contaminated soldering surfaces

Well if it's under the solder of course it was during manufacture, but it could be earlier in the process as well. Right now I assume when you say tags you mean pads, the copper surface on the board right ?

It may have well been the photo resist. I worked for a PCB manufacturer for a short time when I was younger and I know cleanliness is esential. Somebody screwed up, and now I would wonder if the problem is not just a one time occurance. If it is on the same part of the board in more than one unit, the process was faulty. It's more likely though that it was just a one time thing, or maybe just a few. When they run these things through a bath maybe the fluid got low or something like that.

In this case I guess the photoresist was conductive enough to let the unit work, and the thermal mass of the solder during the wave soldering was enough to make some kind of bond. It obviously didn't last forever but a soldering iron simply cannot do what a pool of molten solder can.

I would be VERY interested to know if the same problem is found again on different specimens of the same model.

"Nutcase Kook"

Jack sockets and valve base pins are generally nickel plated, which is very shiny, corrosion resistant and solders easily. However, if the plating solution is contaminated by zinc or other metals - then the result is dull and not corrosion resistant for long.

Peavey may have been supplied such parts ( eg from China ) and installed them on the PCBs when right on the edge of being usable - and now they are unusable.

Anecdote:

I bought some Neutrik Speakon PCB mount sockets from the Australian agent last year. What I got may have been old stock and the solder tags were all but impossible to solder. Had to scrape every one with a blade and apply humongous amounts of heat and extra solder to get a result.

.... Phil

of

process as

over

I did notice an amount of black copper sulphide? corrossion over the brass of the stand-off power switches - more like usual 30 years of black from air bourne sulphurous gases. This was failure to solder onto the pins themselves, the pcb pad solder adherence seemed ok. I still tend to a production problem as just one valve base Belkin and, not at component making, as the jack sockets are Ream UK. Maybe contamination by flood or fire or something like that at pre-production parts storage . If it was greasy hands of a procuction operative I would not expect both surfaces of each tag and all tags to be affected

only,

film

amateur

Replace

brass

air

not

contamination by

If it

surfaces

I'll see if the owner uses it near an oil burner or something that may locally contaminate. The mystery is why just one of the 5 valve sockets affected. Until the surface of each tag was abraided back, the solder would not take, just as though they were made of stainless steel. All the other solder joins look perfect , not the slightest trace of greyness or surface crazing . The owner's cat found the front grill ideal as a scratchpad for itchy claws, perhaps extgremely well aimed cat urine, but again no suspicious staining inside

My guess(tm) is that the lugs were cadmium plated. Cadmium can be soldered with silver solder, but barely with regular 63/37. If you must solder to cadmium plating, use a rather highly activated rosin flux (i.e. acid), and wash off the flux before it rots your wiring and components.

Got a UV torch? Shine it on the wiring and see if anything glows. It will detect fungicide, conformal coatings, mouse urine, some chemicals, and counterfiet money.

Incidentally, the next time you have such a question, kindly supply some kind of physical description or photo. The color of the lugs and tabs might be useful for determining the composition.

"Jeff Liebermann"

Wot bollocks.

... Phil

Good point. I thought that they soldered the large components to the PCB by hand.

I'll admit that I'm speculating on this, but I can't seem to think of a better explanation (mostly due to a lack of a proper description and photos).

"Jeff Liebermann" "Phil Allison"

" My guess(tm) is that the lugs were cadmium plated. Cadmium can be soldered with silver solder, but barely with regular 63/37. "

What maker would use a " barely solderable " plating on valve base pins or jack sockets ?

BTW:

I see Peavey amps all the time and bad solder joints are common in examples over 10 years old - but most of them are due to heat cycling and mechanical stress.

... Phil

I didn't want to confuse you with too much information.

Good question. I usually don't ask why until after I've determined that it's a real problem. It could be a bad lot of parts. However, reading between the lines of the highly abbreviated original description, there are two components involved, the jacks and the valve sockets. It's unlikely that Peavey bought two different barely solderable components. So, my guess is probably wrong. (See... I'm easy).

It seemed like a possible culprit at the time. If I were to limit my replies to only those things which were verifiable, 100.0% accurate, and not subject to debate, then I would never post anything.

Thermal cycling and mechanical damage will create a bad connection, but will not affect the solderability of the lugs.

"Jeff Liebermann"

How pathetic.

Piss off.

It had been kept in a shed for a couple of years

rass

air

ot

by

it

es

Do you mean Belton sockets? I don't believe Belkin makes anything for vacuum tubes.

If so, and if these data sheets are representative, the lugs are either tin plated or solder plated:

I found the korean website for Belton, but their tube socket data sheet would not display for me.

air

not

by

it

surfaces

Do you mean Belton sockets? I don't believe Belkin makes anything for vacuum tubes.

If so, and if these data sheets are representative, the lugs are either tin plated or solder plated:

I found the korean website for Belton, but their tube socket data sheet would not display for me.

mindslip on my part, I'd been playing around with wifi kit