Test Equipment Anonymous (TEA) group therapy thread

[bd139]

I put in an offer for a 4CX250F tube on fleabay. The seller must be high on some good stuff with the BIN price they want. I suspect the 4CX250F in the 519 may be weak, due to odd problems with the sweep on 2 ns/cm.

Need more POWER



Edit: actually 4CX250's aren't as expensive as I thought they were. £50 a pop is probably considerably less than they were new!

[Cerebus]

There's another thing, we all talk about sysadmins, look above for the project (group) name in bold - all this old Multics stuff is a pervasive underpinning of much that we use, do and say in computing, even to this day

Everything, almost, in CS was invented or named by one of:

• A Danish professor who never wrote in anything less portable than a No. 2 pencil
• IBM, as an afterthought, during System/360 development
• Turing
• Someone in Manchester
• A team of model railroaders at MIT

Ok, this is an exaggeration, but only slightly so.

You missed off Grace Hopper. Don't feel too bad, Lise Meitner's still waiting for her Nobel Prize.

[Cerebus]

All righty then... Today was a crappy day for the ol' TinkerDwagon; I've murdered my 54645A. Well, my clumsy fat ass did, anyways...     ...I had pulled out the cart it was sitting on to get a tool that fell off my bench behind it and just backed right into it, knocking it off onto the floor. 

OK. We know BC (Canada, eh) already has Uncle Bumblefuck, does this mean that Ontario now has Uncle Bumblebutt? So, we've now got Penis Fingers and Uncle Bumblebutt. Who's next?

If my past experience is anything to go by, it should be about a week before you stop feeling like slapping your own face every 10 minutes. If it makes you feel any better my car currently has one exhaust pipe 1" shorter than the other from when I managed to reverse it into a particular high kerb a few months back because I too failed to pay enough attention to what was behind me.

[mansaxel]

You missed off Grace Hopper. Don't feel too bad, Lise Meitner's still waiting for her Nobel Prize.

I'm fully aware of the glaring omissions in my list. RADM Hopper did get quite some recognition, though.

The Meitner fiasco, though. What a fuck up. And it even happened in Sweden. (She formulated the theory while taking walks in Kungälv, Sweden, where she lived in exile.)

[Zucca]

My octoprint raspdevil lose serial connection with the printer once every 3 days.
I love to report here how unreliable those boards are.

Now two options:

1) old lenovo laptop with the immense FreeBSD
2)  BeagleBone.

99% I go for FreeBSD, I will at least learn something useful.

[bd139]

All these little single board computers are just e-waste. Need proper kit.

My personal web server is running FreeBSD. Least amount of hassle.

[mnementh]

All righty then... Today was a crappy day for the ol' TinkerDwagon; I've murdered my 54645A. Well, my clumsy fat ass did, anyways...    (SNIP)

PCB repair is underway with resin curing as we speak...

mnem

   

Done... and tested. 

mnem
*toddles off to ded*

A much neater job than most of my board repairs.
The compatibility of FR4 with expoxy is one of  the things I like about it.

My most profound epoxy PCB repair was the power supply of a Sony BVM1410 picture monitor.

The PSU components not only cooked, but some unusual rectifiers with two diodes in the package burnt holes the diameter of my thumb in the board. 

I found some small single sided round boards which had been intended to use in microphones & repurposed them.
With all the charring removed, the small PCBs epoxied in place, individual pairs of diodes wired in place of the combined ones, & any other cooked components replaced, it worked, was "fit for purpose", but still looked like a "bodge".

There's a difference between "making a bodge" and "bringing its soul back from the depths of Hell". I think your repair definitely falls in the latter category.



This one was a bit of a challenge; it was important to have the finished product be very low profile as there is a silicone membrane keypad that lies over all this.

Here is my secret: forming thin (in this case, 0.20mm) strands of wire so they lie side by side like so. Solder in place, then remove the tail by wiggling back & forth until metal fatigue breaks the strand off flush and retouch that end with the iron. If done correctly the result, like this, is that you can't even see the wire. There are two strands in the narrow traces and 3 in the wide GND trace above.

mnem
 

[mnementh]

Thanks... still saying "I can't fucking believe I did that..." to myself about every 15 minutes...

And still  on how to fix the plastic. This part is structural and clips into the metal chassis, so no room to layer anything like epoxy & matting on the inside for strength.

Also, very visible... so I'm gonna get one chance to do the job right or I'll be looking for a donor unit.

