Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

As my grandfather tried to teach me young, but I learned only very late in life after my own string of batshit-crazy redheads... and blondes... and brunettes... "Whenever you talk with a woman... everything you say should first pass this test: 'Would you rather be right, or would you rather be happy...?' "

After 20 years with my wife, and still tail over wings in love with her, happy wins out every time.

mnem

If only you could treat TEA as if it were your wife, how nice a place this would be 

I don't think I could stand the electrical burns all over little mnem.


mnem

[Andrew_Debbie]

Bad news on the Dana 5100 front.   I'm 90% certain the 74188 PROM is faulty.   The meter settled into a fault mode that makes this easy to diagnose from observed behaviour.

I made a video showing the fault and then walking through why I think it is the PROM.    Sorry,  I misspoke a few times.   Can't be bothered to do voice over... 

[Specmaster]

For those that prefer electronics to boxes on wheels, here's the latest acquisition - no thanks to ParcelFarce.

I know the Sinclair/Thurlby SC110A is my Nth 'scope, but it won't take up much room - see the multimeter for comparison

It needs tuning, and the battery compartment is missing, but it will do.



The screen is 3cm*2.5cm.

That's nice, been after one of those for a while now.

I think we all prefer electronics to other topics but don't lose sight of the point that this is also the equivalent of our local pub / social club as there is no way that we could all meet up for drink and chat about anything and as long as it remains good-natured and informative I see nothing wrong in a diversion from time to time, otherwise it just becomes like so many other threads / forums, one dimensional and slowly dies. I'm a member of many other forums, all electronics based, and they are all dying on their feet because the moderators rule them strictly. No word of a lie, some of them I can go on them about 6 times a year or less and nothing hardly changes, no new content on them. Meanwhile, this particular thread is now I think fair to say number one thread of the entire eevblog

[Specmaster]

For German speakers, the Coupé that has been discussed here used to be a two-door version with a slightly lower roof, of a Limousine, the usual two or four-door sedan or saloon. 

Yeah, I can relate to that, I have seen my Škoda Superb referred to as a Limousine in some European magazines and videos.

[mnementh]

On the TinkerDwagon's Bench today:   
   If I can't get the BMS to charge, I'll probably have to remove it and solder a JST/XH pigtail on the cell cluster so I can balance charge with the Reaktor.

Normally this kind of dickery with individual cells is a fool's errand; one is better off rebuilding the pack with known-good or new matched cells. But given the model, this pack is probably 3-5 years old; so it is possible I'll get lucky.

   Ugggh. BMS is totes being a whiny little bitch. 

Refuses to start/turn on to charge, so balance charging the pack on the Reaktor. Safety fuse tests good, each voltage monitor leg tests the same resistance FWD/REV EXCEPT cell 1; it measures approx 630KΩ/10MΩ where the others measure ~5MΩ/10MΩ. This may or may not be a bad thing; cell 1 is where the BMS usually draws power for the supervisor chip.

It is entirely possible the pack sat unused long enough for this miniscule drain to have drawn cell 1 down to the point where the BMS shut down due to imbalance; only time will tell.

mnem
 

Exactly this happens in older Makita cordless tools and their smart chargers  would reject a well drained and forgotten pack after 3 attempts to charge it. 
We learnt to connect them to another source to get that one cell up some so the pack would be accepted and go on to charge. 
Really pissed off our eldest son Larry Major enough to use only Milwaukee tools now.

Well, there's a lot more to it than that. The BMS can only correct so much imbalance in any single cell during charging; it balances at typically 50-150mA rate/cell at most. That is likely the cause of the multiple charge attempts then  ppppbbbppppptttttttt! as it shuts down to prevent overcharging the other cells in the pack. The trick we're doing is obviously not something they can expect any end-user to attempt, with all the risk of personal injury, etc involved in directly handling any high-current Li-xx power source.

Also, more recent generations of BMS work differently; the newer supervisor ICs have quiescent draw in the picoamp range, and some of the designs supposedly can do a "refresh" cycle which I expect is just a balance discharge before charging. These new designs have their own constellation of new considerations however.

Added to the mix is the very expensive nature of these battery-powered tool ecologies; this encourages things like digital handshaking with ESNs in every pack to ensure you aren't putting some cheap Chinesium POS pack in your drill and charger and then blaming the tool manufacturer when it blows up said drill or charger.

mnem
 

As I understand it, modern BMS circuits use MOSFET bypass shunts to limit current on the fully charged cells to allow the others to catch up.

