Test Equipment Anonymous (TEA) group therapy thread

[BravoV]

Gift from a generous forum member, Tek knobs, 4 of them for my new 2465, and the color is still pristine compared to the exiting ones in the background. 

[tautech]

Pressure LOP or even LOP only will only work in your case if an upstream checkvalve holds 100% otherwise you can potentially be in a situation of no flow but pressurised by the Tank and Static head of your water column. That said we used to use them on budget jobs or as belt and braces with a flow switch.

The best option (and most expensive) was at the time https://mackvalves.com/flowswitch-2/ with an integral timer set to about 15-30 seconds. They are a proper industrial control but given the then replacement stack cost at the time on a 4-120 of over $800 they were cheap insurance at $220 (from memory).

Quick check on evilbay for 'paddle flow switch' got a heap of hits for under $20 AUpesos so grab one and 555 timer up a delay and feed in into your 3 phase contactor.

Thanks Bean.
Upstream and suction check valves are 100% and immediately after OFF pump pressure is zero....checked with a gauge.
Really don't want it to run for more than a second or so which is plenty of time to see pressure if pump prime is held and all is OK.
I fill a spray tank from a Tee just before the outlet check valve so I want this dry run/low pressure switch not to have a fit when the pressure is just low.
A flow switch will negate any worry here but it's not a simple as inserting a pressure switch into an existing fitting. 

I'll check the 'bay. 
Thanks again bud. 

[beanflying]

Pressure LOP or even LOP only will only work in your case if an upstream checkvalve holds 100% otherwise you can potentially be in a situation of no flow but pressurised by the Tank and Static head of your water column. That said we used to use them on budget jobs or as belt and braces with a flow switch.

The best option (and most expensive) was at the time https://mackvalves.com/flowswitch-2/ with an integral timer set to about 15-30 seconds. They are a proper industrial control but given the then replacement stack cost at the time on a 4-120 of over $800 they were cheap insurance at $220 (from memory).

Quick check on evilbay for 'paddle flow switch' got a heap of hits for under $20 AUpesos so grab one and 555 timer up a delay and feed in into your 3 phase contactor.

Thanks Bean.
Upstream and suction check valves are 100% and immediately after OFF pump pressure is zero....checked with a gauge.
Really don't want it to run for more than a second or so which is plenty of time to see pressure if pump prime is held and all is OK.
I fill a spray tank from a Tee just before the outlet check valve so I want this dry run/low pressure switch not to have a fit when the pressure is just low.
A flow switch will negate any worry here but it's not a simple as inserting a pressure switch into an existing fitting. 

I'll check the 'bay. 
Thanks again bud. 

Generally accepted run time with no damage for seals and stacks is fine to 15-30 seconds so just make sure you can crank your timer up a bit. 1 second will be a PITA I suspect. With your tank fill LOP switches are out unless you like holding levers 

[tautech]

Yeah OK, for $20 NZD this is looking not too bad:



Now to build the timer. 

[beanflying]

Thats the ones. Generally trim the paddle down a bit in width too. Leave it full depth in a T-piece and then trim to just wide enough to move it or it will act like an orifice plate and drop your flow (gate valve style).

[tautech]

Thats the ones. Generally trim the paddle down a bit in width too. Leave it full depth in a T-piece and then trim to just wide enough to move it or it will act like an orifice plate and drop your flow (gate valve style).

Remember we want that. 

Not done anything to reduce flow rates yet other than run the pump for only an hour or so but that's the easy bit as I've been going the 500m to the pump each time to check prime is held before firing it up when with some flow detection when I could be sitting at home drinking coffee and using the RF ON/OFF remote.

[beanflying]

Depending on the pivot of the CheapCheerfulChinese if you don't trim it you will wear the brass surfaces due to excess load, keep it narrow. Gate valve needs to be before your tap off point to your spray tank outlet don't forget or you will be overloading your motor again.

[tautech]

Depending on the pivot of the CheapCheerfulChinese if you don't trim it you will wear the brass surfaces due to excess load, keep it narrow. Gate valve needs to be before your tap off point to your spray tank outlet don't forget or you will be overloading your motor again.

Got that thanks.

Now the weather is getting a bit iffy some time inside on the lathe is overdue where I'll spin up some baffles for flow restrictors however filling the 1000 litre tank took just 8 minutes with the old pump and this one with some 10-20% more flow with zero head shouldn't have an issue for such a short run.
Got a tank of gorse spray to put on soon so we'll see what this new one can manage unstrangled. 

[Specmaster]

Do you do an ESR test on the smaller value ones to decide whether they're suspect, or just visual inspection and the old "touch your iron to the PCB under/around the cap & smell for burning electrolyte" trick?

mnem
*Learning mode*

Just visual and is it easy to get to. Because I'm NOT pulling boards to do these replacements. Strictly from the top side which can be done on these double sided boards.

That's really good to know because I opened the sucker up and thought, there is no freakin' way i can get these boards out and then get 'em back in.  Will go your route, leave the boards in the box, replace the big ones, inspect the small ones.  Thanks.

What if the small ones blow at a later date?

[beanflying]

I present the Quantum Flux Resistor Rated at 1.21 daW

[VK5RC]

@b-f   Looks a nice DC load 

[beanflying]

That too  I already have a cheapy 150W Electronic load. Paralleled 0.48 14.7A @ 7V 125W or Series/Paralleled 2.5  7A @ 17.5V for 104W.

I built it for a lower care decade than my 0.02% USSR Decade Box.

[tggzzz]

*Passes the Stick of Enlightenment on to beanflying*

"Use it wisely, my son. Use it often and without hesitation; wherever it is most needed."

