Test Equipment Anonymous (TEA) group therapy thread

[Vince]

Question..

After all this, wouldn't it have been easier to just buy a new thermostat for the fridge? Or am I missing something?

Yes you are missing something, you have not been listening ! 

My dad has a replacement thermostat at home, it's already on its way to me, should receive it maybe tomorrow.

so until then I need to cycle the fridge  manually. No big deal, just a pain that's all.

So I thought it would be a good excuse/opportunity to see if I could cobble a time quick and dirty ni the lab, just for fun (and if it works then the better....). Of course it noly makes sense if I can do it with what I have here. Buying anything would defeat  the purpose and be wasted money which I can't afford atm 

[Vince]

Fridge Timer Update

Proto board fixed ! 


...

So I replaced that relay with the one in the picture below. This time with thinner terminals that can go through the pad holes, so I could solder it onto the board, eliminating the risk of overheating the terminals. I wanted to avoid soldering a relay to the board as it now means I have to solder wires to the board hence bring mains to the board, safety and all that. So I hope everything will be alright.

After that, the board came to life just fine, relay is clicking away.

So I can now fit the board into the project box and add the power socket and give it a try !! Right=, right ?!!! NO !!!!  It's 00H50 and freaking tired, I can barely see what I am typing, never mind what I was soldering just a minute ago ! I am going to bed ! !!!   

Hi Vince,
Make sure you completely remove the unused protoboard pads around the ones the contacts of the relay are soldered too. Spikes on the mains (like those caused by fridges turning off) can easily cause the narrow gap between protoboard pads to arc over with unpleasant results like fire. You need at least a 2.5mm gap around any pad with mains (220/240 V not wimpy Dragonland 115 V) on it
An easy way to temove pads is to tin them with a hot iron and lift the pad with a sharp knife while it's still hot and the adheesive is weak.

Good idea... and I guess I would have to do it on the top side of the board as well since there are pads on both sides, so I need to remove the relay.

Or just use a track cutting tool. You can even make a slot with those, if you like.

Yes I do have this very tool !  But it destroys the board, cuts into it. I did it once on a cheap ugly brown vero board, but don't want to do it on this nice FR4 board.

I will try Rob's method instead. Also since I have to pull the relay anyway, I will take that opportunity to relocate it on the edge of the board, near a corner, so that the pads that I will remove aren't in the middle of the board.... that will lessen the tragedy. 

[Vince]

Fridge Timer Update

Proto board fixed !     ...So I can now fit the board into the project box and add the power socket and give it a try !! Right=, right ?!!! NO !!!!  It's 00H50 and freaking tired, I can barely see what I am typing, never mind what I was soldering just a minute ago ! I am going to bed ! !!!   

Uhhhh.... so... just out of curiosity buddy... when was the last time you manually power-cycled the fridge...?

mnem
I am a horrible automaton.

I went to bed at 2AM last night. Temp was negative 2°C. I just woke up. At 10H00 or so looked at it and it was at  +12°C or somehing. 10/15°C can't remember exactly the number. that's the temperature it has been for all year long for the past many years, so all is well.
No not much food in it... a bottle of apple juice and a litee of milk.

[Vince]

And also missing from Vince's lab: a simple, commercial day or week timer switch. 

I have multiples of these, perhaps I should send him one, in the spirit of Entente Cordiale.

That's very nice of you ! 

I guess it would not be economical though !....

But what would I do with such a thing, in the lab ?  Use case example please ?! 

When you are not needing it to control your fridge
- you could switch something on and off repeatedly
- you could limit the charging time for a battery/charger which you do not trust to do it by itself
- you could activate something at a predetermined time for recording or generating a signal.

The one I thought about initially is electromechanic. It has a circle of little tabs with one tab equating 15minutes.
See? pull every 4th one out and plug the fridge in.

Ah these things... yes sure... old man said he has 3 at home. His wall thermostat also uses such a system to set on and off time for the heating.
He said that service techs often also used that to rescue customers when their fridge like mine was waiting for a new thermostat. Kept them going while the part was on its way.

Yeah OK might one....

The ones I have are all 2U DIN rail mount digital.



Not that exact make/model, but pretty much the same thing.

That looks fancy....

Would need one that plugs into a wall socket, though, I guess, for practicality...

[med6753]

Question..

After all this, wouldn't it have been easier to just buy a new thermostat for the fridge? Or am I missing something?

Yes you are missing something, you have not been listening ! 

My dad has a replacement thermostat at home, it's already on its way to me, should receive it maybe tomorrow.

so until then I need to cycle the fridge  manually. No big deal, just a pain that's all.

