Test Equipment Anonymous

25 CPS wrote: ↑Thu Jan 11, 2024 11:27 pm
It's a 750 VA adjustable frequency, adjustable voltage AC power supply.

Very cool. Much envy. About the only thing missing is 16 2/3 Hz as present on some (Germany, Austria, Schweiz, Sweden, Norway) European railway catenaries. This "one third of 50Hz" single-phase supply was especially designed for large low-RPM electrical motors in locomotives. There are power stations in Sweden making it from scratch (Porjus hydroelectric power station is probably the most well known, built to supply the iron ore railway from Luleå via Kiruna to Narvik), and then there of course was single-phase high voltage transmission:



But there also was a widespread network of converter stations where 50Hz was remade into catenary mains using rotary converters. The converters used to be mounted on railway cars parked in mountain tunnels where they would tie in to the grid.



The tunnels were close to railway lines, so the active equipment could be moved:



This was made to protect them in case of war. The location of the tunnels was kept secret and they were surrounded by much myths. Now they are all replaced by semiconductor power converter stations that aren't protected like these. The tunnels now are objects for urbex:

There are still 25Hz overhead centenary rail lines between DC and NYC (ex Penn Central RR) and NYC and Boston (ex New Haven RR). Amtrak passenger locos utilize it but all freight traffic is diesel electric.

Ex New York Central RR from NYC Grand Central Terminal to Croton Harmon, NY is 600VDC third rail. Again utilized only by MTA passenger locos and MU cars. Any freight traffic is diesel electric but those locos cannot enter the tunnels into Grand Central Terminal but really have no need to anyway.

MED6753 wrote: ↑Fri Jan 12, 2024 8:54 pm There are still 25Hz overhead centenary rail lines between DC and NYC (ex Penn Central RR) and NYC and Boston (ex New Haven RR). Amtrak passenger locos utilize it but all freight traffic is diesel electric.

Ex New York Central RR from NYC Grand Central Terminal to Croton Harmon, NY is 600VDC third rail. Again utilized only by MTA passenger locos and MU cars. Any freight traffic is diesel electric but those locos cannot enter the tunnels into Grand Central Terminal but really have no need to anyway.

I think that 25Hz mains in the US must be a very strange choice. 20Hz would make more sense; it's the same to "generic mains" as 16 2/3 is in the parts of Europe using it. I suppose they did as was done in Sweden and built a dedicated power station for it, back when there was no national grid to talk about.

In Europe, we have grids larger than our countries, within which we maintain frequency lock. Whole Nordics is one such, the three Baltic countries have one, most of mainland Europe is one. UK and Ireland (NI and Eire together) are one each. Last addition to this scheme is Ukraine, who relocked from the Russian grid to the European mainland grid in 2021. During war.

The grids are interconnected using HVDC transmission lines, not uncommonly subsea cables.

Well fed, well licquored and at 40,000ft with WiFi and can’t Discord….something about needing a secure connection FFS.
Will drop in for a chat at normal NZ time after we get home…..in roughly 5 hrs.
Later…waves.

Well hello everybody!

I already prepared some time ago and end of last year I went to the FabLab here and got a safety briefing and an introduction.
Yesterday I thought it was time for some amusement, so I took a piece of 4mm PMMA and went to the CO2 laser cutter. After much talking with the people of the FabLab, I got time to use the laser and engraved and cutted my sheet. This is the result:
Now that this worked like a charm, I have more ideas for the future...

hey tggzzz

decided that only a total dumbass would listen to a rascal like you.........and buy a parts tdr to fix a 1502 with a missing hv board.

so my new years resolution was to stay off ebay and never again allow the search term "tektronix tdr" to appear on my screen.

it should come as no surprise to any of you wingnuts that my second 1502 arrived this past week.

