cleared a tray of overage standard electrolytics out of my lab supplies at work. As we have a sizable variac standing along the windows, I found out that they were still useful to scare birds (and coworkers).
Using two long test leads and sturdy clips, we had one ready at the window sill most of the time.
When the tree outside became too noisy, just reach for the variac control! With most of them, the complete cup was gone.

[bd139]

Now that’s a good idea 

Small break to eat (pizza and coke like a proper engineer). Fluke repair going well so far. New display module in and in process of wiring it to the board.  I’ll do a separate thread on this as it’s going to be image heavy.

We are all eagerly awaiting your thread on it with baited breath. 

Speaking off eating reminds that is something that I should go and do right now 

It’s working bar one segment. Need to find out what went wrong... ETA 30 mins.

[Brumby]

Need to find out what went wrong... ETA 30 mins.

Now that's a bold (and dangerous) statement to make.  Luckily you have made it in an environment populated by minds that understand the real world influences on such time references.

Nevertheless .... the clock is ticking.   

[tautech]

We won't talk about the pitiful state of my capacitor collection... I just did a massive haul to the dumpster of capacitors I KNOW were at least 10-20 years old. Ashamed I didn't do it 10 years ago.  But I still haven't braved the hallowed halls of Mouser, DigiKey and Newark to find replacements.

mnem

I cleared a tray of overage standard electrolytics out of my lab supplies at work. As we have a sizable variac standing along the windows, I found out that they were still useful to scare birds (and coworkers).
Using two long test leads and sturdy clips, we had one ready at the window sill most of the time.
When the tree outside became too noisy, just reach for the variac control! With most of them, the complete cup was gone.

Now that’s a good idea 

Until your local armed constabulary puts the place in lock-down looking for some nut with a gun.

Nice quiet air rifle usually does the trick ! 

[0culus]

[...]

Slightly distracted first as my new toy has arrived:

Hah! So I'm not the only "new calculator day"! So I now have three HP calculators. My trusty HP50g, a reissue HP35s just like yours, and the latest addition is one I've always wanted. A classic HP16C which arrived today:

[bd139]

Ooh a voyager! Nice purchase 

HP 50g until recently here as well. Got rid of that and was missing RPN

Need to find out what went wrong... ETA 30 mins.

Now that's a bold (and dangerous) statement to make.  Luckily you have made it in an environment populated by minds that understand the real world influences on such time references.

Nevertheless .... the clock is ticking.   

Fixed it. Shitty soldering on my part. Working now. Uploading pictures and writing up. Total success 

[0culus]

Ooh a voyager! Nice purchase 

HP 50g until recently here as well. Got rid of that and was missing RPN
 *snip*

Thanks! Really enjoying it so far and reading through the manual to learn how to use it!

I like my 50g except that the enter key is just all wrong. It would be nearly perfect if it had a full size enter key like the 35s and pretty much any classic HP calculator. RPN has a bit of a learning curve if you've only ever used infix notation but I'll never go back. Way more keystroke efficient!

[Brumby]

Fixed it. Shitty soldering on my part. Working now. Uploading pictures and writing up. Total success 

Congratulations.  (but that was 50 minutes, not 30)

[bd139]

I had to go for a shit in the middle of it. Lactose is my kryptonite 

https://www.eevblog.com/forum/testgear/fluke-8010a-mains-only-conversion-and-display-replacement/

[pigrew]

My PPM 412 has been using up my free time. One missing pozi-drive screw, one flickering neon light, two broken binding posts, two high-resistance front-panel toggle switches, five cold solder joints, 14 dead batteries.... The next round of parts should be delivered on Tuesday. The output is perhaps 90 ppm high, though 9 of these are likely due to the redefinition of a volt, and a few more due to the bad toggle switches.

Schematics are mostly reverse-engineered, but I still have a few errors to correct.

[Brumby]

@bd139  These things happen.  I was only having a dig.  50 minutes from a 30 minute estimate is within the norm.

In fact, one of my estimation skills when I was sizing software development projects was to break them down into basic components and ask myself "How long do I think it would take me to do this on a good day" for each of them ... and then double it.  (I was sizing it with my team in mind.)

One project I remember well.  I did this estimate and my final figure was something like 120 man-days.
 When I took it to management, this was "rationalised" (despite my protestations) down to the point where it became something closer to half (about 65 man-days IIRC).  At the end of the project, the actual effort came out at around 130 man-days.  I felt pretty good about that and would have liked to have made a point of this to management, but - you know - discretion is the better part.


