Test Equipment Anonymous (TEA) group therapy thread

[mansaxel]

I've only done solder bucket ones for that. It's tedious as hell. I once got volunteered to make up 20-odd DB25 null modem cables to go between Sun boxes and a console server. I was suicidal by the 5th one and definitely drunk by the 15th (as it was a pub lunch)

It is only after the last cable being soldered to the SCSI connector that you find out you forgot to place the housing onto the cable...
Don't ask why I know this...

I know this too, mostly because I've done some large multipole connectors, twice.

These days, I religiously test the assembly before I even heat the soldering iron.

Now looking into crimp D-subs. Well enabled, Cerberus.

[Fungus]

oh, you just found an eddie in the space time continuum.

Who's Eddie?

[med6753]

OK, so here's what happen to the Type 310A.

It was sitting on the bench doing a burn-in and everything appeared normal. I happen to look at it and the trace was horribly out of focus and the intensity was fixed. The intensity control was ineffective. The HV probe was still on the bench so I checked it and it had sagged to about -900V. S/B -1675V. Tried adjusting it with the HV pot and no change. Quickly looked to see if anything was burning or listened for perhaps HV buzzing indicating a short and nothing. That's where it's at right now.

So far I have checked and verified every resistor in the HV adj/focus divider circuit. All good. Today I need to do the same in the intensity circuit. The issue here is access and finding all the components. There are no parts location diagrams and I'm discovering that parts are scattered all over the instrument. I also need to check and eliminate the possibility that the CRT developed a heater to cathode short. I also went back to primary side and verified everything again. All seem good but I don't have a replacement 6AQ5 HV Oscillator tube. I don't think that's the issue but I ordered one anyway. The Type 535A uses the same tube and it would be good to have a spare on hand. And did the same for the 5642 HV rectifiers. Got 3 real cheap coming. The Type 535A uses them too.

I may do a mass replace of the ceramic HV capacitors depending upon what I find today. I don't think I've ever seen one go bad but there's always a first time. I hate working on HV circuits for obvious reasons. If it turns out the CRT or HV transformer are bad this project is fucked big time. I am hopeful it's something stupid and in after thought obvious.         

[tautech]

med, replacing HV ceramics in the EHT has cleaned up traces and Intensity/Focus issues for me in the past.
When everything else seems to measure and check as OK I normally shotgun the whole lot.
There's some well priced sources for them on Aliexpress.

[bd139]

Also https://HVstuff.com

So went through all the junk boxes looking for a project today. Turns out I actually have enough crap lying around for a power supply so I'm building one, because why the hell not.  Will just stuff a 7812 and an LM317 in it on two separate outputs. Lame but is less than half the depth of an HP supply so it can be wedged somewhere



guts currently empty but the annoying bit (panel bashing) is done.

Also put an offer in on another Fluke 25 because quite frankly I like them, a lot.

[med6753]

Bd, what was that site that specialized in HV capacitors?

[bd139]

See top line of my comment above

[tggzzz]

Also put an offer in on another Fluke 25 because quite frankly I like them, a lot.

A man of good taste.

[tggzzz]

A Metrix MX202B meter might be available soon. Anybody interested?

25µA (i.e. 40kohms/V), big scale relative to case, quirky selection mechanism, Hg cell (but conversion kit available on fleabay!)

http://public.beuth-hochschule.de/hamann/MULTIMETER/mx202.html

[Cerebus]

   

Playing the TINIEST Monopoly...

Yes, everything is the same scale as the money. My wife had to put on her glasses to read the property names on the board.

But when we let my daughter play, she is allowed to pay her rent in kisses... so BEST. FIVE DOLLARS SPENT. EVAR!!! 

mnem
Plus... she like sucks up all the doubles... freakiest thing you ever saw.

Sounds a bit sexist, how come the Boi can't pay his rent like that too? 

[bd139]

Also put an offer in on another Fluke 25 because quite frankly I like them, a lot.

A man of good taste.

