Test Equipment Anonymous (TEA) group therapy thread

[xrunner]

Woo-Hoo the FG501A is working again - a bad LM324 quad op amp! 

[smurph]

Nice!  I feel as though I need one now.  You know, pair it up with a SC504 or something.  And maybe a PS503.  The possibilities are endless!

[bitseeker]

The possibilities are endless!

Yes, they are. Long live the TEA thread.

[xrunner]

Something I've wondered about ...

Take for example the FG501A I've been working on. It has 14 pin DIP ICs - 10 of them. Some are in sockets and some are not.

Why did they design it like that? Did they think the ones that they put in sockets would be the ones that might fail? The fact is, the one that did fail was not one they socketed from the factory ...

Any thoughts? 

[Brumby]

Any thoughts? 

Do you have another FG501A...


.... that you don't want?   

[tautech]

Something I've wondered about ...

Take for example the FG501A I've been working on. It has 14 pin DIP ICs - 10 of them. Some are in sockets and some are not.

Why did they design it like that? Did they think the ones that they put in sockets would be the ones that might fail? The fact is, the one that did fail was not one they socketed from the factory ...

Any thoughts? 

Try swapping some of the same IC's around (note their original locations) and see how it might throw the Cal out.
They were clever guys back in the day...............

[xrunner]

Do you have another FG501A...

.... that you don't want?   

Not yet ... 

[Cubdriver]

Do any of the socketed ones show signs of rework?  If so, perhaps as ICs failed in the past, whoever replaced them put sockets in too.

Just a guess.

-Pat

[Cubdriver]

Ok, belay my last post.  I just went down and looked in my to-be-worked-on queue, and have an FG 501A.  I popped it open and just as you found, some chips are socketed and some are not.  I see no evidence of rework on the socketed ones.



-Pat

[tautech]

Ok, belay my last post.  I just went down and looked in my to-be-worked-on queue, and have an FG 501A. 

You know you have it bad when you can't remember what you've got. 

[Brumby]

Ok, belay my last post.  I just went down and looked in my to-be-worked-on queue, and have an FG 501A. 

You know you have it bad when you can't remember what you've got. 

It depends on how the question is asked.

If it's "What gear do you have?" and you miss out on listing something like an FG501A, then you can't be held to be too bad.

However, if someone asks "Do you have an FG501A?" and you say "No" - but find there WAS one in your collection ... then other questions can be asked.

[Housedad]

wow, Xrunner.  I remember something about sockets from long, long ago.  I asked the very same question to a computer system designer/CEO/manufacturer named Bill Godbout. (late 1970's, I believe) I was wondering why he had some ic's in sockets and some soldered on a I/O board for the S100 buss that he manufactured.  His reply was two fold:  that it allowed for critical parts to be upgraded to more reliable and faster ones in the future if needed, and the sockets provided more decoupling capacitance in the circuit.   I did not understand that last part for many years.  I'm still not sure I understand it completely now.

[Cubdriver]

Ok, belay my last post.  I just went down and looked in my to-be-worked-on queue, and have an FG 501A. 

You know you have it bad when you can't remember what you've got. 

It depends on how the question is asked.

If it's "What gear do you have?" and you miss out on listing something like an FG501A, then you can't be held to be too bad.

However, if someone asks "Do you have an FG501A?" and you say "No" - but find there WAS one in your collection ... then other questions can be asked.

    With the TM 500 stuff, at this point other than for a few distinct things, I'd have to say "I gotta go look".  I bought a lot of a dozen or so things in a lot from the 'bay about a year or so ago.  A few of them were power supplies, but as for the rest, I really can't recall off the top of my head.  The SG 505 and AA 501 I clearly recall (as those were what got me started on this stuff), but the others, as I've not yet gone through and wrung them out, merge into a blur.  And now xrunner's got me wanting to revive some of those TM 500 series searches.   

-Pat

[Cubdriver]

And as for memory, I have a mind like a steel trap!!  (Rusty, and illegal in 37 states...)

