Test Equipment Anonymous (TEA) group therapy thread

[worsthorse]

Yeah got to agree there. I don’t own any! I live in properly fitting cargo pants. If it’s hot, the same because I don’t want a tick on my balls 

Lots of locals here actually go to the local shops in their onesies, another cancerous creation. I mean who the fuck invented clothes you have to take the top off to curl one out. Fuuuu does my head in.

Some years ago, when I was doing something vaguely resembling first response, I discovered EMS wear. They wear like iron, have lots of useful pockets and straps for hanging shit on, are comfortable, and actually look presentable.  A couple of years ago, I put two pairs of them through eight weeks of Himalayan hiking, climbing, gear hauling, and clinic work in less than ideal conditions, and they barely looked worn.  I have been wearing them daily since.

Sweats in public, other than a gym? Only if you are an eighty year old mafioso trying to avoid arrest by convincing the authorities that you are some combination of stark raving mad and senile. 

[Martin.M]

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

[med6753]

Into the belly of the beast. The 535A on it's side. The upper section is the power supply and the lower right is the vertical amplifier. Not surprising it's very clean, just a few cob webs. And again, no apparent physical evidence of what went “snap” during the last power up. I'll have to track it down once I apply power.

The plan for power up is check the power supply first. If OK then check for HV. If that's OK then trouble shoot any other apparent issues.

This monster makes me extremely nervous. There are lethal voltages all over and if there are problems lethal voltages could appear in unexpected places. So while trouble shooting I am going to wear rubber gloves as an extra measure of safety.

So onward. Install the CA plug-in and then smoke test. I'll report back later.
 

[Cerebus]

... Not surprising it's very clean, just a few cob webs. And again, no apparent physical evidence of what went “snap” during the last power up. ...

Have you looked for any dead spiders that look like they've been struck by lightning and exploded into lots of scattered legs?   

[WastelandTek]

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

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

my god

it's full of stars

[Martin.M]

connect directly a Voltmeter to the -150V.
When this is not exactly there will be nothing be exactly.
If required adjust that to ± <1V
The tubes in the CA are filamented by the +100V, and this is referenced by the -150V, means when the -150 is not ok that can overheat tubes.

[kj7e]

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

Sets the NPLC to the correct power line frequency which affects the noise rejection.

[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?




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.

[Specmaster]

Into the belly of the beast. The 535A on it's side. The upper section is the power supply and the lower right is the vertical amplifier. Not surprising it's very clean, just a few cob webs. And again, no apparent physical evidence of what went “snap” during the last power up. I'll have to track it down once I apply power.

The plan for power up is check the power supply first. If OK then check for HV. If that's OK then trouble shoot any other apparent issues.

This monster makes me extremely nervous. There are lethal voltages all over and if there are problems lethal voltages could appear in unexpected places. So while trouble shooting I am going to wear rubber gloves as an extra measure of safety.

So onward. Install the CA plug-in and then smoke test. I'll report back later.

Have you got a variac? If so run it up slowly via that and slowly increase the voltage applied up to the point of maximum line voltage (don't forget that most variac's can and do provide a boost to the normal line voltage by up to an extra 20 volts so always have a voltmeter applied to the output to avoid accidentally frying by over volting it. 

[med6753]

Holy shit...we have a trace!! 

The reference is -150.7VDC. Good enough. All the B+ voltages are good.

Channel 1 on the CA plug-in is dead. Channel 2 works but bounces around. But the trace is nice and sharp with good focus. I'm going to assume for now that the HV is OK.

Going to let it cook for a while and see what happens. But so far I a happy camper! 

[mnementh]

   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?

Why would you want to remove it...? That thing used to belong to the OSI... everybody's favorite mythical ^* (nudge-nudge, wink-wink ) alphabet soup agency who created the 6 Million Dollar Man. Totes POS/NSA right there. 

Heat from a heat gun to soften the adhesive & remove the plate, then fold up a piece of paper towel into a cube and soak with Goo Gone. Use an extra-long piece of masking tape to hold it in place over the offending adhesive and apply light pressure overnight. Preferably orient the unit so it is face up for this time.   * Yes, I am aware that there used to be an actual OSI; the precursor to the CIA. That just makes the NSA of this unit even more nebulous.

mnem
I'd settle for a 6 Dollar Burger right now.

[Specmaster]

Holy shit...we have a trace!! 

The reference is -150.7VDC. Good enough. All the B+ voltages are good.

Channel 1 on the CA plug-in is dead. Channel 2 works but bounces around. But the trace is nice and sharp with good focus. I'm going to assume for now that the HV is OK.

Going to let it cook for a while and see what happens. But so far I a happy camper! 

Thats a really nice trace, maybe the "snap" was just due to condensation as if I recall you had just driven some distance to collect it and you had some snow? Either that or in your cleaning process you inadvertently disturbed something that was a loose / dirty connection?

[mnementh]

Nah.... he just let the angry pixies sleep in this morning. Right now only the happy pixies are awake. 

mnem
 

[Martin.M]

CA, that can be a shitty switch.
turn them 15x and try again

the 535 looks fine, a happy scoope,
well done 
Enjoy the dual time base, "intense by A" and so on.