So I'm not going to do anything more than give you a gentle stir for your efforts - which has already been done.

[grizewald]

Greetings TEA folk!

I've been lurking here for a while and thoroughly enjoying the wit, camaraderie and complete lack of "txt spch" and other such afflictions. I thought I should raise my head above the parapet and say hello.

A little background. Despite the Swedish flag next to my user name, I'm actually an expatriate Brit. I ended up in Sweden over a quarter of a century ago as part of a team installing a new system for the banks and never left. I met a Swedish girl (as you do), got married, had kids, got divorced and suddenly realised that I've spent more of my adult life here than I have in the UK. I guess I'll be staying!

Electronics was a hobby when I was a teenager. Then Clive Sinclair released the ZX80. I bought a kit, soldered it up and that was it. My electronics hobby got put on hold and computer programming turned from a hobby to my full time job.

Now my children have grown up and I am once again master of my own disposable income, I realised I could get back into electronics. (The last thing I want to do with my spare time is anything to do with programming computers!) I realised that my single Fluke 8021B wasn't really enough when it came to test equipment.  So followed the acquisition of a Rigol DS1054Z and some cheap Uni-T kit to complement the Fluke.

For a while, this was enough. However, I found Dave's forum and this topic, plus the Metrology section, opened my eyes to the realm of second hand test gear. Soon, I had a Solartron 7150 and a 7151 on my bench. GAS had taken hold of me!

My GAS problem has now lead to my first arriving at grizewald towers today. A Solartron 7075, no less!

With GAS comes the need for repair, even for things you expect (from the eBay "Used" tag) to be working.

My first nasty surprise with the 7075 was the bottom of the unit. There were no photos of the bottom in the listing, and now I understand why!





The mind boggles as to how much weight is needed to put an almost square impression in a cover and fracture the solid plastic frame underneath!

Not a good start. After carefully going over the rest of the meter and pushing all the ribbon connectors back into the IC sockets they were nearly falling out of, I powered the machine up. Sadly, running the self test functions gave me zero readings on all test values and the final test, which should show eleven 8s on the display confirmed my suspicion that the three least significant digits were not lighting up.

Seeing that the displays are actually socketed, I decided to swap the last two groups to see if it was the display or the driver which was at fault. After gingerly levering out the first (and working) display with a thin wooden stick, I did the same for the faulty one - and immediately discovered why it won't light up:



I guess that whatever impact caused the dent in the bottom of the case bounced the insides hard enough to break the vacuum seal on the display.

From what I understand, these displays are made from pure unobtanium. This is a real shame. Despite the damage to the meter's exterior, the circuitry (as far as I've dismantled the machine) seems to be in good nick. Even better, the chassis has a Solartron sticker saying that it was repaired and re-calibrated in 1985. Judging from the date codes on the chips that I can see, they repaired it by replacing all the boards inside the machine as most of the chips are from mid 1984, which must be around when they stopped making the 7075. The BCD interface unit which was attached to the rear has chips with date codes from '75, '76 and early '77 which lends some weight to the idea that it has a 'new' set of boards inside the machine itself.

In view of the comparative youth of the meter's electronics, it still seems to be a good candidate to repair, so I'd like to ask for some advice from the fine gentlemen of TEA if I may?

What should I do about the eBay seller? He listed the meter as "used" not "for parts or repair". It obviously doesn't work and has damage which wasn't stated in the listing. There's no way it could have happened during shipping as the packing was undamaged. As eBay define it, "Used" says that it should work as intended but may have cosmetic damage and this is far from just "cosmetic damage".

Does anyone have any idea as to where I can find a new display? 

[mnementh]

I had to go for a shit in the middle of it. Lactose is my kryptonite 

https://www.eevblog.com/forum/testgear/fluke-8010a-mains-only-conversion-and-display-replacement/

Reviewed, ogled, and inappropriate comments made. Well done old bean. 

mnem
It been MacGyver-fied.

[Specmaster]

@ grizewald, Welcome to the group, I think that'll fit right in here, we are by and large a very friendly bunch.

With regard to your 7075, I'd complain to the seller that it was missold and was not as described and see what their reaction is. If they do nothing I'd refer the case to either Ebay or PayPal (assuming that you paid via PayPal?) and see what they can do for you.

[Brumby]

@ grizewald, Welcome to the group, I think that'll fit right in here, we are by and large a very friendly bunch.

Ditto!

