Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

they are not careful with packets.

Definitely UDP, not TCP/IP. 

mnem
“...delivery is as packets in chunks using UDP.”

[URI]

549 is the scope with the golden CRT 

Looks like painty smurf med was already there..      

..fancy stuff.. high tec of that era. Hats off to Tek!   

[Neomys Sapiens]

There is a seller on German Ebay who sometimes offers interesting devices. They are invariably smeared, soiled and outright covered in dirt. I watch his pictures closely, hoping to discover a snoutprint on one, as it would finally prove that he stores them in a pigsty.

[Martin.M]

when you look exactly on the second picture,
The CRT divides the display field in 3 areas.

At left side, where the dot starts, is a zone what have the full height, non storage.
Then it have a uppercase storage field and a lower case storage field. They have seperate buttons on the scope,
so you can store only the upper half, or only the lower half, or both complete. This was made bec. the storage system have a running life time of calculated 500 hours,
by using a half you can double that.. In normal scope mode without storage there are 10.000 hours to work.
So today the most 549 have a burn out in the storage, the normal mode works allready. A full working 549 is rare.
And this never used spare CRT is not rare, that is obsolete..  (found in a technical university)

Martin

[Neomys Sapiens]

I'm not familiar with instruments of that generation. Is time/cm referring to the horizontal, same as time/div.?

[med6753]

when you look exactly on the second picture,
The CRT divides the display field in 3 areas.

At left side, where the dot starts, is a zone what have the full height, non storage.
Then it have a uppercase storage field and a lower case storage field. They have seperate buttons on the scope,
so you can store only the upper half, or only the lower half, or both complete. This was made bec. the storage system have a running life time of calculated 500 hours,
by using a half you can double that.. In normal scope mode without storage there are 10.000 hours to work.
So today the most 549 have a burn out in the storage, the normal mode works allready. A full working 549 is rare.
And this never used spare CRT is not rare, that is obsolete..  (found in a technical university)

Martin

When I was in college we had a fully functional 549 with working storage in our electronics lab. But that was in 1971. 

[med6753]

I'm not familiar with instruments of that generation. Is time/cm referring to the horizontal, same as time/div.?

Yes.

[AVGresponding]

Yeah, the packing wasn't the best I've seen, but would have protected it from 'normal abuse'.

It must have taken quite an impact to do this much damage

[Martin.M]

I'm not familiar with instruments of that generation. Is time/cm referring to the horizontal, same as time/div.?

Yes.

No 

/cm is written when the graticule fields are 1cm,
if not they write /Div.

[med6753]

I'm not familiar with instruments of that generation. Is time/cm referring to the horizontal, same as time/div.?

Yes.

No 

/cm is written when the graticule fields are 1cm,
if not they write /Div.

In the strictest sense you are correct. It's just a matter of whether it's divided in actual cm or just some random "div". But you read both the same which why I said "yes".

[Martin.M]

ok.

[Martin.M]

... this picture is special.

It`s a high voltage mod in my Tek 551, what enhance the HV from 10kV to 12kV to make it faster.
This enhancement makes lower the deflection sensitivity of the CRT, so Tek used a graticules field of 8.5mm size to get back the cal.
But on the knobs from the scope is still written /cm , so they made the littl text on the graticules glass what is part of this mod. ( Tek 551 mod 108C. I have uploadet the paper to the Tek Wiki)

[0culus]

Very neat stuff, Martin! Thanks for sharing, and keep it coming.   

I can live my glowy Tek fantasies vicariously.   

[med6753]

Yep, I agree...they don't line up. But they are sized for the CRT in which they are intended.

If you set an older 500 series to say 50us/cm and a newer scope to 50us/div and apply a 5kHz square wave they will line up to the dividing lines exactly the same. 

Edit...or in your case the graticle is sized to sensitivity of the CRT.

[bd139]

Well, the PM 3218 arrived, about a week late as the vendor had a brain fart and went on holiday for a week...

Delivered by the Herpes, left on the doorstep in fact, despite requiring a signature, the screen bezel is now a 100 piece jigsaw puzzle, and the control panel is shaped like a satellite dish...



Some of the inner knobs are jammed, many are rotating the whole pot/switch, and there's a certain level of funkiness occurring when the panel is moved 

I always knew I'd have to re-cap it and generally check the innards, but this... the case is crusty af as well, looks like it was stored in a damp and draughty shed at the bottom of the garden for the last 20 years 

At least it works, at least in general...