EDIT: I'm leaning towards Plastruct Bondene: https://plastruct.myshopify.com/pages/technical-info-msds-sheets I think it's what I used to use for my big ship and plane models where you had to hold multiple parts together at once and let the glue wick between. Now trying to find a local supplier.

mnem
 

Hi,
For the bezel you need a solvent adhesive like the Plastruct bondene. I use the similar EMA Plastic weld.  Both are basically just methylene chloride.
They are literally solvent and leave no trace on glass. The metallic coating is  bit of an issue. Uses a sharp blade at 90 degrees to the inside corner of the edge to slightly chamfer it, removing the coating. Tis is just a fraction, "breaking the edge" in engineering terms). Hold the parts together with tape, not covering the crack. Make sure the bit fit tight together. If there are several breaks you may have to do it in stages. Using a small screwdriver or similar apply small drops at regular intervals to the inside of the crack were you removed the metallic coating. Just enough to wet it. Capillary action will draw it into the crack. Leave somwere warm for several hours. You are tyrying t just get a wet, not dripping, track of solvent allong the inside. I use a pipette made from small bore PTFE sleeveing to drop the solvent. If you get it right there will be an invisible join on the outside.  A bit too much (not a bad thing) will leave a "flash line" that can be trimmed back. If there are gaps trim a few scraps of plastic from the inside and dissolve in the solvent to make a filler paste. Apply from inside only.

Robert -

Thanks for confirming my notion that Bondene is a good choice. This is pretty much exactly the same as the process I developed myself over decades of repairing cracked audio gear fascia, only it was usually just plain ABS which responded well to cyanoacrylate adhesive. I'm now trying to find a bottle of Plastruct Bondene from a supplier that won't take weeks to get it to me.

mnem
 

[mnementh]

Busy as hell today being an enabler and thank gawd it's drawing to a close as tiring but nice to get away overseas  to Waiheke island (ferry ride) where one of our dear friends had a knees up for her 60th. Some further time killed dropping in on Tony that bought a SA from us a few weeks ago. (thanks mate for a great afternoon....hic  )

A Song for Tautech - the enabler!

To the melody strain of Tom Lehrer's 'The Old Dope Peddler':

The Old 'Scope Peddler

    When the shades of night are falling,
    Comes a fellow everyone knows.

    It's the old ‘scope peddler,
    Serving TEA wherever he goes.

    Every evening you will find him,
    Around our neighborhood.

    It's the old ‘scope peddler,
    Doing well by doing good.
 
    He shows the kids neat circuits,
    Because he knows full well

    That today's young innocent faces
    Will be tomorrow's clientele.

    Here's a cure for all your troubles,
    And your circuits in distress.
    It's the old ‘scope peddler

    With his Chinese happiness.

(Original version, complete with the dots, available at https://tomlehrersongs.com, courtesy of the great man himself!)

Well and truly filked, good wordsmith!  Thanks for the chuckle over my morning cup of doom!

mnem

[Robert763]

Thanks... still saying "I can't fucking believe I did that..." to myself about every 15 minutes...

And still  on how to fix the plastic. This part is structural and clips into the metal chassis, so no room to layer anything like epoxy & matting on the inside for strength.

Also, very visible... so I'm gonna get one chance to do the job right or I'll be looking for a donor unit.

EDIT: I'm leaning towards Plastruct Bondene: https://plastruct.myshopify.com/pages/technical-info-msds-sheets I think it's what I used to use for my big ship and plane models where you had to hold multiple parts together at once and let the glue wick between. Now trying to find a local supplier.

mnem
 

Hi,
For the bezel you need a solvent adhesive like the Plastruct bondene. I use the similar EMA Plastic weld.  Both are basically just methylene chloride.
They are literally solvent and leave no trace on glass. The metallic coating is  bit of an issue. Uses a sharp blade at 90 degrees to the inside corner of the edge to slightly chamfer it, removing the coating. Tis is just a fraction, "breaking the edge" in engineering terms). Hold the parts together with tape, not covering the crack. Make sure the bit fit tight together. If there are several breaks you may have to do it in stages. Using a small screwdriver or similar apply small drops at regular intervals to the inside of the crack were you removed the metallic coating. Just enough to wet it. Capillary action will draw it into the crack. Leave somwere warm for several hours. You are tyrying t just get a wet, not dripping, track of solvent allong the inside. I use a pipette made from small bore PTFE sleeveing to drop the solvent. If you get it right there will be an invisible join on the outside.  A bit too much (not a bad thing) will leave a "flash line" that can be trimmed back. If there are gaps trim a few scraps of plastic from the inside and dissolve in the solvent to make a filler paste. Apply from inside only.

Robert -

Thanks for confirming my notion that Bondene is a good choice. This is pretty much exactly the same as the process I developed myself over decades of repairing cracked audio gear fascia, only it was usually just plain ABS which responded well to cyanoacrylate adhesive. I'm now trying to find a bottle of Plastruct Bondene from a supplier that won't take weeks to get it to me.

mnem
 

https://canada.desertcart.com/products/4649712-plastruct-plastic-weld-w-applicator-2-oz-bottle

[med6753]

Fluke 8800A with the FUBAR 200mV/200 ohm range LED out.