The big FETs are series-pass elements in the main load circuit. EDIT: Among other things, the BMS monitors voltage drop across the FETs as a measure of current draw from each cell. On what I've had across my bench (and I've dismantled more drill packs than I can count), balancing is still usually done with bleeders and small transistors, though I can't say other solutions aren't already out there.

This stuff is constantly evolving, mostly with an eye to developing a single chip with as few external components as possible. We have complete charging solutions now for single-cell 18650 and small Li-Pos designed to charge from up to 8-9V/500mA in a SOT23-5 package and costing a dime a copy. Every generation brings new tech, and we are still in the Model T stage of development with this kind of portable power.

mnem
 

[Robert763]

Bad news on the Dana 5100 front.   I'm 90% certain the 74193 PROM is faulty.   The meter settled into a fault mode that makes this easy to diagnose from observed behaviour.

I made a video showing the fault and then walking through why I think it is the PROM.    Sorry,  I misspoke a few times.   Can't be bothered to do voice over... 

So it's the 74188 (the 193 is a counter)? At only 32x 8bit I've programme those with switches in the dim and distant past. A dip switch (data) for tables or two HEX switchs for data.
You could also program up a small PIC or similar to do the look-up table and make an adaptor. If it just the range switching it does not need to be high speed.

[Saskia]

New used car. V70 bifuel CNG 2007, 140 bhp 5 cyl. New roadworthiness test

[Vince]

Can't even reply to the dragon, was well motivated but the forum denies me this right : when I click on "Quote"... it quotes.... some random message but not the one I want to reply to.  Bloody forum...  I guess Dragon wins again. But since he said his wife always wins, I guess that explains why he needs TEA to vent all his frustration to balance things out and keep his dragon heart happy. It all makes sense now, I understand.... it's about universe equilibrium, it needs to be in equilibrium, it's a physical, fundamental requirement, there is absolutely no way around it. It's like conservation of energy.

This means it's all hopeless, fighting is useless, and we are all doomed.

Only way out is to leave TEA but I can't resort myself to doing that, as I have grown quite fond of this place already. I despise social media and don't use any... but objectively this TEA place is a social media of sorts.. so I guess I am no better than all the people I laugh at... I just needed to come across "my" type of social media... I guess.

Enough rambling, back to the Wobuloscope.. spent some time reading the service manual, think am getting the hang of it now... I can now start contemplating looking at the schematics and start probing around... because it's definitely not working right. There are signs of life here and there, but definitely needs fixing...

[Vince]

New used car. V70 bifuel CNG 2007, 140 bhp 5 cyl. New roadworthiness test

Cool a 5 pot Volvo ! 

What do you mean by "bifuel" and "CNG" ??

Is it petrol + a box to run on 100% E85, or is it a Petrol + LPG / gas install ?

[AVGresponding]

New used car. V70 bifuel CNG 2007, 140 bhp 5 cyl. New roadworthiness test

Cool a 5 pot Volvo ! 

What do you mean by "bifuel" and "CNG" ??

Is it petrol + a box to run on 100% E85, or is it a Petrol + LPG / gas install ?

CNG is compressed natural gas.

[Andrew_Debbie]

So it's the 74188 (the 193 is a counter)? At only 32x 8bit I've programme those with switches in the dim and distant past. A dip switch (data) for tables or two HEX switchs for data.
You could also program up a small PIC or similar to do the look-up table and make an adaptor. If it just the range switching it does not need to be high speed.

Yes, 74188.      I'm thinking about programming an AVR.    Maybe an ATiny or even a 16U2 on an adapter.   Or I could hand wire something like a ProMicro onto a 16-pin header.   That would be ugly.

Timing is probably ok,  but I should check first.


The other option is to buy NOS PROMS and burn a few until I get it right.   I sort of prefer the '188 but mostly I want to get the meter working without going too far down a rabbit hole.

[med6753]

Well after considerable pulling, prodding, and poking of all the wiring to the CRT did not find the offender. Pulled it all apart and deoxit'ed all the connectors/pins. The result is an improvement but still somewhat flaky. The suspect I might have a resistor or two in the intensity/focus divider circuit has gone noisy or increased in value. That would be a little surprising since the highest voltage is just under 1kV. So next step is check those resistors plus monitor some voltages.

