Test Equipment Anonymous (TEA) group therapy thread

[med6753]

Buy another 465B. I had three once  .  Got two good ones out of it.

That's probably what's gonna happen. I'll keep a look out for a junker. Too bad the 465 junker that I already have is a different attenuator assembly.

[Specmaster]

Spent some time today working on the 465B Channel 2 attenuator deck issue and I found the problem. And unfortunately it's fatal. Some gorilla has been in here before me and they stripped several of stand off screw holes causing inconsistent contact across the entire assembly. And the front plate is bent so the BNC must have taken a shot at one time and was replaced. So this whole mess has got to go. I'll keep and eye out for a cheap junker but this really isn't a priority and it will function just fine as a single trace scope.

This isn't the first time I've had to clean up after this damn gorilla and I'm sure it won't be the last.   

And you won't consider re-tapping them just oversize and fitting a different screw ? 

Maybe a another screw with a locking nut on the other side?

Blind holes in plastic.

Is there no access to the other side at all then?

[med6753]

Spent some time today working on the 465B Channel 2 attenuator deck issue and I found the problem. And unfortunately it's fatal. Some gorilla has been in here before me and they stripped several of stand off screw holes causing inconsistent contact across the entire assembly. And the front plate is bent so the BNC must have taken a shot at one time and was replaced. So this whole mess has got to go. I'll keep and eye out for a cheap junker but this really isn't a priority and it will function just fine as a single trace scope.

This isn't the first time I've had to clean up after this damn gorilla and I'm sure it won't be the last.   

And you won't consider re-tapping them just oversize and fitting a different screw ? 

Maybe a another screw with a locking nut on the other side?

Blind holes in plastic.

Is there no access to the other side at all then?

I don't think so.

[tautech]

Thanks Med......trying to dream up a decent remedy. 

This for a 'bolt right through' solution:
Brass hollow spacers and threaded rod with nuts ?
https://www.aliexpress.com/item/H62-Brass-Seamless-Pipe-Tube-OD-ID-Length-5-3-250mm-6-4-250mm-ASTM-C28000/32843148969.html?spm=2114.search0104.3.141.234a4b3bd2c28i&ws_ab_test=searchweb0_0,searchweb201602_1_10065_10068_10547_319_10059_10884_317_10548_10887_10696_321_322_10084_453_10083_454_10103_10618_10307_537_536_10902,searchweb201603_70,ppcSwitch_0&algo_expid=9e479c48-8781-4d59-bad6-0cab804fd401-20&algo_pvid=9e479c48-8781-4d59-bad6-0cab804fd401&transAbTest=ae803_4

https://www.aliexpress.com/item/Free-shipping-3PCS-LOT-M3-4-250-M4-x-250mm-Metric-Brass-Thread-Rod-Bar-Copper/32894247688.html?spm=2114.search0104.8.5.7f756864z3DWJp&transAbTest=ae803_4

[Specmaster]

tautech, you beat me to it. I'm not quite a 100% sure which part of the standoffs is stripped. Is the tapped thread on the top as we look at it, or is it the screw bit that goes through in the switch which plastic?

If it is the part that goes into the switch, you could try some super glue gel or even super glue with a bit of baking powder to speed up the drying process and increase the bonding strength?

[Inverted18650]

Has anyone tried DIY injection molding recycled plastic? I have seen a few YouTube videos on the topic, and I have my own DIY metal foundry, but the injection molding is interesting and would be fun to compare to 3D printing; or somehow combine the two/three. (make the molds from DIY cast metals, and use them for the injections, then supplement detail with the 3D printed parts...more time than sense I guess but it handy to make your own sh*t..

[mnementh]

That’s why they invented beer. To take the pain away.

A little pleasure... a little pain... it's ALLLL good, man.  And doobie doesn't give you a hangover. 

mnem
I eat chirpy people.

[mnementh]

I still don't know if she called them and compared notes, or if she just knew most of the same people as I did and guessed on the rest. Don't wanna know either. I just put it back in the back of my dresser and went on about my life as if I'd never looked in it. We lasted almost a year after that; and no blood was spilled. Well, none that wasn't voluntary. 

mnem
Life is complicated.

Relationships are complex:they have a real part, and an imaginary part...