So I thought it would be a good excuse/opportunity to see if I could cobble a time quick and dirty ni the lab, just for fun (and if it works then the better....). Of course it noly makes sense if I can do it with what I have here. Buying anything would defeat  the purpose and be wasted money which I can't afford atm 

This.....


Plus this...


Would have worked a treat. 

[Ice-Tea]

Plenty of them:

https://tinyurl.com/5n8dnyhy

[Vince]

Question..

After all this, wouldn't it have been easier to just buy a new thermostat for the fridge? Or am I missing something?

Yes you are missing something, you have not been listening ! 

My dad has a replacement thermostat at home, it's already on its way to me, should receive it maybe tomorrow.

so until then I need to cycle the fridge  manually. No big deal, just a pain that's all.

So I thought it would be a good excuse/opportunity to see if I could cobble a time quick and dirty ni the lab, just for fun (and if it works then the better....). Of course it noly makes sense if I can do it with what I have here. Buying anything would defeat  the purpose and be wasted money which I can't afford atm 

This.....


Plus this...


Would have worked a treat. 

No, no go because I don't have that here so would need to buy them hence defeats the purpose of a free home made timer.
Anything that requires to be bought is immediately pointless hence disqualified. 

[bd139]

Heads up for UK'ers. It's 80% off fees this weekend on eBay apparently (I haven't got an offer for that yet but someone else has reported). That means lots of TE potentially being listed

[Specmaster]

I have it, it actually works out to be a better deal if you use their new system of payment than their old £1 listing with PayPal

[bd139]

Yeah agree there. No complaints here.

Edit: fuck it to previous comment that was here. Now own a 34401A. Display looks mostly ok. Circa 1999 HP brand so just pre Agilent. Should have an -02 display board in it. Down the rabbit hole I go...

Edit 2: Seller confirmed 10-05-02 rev so fine 

[mnementh]

Fridge Timer Update

Proto board fixed !     ...So I can now fit the board into the project box and add the power socket and give it a try !! Right=, right ?!!! NO !!!!  It's 00H50 and freaking tired, I can barely see what I am typing, never mind what I was soldering just a minute ago ! I am going to bed ! !!!   

Uhhhh.... so... just out of curiosity buddy... when was the last time you manually power-cycled the fridge...?

mnem
I am a horrible automaton.

I went to bed at 2AM last night. Temp was negative 2°C. I just woke up. At 10H00 or so looked at it and it was at  +12°C or somehing. 10/15°C can't remember exactly the number. that's the temperature it has been for all year long for the past many years, so all is well.   No not much food in it... a bottle of apple juice and a litre of milk.

Yeeeahhh...

Okay. I see why you're willing to play around at this. In our household, the fridge is an absolute necessity; we are a family of 5, and we go through a lot of fresh food. Half a gallon of milk a day between the kids and coffee, and I cook a dozen eggs plus some form of breakfast meat almost every morning. And easily 6 yogurts, plus breadstuffs; I also shop reduced for quick sale breads and meats on Sunday mornings and stock up on 'em right into a upright freezer in the garage. We couldn't afford for me to eat high-protein/low-carb any other way.

So yeah... a fridge thermostat fail...? THAT is a fucking emergency. Hundreds of dollars worth of food hanging in the balance. I'd have the new one in same day via Prime, and in the meantime, I'd be taking the old one apart to see if I can tinker-dwagon it back into service until the new one arrives... or replace it with that industrial controls model I showed earlier.

mnem

[Specmaster]

Postman has been and left me a parcel that was only posted yesterday, so that's a result. In it was another calculator (no not an RPN one either) but a rather complicated one nonetheless, this HP 10bii+ has a steep learning curve, no manual came with it, but have downloaded one, all 187 pages of it 

In other news, the parts for the monitor power supply repair have all now arrived as well, so will be cracking on with that soon. In the meantime, I have been working on a Texas TI58 programmable old school calculator that had suffered the rechargeable battery clusterfuck that these early calculators suffered when they built the batteries into the plastic compartment door in the back. That meant you had to buy new packs from Texas  . This is a project that I started sometime ago and then shelved awaiting a suitable solution, which I now have, some battery packs for old BT cordless phones.

I show photos of this now working, but still some refinements to do yet, one of which is sourcing some of the power sockets that plug in the side of the Calc to recharge the battery, can anyone identify the cable mounted socket that I need?

[Zucca]

I still have my old analogue, Nokia Mobira Cityman 100.

[img witdh=200]https://museum.helsingborg.se/web/image/zoom/1286171/844-2017.jpg[/img]

This picture is from the museum in Helsingborg in southern Sweden, which is the town where I bought mine. So, probably this pictured example was sold in the same store.  I paid 10000 SEK used, in 1991.. Those were the days.