A couple of pics to show off the dual timebase:


100KHz sinewave (allegedly)


1MHz squarewave

The vendor has told me they had it 'covered' with SHermes to the tune of £35, so will look at screwing some pennies out of them to cover the insult to the CRO gods

Quick tips on this:

1. Screen bezel is the first thing to break on these. Always is. I have a good one here. 3d print? Possibly when I get some time (and more CAD skills ).
2. The jammed inner knobs is normal after a front impact. Pull them straight off then put them back on and all should be good. If it's a really hard impact the attenuators could be fucked. Mine were but I have spent a very long time rebuilding the damn thing and it's ok now.  Also with the knobs, the cap is glued on. Don't try and remove it.
3. There's a RIFA in the back panel under the bit of fibreglass. Replace it lest the firey spooge be emitted into your scope. It'll never smell the same again.

Edit: posting some pictures for tips ... 1 min

RIFA bastard. This is the replacement. Watch the solder tags - they are mega fragile.



Power supply recap. Don't bother with Philips caps like I did. Too much effort. I made an adapter PCB for the big one. Watch the board. Single sided and quite fragile too.



Bingo



This is the 3rd PM3217 I've had. Probably my favourite analogue if I'm honest.

Also you can bring the entire scope up on DC. Just whack 24V across the main filter cap on the power supply. Takes about 1500mA max I think (could be less. It's not a hungry device for sure!)

BTW this is what happens when you forget to change the RIFA. Yes this was my last one:

[Martin.M]

Yep, I agree...they don't line up. But they are sized for the CRT in which they are intended.

If you set an older 500 series to say 50us/cm and a newer scope to 50us/div and apply a 5kHz square wave they will line up to the dividing lines exactly the same. 

Edit...or in your case the graticle is sized to sensitivity of the CRT.

Calibration of the time base and adjust is to do with a 181 time mark generator. This very glowing friend have 20 tubes and a crystal oven 

[med6753]

Yep, the Type 181 is a very handy device.  One of these days I'll get one. In the meantime I use other, but slightly less accurate, means to check the timebase on my Tek Tribe. 

[Martin.M]

but the 10 MHz output is worst case 
bec. the crystal is a 1MHz, they got it with a simply LC in resonance to x10.

Delivery: tick + 9x tak where each following tak is smaller in height up to the next tick 
the dividers are true american engineering, 3 tubes are enough for a /10. So you have a adjust pot for each of them at the front:

The Tek /10 clock dividers are trigger sensitive monoflops with a waiting time (what you will adjust please) of 9 clocks, then they get the trigger and give out /10 

[Cubdriver]

Yep, I agree...they don't line up. But they are sized for the CRT in which they are intended.

If you set an older 500 series to say 50us/cm and a newer scope to 50us/div and apply a 5kHz square wave they will line up to the dividing lines exactly the same. 

Edit...or in your case the graticle is sized to sensitivity of the CRT.

Calibration of the time base and adjust is to do with a 181 time mark generator. This very glowing friend have 20 tubes and a crystal oven 

7844 with P11.  Drool...

-Pat

[Martin.M]

78 = p11 + 21 = dedicated slots.

[Martin.M]

One of these days

 

[bd139]

I love how this thread periodically drifts onto Pink Floyd 

[med6753]

One of these days

 

"I'm going to cut you into little pieces!" 

[med6753]

I love how this thread periodically drifts onto Pink Floyd 

Always....my fav band anyway. 

[nixiefreqq]

ok......this is my last post on the gonad straining hp 8569b.   promise.

decided to use it to test return loss on a 1296 Mhz 10 element home brew antenna.

swept the antenna from 1275 to 1325 Mhz.

a reference line was established by sweeping with the dut port on the bridge open.  analyzer was set for peak hold and multiple sweeps ran until the line smoothed out.  the reference line was saved as "trace A".

the antenna was then connected to the dut port on the bridge and the process was repeated and a return loss trace was saved as "trace B".

do i believe my crap homemade antenna really has more than -35 dB of return loss.  nope not for a second.  first, my bridge is not that good. AND the deeper the RL dip the larger the possible error due to it being only a scalar measurement.  but i am pretty confident that the antenna has a RL of at least -20 or -23 dB,  and that is plenty good for my use.

why is the reference trace tilted.  don't know for sure.  could be that the bridge is only rated to 1200 Mhz,  or could be the crap coax between the bridge and the 8569b.  but it does not appear to be caused by the sweep source or the analyzer.

am i happy with the 8569b?  is it a useful instrument?  damn right it is!

winner winner chicken dinner!