Test Equipment Anonymous (TEA) group therapy thread

[worsthorse]

was actually looking for one with the dot led display.

but am impressed with this guys honesty.

https://www.ebay.com/itm/Butt-Ugly-HP-3490A-AC-DC-Ohms-5-Digit-Multimeter-No-Feet/323912320252?epid=1003943261&hash=item4b6aadc4fc:g:lCgAAOSw6ZFdeRwm

It's big. It's ugly. It's heavy. I don't need it. And... it matches some of my other HP gear like the 8640B  so maybe I should buy it. 

[GreyWoolfe]

That’s begs a question: what’s a group of tektronix scopes called? Herd, gaggle, flock?

How bout simply THE TEK, as in WE are the TEK.  You will be assimilated.

[Addicted2AnalogTek]

This is likely known to some, but I've run into an interesting "catch" while working on this Tek 475 scope. (SN B281657)
It seems, at some point during manufacture, that the vertical preamplifier board was changed to a design more resembling the 475A vertical preamp board.
I encountered this while referencing both the 475 and 475A manuals for my calibration procedure.  I've been doing so because I have all of the calibration tools used by the 475A manual, but not the 475 manual.
Additionally, vertical calibration on these 400 series scopes is no trivial thing, and the 475A manual has several "Calibration Aid" tips that are very useful.

[bsfeechannel]

Ah, missolder. Couldn't find "verlöten" anywhere in my regular dictionaries, and the Google translator just gave me "solder" as an answer.

Heute habe ich etwas Neues gelernt. Vielen Dank. 

The correct translation of "verlöten" would be "to solder sth." not to "to mis-solder" - it's just a fun / pun intended interpretation. Maybe bd139 gets married to Miss Solder at some time

Miss Solder is pretty schmart.



He can't miss (pun intended) that opportunity.

[0culus]

At least she's not holding the iron by the tip like that one stock image.

[neo]

That’s begs a question: what’s a group of tektronix scopes called? Herd, gaggle, flock?

How about a hernia? That's what I call mine. 

[GregDunn]

was actually looking for one with the dot led display.

but am impressed with this guys honesty.

https://www.ebay.com/itm/Butt-Ugly-HP-3490A-AC-DC-Ohms-5-Digit-Multimeter-No-Feet/323912320252?epid=1003943261&hash=item4b6aadc4fc:g:lCgAAOSw6ZFdeRwm

I'd trade mine with the dot LEDs for one of those.  It's a boat anchor, but it's stable and accurate - and the self test mode is pretty cool.

[worsthorse]

I picked an HP 3400A up a couple of weeks ago. While it is in pretty good shape, the power plug was damaged (broken phenolic board):



and it looked like it was banged pretty hard, as you can see by the bent metal:



I removed the old plug socket and will replace it with a power cord. I can probably get most of the bend out of the back panel. Here's my question:



This board, with the nuvistor, is loose. There's no mounting hardware that I can see. There was a bunch of decayed foam in there, too. Does anyone here have a 3400A? I'd like to know how this board was secured in the meter.

[med6753]

At least she's not holding the iron by the tip like that one stock image.

But she's pretty damn close to burning her fore finger. 

[0culus]

I picked an HP 3400A up a couple of weeks ago. While it is in pretty good shape, the power plug was damaged (broken phenolic board):



and it looked like it was banged pretty hard, as you can see by the bent metal:



I removed the old plug socket and will replace it with a power cord. I can probably get most of the bend out of the back panel. Here's my question:



This board, with the nuvistor, is loose. There's no mounting hardware that I can see. There was a bunch of decayed foam in there, too. Does anyone here have a 3400A? I'd like to know how this board was secured in the meter.

IIRC, k7je has one or two of them. Perhaps he will chime in. 

[kj7e]

One of the Brits here has one too, at work at the moment but Ill pull the covers off mine and send some photos when I get home.

[mnementh]

At least she's not holding the iron by the tip like that one stock image.

But she's pretty damn close to burning her fore finger. 

And for some reason, she seems to think a screw hole on the corner of the board needs soldering... 

mnem
*heeding Hypnos' siren call*

[Cubdriver]

WCH, I went and looked in my repair queue, and I apparently picked one up at some point.

It appears that the nuvistor board is cradled in those end caps, and held 'down' (actually up when the meter is sitting normally; it is on its back in these photos) by small blocks of foam between the component side of the board and the brackets.

Here are some quick-and-dirty iPhone pics:







Based on the limited amount of foam crumbs in the bottom of mine, the lack of any evidence of foam between the solder side of the board and the brackets, and how close the leads coming off the board are to the cover, it looks to me that foam is only meant to be between the component side of the board and bracket, and that the solder side rests directly on the inside of the bracket.

-Pat

[worsthorse]

WCH, I went and looked in my repair queue, and I apparently picked one up at some point.

It appears that the nuvistor board is cradled in those end caps, and held 'down' (actually up when the meter is sitting normally; it is on its back in these photos) by small blocks of foam between the component side of the board and the brackets.