   

[mnementh]

Can't even reply to the dragon, was well motivated but the forum denies me this right : when I click on "Quote"... it quotes.... some random message but not the one I want to reply to.  Bloody forum...  I guess Dragon wins again. But since he said his wife always wins, I guess that explains why he needs TEA to vent all his frustration to balance things out and keep his dragon heart happy. It all makes sense now, I understand.... it's about universe equilibrium, it needs to be in equilibrium, it's a physical, fundamental requirement, there is absolutely no way around it. It's like conservation of energy.

This means it's all hopeless, fighting is useless, and we are all doomed.

Only way out is to leave TEA but I can't resort myself to doing that, as I have grown quite fond of this place already. I despise social media and don't use any... but objectively this TEA place is a social media of sorts.. so I guess I am no better than all the people I laugh at... I just needed to come across "my" type of social media... I guess.

Enough rambling, back to the Wobuloscope.. spent some time reading the service manual, think am getting the hang of it now... I can now start contemplating looking at the schematics and start probing around... because it's definitely not working right. There are signs of life here and there, but definitely needs fixing...

Oh fuck... WhaddIsay THIS TIME...?!?     

mnem
*toddles off to scorch some sausages*

[Vince]

New used car. V70 bifuel CNG 2007, 140 bhp 5 cyl. New roadworthiness test

Cool a 5 pot Volvo ! 

What do you mean by "bifuel" and "CNG" ??

Is it petrol + a box to run on 100% E85, or is it a Petrol + LPG / gas install ?

CNG is compressed natural gas.

Ah OK thanks, didn't know.  I always saw these cars being referred to as " LPG ". I guess I needed to be updated ! 

[mnementh]

Well after considerable pulling, prodding, and poking of all the wiring to the CRT did not find the offender. Pulled it all apart and deoxit'ed all the connectors/pins. The result is an improvement but still somewhat flaky. The suspect I might have a resistor or two in the intensity/focus divider circuit has gone noisy or increased in value. That would be a little surprising since the highest voltage is just under 1kV. So next step is check those resistors plus monitor some voltages.

Hmmm... maybe not the wires, but the pressure they put on one of the PCBs causing flex...?

mnem

[Vince]

Can't even reply to the dragon, was well motivated but the forum denies me this right : when I click on "Quote"... it quotes.... some random message but not the one I want to reply to.  Bloody forum...  I guess Dragon wins again. But since he said his wife always wins, I guess that explains why he needs TEA to vent all his frustration to balance things out and keep his dragon heart happy. It all makes sense now, I understand.... it's about universe equilibrium, it needs to be in equilibrium, it's a physical, fundamental requirement, there is absolutely no way around it. It's like conservation of energy.

This means it's all hopeless, fighting is useless, and we are all doomed.

Only way out is to leave TEA but I can't resort myself to doing that, as I have grown quite fond of this place already. I despise social media and don't use any... but objectively this TEA place is a social media of sorts.. so I guess I am no better than all the people I laugh at... I just needed to come across "my" type of social media... I guess.

Enough rambling, back to the Wobuloscope.. spent some time reading the service manual, think am getting the hang of it now... I can now start contemplating looking at the schematics and start probing around... because it's definitely not working right. There are signs of life here and there, but definitely needs fixing...

Oh fuck... WhaddIsay THIS TIME...?!? 
   

mnem
*toddles off to scorch some sausages*

No worries Dwagon, was not referring to anything in particular, just you being you that's all. 

Don't worry I am not wanting a fight, as I said I am done now, I am out of the Dwagon game for good. I won't be in your way any more, you can refuel and ignite your fire, I won't be in the path... I will let others be roasted and watch silently from a distance. Hell I might even find it fun who knows, it's like a spectacle of sorts...

[Vince]

For those that prefer electronics to boxes on wheels, here's the latest acquisition - no thanks to ParcelFarce.

I know the Sinclair/Thurlby SC110A is my Nth 'scope, but it won't take up much room - see the multimeter for comparison

It needs tuning, and the battery compartment is missing, but it will do.



The screen is 3cm*2.5cm.

Can't believe it..... what are the odds of coming across such an odd device, HERE, never mind while we are discussing it ?!

Look at that :

https://www.leboncoin.fr/bricolage/2061617642.htm

I will probably never see another one for sale here, for sure !

Guy wants 25 Euros, that's like what, 20 pounds or something ??
Fair price  ?

Guy refuses to ship anyway, so neither you nor I will get it...

EDIT : OH !!  Just looked, by some miracle the seller actually lives nearby, like 25 miles away from me or so ! Hmmm... could pick it up for you if you want...