Hmmm. Apparently you don't need to explicitly copyright a media work in order to be able to extract royalties. I'm going to be rich at this rate

[Ero-Shan]

For those in search of ancient counters: yet unbidden HP5300A and HP5304A on Ebay.de!

I searched for them, but all that comes up are 5300A+5302A combos for preposterous 130+ €!
No way I will pay that for a 50 MHz counter with a mere 6 digits, even if those are dotted LED.

Thank you anyway. I tend to miss the best bits all too often.

[tautech]

I present the Quantum Flux Resistor Rated at 1.21 daW

Can ya make it glow ? 

[Brumby]

Maybe test it out roasting coffee beans?

[beanflying]

Need more power for Beans  And yes it will glow under high load, LED high flow fans coming to compete with the Disco Green Fans on my Electronic Load 

No Fans, No Heatsink paste, time to break out 60A supply  51C on the body of the 4 in series/parallel so I think it will cope will plenty more than spec with fans under it if needed.

On the numbers should be 2.5  measured 2.498  I can live with that 

[mnementh]

Yeah OK, for $20 NZD this is looking not too bad:      Now to build the timer.

https://www.ebay.com/itm/183425524033

Hardly even worth your time, buddy. These have been around for years, and cost ~US$1.50-2.00. Will probably fit inside the box for your paddle valve.


https://www.ebay.com/itm/121945988830

If you wanna spend a little more (~US$5),these have a LED display.

mnem

[bd139]

Waiting for my Tek 2225 to turn up. Apparently focus is shot but the focus pot changes the shape of the beam. Place your bets:

1. It's going to just be the focus chain resistors that need replacing.
2. It's going to devolve into a money sink and sit in the cupboard for 6 months awaiting an organ donor like the other scopes in there 

[med6753]

Do you do an ESR test on the smaller value ones to decide whether they're suspect, or just visual inspection and the old "touch your iron to the PCB under/around the cap & smell for burning electrolyte" trick?

mnem
*Learning mode*

Just visual and is it easy to get to. Because I'm NOT pulling boards to do these replacements. Strictly from the top side which can be done on these double sided boards.

That's really good to know because I opened the sucker up and thought, there is no freakin' way i can get these boards out and then get 'em back in.  Will go your route, leave the boards in the box, replace the big ones, inspect the small ones.  Thanks.

What if the small ones blow at a later date?

I'll take that chance and deal with it at that time if it happens.

[med6753]

Waiting for my Tek 2225 to turn up. Apparently focus is shot but the focus pot changes the shape of the beam. Place your bets:

1. It's going to just be the focus chain resistors that need replacing.
2. It's going to devolve into a money sink and sit in the cupboard for 6 months awaiting an organ donor like the other scopes in there 

It should be the former but with your luck the latter.  My B&K 2120 scope pulled the same stunt twice until I replaced ALL the focus divider resistors.

[mnementh]

Do you do an ESR test on the smaller value ones to decide whether they're suspect, or just visual inspection and the old "touch your iron to the PCB under/around the cap & smell for burning electrolyte" trick?

mnem
*Learning mode*

Just visual and is it easy to get to. Because I'm NOT pulling boards to do these replacements. Strictly from the top side which can be done on these double sided boards.

That's really good to know because I opened the sucker up and thought, there is no freakin' way i can get these boards out and then get 'em back in.  Will go your route, leave the boards in the box, replace the big ones, inspect the small ones.  Thanks.

What if the small ones blow at a later date?

   Then you make a face like this and open all the doors to let the stink out.

I'm with med on this one; pulling the boards to do every one is like begging Murphy to bitch-slap me insensible. I've learned the hard way that even as careful as I can be, I'm still klutzy enough that there's a significant chance I'll do more damage than good if I go rooting around in something this complex & delicate when it's still working properly. It's a balancing act; you balance the odds of doing good against the odds of doing damage, then try to follow the Hippocratic Doctrine: First: Do no harm.

mnem
 

[bd139]

Waiting for my Tek 2225 to turn up. Apparently focus is shot but the focus pot changes the shape of the beam. Place your bets:

1. It's going to just be the focus chain resistors that need replacing.
2. It's going to devolve into a money sink and sit in the cupboard for 6 months awaiting an organ donor like the other scopes in there 

It should be the former but with your luck the latter.  My B&K 2120 scope pulled the same stunt twice until I replaced ALL the focus divider resistors.

Yeah I'm siding with 2 as well.

Possibly option 3:

3. The seller packed it really badly and it gets smashed by my UPS driver who turns into the incredible hulk the moment he gets into the back of his van.

[mnementh]

   I present the Quantum Flux Resistor Rated at 1.21 daW

Okaaaaaaayyyy... That is pretty much the EXACT OPPOSITE of what I thought you were going to do; I was expecting the heat sink stack to be on the INSIDE of that casting, which was to be used as a faceplate for a shelf-standing unit.

mnem


That's what I get for thinking.

[mnementh]

*Passes the Stick of Enlightenment on to beanflying*

"Use it wisely, my son. Use it often and without hesitation; wherever it is most needed."

Hmmm. Apparently you don't need to explicitly copyright a media work in order to be able to extract royalties. I'm going to be rich at this rate

*Arrrou?!?* I know where I snurched this pic from... was that YOUR auction all those years ago?

As for it being the "Stick of Wisdom" or "Stick of Enlightenment"... to my knowledge, that was a term coined years decades ago inside HP; I think Rick Jones was one of the originators thereof...?

mnem
*puttin' on muh NOMEX jammies, just in case*