Test Equipment Anonymous (TEA) group therapy thread

[bd139]

That's more like it!

I was reading through some old Ham Radio (the actual magazine not generic term) magazine from the late 1960s a while back and there was a lot of decent stuff like that back then. Things were a hell of a lot more exciting than now. All the cutting edge technology was possible to wholly understand and replicate yourself with some effort from just parts.

Same with audio stuff, broadcast radio, the lot. Moment software came along...

[BU508A]

done  enough for today.

The HP 3456A is a very nice meter, congrats to yours.  

Do you know which crystal is actually installed in your 3456A?

Mains input 60Hz - 5.85MHz
Mains input 50Hz - 4.875MHz



If you need/want one of the 50Hz / 4.875MHz crystals I can send you one.

No I have to open and look what is inside. The source of the unit is Hamburg, so I hope it have the 50Hz. What is the different ?
If you find a junk unit, I am still very interested to buy a original Transformer, my rebuild is working but this may be better.

Martin

I got mine from a seller here in Germany, too. The crystal installed was the 60Hz - 5.85MHz type.
You can't rely on where you've bought it. And as kj7e mentioned: it is about the noise rejection which is related to the mains frequency.
Details can be found here in this thread:
https://www.eevblog.com/forum/projects/modyfing-50hz-to-60hz-hp-3456a/

Are they the same crystals used for the HP3455A. Because I am looking for a 50Hz crystal for a HP3455.
I bought a few year ago from the states, when the Australian dollar  was pegging with the US Dollar

How much to buy and send on to Australia?

I have no idea if this crystal fits into the 3455A. If so and if you want a crystal (I have 2 spares) I can sent you one.
I'd ask EUR 12.- for one crystal plus shipping (I estimate shipping something between 5 and 10 Euros including a jiffy bag).

For further information I'd consult the 3456A repair page from TiN. There you can find also some links to the
manual and schematics of the 3455A.
https://xdevs.com/fix/hp3456a/

HTH

Edit: typos

[worsthorse]

That's more like it!

I was reading through some old Ham Radio (the actual magazine not generic term) magazine from the late 1960s a while back and there was a lot of decent stuff like that back then. Things were a hell of a lot more exciting than now. All the cutting edge technology was possible to wholly understand and replicate yourself with some effort from just parts.

Same with audio stuff, broadcast radio, the lot. Moment software came along...

Maybe you should consider an AM broadcast transmitter. I recently saw one being restored (it was taller than me and the output amp tubes weighed six or seven pounds each) and it is a beautiful piece of gear.  And when it is powered up, you know it is powered up. 

[bd139]

Been there done that. I actually made an AM broadcast transmitter out of old valve radios when I was a kid using the audio output transformer as a modulation transformer. The LO coil was rewound so it oscillated near the broadcast frequency and an IF stage was repurposed as a rudimentary PA. Antenna was a bit of mains flex out of a skip. It was good enough to transmit around the house but the linearity was poor so it didn't sound too good. I wasn't old enough to know why then

[med6753]

That's more like it!

I was reading through some old Ham Radio (the actual magazine not generic term) magazine from the late 1960s a while back and there was a lot of decent stuff like that back then. Things were a hell of a lot more exciting than now. All the cutting edge technology was possible to wholly understand and replicate yourself with some effort from just parts.

Same with audio stuff, broadcast radio, the lot. Moment software came along...

Maybe you should consider an AM broadcast transmitter. I recently saw one being restored (it was taller than me and the output amp tubes weighed six or seven pounds each) and it is a beautiful piece of gear.  And when it is powered up, you know it is powered up.

I agree. With a massive modulation transformer with full 10Khz audio bandwidth to completely piss off all the crew on slop bucket. 

[med6753]

After having the 535A powered up for a few hours and putting it through a few power cycles the only thing additional that has cropped up is the Amplitude Calibrator died. I expect minor issues like this to occur so I'm not concerned.