I only do what the voices tell me to do. 

mnem
Right now they're telling me to eat a whole bag of Valentine's Hershey Kisses... 

[beanflying]

Has anyone tried DIY injection molding recycled plastic? I have seen a few YouTube videos on the topic, and I have my own DIY metal foundry, but the injection molding is interesting and would be fun to compare to 3D printing; or somehow combine the two/three. (make the molds from DIY cast metals, and use them for the injections, then supplement detail with the 3D printed parts...more time than sense I guess but it handy to make your own sh*t..

Two part Urethane Resins in syringes is about the only practical method unless you get heaters hydraulics and such you will also have to buy a big baggy of pellets or pay way over the top for kg lots. Similar to these https://www.polytek.com/product-type/polyurethane-liquid-casting-plastics Low viscosity and some of the better quality ones are more like 60 seconds work time so work fast  Also have a look around at RIM (Rapid Injection molding) which is more of an industrial version with Urethanes.

[beanflying]

As for sniping... I see it as just leveling the playing field. If you wanna win against the professional eBayers, you gotta step up your game and use the same tools they use. Plus, it saves you the agony of "Knock at the door, missed my auction" blues. 

mnem
*Building the perfect Beast*

I have an evilbay Auction I want to bid on that finishes at stupid o'clock local time what are your sniping weapons of choice?

So far Gixen looks like a decent option 

[Kosmic]

I have an evilbay Auction I want to bid on that finishes at stupid o'clock local time what are your sniping weapons of choice?

So far Gixen looks like a decent option 

Has been working well for me. And it's free.

[mnementh]

I have an evilbay Auction I want to bid on that finishes at stupid o'clock local time what are your sniping weapons of choice?

So far Gixen looks like a decent option 

Has been working well for me. And it's free.

Gixen.com for over a decade.    I have no alternate; they've never let me down.  I either win or get outbid long before the feeding frenzy. 

If you really want to take no chances, they have their mirror service for 99¢ for a week; it gives redundant service in case "the tubes get clogged" and your bid is delayed. I've used it a couple times on "I really want this" items; no idea if it worked but I won them both at my price.

mnem
evilBay fears me.

[Inverted18650]

I set the Fluke 332B & the 332D side by side and fired off a few pics with their respective tops off.

[Brumby]

...I might pull the 7404 it feeds into in the desperate hope there is a fault with the 7404 that's holding the output low.  If it's the MK500P, then it looks like they are around, but not in great numbers.  If you want a laugh - have a look at the one offering on eBay: https://www.ebay.com/itm/143112726483

Well that's totally pants. Like he's trying to get the price of the whole instrument from one part; and no way of knowing if that would fix anything. There's a lot of "tested, working" parts on fleaBagy that are neither. 

I pulled the 7404 as indicated - and the MK500P performed like a champ, so that's one less problem.
Edit: I should probably load the MK500P output with a TTL input to make sure it can drive it ok.

Good job you have got further in a day than I 'felt' the need to in 6 months 

I have a few 7404 circa 1978 vintage IC's I could have included 

I think the ones I have might be a better match ... circa 1975, I think.   

   Be a REAL MAN; build it from discretes! It's  ONLY 6 of these!!!

Then you are likely to groan over at least one of the ideas I had for chip substitution.  The first is a little sub board with two 7400's wired up as a 7404 - but I'll probably just jump in the car for a 20 minute drive to Jaycar where I can get a real 7404 for $4 (ouch).

The second idea I'll keep to myself for now.  I might try it first and see how it goes before sharing...

[mnementh]

Thinking of jumpering the dead gate over to one of the unused ones? No, I've NEVER done THAT... 

mnem
 

[Brumby]

No.  Something that I fear might bring a dwagon to huff and puff....

[mnementh]

The only thing THAT BAD I can think of off the top of my head would be to rob it out of a 24xx family Tek... 

mnem
I don't bite. Well, not without permission. 

[mnementh]

Okay... I want to post a teardown on my 1KW Computer PSU... where is best? Other Equipment & Products?

Please advise soon; I'm working on the text of the teardown now.

mnem

[Brumby]

The only thing THAT BAD I can think of off the top of my head would be to rob it out of a 24xx family Tek... 

mnem
I don't bite. Well, not without permission. 

