Op Amp Test Jig (Five Fish) Questions....

[PeteJE]

I have built an op amp test jig (the one from Five Fish Audio).  Now I need to know how to use it, lol!  I am not an electrical engineer, more of an assembler with good success and some projects.  I am building my own op amps (gar kits and whistle rock audio kits), and want to at least power them up and do any basic test I can with dmm and/or oscilloscope.  Any overview advice would be of great help! 

Specifically on the test jig:
-jumper for buffer or amplifier
-jumpers for Non-inv. buffer or Inverting
-jumpers for 0db through 72 db of gain
-a switch for 10k or 600 ohm load
-input and output bnc jacks for signal gen. and oscilloscope
-probe spots for TIN+ and TIN- and TOUT
-probe spots for TV+ and TV-

How should I use and what is bare minimum to check?  What if DMM only (until I get sig. gen and oscillator)?

Op amps will be used in CAPI LC53A, VP28, other mic pres, etc.

My experience - I have successfully built 2 JLM LA500s; untested gar 1731 and gar 2520; and have more op amps and an LC53A waiting here to start on......

I am admittedly just a good instruction follower and build these like legos, lol, but not knowledgable enough to know exaclty what to look for to help me assure success with my op amps on this test jig.  I appreciate any information and help!

 

[pucho812]

I have one of those test jigs. All those jumpers are for testing your opamp and how it is functioning in circuit

i don't use it till it's fullest potential but I run any suspect opamps on it to see if they are working. I go in and out via the AP machine in the shop. So many times I have had other techs saying must be the opamps, only to show them those doa's are working just fine. When they go at around 50 dollars on up, you better be sure replacing is the right move for a customer.

 

[woolie]

Did you ever make any progress? I have exactly the same issue. Most importantly, I'm not sure which way to put in the two leds on the testing jig board. There don't seem to be any polarity indicators on the board.

 

[pucho812]

I had to trial an error my leds. I have a full desoldering station so easy to remove them and place with the correct polarity.

MY only issue, I used the same color for both leds which in hindsight I would have done different colors for each power leg.

 

[noiro]

Ok it's an old topic but anyone ever had some inside on how to use the jig and run a proper test with it? better late then never don't you think ;-)

 

[Bullfish]

I could use some guidance on this thing as well. I think I’m using it properly but I’m truly unsure.

 

[JohnRoberts]

dead thread walking....
===
Back in the 70s when op amp QC was not as good as now, I used to test op amps 100% before shipping them to my kit customers, mainly so we could both know that the op amps were good before the customers touched them.

I would buy thousands at a time of TL074s. To test them I would run all four sections in series, unity gain inverting. To trick the op amps into thinking they were operating at high gain, I would wire in a small resistor capacitor coupled from the - input to ground.

Out of a thousand op amps each test run I would find low single digit culls. They mostly still worked but were unusually noisy a sign they may have other things wrong. By the end of my kit business days the IC makers QC was good enough that I stopped testing them.

JR

 

[Bullfish]

I got it to test the Opamps I was building. I’m not as sure about my abilities and wanted to have a way of independently verifying if the opamps I built were functional. Well at least some sort of semi quantifiable info about the opamps.

 

[JohnRoberts]

Test them similar to how you plan to use them...

over stressing them with higher noise gain and perhaps heavier loading may help weed out weak sisters,

JR

 

[ct.waveform]

dead thread walking....
===
Back in the 70s when op amp QC was not as good as now, I used to test op amps 100% before shipping them to my kit customers, mainly so we could both know that the op amps were good before the customers touched them.

I would buy thousands at a time of TL074s. To test them I would run all four sections in series, unity gain inverting. To trick the op amps into thinking they were operating at high gain, I would wire in a small resistor capacitor coupled from the - input to ground.

Out of a thousand op amps each test run I would find low single digit culls. They mostly still worked but were unusually noisy a sign they may have other things wrong. By the end of my kit business days the IC makers QC was good enough that I stopped testing them.

JR

I wonder how many weeks of testing it would have been before I realised you could test all four at the same time? Ironic to think that TLOs must be high on the leader board of op amps that have been tossed in the bin without checking whether they were the culprit or not. So cheap as to not be worth a second thought but they were once right up there at the cutting edge. I still like them as a budget audio op amp, though the LF353 is rather more refined, if a little less ballsy.

 

[FIX]

When I tested 2520s (when I owned API) I had a small AC transformer with 6V AC out, ran that into the input of a rack of 100 2520s running at 2X gain, then they all went into a 100 ohm load, with a 3K R into a red/green LED. Each amp had thermal fuses in case one bit it. If the LED was orange, it was fine. If off, it was dead, if red it was latched to the + rail, if green, the - rail. That all went into a burn in oven at 125 degrees for 48 hours...