The amount of money Nokia made and lost in a few years in still incredible to my poor mind.

[mnementh]

I'd love to have just the toaster leavins from the N-Gage debacle... 

mnem
*toddles off to play free tech support for SWMBO*

[Peter_O]

... one of which is sourcing some of the power sockets that plug in the side of the Calc to recharge the battery, can anyone identify the cable mounted socket that I need?

That connector is some proprietery TI thingy, I think.

I found some pictures of my teenage TI58C, I took some weeks ago, when rummaging through my sentimental boxes.



About 40 years ago, the keys ceased to funktion, as was normal with TI keys at that time.

I got three garbage keybords of old gaming machines from my friend, who's father was repairing those at that time.

Took some plywood, adhesive foil and rub on characters, a DB connector and some cable and put an external keyboard together.



Teenage style.   



The keyboard works with the internal in parallel. There was enough place for the connector, as the brother calculator TI59 used to have an internal magnetic drive in that place.

And it works today.

The caculator does not need an akku to run.
I had changed them - some 30 years ago I think - by cutting the platics casing and taping it again.



Now the akkus were rotten and it was time to dump them.

[Specmaster]

My connectors were toast, so I have had to solder the battery connections to the calculator, less than ideal as the wire is to thick, will replace with smaller gauge so the case will close up.

[Peter_O]

Shortly after my TI58C purchase the new HP calcs were available. Just the next generation in every aspect.

Today I use on of those, an HP11C from 85. Works like new.

[Zucca]

Now own a 34401A.

It always a great joy when one of the most sexy DMM ends up in TEA member hands.
I believe the chips inside that 34401A are also cheering up with champagne, they won the lottery.

Well done bd!

[Vince]

Fridge Timer Update


OK so I went to remove the relay from the protoboard so I can relocate it nearer the edge of the board to avoid mutilating the board in its center by removing pads.
I almost failed to remove the relay !  With 6 terminals and pads on both sides of the board, solder wick didn't cut it, relay would not budge 
Didn't want to damage / ruin the relay, nor overheat the board as it's a nice one, so I immediately reached for the hot air station instead. Luckily it did it nicely. In just a few seconds I could heat up all the pins at once and the relay could be removed without any mechanical stress whatsoever, it just pulled off nicely. 
As cheap as my hot air station  might be, it is extremely useful. 50 Euros well spent back 5 years ago.

So then I decided no I am not going to solder that relay back to the board... don't want to remove pads from the board, it does not deserve this. So I reverted back to my previous relay (I have a few of this model) with clear case and bigger pins. So back to fixing it with hot glue upside down but... well if I am too hot glue it, why not glue it away from the board, and secure it to the inside of the project box instead ? So I did just that. Now there is nothing but low voltage on the board, I much prefer that... Safest option and no need to mutilate that poor board.

I added rubber feet  under the board to raise it a bit so that the fragile 309AWG wire wrap/mod wires on the solder side, don't get damage and ruin my day. These wires are so fragile it only takes mild flexing for them to break, I hate them. So that makes the board much more reliable, as well as keeping the board from sliding all over the place.

Then I also added an IEC socket for the mains input to the timer. At first I just wanted to hard wire a cable the the box, for simplicity, but somehow I couldn't find any power cable with no plug at the end, and I could not get myself to cut the plug off of a perfectly good cable ! So in order not to do that, I decided to add an IEC socket. Even went through the trouble of actually securing it to the box.. cut a notch in the edge, a bit of hot glue and bob's your uncle.

Also decided to secure the power socket for the mains output to the fridge. Even drilled a hole behind it so I could sneak the wires out of it nicely, rather than having them stick out of the socket housing downward  or upwards. Yes, refinement all over the place, I am telling you 

Even  fitted a couple binding posts to plug for the 12Vdc power supply, because I found a couple laying around. So that means two more holes to drill in the case... yes a LOT of work went into this build ! 

Even put heatshrink tubing on the two mains wires that are soldered to the relay. Yes of course this time I made sure I did not overheat the terminals so as not to ruin the relay again... but I tested the board anyway to make sure the relay was working. It was. Good. So then I flipped the board and relocated the two wires going to the NOR gate so taht they tap teh two slowest divider outputs Q13 and Q14, to get the correct one hour period, rather than the two fastest Q4 and 5 that I was using to easy the design and trouble-shooting phase.

So.... I put the timer into service as you can see, and nothing happens... because at power up sequence starts with the ' OFF 'time first... so I had to wait 45 minutes hoping that it would turn on ! And it did !!!

Yes, my timer works !!!! To hell with the skeptics !!!!

Now I just need to patent my design. Such a beautiful construction, hand made, custom design, has to be worth at least 500 Euros retail. I am rich. 