-Pat

[Brumby]

With the TM 500 stuff, at this point other than for a few distinct things, I'd have to say "I gotta go look".  I bought a lot of a dozen or so things in a lot from the 'bay about a year or so ago.  A few of them were power supplies, but as for the rest, I really can't recall off the top of my head.

Knowing there's a group of unspecified things that may contain the item of interest is a positive indication.  It means you're still OK .... for now.

[Cubdriver]

Knowing there's a group of unspecified things that may contain the item of interest is a positive indication.  It means you're still OK .... for now.

LOL - yes, being aware of their presence is a good thing, and even better, I actually know where they are and can put my hands on them!

-Pat

[Brumby]

    Brilliant.  That means you are as right as rain!

[mtdoc]

Damn, this discussion is making me realize I need to go look in my lab and see which 500 series modules I have. It's late here now, I'd better write a note to myself so I remember to do that tomorrow...

[Rerouter]

I think a few of us might have developed Pokemon syndrome about these plug ins, there is a compulsion to collect them all..

[rachaelp]

You know you've been looking at this thread too much when you write in a google chat message to your partner "Time to go get a cup of TEA" and capitalise it like its the acronym from this thread!

[xrunner]

Try swapping some of the same IC's around (note their original locations) and see how it might throw the Cal out.
They were clever guys back in the day...............

The original socketed chips (not the one I put a socket in for):

CA3046 Quad NPN transistors (3 chips)
74LS132 NAND gate
UA723 Vreg
LM324 Quad Op Amp

Not socketed:

74S74 D flip flop
MC1514 differential comparator
LF356 JFET
741 Op Amp
Numerous transistors ...


What Tautech mentioned is intriguing. The only place where I might think they put in sockets for swapping would be the sine shaper circuit. It uses 3 quad NPN transistor arrays to make the sine wave from a triangle wave. It's possible they wanted to swap the arrays I guess, for the least distorted sine wave (but there are adjustments for that too). However that would not explain the others, which aren't really that critical, as far as a generic part. I mean a quad NAND gate swap? But I might buy it for the NPN arays.

wow, Xrunner.  I remember something about sockets from long, long ago.  I asked the very same question to a computer system designer/CEO/manufacturer named Bill Godbout. (late 1970's, I believe) I was wondering why he had some ic's in sockets and some soldered on a I/O board for the S100 buss that he manufactured.  His reply was two fold:  that it allowed for critical parts to be upgraded to more reliable and faster ones in the future if needed, and the sockets provided more decoupling capacitance in the circuit.   I did not understand that last part for many years.  I'm still not sure I understand it completely now.

Possibly, but I don't think a quad NAND gate is going to be upgraded.  The decoupling capacitance - maybe, but I don't think a socket contributes that much. It would depend on the application - maybe in a high frequency RF circuit it would contribute enough to make a difference.

[tautech]

There will have been very good reason why Tek put in sockets for some and not others, my idea is just a hunch but Housedad might be closer to the mark.
Park this one away, in time we'll spot something that points to why this is so, the trouble will come when we need to find this again to set the record straight. 

[mtdoc]

Someone could post that question on the Yahoo Tek scope group. One of the retired Tek engineers there would likely know.

[smurph]

I'm Jonesing for some TM500 plugins and maybe a TM5006 chassis but I just had to get new glasses.  Trifocals this time around!  Damn.  That hit hard.  That will teach me to lose my glasses!  So there went the money for my addiction.    I think it is God's cruel way of telling me I have a problem.  It turns out I'm pretty addicted to seeing as well.  I was just about to pull the trigger on a Fluke 6060A too.  Bummer. 

Steve

[xrunner]

There will have been very good reason why Tek put in sockets for some and not others, my idea is just a hunch but Housedad might be closer to the mark.

Someone could post that question on the Yahoo Tek scope group. One of the retired Tek engineers there would likely know.

Until then -

"It is a riddle wrapped in a mystery inside an enigma"

Sir Winston Churchill

I'm Jonesing for some TM500 plugins and maybe a TM5006 chassis but I just had to get new glasses.

Oh yea the TM5000 takes the more advanced units that can do GPIB - I have many fond memories of them. I'm only into the 500 series now but it's only a matter of time.