Test Equipment Anonymous (TEA) group therapy thread

[Robert763]

What's opposite? I said most traction systems are DC.
The difference I was referring to was industrial electricians working mostly with AC motors etc.

Was referring to the electricians. They would have vast experience working on DC control systems.

DC high voltage high power systems are worlds apart from low voltage and power industrial control. A person used to control DC is unlikely to have the competence required for DC traction system work.

[factory]

Update on the HP 5340A.

Replacement capacitors assembled & fitted.


All low voltages checked & verified as good. I left the Sangamo caps as they tested OK and didn't have crust underneath or that fishy smell, all the failed caps were Sprague, two of which were shorted.


It now has at least two other problems, first one is the display supply (+175V) is low & the displays dim or barely lit at a result. It's below the 135V-ish that the book states most voltmeters will display, as no smoothing cap is used.
The second problem, the displays are mostly stuck on 7s in self check mode, need to fix problem one first.


David

Ooh, I should get back onto fixing mine, I have a nixie version (actually two of them, and a third that was firmly a parts unit that got stripped down).

I just replaced those PSU caps with new Japanese ones of the same form factor, the original ones were so old and dried out that some sounded like they were full of dirt!

I've made reproduction OCXO Option PSU boards ready to populate one when I get to it, as I came across the needed transformer in the parts unit. Still have to source the actual OCXO though.


I'm definitely looking forward to seeing if the 18GHz inputs have been blown or not.... Hopefully I can cobble a fully working unit from the parts I have on hand..
I'd love to get my hands on the upgraded input section that was reportedly much more resilient, but that seems practically unobtanium unless you luck across it somehow.

Guess I sort of had some luck there, as both of mine seem to have been updated with the later front end assemblies, but both arrived in quite a state.
First 5340A from Germany had lots of fasteners missing, a hole where the I/O board had been robbed and loose RF connectors in the front end. After all those issues had been addressed, it only required the switches cleaning to work.

The second 5340A had two shorted PSU can caps, two failed rectifiers and the odd loose/missing fastener.
I couldn't easily obtain replacements screw terminal can caps, those at Mouser were quite expensive & some values were not stocked. Plus I have lots of surplus caps from the components I bought from work.
Still working on the +175V power supply, but since checking everything on the regulator board (all transistors, zeners & passives checked) I'm beginning to suspect the rectifier or transformer winding. I would check voltages against the good 5340A but can't access it until the storage unit reopens tomorrow.


Here is the output of the transformer with red wires disconnected from the rectifier, the book states the winding is 155V (but no mention of whether that is peak-to-peak or RMS).


With the wires reconnected to the rectifier & regulator board removed, I get this on the output of the rectifier, looks odd to me. Note: the rectified supply here is added to the unregulated +15V before going to the +175V regulator board.


Note: the rectified supply above is added to the unregulated +15V before going to the +175V regulator board.


David

Looks OK to me.
As it is smoothed DC + rectified AC  you need to be careful what you use for voltage measurements. What voltmeter is specified in the manual. A modern digital meter or TRMS meter will give different readings to an old avereage reading moving coil.
The AC does look clipped. Check  the input voltage and settings. What do the other windings measure?

Pretty sure it had the 3480/3482A as the voltmeter used, the book mentioned the measured value would be nearer 135V RMS on most meters, due to the high ripple.
Neither the Tek THS710 or Wavetek DMM have been near the 135V quoted in the book. Closest was around 100Vdc with 37Vac on the DMM.

David

[med6753]

What's opposite? I said most traction systems are DC.
The difference I was referring to was industrial electricians working mostly with AC motors etc.

Was referring to the electricians. They would have vast experience working on DC control systems.

DC high voltage high power systems are worlds apart from low voltage and power industrial control. A person used to control DC is unlikely to have the competence required for DC traction system work.

Of course. They would gain that experience on the job just as AVG suggested.

[factory]

The second 5340A had two shorted PSU can caps, two failed rectifiers and the odd loose/missing fastener.
I couldn't easily obtain replacements screw terminal can caps, those at Mouser were quite expensive & some values were not stocked. Plus I have lots of surplus caps from the components I bought from work.
Still working on the +175V power supply, but since checking everything on the regulator board (all transistors, zeners & passives checked) I'm beginning to suspect the rectifier or transformer winding. I would check voltages against the good 5340A but can't access it until the storage unit reopens tomorrow.


Here is the output of the transformer with red wires disconnected from the rectifier, the book states the winding is 155V (but no mention of whether that is peak-to-peak or RMS).


With the wires reconnected to the rectifier & regulator board removed, I get this on the output of the rectifier, looks odd to me. Note: the rectified supply here is added to the unregulated +15V before going to the +175V regulator board.