This scope does throw off massive amounts of heat but what is amazing is that there is no smell. No musty mildew smell or any burning odors. Unlike the RCA 54-45 scope which still smells of musty every time it gets powered up.   

This is such a throw back to pleasant memories. The first time I came face to face with a 547 in college in 1971. Now the 535A doesn't have the B/W of a 547 but the look, feel, and quality construction are the exactly the same.   

[0culus]

The internal construction of those valve Teks is just gorgeous. Handcrafted too...that stuff wasn't assembled by pick and place machines. 

[med6753]

The internal construction of those valve Teks is just gorgeous. Handcrafted too...that stuff wasn't assembled by pick and place machines. 

And most of the Assemblers were women. Was the same at IBM many years ago when power supplies and other assemblies were still built in house. And yes, their build quality and soldering skills are second to none. 

[BU508A]

Been there done that. I actually made an AM broadcast transmitter out of old valve radios when I was a kid using the audio output transformer as a modulation transformer. The LO coil was rewound so it oscillated near the broadcast frequency and an IF stage was repurposed as a rudimentary PA. Antenna was a bit of mains flex out of a skip. It was good enough to transmit around the house but the linearity was poor so it didn't sound too good. I wasn't old enough to know why then

If you like AM broadcasting, how about this nice puppy?
A R&S SK-050.
500W output average afaik, weight 270kg, lots of vacuum tubes, nice design.

[kj7e]

Friend of mine, Eliot Kline - K7ER had a pair of commercial Collins transmitters converted to 75m.  He built them into the wall between his master bedroom and ham shack, the closest door in the master bedroom opened to to the rear the the transmitters.



From the operating position

[med6753]

I used listen to the AM'ers on 3.885MHz. Some of those guys had audio quality and dynamic range better than commercial broadcast. 

[WastelandTek]

I used listen to the AM'ers on 3.885MHz. Some of those guys had audio quality and dynamic range better than commercial broadcast.

If I am not mistaken, some of those gentlemen were running plate modulation.

[kj7e]

I used listen to the AM'ers on 3.885MHz. Some of those guys had audio quality and dynamic range better than commercial broadcast.

You may even have heard folks like Joe Walsh - WB6ACU.

[med6753]

I used listen to the AM'ers on 3.885MHz. Some of those guys had audio quality and dynamic range better than commercial broadcast.

You may even have heard folks like Joe Walsh - WB6ACU.

I haven't listened in many years and perhaps I've heard him. I only recall one call sign....Tim in Vermont (I think). WA1HLR (I think that was his call sign)

[bitseeker]

It's fortunate that Discord's UI makes the mic mute so convenient; you can easily do as I did during the test and leave yourself muted all the time EXCEPT when you actually have something to say.

I do a LOT of day-job work in various teleconferences, and "all mute unless given the token" is a very strongly enforced rule. It makes for sooo much better environment. Oughta build me a footswitch thingamabob. And get me an external sound card to interface with it.

I too have spent too much of my working life over the past year or so in teleconferences and I have come one to one conclusion that is true for all conferencing software - they do muting wrong. What you need is an honest to god physical Push To Talk button, not a mute toggle button on the screen or inline in a headset lead where you can't find and hit it quickly.

Absolutely, 100%.

[bitseeker]

More HP goodness. This guy out-HP's all of us 

http://www.kennethkuhn.com/hpmuseum/hp_tour.htm

God god, he has a whole warehouse !

No bench is complete without a nice HP calculator. Can you spot it? 
The description below of that picture is saying:
"(temporary picture)  This is a close up view of my old main shop table.  You can see my 30 year old HP25 calculator that still works perfectly. [...]"

I thought only my bench looked like that. Thanks, I think.

[bitseeker]

Been looking for a few years for a nice Power Designs 2020B (LM399 reference) precision power supply.  Found one and snatched it up this morning!  Looks like it its dent and mostly scratch free.  Looks like it will clean up well.  Anyone know a good way to remove the epoxy like glue used for the inventory tags?

