ever had an 4X4 opamp socket be the culprit?

[Derringer]

I just spent many hours debugging a homebrewed circuit and pcb layout
went over the schematic
re-breadboarded it to make sure it worked
compared the known working schematic to my pcb layout multiple times
kept getting about 7.5 volts on every pin except 4 and 8 on my pcb (not on the breadboard)
looked all over for bad joints
tried isolating sections and testing on the pcb and the breadboard

WTF?!?!?!?

finally said screw it, the only thing that's different from the breadboard and my pcb was the socket
replaced it and BAM .. normal voltages

Could it have been a bad solder joint on the socket? Absolutely, that makes most sense.
But I checked them all with my DMM with and without the chip in. Everything read right compared to my breadboard when I had the chip out (chip out on BBoard too).
With the chip installed in the socket, 7.5 volts on 1, 2,3 5, 6, 7

soooo frustrating

but now my modded opamp bigmuff with switchable octave section (this was the section that gave me problems) is finally boxed up and works!
phew

[Kipper4]

Good work.
Debugging can be a pain in the proverbial.

[R.G.]

People laugh at me about this, I'm sure, but I don't use sockets at all unless (a) the chip is very expensive and hard to unsolder or (b) I am planning to swap out things for trials.

Opamps cost $0.25 mostly, with a few in the $1.00 range, and a very few lah-de-dah ones for special purposes in the several dollar range. A socket can cost more than the opamp going into it, and sockets are harder to remove and replace than ICs.

I solder them all in and count on being able to unsolder or clip out the ones I want to replace. But then I hardly ever replace a chip.

And yes, I've had enough bad socket contacts to be suspicious of socket connections - as you will always be now.

[Derringer]

as always, you make a good point R.G.

I bypased the sockets for transistors on this build (a first for me) ... perhaps I should take that plunge with my run-of-the-mill dual opamps next

[midwayfair]

The cheap sockets, yes. I had a delay that drove me nuts because the chip wouldn't make contact with some of the socket holes. But the ones with the pins like in the in-line sockets, never.

I fried one too many chips with my iron to go back to not using sockets ...

[petey twofinger]

i seem to remember a few maybe 6 months back someone here had a bad one that wasted a decent amount of time . i BELIEVE there is a superior design of socket :

( http://images.monstermarketplace.com/electronic-component-adapters/8-pin-dip-ic-socket-p-n-081001-640x640.jpg )






, i did order some although couldnt find them the other day ... lucky enough the cheapo worked well in he uglyface . perhaps these bad socket issues are becoming more prevalant , either way ... i shudder .

i swappped several chips in the uglyface , the lm386 pjp sent me was the winner , also the 555cn was better than the ICM7555 . thanks to dino for the mod notes and Pnk Jimi for the chip !!

[R.G.]

there is a superior design of socket , i did order some although couldnt find them the other day

I won't use a socket that's not a "machined pin" style. These are NOT the folded-up sheet metal terminals. Each pin gets a round "cup" terminal with a round or square-post leg. They are not cheap.

But then, increasingly, neither is my time.

[petey twofinger]

oops i added that pic , edited that in to be a bit more clear , but honestly i am just asuming this design of socket pictured above are the superiour design .

[Mark Hammer]

1) Many of the chips we use do not have shiny pins.  Perhaps they are dull-looking because they've been sitting in the parts drawer too long, and maybe they arrived at the parts-distributor we bought them from that way.  Sometimes, it's a good idea to take your X-acto knife and scrape them back to shinyness.

2) Many of the sockets we use are of questionable quality, in terms of the contact they make.  As I keep harping about, in the land of electrons, a micron gap is like jumping across the Grand Canyon.

3) Brother Keen's inclination to avoid sockets, wherever feasible or prudent, notwithstanding, if you are going to use them, use the ones with machined pins.  Personally, I have taken to buying strips of machined pins, which can then be broken off, as needed, in fixed amounts.  So, the same strip of 40 pins could be used for transistor sockets, LED sockets, or pairs of 4 pins for chips, and so on.

4) People are probably getting sick of hearing me blather on about it, but there have been several occasions when I have been able to resurrect pedals with the stuff called Stabilant.  It is a contact enhancer, and a little poppy-seed-sized droplet on IC socket pins can bring the dead back to life by bridging that perilous micron gap.

5) Don't forget that sometimes, a pin may not even BE in the socket, even though it might look like it.  I've had plenty of occasions when a pin got bent underneath the chip, and looked for all the world like it was inserted, taking me irritating amounts of time to realize it.

So, yeah, now that I've gotten over the urge to swap dual op-amps, I tend to solder many chips straight to the board now.  he advice to clean the surface of the IC pins still holds, though.

[R.G.]

1) Many of the chips we use do not have shiny pins.  Perhaps they are dull-looking because they've been sitting in the parts drawer too long, and maybe they arrived at the parts-distributor we bought them from that way.  Sometimes, it's a good idea to take your X-acto knife and scrape them back to shinyness.

Use a pencil eraser instead. Too easy (for me, anyway) to cut through the plating to harder-to-solder base metal.

4) People are probably getting sick of hearing me blather on about it, but there have been several occasions when I have been able to resurrect pedals with the stuff called Stabilant.  It is a contact enhancer, and a little poppy-seed-sized droplet on IC socket pins can bring the dead back to life by bridging that perilous micron gap.

Caig Labs DeOxIt 5 is good too.

[Kesh]

Almost related anecdote: I designed a board upside down style, so everything is mirrored, then forgot I was doing this. Easy to turn transistors around, but ICs, impossible. Or so I thought. I realised I could turn them upside down like an upturned %^&*roach, bend all the pins backward, and insert upside down. No problem.

[artifus]

haha! the phantom raspberry blower strikes once again! 

[Paul Marossy]

Funny how people can have such varied experiences. I have used the cheapie folded metal opamp sockets on dozens of builds and never once had a problem with the socket itself.

[R.G.]

As we say in Texas, never a horse that couldn't be rode, never a rider that couldn't be throwed.

[Paul Marossy]

As we say in Texas, never a horse that couldn't be rode, never a rider that couldn't be throwed.

Ha ha, that's true. 

[Mark Hammer]

4) People are probably getting sick of hearing me blather on about it, but there have been several occasions when I have been able to resurrect pedals with the stuff called Stabilant.  It is a contact enhancer, and a little poppy-seed-sized droplet on IC socket pins can bring the dead back to life by bridging that perilous micron gap.

Caig Labs DeOxIt 5 is good too.

What several people with busy repair shops have recommended is the one-two punch of a shpritz of DeOxit, plus a dab of Stabilant.  DeOxit only cleans the surface; Stabilant bridges the contact gap.

[bluebunny]

Any tips for soldering ICs, R.G?  Other than practise your technique and get in and out fast?  If I'm lazy, I'll solder diodes and transistors without using a heatsink, and I haven't fried anything yet, so are ICs any more/less susceptible to heat?