Note: the rectified supply above is added to the unregulated +15V before going to the +175V regulator board.


David

Weird how they've drawn the two bridges differently.

Have you tried inverting the phase on one of them?

No not tried that yet, the wiring underneath to the PSU motherboard does have the look of being de-soldered at least once in the past.

The other two bridges are drawn the same way as the second.


David

[factory]

What's opposite? I said most traction systems are DC.
The difference I was referring to was industrial electricians working mostly with AC motors etc.

Was referring to the electricians. They would have vast experience working on DC control systems.

I'd expect the electricians working on DC traction motors to have knowledge and experience of said systems, however the majority of industrial electricians that I know personally, wouldn't have a clue with DC stuff.

It's not something gone into during the college work part of an apprenticeship here, knowledge like that is acquired during on-the-job training, so you only get it if you're in that specific field.

Where I work DC traction is going the way of the dodo, all the modern trains use AC motors & VF drives and some of the old DC traction EMUs out there have been converted to AC traction, with new power/control gear for the AC motors. We don't see any of the control gear these days unfortunately.

David

[med6753]

These guys do it all. Croton Harmon Shops of Metro North RR. Diesel engine rebuilds, DC and AC traction motors, control systems, and board HV AC for New Haven branch. Separate crews handle the overhead cantenary for New Haven branch.



   

[AVGresponding]

One of my work colleagues likes trains quite a lot. I think he'd give his eye teeth and probably several other body parts to work at a place like that!   

[dl6lr]

Weird how they've drawn the two bridges differently.

Have you tried inverting the phase on one of them?

I suspect that is drawn that way to indicate that the bridge rectifier is used as two rectifiers for symmetrical voltages in a transformer with a middle tap. In germany this circuit is called Mittelpunktgleichrichtung M2 where a bridge rectifier is a Brückengleichrichtung B2.

[dl6lr]

With the wires reconnected to the rectifier & regulator board removed, I get this on the output of the rectifier, looks odd to me. Note: the rectified supply here is added to the unregulated +15V before going to the +175V regulator board.


Note: the rectified supply above is added to the unregulated +15V before going to the +175V regulator board.

Looks strange to me, the two half waves are not identical. You are sure the +15V rectifier is OK and the cap too? I would scope the +15V in addtion. Regarding the 155V AC: it must be a means value, otherwise you wont get +160V (175V minus the +15V) out of it As 155V pk2pk is 77.5V pk (which you would get without any load on the cap after rectification) and 55V RMS.

[med6753]

One of my work colleagues likes trains quite a lot. I think he'd give his eye teeth and probably several other body parts to work at a place like that!   

That shop dates back to New York Central Steam Loco Shops. It has been completely modernized and rebuilt.

[factory]

OK checked the other windings on the Tek scope & Wavetek DMM, all have the slight clipping to the waveform, as does the incoming mains. RMS Values measured with the Tek & DMM.

Red wires (155V), Tek 85V, DMM 87V.

Orange wires (18.5V+18.5V), Tek 19.5V+19.7V total 39V, DMM total 39.7V.

Yellow wires (9.5V+9.5V), Tek 10V+10V total 20V, DMM total 20V.
Green wires (1.7V+9.5V+9.5V+1.7V) Tek total 25V, DMM total 25.7V

With the wires reconnected to the rectifier & regulator board removed, I get this on the output of the rectifier, looks odd to me. Note: the rectified supply here is added to the unregulated +15V before going to the +175V regulator board.


Note: the rectified supply above is added to the unregulated +15V before going to the +175V regulator board.

Looks strange to me, the two half waves are not identical. You are sure the +15V rectifier is OK and the cap too? I would scope the +15V in addtion. Regarding the 155V AC: it must be a means value, otherwise you wont get +160V (175V minus the +15V) out of it As 155V pk2pk is 77.5V pk (which you would get without any load on the cap after rectification) and 55V RMS.

The voltages shown of the diagram for the transformer are looking to be RMS, the scope & DMM agree for the low voltage windings, it's just the +155V (red) winding that is low and was still low with the wires disconnected from the motherboard.

The +15V rectifier is new, as are most of the can caps apart from the two 4000uf. The +155V rectifier is still original and the same type as those that failed, no cap is used for the +155V rail or +175V regulated supply.

David

[dl6lr]

OK checked the other windings on the Tek scope & Wavetek DMM, all have the slight clipping to the waveform, as does the incoming mains. RMS Values measured with the Tek & DMM.

Red wires (155V), Tek 85V, DMM 87V.