With regard to your 7075, I'd complain to the seller that it was missold and was not as described and see what their reaction is. If they do nothing I'd refer the case to either Ebay or PayPal (assuming that you paid via PayPal?) and see what they can do for you.

I agree.  Include your observation about the packaging not showing signs of damage.  At this point, I would leave out the fact that you've opened it up.  Some sellers will get very uptight and may start trying to point the finger at you.  See how the conversation goes.  If you first establish yourself as being reasonable and competent, opening it up might be better received.

But that is a cringeworthy ding!   

[med6753]

@ grizewald, Welcome to the group, I think that'll fit right in here, we are by and large a very friendly bunch.

Ditto!

Double ditto, welcome!  Just watch out for mnem.    He'll use big words on you and you won't know if he's praising you or cursing you. So keep a dictionary handy.   

[Specmaster]

@ grizewald, Welcome to the group, I think that'll fit right in here, we are by and large a very friendly bunch.

Ditto!

Double ditto, welcome!  Just watch out for mnem.    He'll use big words on you and you won't know if he's praising you or cursing you. So keep a dictionary handy.   

Or of course get your Google out, its your friend. 

[tggzzz]

Now my children have grown up and I am once again master of my own disposable income, I realised I could get back into electronics. (The last thing I want to do with my spare time is anything to do with programming computers!)

Understandable, but some forms of programming are more interesting than others. Personally I like close-to-the-Si stuff with hard realtime constraints and without an OS in the way.

In view of the comparative youth of the meter's electronics, it still seems to be a good candidate to repair, so I'd like to ask for some advice from the fine gentlemen of TEA if I may?

What should I do about the eBay seller? He listed the meter as "used" not "for parts or repair". It obviously doesn't work and has damage which wasn't stated in the listing. There's no way it could have happened during shipping as the packing was undamaged. As eBay define it, "Used" says that it should work as intended but may have cosmetic damage and this is far from just "cosmetic damage".

Does anyone have any idea as to where I can find a new display? 

Definitely complain to the seller.

I suspect you might also need a cable. Now you can get displays on fleabay, but the connector is stunningly expensive: £45 each with a minimum order of £150m IIRC https://www.eevblog.com/forum/buysellwanted/group-buy-fischer-connector-plug-s104-a053-130/msg1538426/#msg1538426. And then you would like PTFE cables and good banana/spade connectors. And then you will need a sufficiently accurate 10V source and resistors to calibrate it. At which point you will be be descending into the depths of voltnuttery.

Other bits are more difficult, however it may be your lucky day... I'm currently fiddling around with two 7075s and expect to have bits available, probably after Christmas. I was planning on keeping the display and repurposing it for something, since I just can't bear the thought of the Panaplex displays being unused. However, if you would use it...

My cable has Fischer connector but not the same as on your 7075: the pin arrangement is different. I also have the matching front-panel connector, so itshould be easy to replace the socket in the front panel with the socket from my 7075.


And yes, I expect to have other bits you might like: top and bottom covers, the orange plastic window, bezels around the switches, and other bits from the carcass

Oh yes, welcome. It sounds like you are already fitting in just nicely.

[Brumby]

You've gotta love this place...  A place where unobtainium may appear from nowhere by simply expressing a need.

[bitseeker]

Greetings TEA folk!

I've been lurking here for a while and thoroughly enjoying the wit, camaraderie and complete lack of "txt spch" and other such afflictions. I thought I should raise my head above the parapet and say hello.

Greetings and salutations! So good of you to pop in and say g'day.

Our afflictions are much worse than a bit of txt, I assure you.

My GAS problem has now lead to my first arriving at grizewald towers today. A Solartron 7075, no less!

With GAS comes the need for repair, even for things you expect (from the eBay "Used" tag) to be working.

My first nasty surprise with the 7075 was the bottom of the unit. There were no photos of the bottom in the listing, and now I understand why!

Yeah, tell me about it. Join the club. However, your bottom was quite a bit worse than mine. Ouch!

Seeing that the displays are actually socketed, I decided to swap the last two groups to see if it was the display or the driver which was at fault. After gingerly levering out the first (and working) display with a thin wooden stick, I did the same for the faulty one - and immediately discovered why it won't light up:

Nooooo!

What should I do about the eBay seller? He listed the meter as "used" not "for parts or repair". It obviously doesn't work and has damage which wasn't stated in the listing. There's no way it could have happened during shipping as the packing was undamaged. As eBay define it, "Used" says that it should work as intended but may have cosmetic damage and this is far from just "cosmetic damage".