I just know your perverts want to see some Fluke porn so I'll strip off the shield and put it in the limelight. 



Feast your eyes. 




Anyway, long story short. The LED itself has bought the farm. Just in case I changed  the driver transistor (2N3904) on the main board and no joy. Everything is switching properly but the LED doesn't respond. Here's the issue....in order to get at the LED I would have to remove the entire front panel. That means pulling the binding posts with the plated hardware. That's a super high impedance area best left alone. Any contamination such as skin oils and other debris will permanently change the input characteristics and the DMM will be junk. The risk vs reward here isn't worth it. I can live without an indicator warning me it's on low range. Most of the time it's in AUTO mode anyway. 

[0culus]

I put in an offer for a 4CX250F tube on fleabay. The seller must be high on some good stuff with the BIN price they want. I suspect the 4CX250F in the 519 may be weak, due to odd problems with the sweep on 2 ns/cm.

Need more POWER



Edit: actually 4CX250's aren't as expensive as I thought they were. £50 a pop is probably considerably less than they were new!

Powaaaaa! 

[med6753]

I put in an offer for a 4CX250F tube on fleabay. The seller must be high on some good stuff with the BIN price they want. I suspect the 4CX250F in the 519 may be weak, due to odd problems with the sweep on 2 ns/cm.

Need more POWER



Edit: actually 4CX250's aren't as expensive as I thought they were. £50 a pop is probably considerably less than they were new!

Powaaaaa! 

What the hell....the 519 chassis is big enough to accommodate it so go for it! 

[0culus]

I could heat my whole house. Give the furnace a break. 

[mnementh]

All righty then... Today was a crappy day for the ol' TinkerDwagon; I've murdered my 54645A. Well, my clumsy fat ass did, anyways...     ...I had pulled out the cart it was sitting on to get a tool that fell off my bench behind it and just backed right into it, knocking it off onto the floor. 

OK. We know BC (Canada, eh) already has Uncle Bumblefuck, does this mean that Ontario now has Uncle Bumblebutt? So, we've now got Penis Fingers and Uncle Bumblebutt. Who's next?

If my past experience is anything to go by, it should be about a week before you stop feeling like slapping your own face every 10 minutes. If it makes you feel any better my car currently has one exhaust pipe 1" shorter than the other from when I managed to reverse it into a particular high kerb a few months back because I too failed to pay enough attention to what was behind me.

Don't fuck with me. I'm cooking so I have large, heavy blunt objects within easy reach. And sharpy things. Oh, and FIRE. 

Also, ouchies. One of my first gigs working in Tejas was at a Monkey-kee Muffler. Once I knew how the work was done, uneven or crooked exhaust became a pet peeve that always jumped out at me; an "un-finished" project.

mnem
Ehhh... I cannae deny it; may as well own it. BumbleButt it is, I guess.

[med6753]

mnem
Ehhh... I cannae deny it; may as well own it. BumbleButt it is, I guess.

Where's the "Like" button? 

[mnementh]

Robert -

Thanks for confirming my notion that Bondene is a good choice. This is pretty much exactly the same as the process I developed myself over decades of repairing cracked audio gear fascia, only it was usually just plain ABS which responded well to cyanoacrylate adhesive. I'm now trying to find a bottle of Plastruct Bondene from a supplier that won't take weeks to get it to me.

mnem
 

https://canada.desertcart.com/products/4649712-plastruct-plastic-weld-w-applicator-2-oz-bottle

Nope... wrong product. That's Weldene; made for joining dissimilar plastics per the Plastruct page I linked to earlier. I'm looking for Bondene, a different product made for joining similar plastics. Your site shows it, but imported from the US and at a cost of $30. That is majorly ouchies, and will take weeks to get to me thanks to the combination of COVID precautions and Customs.

This is what I'm currently  my head against all over the intardnet right now.

mnem
 

[Cerebus]

mnem
Ehhh... I cannae deny it; may as well own it. BumbleButt it is, I guess.

Where's the "Like" button? 

Careful Captain Capacitor...

[Specmaster]

Used the PL310 to charge a battery pack today  When it arrived it was missing the shorting links and it needs these to perform properly. When I was talking to TTi the other day I casually asked the price of these, and was told that they would pop a couple of sets in the post to me FOC, what brilliant service.

I will be getting more of their gear in the future, not only is it really good VFM and has pretty good specs, but what wonderful customer support and service, maybe a few other companies could learn a thing or two from them, yes the PL310 is an obsolete product now, but they are still willing to support it and the customer where ever possible, well done TTi.

[med6753]

mnem
Ehhh... I cannae deny it; may as well own it. BumbleButt it is, I guess.