Orange wires (18.5V+18.5V), Tek 19.5V+19.7V total 39V, DMM total 39.7V.

Yellow wires (9.5V+9.5V), Tek 10V+10V total 20V, DMM total 20V.
Green wires (1.7V+9.5V+9.5V+1.7V) Tek total 25V, DMM total 25.7V

Ah, that looks bad. So the transformer seems to be toasted. You should measure the idle consumption of the transformer alone. If the transformer does not get hot without load and idle losses are marginal, you could add a second small transformer for the 155V and leave the red wires open. If it gets hot you are lost with the transformer...

[mansaxel]

I'm guessing you meant 16²/₃Hz?

That I did, indeed!

[Martin.M]

Heathkit SB-610?

The extra crunchy version!

yes, SB-610 chipottle Line

[mansaxel]

Re: the rebooting Of Siemens trains, the slow train (London Midland CL 350) from Birmingham to Crewe I used once refused to leave Birmingham, until the driver had completely powered down the train and rebooted it. It also had the most uncomfortable seats, would hate to have to go all the way to London using one of those PoS.

David

Birmingham New Street once saved our parental asses, because there's one at least passable "tex-mex" fast food joint in the concourse. It was Friday, every other Friday, and that means tacos. Wherever we are. (The other friday it's Pizza, which for the most part is much easier to fulfill.)

[Cubdriver]

Note: the rectified supply above is added to the unregulated +15V before going to the +175V regulator board.


David

Weird how they've drawn the two bridges differently.

That’s because the second one isn’t a bridge - it’s two center-tapped full wave rectifiers sharing a winding, and configured to provide both positive and negative rails from it.  HP did this frequently - my 3561A has several dual rail supplies made like this:


Oddly, in the later stuff they seem to have taken to drawing one as a diamond shaped bridge and the others with the diodes next to one another, making things somewhat less obvious in my opinion.

-Pat

Second edit and attempt to add schematic pic.  I hate trying to post from an iPad.   

[BU508A]

To the German viewers here:

There is currently a Keithley 2400 sourcemeter for EUR 600.- in the German ebay ads online:

https://www.ebay-kleinanzeigen.de/s-anzeige/keithley-2400-digital-sourcemeter/1972753315-168-2235

I think, this is a scam and I've reported this ad to the ebay Kleinanzeigen team.

Reason:

a reverse picture search at google brought up this:


As you can see, the picture is the same, but this is from an earlier ad and the location is different (Haltern am See in NRW vs. Magdeburg in Sachsen)

Be careful and ask for pick up and paying with cash only if you are interested!

[Cerebus]

I'd expect the electricians working on DC traction motors to have knowledge and experience of said systems, however the majority of industrial electricians that I know personally, wouldn't have a clue with DC stuff.

It's not something gone into during the college work part of an apprenticeship here, knowledge like that is acquired during on-the-job training, so you only get it if you're in that specific field.[/color][/size][/b]

Agreed. Although HV electricity transmission systems only get some little coverage in those sort of courses, I wonder if that little coverage nowadays includes some high voltage DC stuff given the increasing usage of DC for high voltage transmission. It won't be much, but there might be a bit of coverage nowadays. That said, every working general sparkie I've know had forgotten everything above 440V by the time their college courses were only a year or two behind them.

[med6753]

More work on the Type 1A4 plug-in. Tested all the transistors in the on board PSU and all are OK except that crusty TO-66. Showing some excessive leakage. It's Tek P/N 151-0148-00 which is a select standard 40250 which crosses to NTE-175 which is on order.

If for some reason that supply still won't come up I've determined that it can be totally scrapped and replaced after the first filter cap with one LM317T, one LM337T, two 5K trimmers, two 120 ohm resistors, and four 2.2uf/35V tants. I really don't want to go that route and keep it original but it might force my hand. We'll see. The parts will be in stock.

[Specmaster]

The second thing they found was, that arcing during switching the contacts confused the trains computerized control system, which then refused to do anything and had to be rebooted, including all safety procedures on  train startup (like brake check, horn check etc.)

In Ghent, Belgium, they're keeping some of their old PCC trams for de-icing the catenary. The new Bombardier and CAF stock can't cope with the transients caused by icing on the contact wire.

https://www.standaard.be/cnt/dmf20190131_04144270

I keep an old transformer based car battery charger around...   when a battery gets completely flattened, the modern charger refuses to start charging, as the computer gets confused....

Just yesterday, I wast watching some videos of 4x4 off-road driving, where modern vehicles get stuck in the sand because the computers get confused and refuse to apply power to the wheels....

Moral of the story:   when you are designing computer controlled equipment, include some kind of manual override - and don't make it too obscure to find! 