Hang him by his toenails! Geez, I'm getting so tired of these sellers (in case you missed it, I got caught out this week, too). Let your guard down for even one listing, and they'll get ya.

This is "not as described" and is covered by eBay Buyer Protection (I assume it works the same in Sweden, but not sure). Even though these kinds of sellers piss me off, I avoid being confrontational on the initial communication by contacting them via the "I have a question about using my item or I want to send the seller a message" option, even if I intend to return it.

Some sellers will immediately offer to initiate a return and refund you, whether or not that's what you want. Others will ask you what you want to do. A few will offer compensation for the damage. Depending on factors such as the value of the item, the cost of shipping, etc., once in a while a seller will offer to refund you and not want to deal with the item's return. Then, you can do with it what you please.

So, start the conversation and see where it goes. If you do want to return it and the seller resists, initiate the return and eBay will step in after a specified period of time has elapsed for the seller to accept (it'll say on the return page).

Does anyone have any idea as to where I can find a new display? 

The magic of the TEA pot seems to have granted your wish. Thanks, tggzzz!

[tggzzz]

Does anyone have any idea as to where I can find a new display? 

The magic of the TEA pot seems to have granted your wish. Thanks, tggzzz!

Let's save that until the union is consummated!

I was going to offload my first 7075, but then two more fell off the back of a lorry[1]. So I need to finish making two out of those three. I'll get there, eventually.

[1] not quite; they did fall into my car, however.

[mnementh]

[...]      Slightly distracted first as my new toy has arrived:

   Hah! So I'm not the only "new calculator day"! So I now have three HP calculators. My trusty HP50g, a reissue HP35s just like yours, and the latest addition is one I've always wanted. A classic HP16C which arrived today:

Fine, fine... I didn't wanna have to do it, but y'all MADE ME drag out MY old HP calculator... 

Yes, it has the 16MB RAM upgrade. And 32MB Genuine HP CF card.

And the original stylus is nestled softly in its bed, and it is chugging along quite happily under its own power, completely unaware of all that has changed in the last 18 years. 

mnem
 

[mnementh]

@ grizewald, Welcome to the group, I think that'll fit right in here, we are by and large a very friendly bunch.

Ditto!

Double ditto, welcome!  Just watch out for mnem.    He'll use big words on you and you won't know if he's praising you or cursing you. So keep a dictionary handy.   

Or of course get your Google out, its your friend. 

Hey! I resemble that remark!!! 

While I may be a bit loquacious and prone to alliteration, obfuscation, aberrant mellifluousness,  and generally disruptive verbocity, and occasionally I may even pontificate, I pride myself on being at least marginally mondaine, with a predominately positive disposition!

mnem
I may be a dwagon, but I don't bite; at least not without permission. 

[0culus]

[...]      Slightly distracted first as my new toy has arrived:

   Hah! So I'm not the only "new calculator day"! So I now have three HP calculators. My trusty HP50g, a reissue HP35s just like yours, and the latest addition is one I've always wanted. A classic HP16C which arrived today:

Fine, fine... I didn't wanna have to do it, but y'all MADE ME drag out MY old HP calculator... 

Yes, it has the 16MB RAM upgrade. And 32MB Genuine HP CF card.

And the original stylus is nestled softly in its bed, and it is chugging along quite happily under its own power, completely unaware of all that has changed in the last 18 years. 

mnem
 

Wow, have not seen one of those for a while. What flavor of Windoze does it run?

[Buzz39]

I put in a lot of hours using the Tektronix 454 scope as an IBM Customer Engineer servicing IBM  System 360 mainframes and associated equipment. When IBM came out with the System 360 series of computers, the Tektronix 310A scopes (single channel) were not fast enough to scope the signals in the 360 equipment. They went to Tektronix with a set of  specifications for a scope (had to be small and portable, SS no tube stuff)   and that is how the 454 came about. There was a rumor that some IBM engineers even designed some of the  circuits in conjunction with the engineers at Tektronix but not sure if that is true. I saw someone mention how the scope was built like a tank.  It had to be pretty rugged because every account Customer Engineer who had a System 360 account was given a 454 as part of their "tool kit" which meant these things would be bounced around in the trunks of cars and could experience some rather rough handling. I just acquired a 454 that has some vertical problems and one of the output transistors on the vertical output board is defective. Since the parts list in the manual only list  transistors by a Tektronix number, does anyone know of a cross reference to the manufacture transistor type or know what the  vertical output transistor type is?

Bill Harris
Colorado