Alas too cheap as well as it was a declined offer. Boo hiss.

[bd139]

I've only done solder bucket ones for that. It's tedious as hell. I once got volunteered to make up 20-odd DB25 null modem cables to go between Sun boxes and a console server. I was suicidal by the 5th one and definitely drunk by the 15th (as it was a pub lunch)

It is only after the last cable being soldered to the SCSI connector that you find out you forgot to place the housing onto the cable...
Don't ask why I know this...

In circumstances like that, which do happen, I bless the people who invented the two part housings 

[Cerebus]

I've only done solder bucket ones for that. It's tedious as hell. I once got volunteered to make up 20-odd DB25 null modem cables to go between Sun boxes and a console server. I was suicidal by the 5th one and definitely drunk by the 15th (as it was a pub lunch)

It is only after the last cable being soldered to the SCSI connector that you find out you forgot to place the housing onto the cable...
Don't ask why I know this...

I know this too, mostly because I've done some large multipole connectors, twice.

These days, I religiously test the assembly before I even heat the soldering iron.

Now looking into crimp D-subs. Well enabled, Cerberus.

Remember to get the pin extraction tool too, for when you discover that you've got pin 2 and 3 the wrong way around.

It looks like the Amphenol crimps might work with a quite generic crimp tool of the "fold around and stake" variety. Might give those a try because, much as I'd love one of the tube crushing and staking variety, I probably don't want to pay for it for the volumes that I'll ever have to do.

[Cerebus]

oh, you just found an eddie in the space time continuum.

Who's Eddie?

"When Eddie said he didn't like his teddy
You knew he was a no good kid
But when he threatened your life
With a switch blade knife"


"What a guy"

"Makes you cry"

"And I did"

[0culus]

Gotta love the cheesy action movie sequence at the beginning.  In all seriousness, though, these little radar sets were pretty neat and by all accounts used to great effect (along with early IR riflescopes) in Vietnam to detect Viet Cong ambushes on fire bases at night and remove their advantages in the dark.

That’s pretty awesome. I’ve added it to my YT queue for this evening during discord

(Along with Tony’s lab tour  )

Hah, sounds good. Of course, the radar sets were only part of an effective defense-in-depth posture that was developed to stymie all-too-effective nighttime raids by the Viet Cong. Pre-arranged fields of fire for the machine guns and mortars, acoustic sensors hidden along the trails leading to the fire base. The latter were often accompanied by remote control explosives (often carefully sited Claymore mines) in order to quickly deal with whatever was making noise in the dark.

[mnementh]

      Playing the TINIEST Monopoly...

Yes, everything is the same scale as the money. My wife had to put on her glasses to read the property names on the board.    But when we let my daughter play, she is allowed to pay her rent in kisses... so BEST. FIVE DOLLARS SPENT. EVAR!!! 

mnem
Plus... she like sucks up all the doubles... freakiest thing you ever saw.

Arh,  monopoly great game that can take simply ages to complete, without cheating that is. I have never seen one as small as that though. Was it another thrift store find?

Yup. It's the "Travel Edition." Everything you love about Monopoly but shrunk down small enough to set up on the back seat of the station wagon. 

There is one concession to the "portable" nature of this version that does change the dynamic of the game tho... Chance and Community Chest are now events on a card (the events are also slightly different from classic Monopoly, but mostly the same effect), which are chosen by a 3D6 roll. What this does is make EVERY possible event an even probability EVERY TIME, where before an event would be taken out of rotation until the stack was used up & reshuffled. This made it possible for my son and I to trade off "Advance to St Charles Place" and "Take a ride on the Reading RR" 3 or 4 times during a single game... something which normally would be almost impossible. It really does affect the balance of gameplay, which eventually resulted in me wiping him out once I had hotels on the St Charles, etc monopoly.

This makes properties which show up as events on the card ... St. Charles, Reading & Pennsylvania RRs, Illinois & Mediterranean Aves, & Boardwalk... each have an extra 2 chances (2 each at 1:15 odds for Chance & Community Chest) of a player hitting them every trip round the board.

