missing pin on 500 series gear

[Seditionary]

Hey guys,

As I am (as always stated) a sort of electronics beginner even though I've worked on lots of stuff... how do you fix a broken pin / trace on a 500 series board?  I bought a 550a eq that was soldered to and is missing a pin/trace.  I guess it is for the "low" output according to the schematic.  The eq seems to function (and still sound awesome somehow), but I'm sure I'm missing the "lo" of the signal, right? 

Is there a good way to fix this? 

Thanks as always, friends.

 

[mitsos]

actually that's pin 5. Pin 1 is above the cut  in the edge connector.  pin 5 = common, it's also connected to the power ground (pin 13), so no need to fix anything.

 

[bruce0]

so no need to fix anything....

because 5 is usually strapped to (corrected - mitsos is correct) 13 (and sometimes 1 too) somewhere (back in the psu, in the rack slot, or (hopefully on your card), on the card.

The pinout is...

you can get adhesive copper trace repair tape, though you may have to dissolve the glue and use epoxy for the stresses involved here. You could try just sicking it on but epoxy would work


Suggest you see if 5 is strapped to 1 before moving on. 

 

[mitsos]

I should be sleeping... too much coffee today.

so no need to fix anything....

because 5 is usually strapped to 1 somewhere (back in the psu, in the rack slot, or (hopefully on your card), on the card.

Do you mean pin 13?    Pin1 = chassis, not ground. 

Maybe I wasn't clear in my previous post, but Pin 5 (the missing pin in his picture) and pin 13 are both ground (pin 5 is audio ground and 13 is power ground), the different pins exist to allow for the possibility to separate audio ground from PSU ground, if/when necessary. (hardly ever necessary in most stuff we do here).  It's not necessary to separate grounds in his EQ because, as you can see in his picture, API connected audio ground to pin 13. Most 500 series modules are like that.  The pins exist so you have the option. Some modules might leave them disconnected and use a jumper, his 550 connects them outright.

That's why I said there is no need to fix anything, there is nothing wrong.

 

[mjrippe]

Grounding aside, you might want to take some desoldering braid and clean the excess solder off of those traces so you don't damage the card edge connector contacts.

 

[pucho812]

careful with that wic, it can potentially cause more damage then good or maybe that's just my experience as I never was good with the wic. I prefer a proper desolder station for any of that kind of work.

 

[JohnRoberts]

Welcome to the confusion surrounding ground and power ground and audio ground, etc.

In that case the parallel connection of multiple grounds works in your favor to prevent catastrophic failure but the module may experience inferior performance or issues in some applications.  For example an external unbalanced connection frying to grab the audio low through that finger will get nada.

I am not aware of a robust way to repair a lifted edge finger. I can imagine a very thin piece of copper glued to the PCB but I would not expect that to survive multiple plugging. 

From that picture it looks like somebody added solder to the fingers to try to improve marginal mechanical contact connections. Putting solder on top of gold plating seems counter productive, or less than professional.

I would be tempted to clean up the very sloppy added solder, especially between fingers, but be careful since too much heating is probably how you lost that one missing finger.

JR

 

[abechap024]

Looks like somone wanted to rack it without a 500 series box?

I would take a gold finger from an unused pin, and super glue it in place and solder the broken trace and the new finger together.

 

[joaquins]

Just asking... conductive paint wouldn't help here? some of them could be soldered on it to have better contact...

JS