DOH! the new tdr makes the old one look like a POS. it came with an accessory pouch, 2 genuine labeled tektronix 3ft launch cables, a tdr slide rule, and a manual for a chart recorder (which it does not have). the case does not have any cracks (unlike the first one).

had to change out the fuse holders for a twist snap pair from the junk box because the screw in's were missing from the originals. the battery was a leaky mess, but pulling it out and replacing it with a 330 ohm 5 watt resistor in parallel with 2 each 1000 uF 35V caps does indeed fool the AC supply into thinking the battery is still in place inside the battery case.


so now what to do with the first one? hate to see it just be an organ donor.

BUT i hereby resolve not to go looking for a third 1502 tdr to fix the first one.

mansaxel wrote: ↑Sat Jan 13, 2024 6:28 am

I think that 25Hz mains in the US must be a very strange choice. 20Hz would make more sense; it's the same to "generic mains" as 16 2/3 is in the parts of Europe using it. I suppose they did as was done in Sweden and built a dedicated power station for it, back when there was no national grid to talk about.

These rail lines were electrified in the early 1900's before 60Hz became the US standard. In some areas they were upgraded to 60Hz but in others remained 25Hz to this day.

mansaxel wrote: ↑Sat Jan 13, 2024 6:28 am

In Europe, we have grids larger than our countries, within which we maintain frequency lock. Whole Nordics is one such, the three Baltic countries have one, most of mainland Europe is one. UK and Ireland (NI and Eire together) are one each. Last addition to this scheme is Ukraine, who relocked from the Russian grid to the European mainland grid in 2021. During war.

The grids are interconnected using HVDC transmission lines, not uncommonly subsea cables.

There are 6 grids in US/Canada and parts of Mexico. There are interlocks and one grid failure can affect others. Years ago there was a failure in Ohio (RF) which caused that grid to go down as well as the Northeast grid taking out NY, New England, and much of Eastern Canada. (NPCC)

nixiefreqq wrote: ↑Sat Jan 13, 2024 6:20 pm hey tggzzz

decided that only a total dumbass would listen to a rascal like you.........and buy a parts tdr to fix a 1502 with a missing hv board.

so my new years resolution was to stay off ebay and never again allow the search term "tektronix tdr" to appear on my screen.

it should come as no surprise to any of you wingnuts that my second 1502 arrived this past week.

Tee hee

DOH! the new tdr makes the old one look like a POS. it came with an accessory pouch, 2 genuine labeled tektronix 3ft launch cables, a tdr slide rule, and a manual for a chart recorder (which it does not have). the case does not have any cracks (unlike the first one).

That's a very good flat pulse; don't try to improve it

If those really are the pukka test cables with a "correct" Tek part number, one can probably be sold for more than you paid for the 1502

New RF cables aren't cheap; metrology ones quadruply so

had to change out the fuse holders for a twist snap pair from the junk box because the screw in's were missing from the originals. the battery was a leaky mess, but pulling it out and replacing it with a 330 ohm 5 watt resistor in parallel with 2 each 1000 uF 35V caps does indeed fool the AC supply into thinking the battery is still in place inside the battery case.

That's never worked reliably for me.

The batteries are more or less guaranteed to be a toxic waste site requiring protective gear during remediation. Contemporary ones from different equipment (e.g. Fluke 893A) are usually a short, but their cases are intact. That's probably a consequence of the ineffably weird PSU design.

Your battery box looks good and clean; I've often had to repair and strengthen the ones I've received.

so now what to do with the first one? hate to see it just be an organ donor.

BUT i hereby resolve not to go looking for a third 1502 tdr to fix the first one.

Spend some time playing with it, making measurements you never thought worthwhile (e.g. PCB transmission lines, taking it to hamfests to measure cable length/impedance), becoming hypnotised looking at the twinking mindfulness concentration tool.

After a while, your future course of action(s) will become clear.

Or you could do a few soduku while watching the fog of daytime TV.

tggzzz wrote: ↑Sat Jan 13, 2024 7:22 pm ...becoming hypnotised looking at the twinking mindfulness concentration tool.

Hmmm.

Think I'll resurrect one of mine and sell it to Gwyneth Paltrow for an unholy sum.