[med6753]

Can't even reply to the dragon, was well motivated but the forum denies me this right : when I click on "Quote"... it quotes.... some random message but not the one I want to reply to.  Bloody forum...  I guess Dragon wins again. But since he said his wife always wins, I guess that explains why he needs TEA to vent all his frustration to balance things out and keep his dragon heart happy. It all makes sense now, I understand.... it's about universe equilibrium, it needs to be in equilibrium, it's a physical, fundamental requirement, there is absolutely no way around it. It's like conservation of energy.

This means it's all hopeless, fighting is useless, and we are all doomed.

Only way out is to leave TEA but I can't resort myself to doing that, as I have grown quite fond of this place already. I despise social media and don't use any... but objectively this TEA place is a social media of sorts.. so I guess I am no better than all the people I laugh at... I just needed to come across "my" type of social media... I guess.

Enough rambling, back to the Wobuloscope.. spent some time reading the service manual, think am getting the hang of it now... I can now start contemplating looking at the schematics and start probing around... because it's definitely not working right. There are signs of life here and there, but definitely needs fixing...

Don't leave. I enjoy having you here. In fact, I enjoy everyone here including...ahem....the dragon when he stays off his soap box. 

I don't use social media either like Twitter, etc. Why would I? I've made it plain many times I hate people. I do have a Facebook page but only because I'm a member of an Old Tek Scopes group. I rarely post on my home page and even more rarely read the drivel other people post. When Facebook/Twitter went down several weeks ago I LMAO because all those numb nuts that update their status every 5 minutes were having shit fits.

If there were a page dedicated to grouchy old bastards I might consider joining but then again, I don't need justification for who am I.     

[PA0PBZ]

Guy refuses to ship anyway, so neither you nor I will get it...

So why does the listing say "Livraison : à partir de 10,99 €"

[med6753]

Can't believe it..... what are the odds of coming across such an odd device, HERE, never mind while we are discussing it ?!

Look at that :

https://www.leboncoin.fr/bricolage/2061617642.htm

I will probably never see another one for sale here, for sure !

Guy wants 25 Euros, that's like what, 20 pounds or something ??
Fair price  ?

Guy refuses to ship anyway, so neither you nor I will get it...

How far is it from you? Would you not consider a road trip?

Edit.....nevermind, saw the edit.

[Saskia]

Cng is cow farts at 200 bar. LPG is liquified propane/butane . Vol o offered both version the energy density of cow farts is considerably higher than LPG

[med6753]

Well after considerable pulling, prodding, and poking of all the wiring to the CRT did not find the offender. Pulled it all apart and deoxit'ed all the connectors/pins. The result is an improvement but still somewhat flaky. The suspect I might have a resistor or two in the intensity/focus divider circuit has gone noisy or increased in value. That would be a little surprising since the highest voltage is just under 1kV. So next step is check those resistors plus monitor some voltages.

Hmmm... maybe not the wires, but the pressure they put on one of the PCBs causing flex...?

mnem

I considered that and was flexing that top board too. No joy. 

[Neomys Sapiens]

@med6753: Just look out for hashtag concentrations like #stayoffmylawn

[Neomys Sapiens]

Can't believe it..... what are the odds of coming across such an odd device, HERE, never mind while we are discussing it ?!

I will probably never see another one for sale here, for sure !

Guy wants 25 Euros, that's like what, 20 pounds or something ??
Fair price  ?

Guy refuses to ship anyway, so neither you nor I will get it...

EDIT : OH !!  Just looked, by some miracle the seller actually lives nearby, like 25 miles away from me or so ! Hmmm... could pick it up for you if you want...

It is not as rare as you might think. I've seen several on Ebay Germany and was not very tempted.
But that depends on the needs and preferences.

[Vince]

Well after considerable pulling, prodding, and poking of all the wiring to the CRT did not find the offender. Pulled it all apart and deoxit'ed all the connectors/pins. The result is an improvement but still somewhat flaky. The suspect I might have a resistor or two in the intensity/focus divider circuit has gone noisy or increased in value. That would be a little surprising since the highest voltage is just under 1kV. So next step is check those resistors plus monitor some voltages.

   

If the problem is intermittent and only happens once everything is crammed in / buttoned up, got to be a mechanical issue / bad joint in the CRt section, but if you are unlucky, the bad joint could be.... an internal bond inside a resistor... or cap.  So not fun to hunt for.

But I guess you could pull it apart and torture every component in the CRT section until you can force it to misbehave, and progressively narrow it down to the offending component...

Good luck ! You fixed that  547 so I am not too worried about this tiny little scope !