How about better still, scrap all ideas of going electric for road vehicles and spend money resolving the emissions problem, why? Because I watched a video yesterday about routemaster fans, having a look round a bus scrapyard in Barnsly, and in this scrapyard they also had scraped electric double-decker buses already. Thats says to me that the future is not electric. Fact is that they are just way to complicated.

[Specmaster]

Bah humbug, did anyone here get this https://www.ebay.co.uk/itm/Blackstar-4503-Intelligent-Multimeter-/324948140926 ?

I was convinced that it would go for more than it did seeing as it had 38 watchers, so much so that I never bid on it  If I had a clue it would go for so little, I'd have placed a bid for it.

[med6753]

Bah humbug, did anyone here get this https://www.ebay.co.uk/itm/Blackstar-4503-Intelligent-Multimeter-/324948140926 ?

I was convinced that it would go for more than it did seeing as it had 38 watchers, so much so that I never bid on it  If I had a clue it would go for so little, I'd have placed a bid for it.

Located in Leighton Buzzard, United Kingdom.  Does that mean vultures hang out there? 

Oh never mind. "Buzzards" to you are hawks. "Buzzards" to us here across the pond refer to vultures. How could I be so stupid to think the meaning is the same? 

[mansaxel]

Thats says to me that the future is not electric. Fact is that they are just way too complicated.

I'd argue that the keeping-track-of-things amount of electronics is roughly equivalent in a modern premium EV and a simple ICE car. Only the "simple" ICE car has a couple 1000  parts in the engine bay, gearbox (if automatic a command and control problem in and of itself) and transmission, whereas the EV has 2 induction motors, at most some reduction gears, all of which can be lubricated to a service interval of at least 10 years, if not life.

The induction motor has 1 (one) moving part. No pressure compartments, no fluid containment, no fire, all in all less fuss.  The rest is electronics, which in component count you need to have at least as much in a ICE car built the last 30 years -- or it won't meet emission regulations. 

Further, the ICE car needs a lot of finicky sensors; lambda, angle, pressure, absence of pressure, fluid level, fluid flow, fluid regulation (injectors) and so on. Those are what breaks.  The temperature sensing problem is about the same, probably a bit easier in the EV case.

I'd like to quit with a quote from a previously secret report on BAOR trials of the Swedish "S" tank, the wedge without a turret model.  They were shipped to Soltau and BAOR and tried together with the Chieftain tanks 2nd Royal Armoured Regiment usually drove around and annoyed German farmers with.

Whenever a Chieftain tank is parked or stands idle for some time an oil puddle is left behind.

[Neper]

To the German viewers here:

There is currently a Keithley 2400 sourcemeter for EUR 600.- in the German ebay ads online:

https://www.ebay-kleinanzeigen.de/s-anzeige/keithley-2400-digital-sourcemeter/1972753315-168-2235

I think, this is a scam and I've reported this ad to the ebay Kleinanzeigen team.

Reason:

a reverse picture search at google brought up this:


As you can see, the picture is the same, but this is from an earlier ad and the location is different (Haltern am See in NRW vs. Magdeburg in Sachsen)

Be careful and ask for pick up and paying with cash only if you are interested!

Ebay Kleinanzeigen is an incredible den of thieves. I've recently reported an ad for a Quad Hifi system, offered by someone claiming to be located 10 km from here, that had been auctioned on 'big Ebay' just the night before in deepest East Germany. The photos were of course identical.

Years ago, I almost paid for an expensive film scanner offered at a very attractive price. I contacted the seller, purporting to be located somewhere in Westphalia, and he answered  asking to communicate in English as his German girlfriend had left him and he had returned to England in the meantime. All this, he claimed, wouldn't be a problem as the transaction would be done through a renowned escrow service. This service had a very elaborate website explaining the whole process with lots of text and photos. Looked really good.

At his point, literally minutes before I made the payment, the bestest of all halves suggested having a look on Google for this service. And, lo and behold, the escrow service was indeed an escroc service (escroc = French for crook).

As you say, BU, never buy anything on Ebay Kleinanzeigen unless by pick-up and cash.

As of late, Ebay Kleinanzeigen are advertising some kind of escrow service of their own but the fees are exorbitant.

[Neper]

Further, the ICE car needs a lot of finicky sensors; lambda, angle, pressure, absence of pressure, fluid level, fluid flow, fluid regulation (injectors) and so on. Those are what breaks.

My last few cars all had to go not because of the usual mechanical probs - low compression, run-out bearings, corrosion - but because of galloping dementia in their electronics and sensors.

Methinks the infernal combustion engine is well on the way out. I for one won't miss it.