Or maybe just market it as a self-help tool to allow her devotees to wean themselves off her vagina candles (etc).

Major crisis in the Smurf house this morning. The coffeemaker crapped out. Can't have that. So off to Walmart. On a Saturday. That in itself spells gloom, doom, and massive crowds of unwashed idiots. Get there, pick out new coffeemaker. Go to the check outs. Each line must be 50 or more people long. WTF. Then I notice something. No beeps at any of the registers. Yep, the entire checkout system in the store is dead. A PA announcement to please be patient. No freaking way. This boy dumped the unbought coffeemaker on a shelf with some clothes and walked out. Yell at me if you want. Don't give a flying fuck.

Get home. Ordered one on Amazon. Will be here Sunday. So in the meantime this uncivilized Yank is drinking tea but it ain't like having a good cup of coffee. And no biscuits or crumpets. Yep, uncivilized.

nixiefreqq wrote: ↑Sat Jan 13, 2024 6:20 pm hey tggzzz

decided that only a total dumbass would listen to a rascal like you.........and buy a parts tdr to fix a 1502 with a missing hv board.

He's not a rascal. He's a very decent and proper person. I've shaken hands with him on several occasions, although I did take the precaution of wearing a chain mail butcher's glove and afterwards only noted light bruising to my fingers!

nixiefreqq wrote: ↑Sat Jan 13, 2024 6:20 pm
so my new years resolution was to stay off ebay and never again allow the search term "tektronix tdr" to appear on my screen.

it should come as no surprise to any of you wingnuts that my second 1502 arrived this past week.

DOH! the new tdr makes the old one look like a POS. it came with an accessory pouch, 2 genuine labeled tektronix 3ft launch cables, a tdr slide rule, and a manual for a chart recorder (which it does not have). the case does not have any cracks (unlike the first one).

had to change out the fuse holders for a twist snap pair from the junk box because the screw in's were missing from the originals. the battery was a leaky mess, but pulling it out and replacing it with a 330 ohm 5 watt resistor in parallel with 2 each 1000 uF 35V caps does indeed fool the AC supply into thinking the battery is still in place inside the battery case.


so now what to do with the first one? hate to see it just be an organ donor.

BUT i hereby resolve not to go looking for a third 1502 tdr to fix the first one.

1502 TDRs are a heavy scene. I've never been drawn to them myself, although tggzzz is fully into them. I've seen them as some of the Evil One's favourite lures, which he uses to drawn in weak souls. I have warned tggzzz about this and have been summarily dismissed.

Tek 475s on the other hand, are a thoroughly wholesome pursuit, and a chap should consider himself naked without at least 10 working ones and a similar number of parts mules.

MED6753 wrote: ↑Sat Jan 13, 2024 9:19 pm Major crisis in the Smurf house this morning. The coffeemaker crapped out. Can't have that. So off to Walmart. .......................

Long ago I decided that the answer to making coffee was a cafetiere - a French Press. Simple, it works, I've broken the glass on average every ten years, but far better than this hi tech stuff.

MED6753 wrote: ↑Sat Jan 13, 2024 9:19 pm Major crisis in the Smurf house this morning. The coffeemaker crapped out.

<snip>

So in the meantime this uncivilized Yank is drinking tea but it ain't like having a good cup of coffee. And no biscuits or crumpets. Yep, uncivilized.

Unprepared, rather. Which is a worse crime than playing uncivilized.

This home here has five ways to boil water for coffee; kitchen range, kettle, Moccamaster, Trangia stoves and Optimus 111 milspec kerosene stove. The last two do not require mains power. Guess I can light up the Weber grill and put a kettle on that too.

Three complete production chains (funnel, pot, just add water, filter and grounds) for filter brew coffee, and an ample supply of filters; all funnels are the same size to optimise stores. There are strict rules on maintaining stores for grounds.

Failing that, I have a stash of coarse grounds for boiling coffee, and a last resort of Nescafé.
Then, we can fall back to tea.