(Attachment Link)

That was a nice one. I didn't realize it was Erik's until just now. Looks like he's downsizing. Are you going to grab a 5020, too?

And have a supper clean, 1998 version HP 8920A with the OCXO and Tracking Gen options waiting at the UPS hub now.  The 98 version is preferred, they came with mechanical attenuator that gave better overall level accuracy and operated down to 400 KHz.  From 99 on they had electronic attenuators and the mechanical became an option (Option 55) which limited the lower feq range to 30MHz for level accuracy.

(Attachment Link)

Amazing no one else bid on that one. Let me know how it turns out. That sellers seems to sell most things as "for parts."

[worsthorse]

I used listen to the AM'ers on 3.885MHz. Some of those guys had audio quality and dynamic range better than commercial broadcast.

If I am not mistaken, some of those gentlemen were running plate modulation.

You are definitely not mistaken. I traded a couple of Hammarlund receivers for a crate full of semiconductors with a ham that was restoring a AM broadcast system to use on 75M, transmitter, sound board, the whole works. The man had the knack, not just for electronics but for mechanical design/build.  It sounded great on the air and was a marvel to look at, too.  Talk about tubes with a BIG glow!

[kj7e]

Been looking for a few years for a nice Power Designs 2020B (LM399 reference) precision power supply.  Found one and snatched it up this morning!  Looks like it its dent and mostly scratch free.  Looks like it will clean up well.  Anyone know a good way to remove the epoxy like glue used for the inventory tags?

(Attachment Link)

That was a nice one. I didn't realize it was Erik's until just now. Looks like he's downsizing. Are you going to grab a 5020, too?

And have a supper clean, 1998 version HP 8920A with the OCXO and Tracking Gen options waiting at the UPS hub now.  The 98 version is preferred, they came with mechanical attenuator that gave better overall level accuracy and operated down to 400 KHz.  From 99 on they had electronic attenuators and the mechanical became an option (Option 55) which limited the lower feq range to 30MHz for level accuracy.

(Attachment Link)

Amazing no one else bid on that one. Let me know how it turns out. That sellers seems to sell most things as "for parts."

Just want the 2020B,  and the seller of the 8920A has a nice 53310a MDA for sale.  I hope the 8920A is an as good of shape as it appears.  Cant wait to get home from work tomorrow and play with it.

[bitseeker]

Yep, got my eye on the MDA. Looking forward to your 8920A, too. I don't yet have a need for one, but I've been curious.

[bitseeker]

In case anyone missed Larry's Tek scope collection:

https://www.eevblog.com/forum/chat/whats-your-work-benchlab-look-like-post-some-pictures-of-your-lab/msg2857854/#msg2857854
https://www.eevblog.com/forum/chat/whats-your-work-benchlab-look-like-post-some-pictures-of-your-lab/msg2858654/#msg2858654

 

[Ero-Shan]

Warning: I'm replying to a weeks-old posting, as I'm trying to catch up >50 pages

I need a ac transformer for 3456A

If finding a replacement is impossible you could re-wire the transfo. Not a fun job but it's doable. Need to re-wire a 1Kv transfo and I have been procrastinating for a year now  Not a pleasant job indeed.

I also need a new transformer for a 3456A. I did rewire a few transformers in the seventies which told me one lesson: Never ever do that again!
Luckily, my second 3456A works fine, so I'm in no hurry.

[bd139]

I used listen to the AM'ers on 3.885MHz. Some of those guys had audio quality and dynamic range better than commercial broadcast.

You may even have heard folks like Joe Walsh - WB6ACU.

I haven't listened in many years and perhaps I've heard him. I only recall one call sign....Tim in Vermont (I think). WA1HLR (I think that was his call sign)

Problem with AM'ers is not the quality it's the content

Far warmer and more dynamic sounding prostate exams 

[beanflying]

So seems my Chinese parcels are taking a little detour via Germany 

[bd139]

There are massive drop shipping warehouses in Germany. May be related.