No, nothing so cannibalistic.

I might as well just say it.... An Arduino based emulator.  Yes, the propagation delay will be poor, but in some applications that won't matter at all - and in the ones that do matter, I'll just have to take that into account.  The main purpose is to enable function of a dead chip so the rest of the circuit can be checked out, ideally making my purchase of proper replacement chips a one-stop shop.  The good thing is that you can turn it into any chip you like.  Maybe use my stash of 7400's for input/output buffering.

The 7404 I will do with 7400's, but the 7442 is a definite candidate for emulation.

[beanflying]

Right Gixen sorted and beaten into ebay.com.au submission  3am alarm can be cancelled 

Laughed at the dis-functionality and farcical nature of the USA, UK and OZ governments because otherwise I would just want to see horrible things happen to them all One way rocket ride to the sun, free diving with cement flippers over the Mariana trench, Parachute training without parachutes from 10,000' ...... 

Time for more TEA and a Coffee to drink because it's to early for Gin or maybe look at migrating to NZ seems how they are finally getting a decent beer .......

[bitseeker]

Okay... I want to post a teardown on my 1KW Computer PSU... where is best? Other Equipment & Products?

Yes!

[bitseeker]

The only thing THAT BAD I can think of off the top of my head would be to rob it out of a 24xx family Tek... 

mnem
I don't bite. Well, not without permission. 

No, nothing so cannibalistic.

I might as well just say it.... An Arduino based emulator.  Yes, the propagation delay will be poor, but in some applications that won't matter at all - and in the ones that do matter, I'll just have to take that into account.  The main purpose is to enable function of a dead chip so the rest of the circuit can be checked out, ideally making my purchase of proper replacement chips a one-stop shop.  The good thing is that you can turn it into any chip you like.  Maybe use my stash of 7400's for input/output buffering.

The 7404 I will do with 7400's, but the 7442 is a definite candidate for emulation.

Arduino IC emulator? Don't forget the requisite 16x2 LCD display and keypad for IC selection to complete the Arduino look-and-feel.

[mnementh]

The only thing THAT BAD I can think of off the top of my head would be to rob it out of a 24xx family Tek... 

mnem
I don't bite. Well, not without permission. 

No, nothing so cannibalistic.

I might as well just say it.... An Arduino based emulator.  Yes, the propagation delay will be poor, but in some applications that won't matter at all - and in the ones that do matter, I'll just have to take that into account.  The main purpose is to enable function of a dead chip so the rest of the circuit can be checked out, ideally making my purchase of proper replacement chips a one-stop shop.  The good thing is that you can turn it into any chip you like.  Maybe use my stash of 7400's for input/output buffering.

The 7404 I will do with 7400's, but the 7442 is a definite candidate for emulation.

Yeah, but the 7442 is like the 7404... a $2 chip retail. Jaycar doesn't have them too? I mean... you're talking about a lot more than $8 and 40 minutes worth of hassle between the two, and if you're going for 2 parts, it seems worth it even just for troubleshooting. Especially if you can online order/pick up in store and add some resistors, caps, etc to get the online price break. 

mnem
It's a sad day when I'm the voice of reason... 

[0culus]

Successful property auction haul today. Grabbed another HP spectrum analyzer display (contemplating doing the LCD upgrade to it) which hopefully eventually will go with the 8568B RF unit I'm repairing. And got another 3455A voltmeter. And I spent less than $100 so that was a win. A number of other things were for sale that I kind of wanted, but they got bid way out of my price range.

[Brumby]

Source	7404	$ (ea)	7442	$ (ea)
Jaycar	Y	3.95	N	-
Altronics	N	-	N	-
Mouser	Y	2.96	Y (non stocked)	Call for quote
Digikey	Y	2.94	Listed, No stock	Obsolete
RS Components	Y	3.3	N	-
Wagner	Y	1.5	N	-
Element 14	Variants: HC, AC, AHC, AS, F, HCT, AHCU, LS, HCU	$0.43 - $2.15	HC variant only	2.43
Octopart	Yes, various	From $1.55	LS and HC varieties and nothing in DIP	From $0.89

Not rockin' my socks.

Then there's eBay ... Do I dare?