Zenith wrote: ↑Sat Jan 13, 2024 9:23 pm Tel 485s on the other hand, are a thoroughly wholesome pursuit, and a chap should consider himself naked without at least 10 working ones and a similar number of parts mules.

FTFY.

One working, one dead, one in need of some TLC.

Current projects are resurrecting the car horn on sproglet's bicycle, and reducing the 20V ripple on a 1kV 250W electrophoresis PSU. Fortunately my max load will be 10W, a 100kohm KVD.

The former might have saved sproglet's life a couple of times. The latter might end mine. LTSpice simulation works, but that doesn't include breakdown/flashover effects

Zenith wrote: ↑Sat Jan 13, 2024 9:23 pm

Tek 475s on the other hand, are a thoroughly wholesome pursuit, and a chap should consider himself naked without at least 10 working ones and a similar number of parts mules.

One 475A, two 465B's, and two 485's plus a bunch of parts units so I think I'm covered. But I do have dreams of being naked in public.

MED6753 wrote: ↑Sat Jan 13, 2024 10:18 pm But I do have dreams of being naked in public.

Been there. Do not recommend it. Many awkward questions get asked.

MED6753 wrote: ↑Sat Jan 13, 2024 9:19 pm Major crisis in the Smurf house this morning. The coffeemaker crapped out. Can't have that. So off to Walmart. On a Saturday. That in itself spells gloom, doom, and massive crowds of unwashed idiots. Get there, pick out new coffeemaker. Go to the check outs. Each line must be 50 or more people long. WTF. Then I notice something. No beeps at any of the registers. Yep, the entire checkout system in the store is dead. A PA announcement to please be patient. No freaking way. This boy dumped the unbought coffeemaker on a shelf with some clothes and walked out. Yell at me if you want. Don't give a flying fuck.

Get home. Ordered one on Amazon. Will be here Sunday. So in the meantime this uncivilized Yank is drinking tea but it ain't like having a good cup of coffee. And no biscuits or crumpets. Yep, uncivilized.

Wow, I bet that really beautiful after all those years of floating around in Boston Bay

Just keep your fingers crossed that the Amazon driver delivers to the right house tomorrow

How is Blondie doing now?

bd139 wrote: ↑Sat Jan 13, 2024 10:32 pm

MED6753 wrote: ↑Sat Jan 13, 2024 10:18 pm But I do have dreams of being naked in public.

Been there. Do not recommend it. Many awkward questions get asked.

Haha, reminds me of last night, it was the rearranged Birthday/Xmas present from my boys. Started with dinner at Burger King and I found a £1 coin, great thought I, the night's going to be great. Got to the snooker hall, and it was rammed full of pool tables and noisy as f**k. The attendant took us to another room with 4 snooker tables, 2 were in use, but snooker is a far quieter game, so that was great.

We had it booked out from 7pm to midnight and after a few drinks and frames, at around 11pm I needed to go for a dump, off I go and there was only the one cubicle in the whole building, probably breaking regulations seeing how many people were in the place. In I go, very dark in there too, anyway, I do the business and then to my horror there was no bleeding bog paper in the dispenser, and I'd left my phone in the room with the boys, so used the three tissues I put in my pocket prior to going out.

I then had to walk through the crowded room with the pool tables to go to the snooker room, and on reaching the room my boys started laughing and said "you pi**ed yourself", to my further horror, with all the debacle with bog roll, in fishing out the tissues from my trouser pocket, they had fallen to the floor and had got rather wet, someone had pi**ed on the floor or the bog was leaking. So we donned our coats and left rather quickly and on arrival home, I need a change of clothes and a shower.

So not quite the same thing as being naked in public, but very humiliating just the same, I certainly will not be forgetting that night out in a hurry that's for sure

What a perfectly revolting evening out.