Which is okay... it made last night's game a reasonable 2 hours. Definitely less annoying than Cheater's Edition, another Thrift store score which is just plain a rolling fustercluck.

Monopoly is a favorite "Family time" activity going back to my own childhood... it's wondermous that I get to infect my own chiddlers with this particular madness.

Sounds a bit sexist, how come the Boi can't pay his rent like that too? 

No; nothing more than a simple concession to the fact that she's LD. We still include her in family time; we just allow her to play at the level she can comprehend.

mnem
 

[bd139]

Hah, sounds good. Of course, the radar sets were only part of an effective defense-in-depth posture that was developed to stymie all-too-effective nighttime raids by the Viet Cong. Pre-arranged fields of fire for the machine guns and mortars, acoustic sensors hidden along the trails leading to the fire base. The latter were often accompanied by remote control explosives (often carefully sited Claymore mines) in order to quickly deal with whatever was making noise in the dark.

Interesting stuff. Think this might be a reading and watching rabbit hole. That entire channel is rather interesting actually. Have subscribed 

Well I just spent the last 2 hours dredging through 100x 2N3819 JFETs from Aliexpress with a test rig. Test process was:

1. Measure Idss
2. Measure Vgs(off)

Some findings:

38 matched the specification sheet for 2N3819 (marked with tippex)
40 were slightly out but probably usable so are being kept for less critical (put in "dubious but usable" bag)
17 were completely out of spec (binned)
2 let the magic smoke out (not human error -> probably high Id devices like J310's) (binned)
3 were either knackered or not JFETs (binned)

Not a terrible haul but it shows the pitfalls of buying stuff on there.

[capt bullshot]

My project for the "Tag der Deutschen Einheit":

Add some reasonable power distribution to the lab cart:

[mnementh]

oh, you just found an eddie in the space time continuum.

Who's Eddie?

"When Eddie said he didn't like his teddy
You knew he was a no good kid
But when he threatened your life
With a switch blade knife"


"What a guy"

"Makes you cry"

"And I did"

   https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg3257892/#msg3257892



Aaaaand now we've gone recursive... 

mnem

[mnementh]

My project for the "Tag der Deutschen Einheit":
Add some reasonable power distribution to the lab cart:      

Jeezus... you poor suffering bastard. I understand that it is safer overall... but the sheer volume of oversized plastic electrical connectors there is just... painful. 

mnem
Like watching a guy stuff 6 lbs in a 5lb sack.

[Saskia]

You mean Tag der Kulturrevolution

[Kosmic]

My project for the "Tag der Deutschen Einheit":
Add some reasonable power distribution to the lab cart:      

Jeezus... you poor suffering bastard. I understand that it is safer overall... but the sheer volume of oversized plastic electrical connectors there is just... painful. 

mnem
Like watching a guy stuff 6 lbs in a 5lb sack.

hehe I was thinking the same.

[med6753]

Been working on the Type 310A for a few hours and just getting more pissed off and disgusted. 

But I have verified every single resistor in the primary and secondary side of HV as being good. I also verified no heater to cathode short in the CRT. It measures 27K right across R745 as it should. At least when the CRT is cold. Powered up could be a different story but for now I'll assume it's OK. I also verified all the pots.

So I'm at a halt now until the 6AQ5 and 5642 tubes arrive. I'm also going to bite the bullet and order then mass replace all those ceramic HV caps. I'll check Mouser first and if they don't have them then go with the site that bd posted.


   

[med6753]

Capacitors have been ordered. Turns out Mouser had everything needed in stock. Should have them Tuesday or Wednesday.

[capt bullshot]

So, finished the power distribution.
Added that under-desk cable organizer from Ikea-Land.

The orange strips are old ones, but I've rarely seen better ones.

For our North American friends, this bulky red connector with the 5 * 2.5mm^2 cable can deliver a proper 10kW (3-phase 400V / 16A).