Based on the limited amount of foam crumbs in the bottom of mine, the lack of any evidence of foam between the solder side of the board and the brackets, and how close the leads coming off the board are to the cover, it looks to me that foam is only meant to be between the component side of the board and bracket, and that the solder side rests directly on the inside of the bracket.

-Pat

Thanks Pat. What a weird way to mount that board. Why do you suppose it was done?  I mean the rest of the box is built like a tank, right?

[Cubdriver]

WCH, I went and looked in my repair queue, and I apparently picked one up at some point.

It appears that the nuvistor board is cradled in those end caps, and held 'down' (actually up when the meter is sitting normally; it is on its back in these photos) by small blocks of foam between the component side of the board and the brackets.

Based on the limited amount of foam crumbs in the bottom of mine, the lack of any evidence of foam between the solder side of the board and the brackets, and how close the leads coming off the board are to the cover, it looks to me that foam is only meant to be between the component side of the board and bracket, and that the solder side rests directly on the inside of the bracket.

-Pat

Thanks Pat. What a weird way to mount that board. Why do you suppose it was done?  I mean the rest of the box is built like a tank, right?

I'm not certain, but would guess at least to some extent to isolate the tube a bit from vibration that, if it were slightly microphonic, could cause variations in its gain during operation.  Weird that they wouldn't center it, and cushion it in both directions, but it doesn't appear that they did.  Or, since it cushions in the downward direction, perhaps to provide some shock absorption to the tube if the meter is put down hard onto  a bench?

Regardless, it looks like the foam is present only on the one side.  Strange, though knowing HP I'm sure that there was some method to their madness...

-Pat

[paschulke2]

This board, with the nuvistor, is loose. There's no mounting hardware that I can see. There was a bunch of decayed foam in there, too. Does anyone here have a 3400A? I'd like to know how this board was secured in the meter.

It was embedded in foam plastics to fight the microphonics of the nuvistor. The board should not have any solid contact with the chassis. I cut a slit in some foam plastics and placed the input amplifier board in it:



Edit: You can see the original arrangement with the foam plastic quite nicely here (at 9:35):



- Thomas

[tautech]

My office today.


All Ubiquity 5 GHz gear for a wider community data service and also serving as a midpoint hop to 2 other installations to cover more subscriber connections.

Three 300W PV panels via a solar controller charging four 165AH 12V SLA's in a series parallel configuration for 24V powering a single 6 port DC POE switch that powers everything. No inverters !
https://www.netonix.com/wisp-switch/ws-8-150-dc.html

Panels, cabinet and pole HW.

[Sam Spastic]

My office today.


All Ubiquity 5 GHz gear for a wider community data service and also serving as a midpoint hop to 2 other installations to cover more subscriber connections.

Three 300W PV panels via a solar controller charging four 165AH 12V SLA's in a series parallel configuration for 24V powering a single 6 port DC POE switch that powers everything. No inverters !
https://www.netonix.com/wisp-switch/ws-8-150-dc.html

Panels, cabinet and pole HW.

Is the ELECTRIC fence for cattle or unsuspecting kids.

[bd139]

If it was here it’d be keeping the pikeys out 

[tautech]

Is the ELECTRIC fence for cattle or unsuspecting kids.

Primarily cattle but anything else too ! 

The buddy with me today asked how to tell if it was ON or OFF to which I said consider it ALWAYS ON !
With that I grabbed my rubber handled Estwing and hooked the claw over the hot and swung the shank onto another ordinary fence wire......ZAP and it was plainly clear it was ON ! 
Not too bad considering it's ~2km from the mains unit and still jumps 1mm+. 

You won't ever catch me peeing on it !

[bd139]

I love it when people pee on fences. City lot are used to peeing up walls so will go to the country and pee up a fence. Country lot know to pee on the ground away from fences. 

Victory on the T440 front. My nice little PowerPak MOSFETs and 0402 caps arrived and has been soldered in. I stuck it to some blu tak, tinned the pads on it (bastard as it's only 3x3mm) and fluxed and tinned the board, then fluxed it again and heated it and it went right on! No hot air gun of which buying one was plan B. Quick (lack of) continuity check across G/D and then swapped the 0402 out and cleaned it up. Fired it up expecting smoke but nope it works perfectly! My eyes are killing me though now. Need a microscope for this! Good job I bought 100 of the caps as I pinged 4 on the floor before I even got one on the board  . Laptop is burning in now running "stress" on Linux. Win  . Cost £13 in parts though due to the stupid minimum quantities that RS kick out  . Should have been a £1 fix!

[med6753]

You got lucky on that fix. 

[bd139]

Yeah it looked like the PMC had blown up on it to start with which is a weird ass Microchip MEC1633 one off with firmware in an LFBGA package. That would have been a bin it job 

Oh well, my eldest gets a new laptop out of it 

[BU508A]

Oh well, my eldest gets a new laptop out of it 

Teens these days are more interested in Smartphones instead of laptops, aren't they?

[bd139]

They are but they still need to get productive work done and you can't do that on a phone. If you can do productive work on a phone I question the definition of productive work