535A can run also some very amazing plugins, by example:

Spectrumanalyzers up to 40GHz (requires seperate cable for sawtooth and RTFM) (1L5, 1L10, 1L20, 1L30, 1L40) ! rearswitch is to set for 150V)
Sampling 1GHz = 1S1 or N
Diff !  10µV/cm comes from 1A7 or 1A7A
Diff with comparement voltage: 1A5
1 Channel, L, A, B
2 Channel, CA, 53/54C, 1A1, 1A2
4 Channel: M, 1A4

Plugins begin with a letter are made for 15MHz scopes,
Plugins with a 1 are made for faster scopes and work also in the 53x

[med6753]

So after nearly an hour powered up here's what I got:

The reference has settled at exactly -150.0VDC. All other B+ voltages in spec. 

The trace is sharp, bright with excellent focus. Going to assume HV is OK and gonna let it alone. 

Time Base A Trigger – stable. 

Time Base A Time/cm – stable and appears to be in spec to the 1Khz Calibrator. 

Time Base B Trigger – stable. 

Time Base B Time/cm – stable and appears to be in spec to the 1Khz Calibrator. 

CA plug-in Channel 2 – has settled down but DC balance way off but the Gain appears OK. 

CA plug-in Channel 1 – Trace keeps going off screen. DC balance won't bring it back. 
 

So it looks like the issues are in the Vertical plug-in/amplifier area. Shouldn't be difficult to trouble shoot.     

And I guess for now that "snap" will remain a mystery. Didn't see any cooked spiders in there and maybe it was condensation....but it was in a heated car for 2 hours on the drive home. 

[Martin.M]

CA plug-in Channel 1 – Trace keeps going off screen. DC balance won't bring it back.

identify the tired tube by swapping with the tube from other Ch., most of them are double.

[med6753]

CA plug-in Channel 1 – Trace keeps going off screen. DC balance won't bring it back.

identify the tired tube by swapping with the tube from other Ch., most of them are double.

Yea, there's definitely some issues in that CA plug-in. We'll find it. 

[Specmaster]

@med, yes it might well have been in a warm car for 2 hours on the drive home, but where did the seller store it prior to you buying it. Fingers crossed that is what it was and you get any further problems.

Martins idea of swapping valves over 1 by 1 in the CA plug-in is a good one, thats an advantage the tubes have over transistors.

I still think that you have a long way to go yet to rival me with growing meter collection, none of which are yet blue but the Solartrons do have a blue strip on each side and blue legends on the face plat and the Thurlby 1905A does have some same shade of blue membrane switches 

[Martin.M]

Martins idea of swapping valves over 1 by 1 in the CA plug-in is a good one, thats an advantage the tubes have over transistors.

Tek Oldies have Transistors and Nuvistors also in sockets.

[med6753]

Here's a copy cat of Martin. 

Hollow state goodness. 

[worsthorse]

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)


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)

Sweet acquisitions! You must have a lot of room on that bench of yours cause most of the stuff you buy is freakin' huge. 

[Martin.M]

the new home for 3456A is on my 535A... 



here you see how to manage the workbench.
left side of tabe: 2 Classic Tek,  (here: 549 + 533A)
right side of table: 2 classic Tek, (here: 535A + 585A)
and the table is complete free. 

More then 4 of them are not required bec. when they all are working that can blow out the fuse ..

btw. look at the serial from the 585A, it is a first-day-scope, the No 15 from Heerenveen NL = 700015

[worsthorse]

I have been lost in a maze of twisty little RF passages, all alike, for the last three days... the 2M packet system I helped design and install a year ago suddenly stopped working.

/begin 

Of course, the system is at the other end of a very small internet pipe, in a locked building to which I have no access other than the VNC server installed on the anemic windows ten box I was given to build the gateway. 

So I've been sitting on this end of the pipe for a couple of days trying to find the problem while dealing the time between point and click and response of anywhere from three to forty seconds.  And all the time hoping that Windows 10 wouldn't force an unscheduled update.

Yesterday I figured out it was a bug in the packet gateway software, apparently one that that dev team has known about for quite some time (like years). One of the dev guys responded by suggesting I re-install Windows 10. Another said it would be good for me to buy a different modem even though the one we use is in their supported equipment list.   

Luckily another operator (in Norway) had seen a similar problem and gave me the clue needed to come up with a workaround.  So we are up and running again and I will not, hopefully, have to deal with this system again for a year. 

/end 

Now if I remember where I left off debugging the 184...

[bd139]

QRP Labs 50W amp done. Utterly boring build and works in spec without any explosions. Has full electronic QSK which means it’s silent. Just an LED comes on. Doesn’t feel like it’s doing anything. Totally drive by wire. It’s really missing something human about it. Just doesn’t feel right. Same sort of feeling that the new digital scopes have.

Going to sell it and spend the money on something with tubes in it I think. Was considering an old ARC5 R27 receiver with dynamotor. Now that’d have some soul in it.

[kj7e]

QRP Labs 50W amp done. Utterly boring build and works in spec without any explosions. Has full electronic QSK which means it’s silent. Just an LED comes on. Doesn’t feel like it’s doing anything. Totally drive by wire. It’s really missing something human about it. Just doesn’t feel right. Same sort of feeling that the new digital scopes have.

Going to sell it and spend the money on something with tubes in it I think. Was considering an old ARC5 R27 receiver with dynamotor. Now that’d have some soul in it.

I know what you need.  A real amp that you can feel, some of the Henry's I had in the past;