Oh I don't know, I did rather the evening upto that point

Specmaster wrote: ↑Sun Jan 14, 2024 10:42 am

MED6753 wrote: ↑Sat Jan 13, 2024 9:19 pm Major crisis in the Smurf house this morning. The coffeemaker crapped out. Can't have that. So off to Walmart. On a Saturday. That in itself spells gloom, doom, and massive crowds of unwashed idiots. Get there, pick out new coffeemaker. Go to the check outs. Each line must be 50 or more people long. WTF. Then I notice something. No beeps at any of the registers. Yep, the entire checkout system in the store is dead. A PA announcement to please be patient. No freaking way. This boy dumped the unbought coffeemaker on a shelf with some clothes and walked out. Yell at me if you want. Don't give a flying fuck.

Get home. Ordered one on Amazon. Will be here Sunday. So in the meantime this uncivilized Yank is drinking tea but it ain't like having a good cup of coffee. And no biscuits or crumpets. Yep, uncivilized.

Wow, I bet that really beautiful after all those years of floating around in Boston Bay

Just keep your fingers crossed that the Amazon driver delivers to the right house tomorrow

How is Blondie doing now?

The new coffeemaker has arrived so the tea has been dumped back into Boston Harbor where it belongs.

Blondie is doing much better and is able to get out with me in our daily travels to the store, etc. But she has numerous follow up specialist appointments plus as a safety she is wearing a heart monitor.

dl6lr wrote: ↑Sat Jan 13, 2024 5:28 pm Well hello everybody!

I already prepared some time ago and end of last year I went to the FabLab here and got a safety briefing and an introduction.
Yesterday I thought it was time for some amusement, so I took a piece of 4mm PMMA and went to the CO2 laser cutter. After much talking with the people of the FabLab, I got time to use the laser and engraved and cutted my sheet. This is the result:

20240113_163349.jpg

Now that this worked like a charm, I have more ideas for the future...

That's cool but it's been done before. This used to be available on Ebay but apparently sold out.

and the 1502 rabbit hole gets deeper.

was doodling around with it as tggzzz suggested. after about an hour noticed a funny smell.

opened it up and sniffed around. strongest smell was around the low voltage power supply over by the battery charger area.

holy shit balls! how did i not notice the scorch under the bridge rectifier and scr. both were cool to the touch.......the problem appeared to be happening inside the board itself. have only dealt before with carbon tracking around high voltage, but this board seemed to be toasting from the inside out from only 20V or so. had to do some surgery on the board and then epoxied a piece of perf board back in. reinstalled the bridge rectifier but the legs on the old scr were too short, so it was replaced with one from radio shack that has been in the junk box for at least 30 years. (had to tip it over because there is very little head room above that board.

the next guy to look inside this unit will probably curse me as an unskilled ape. but it works and no longer stinks.

oh....and the 3ft bnc jumper that came with it is NOT a magic 012-0482-00 cal cable. bummer.

nixiefreqq wrote: ↑Mon Jan 15, 2024 7:51 pm and the 1502 rabbit hole gets deeper.

was doodling around with it as tggzzz suggested. after about an hour noticed a funny smell.

opened it up and sniffed around. strongest smell was around the low voltage power supply over by the battery charger area.

holy shit balls! how did i not notice the scorch under the bridge rectifier and scr. both were cool to the touch.......the problem appeared to be happening inside the board itself. have only dealt before with carbon tracking around high voltage, but this board seemed to be toasting from the inside out from only 20V or so. had to do some surgery on the board and then epoxied a piece of perf board back in. reinstalled the bridge rectifier but the legs on the old scr were too short, so it was replaced with one from radio shack that has been in the junk box for at least 30 years. (had to tip it over because there is very little head room above that board.

the next guy to look inside this unit will probably curse me as an unskilled ape. but it works and no longer stinks.

oh....and the 3ft bnc jumper that came with it is NOT a magic 012-0482-00 cal cable. bummer.

Eeeurgh! I wonder what could have caused that?!

On my first 1502 those two bastard tants (C6341/C6246) had vomited and removed the tracks, but no damage inside PCB.

The nearest I've had to that was in a Tek2901 where the bridge rectifier ran excessively hot to the touch. Couldn't find any reason why.

Oh, one of the Tek475 bridge rectifiers isn't cool, either.