Where's the "Like" button? 

Careful Captain Capacitor...

Just don't call me late for supper. 

[Wolfgang]

      

All righty then... Today was a crappy day for the ol' TinkerDwagon; I've murdered my 54645A. Well, my clumsy fat ass did, anyways...     ...I had pulled out the cart it was sitting on to get a tool that fell off my bench behind it and just backed right into it, knocking it off onto the floor. 

Did exactly the kind of damage it had when I bought it... even in the same areas of the front panel... only worse. Oh, and cracked the corner of the control PCB that somehow escaped destruction the first go-round.

PCB repair is underway with resin curing as we speak; however the front panel is another story. I need to cement these two chunks back in place, and I don't know what type of cement to use, so I'm calling for a lifeline from any of you chemistry freaks.

I do know that ordinary consumer-product cyanoacrylate doesn't work; I tried it the first go-round with a bunch of support tabs I found broken loose. It started out looking good, etching into the material just like regular model-plastic ABS; but it just turned the plastic crumbly and never set up like CA & ABS usually does. As you can see in the 2nd pic, it is marked as a ABS/polycarbonate blend, so I'm sure that's the cause. I just don't know what WILL work.

Anyhoo... I have the parts placed and the outer surface masked off with tape to seal the edges of the crack. This is my preferred method; I've used it more times than I can count to repair cracked VCR/CD/DVD/Audio gear fascia made of ABS. This tactic usually yields as close to a invisible repair as you can get, however it requires a watery consistency cement that will infiltrate into the cracks like CA does.

I would prefer an actual brand or product known to work with this stuff; ideally one which can be ordered off Amazon.

EDIT: I'm leaning towards Plastruct Bondene: https://plastruct.myshopify.com/pages/technical-info-msds-sheets I think it's what I used to use for my big ship and plane models where you had to hold multiple parts together at once and let the glue wick between. Now trying to find a local supplier.

Thanks,

mnem

German proverb: You destroy with your ass what your own hands have created.
Special case: Dragons have small hands. 

[nixiefreqq]

mnem
Ehhh... I cannae deny it; may as well own it. BumbleButt it is, I guess.

Where's the "Like" button? 

well he did fess up to it.  (i'da blamed the dog)

[Robert763]

Robert -

Thanks for confirming my notion that Bondene is a good choice. This is pretty much exactly the same as the process I developed myself over decades of repairing cracked audio gear fascia, only it was usually just plain ABS which responded well to cyanoacrylate adhesive. I'm now trying to find a bottle of Plastruct Bondene from a supplier that won't take weeks to get it to me.

mnem
 

https://canada.desertcart.com/products/4649712-plastruct-plastic-weld-w-applicator-2-oz-bottle

Nope... wrong product. That's Weldene; made for joining dissimilar plastics per the Plastruct page I linked to earlier. I'm looking for Bondene, a different product made for joining similar plastics. Your site shows it, but imported from the US and at a cost of $30. That is majorly ouchies, and will take weeks to get to me thanks to the combination of COVID precautions and Customs.

This is what I'm currently  my head against all over the intardnet right now.

mnem
 

Doh
You are correct. I didn't check properly. Two other versions are Tensol 7R and Same Stuff https://www.micromark.com/SAME-STUFF-APPLICATOR The chemical wanted is Methylene Chloride aka dichloromethane. You could try just looking for that but will probably have to buy a litre. Do you know a chemist?

[mnementh]

Nope... wrong product. That's Weldene; made for joining dissimilar plastics per the Plastruct page I linked to earlier. I'm looking for Bondene, a different product made for joining similar plastics. Your site shows it, but imported from the US and at a cost of $30. That is majorly ouchies, and will take weeks to get to me thanks to the combination of COVID precautions and Customs.

This is what I'm currently  my head against all over the intardnet right now.

mnem
 

Doh
You are correct. I didn't check properly. Two other versions are Tensol 7R and Same Stuff https://www.micromark.com/SAME-STUFF-APPLICATOR The chemical wanted is Methylene Chloride aka dichloromethane. You could try just looking for that but will probably have to buy a litre. Do you know a chemist?

None that aren't currently serving time. 

mnem
 

[bd139]

Used the PL310 to charge a battery pack today  When it arrived it was missing the shorting links and it needs these to perform properly. When I was talking to TTi the other day I casually asked the price of these, and was told that they would pop a couple of sets in the post to me FOC, what brilliant service.

I will be getting more of their gear in the future, not only is it really good VFM and has pretty good specs, but what wonderful customer support and service, maybe a few other companies could learn a thing or two from them, yes the PL310 is an obsolete product now, but they are still willing to support it and the customer where ever possible, well done TTi.

That’s pretty awesome service. Can’t be beaten