Thanks to Zoli  for the help / design ideas !

And thanks to the guy who invented hot glue because clearly without it this project could not have seen the light of day.   

Wow that design marathon was so fun !  That proves that though far from fully operational, my lab is now actually in a state where I can actually do something like this !  Components sorted and easily accessible, lots of diverse salvaged parts, enough that I could cobble something together for free, in a record time.
I am over the moon... motivates me to keep sorting my components (still lots to do ni the semiconductor department...) and keep buying all the essential things one need for an operational lab.

I need to buy lots of these Dupont wires for my breadboard.... they are more practical than me having to cut tiny bits of wires and stripping their ends, then the ends get damaged after few times trying to insert them in the holes... yeah, Dupont wires would be a good addition.

Took 20 minutes to clean the mess on the bench ! Putting all the components back to where they belong, one by one...  but now bench is clear and whatever comes next, I can do ! 

Need to resume work on my Rochar Nixie DMM...

[mnementh]

Lets light the tires and kick some fires... You go, old man. 

mnem
ass-gas. heh. 

[25 CPS]

I miss the analogue ones. Used to sit on the coach with a scanner and earphones listening into people 

Did the same with 48MHz cordless phones. Heard some juicy stuff. 

That takes me back to when I was a teenager and starting out with electronics.  One of my best friends had just gotten a scanner and we picked up cordless phones and analog cell phones with it.  To this day I remember one cell phone conversation we over heard from some guy asking how much further Yonge and Finch was in Toronto and said he was walking past some street near Yonge and Eglinton.  The reply was, "Keep walking, you're almost there..." which was completely wrong.  You're near Yonge and Eglinton and on foot wanting to get to Yonge and Finch?  You get on the subway and ride it to the end of the line - that's Yonge and Finch.  We cracked up laughing as this went on until the cell phone went out of range wondering how far the poor guy was going to end up walking.

[TERRA Operative]

Question..

After all this, wouldn't it have been easier to just buy a new thermostat for the fridge? Or am I missing something?

That’s not how we work in these parts.

If it’s broken, we fix it, even if it’s financially and logically insane to do so.

If it’s not broken, we make it better, even if it’s perfectly good.

If it’s done, then we unfinish it so we can finish it again.

_{Disclaimer: some items may not be repaired, some may be ruined and most will never be finished and left in an eternal repair queue}

I feel this in my soul..... 

Yes you are missing something, you have not been listening ! 

My dad has a replacement thermostat at home, it's already on its way to me, should receive it maybe tomorrow.

so until then I need to cycle the fridge  manually. No big deal, just a pain that's all.

So I thought it would be a good excuse/opportunity to see if I could cobble a time quick and dirty ni the lab, just for fun (and if it works then the better....). Of course it noly makes sense if I can do it with what I have here. Buying anything would defeat  the purpose and be wasted money which I can't afford atm 

Ah ha, icic, carry on then.  

[bd139]

Yes, my timer works !!!! To hell with the skeptics !!!!

Good job.

For ref, if you want to save some cash and actually not have to build the entire thing twice, firstly on a flakey ass breadboard, I can thoroughly recommend "dead bugging" the circuit on some FR4 single sided PCB.

Example I built (crystal frequency source):



When you're done you cut the board to size, drill a couple of holes to it and screw it to the bottom of the box and job done 

[tggzzz]

I miss the analogue ones. Used to sit on the coach with a scanner and earphones listening into people 

Pagers are plaintext. I've seen messages like "the fat man will be at the pub at 1pm", and "there's a police car at...".

Nowadays the only thing I expect you would see in the UK are "<consultant name> please get to ward X ASAP".

AFAIK the NHS still uses pagers as the most practical technology for that purpose. Tetra - no; see how police carry Tetra radios plus cellphones. Cellphones for SMS - no; too many places there's no reception, e.g. in the basement of an old house. (That last will be relevant for the next occupant of my parents' house )

[Vince]

Yes, my timer works !!!! To hell with the skeptics !!!!

Good job.

For ref, if you want to save some cash and actually not have to build the entire thing twice, firstly on a flakey ass breadboard, I can thoroughly recommend "dead bugging" the circuit on some FR4 single sided PCB.

Example I built (crystal frequency source):



When you're done you cut the board to size, drill a couple of holes to it and screw it to the bottom of the box and job done 

Looks cool BD but I have one problem with that 

What if you need to replace one of the DIP IC for whatever reason, like t's defective to begin with, or you blow it while working on the device ? That does not look like a lot of fun to replace those ICs.... whereas a socket saves your bacon 

I guess no solution is perfect, you gotta weight the pros and cons for each particular project / circumstances...