Another bad repair job.

[Sglaw461]

Yet another fine example of a repair done at a reputable electronics shop, this time on a, Pioneer SX-850. More solder please, that'll fix it. Anyhow, soon it will breathe a sigh of relief.

 

[nj pheonix]

While its clearly not a nice solder flow.
I've seen boards where you don't get the flow you want. If you know the traces are iffy and lift and you tried to get it to flow more than once and it didn't. Sometimes you're better off not forcing the issue.
No idea why that looks like that. If it works fine its less than butcher work IMO

 

[gadget73]

Seen and done worse myself. As above, sometimes it just won't flow cleanly. Usually its contamination on something but I have had issues mixing leaded and unleaded solder. Probably not the issue here though.

 

[Sglaw461]

It wouldn't be so bad if it worked but 5 out of 6 tracks were cracked. I have also done this but I at least scrape the track down to bare copper for 1/4" so the solder can extend across the bad area. I agree about the "unleaded" silver solder, seems to me to be more of an issue in Yamaha though.

 

[Sglaw461]

Nasty. I don't know if the pads are gone or if there is flux hiding them?

3 of the pads were gone, 5 out of 6 had broken tracks.

 

[the skipper]

When a PCB is assembled, they use a method called "wave, or flow, soldering. That turns out a very pretty solder joint which is difficult, if not impossible to recreate when servicing the equipment. They employed this stuff in a facility I worked at in the mid 70's.

When repairing the boards, one runs the risk of destroying or lifting the runs with too much heat. If it works, be happy.

https://www.pcbway.com/blog/Engineering_Technical/Wave_Flow_Soldering_Process.html

 

[cpt_paranoia]

No idea why that looks like that

Lots of possible reasons.

Solder heated too long, without additional flux. Solder has gone 'pasty', rather than flowing nicely.

Too much solder applied (either they didn't remove the original, or they just added too much).

Too small or too cold/low power an iron.

Mixing lead and lead free solders.

But, judging by the (overheating) discolouration of the pcb, I'd go for the first option.

 

[nj pheonix]

If the pads are gone as the OP says, there's little for the solder to flow to

 

[nj pheonix]

When a PCB is assembled, they use a method called "wave, or flow, soldering. That turns out a very pretty solder joint which is difficult, if not impossible to recreate when servicing the equipment. They employed this stuff in a facility I worked at in the mid 70's.

When repairing the boards, one runs the risk of destroying or lifting the runs with too much heat. If it works, be happy.

https://www.pcbway.com/blog/Engineering_Technical/Wave_Flow_Soldering_Process.html

Thanks for the link
About 40 years ago (feels like longer) i worked for a company that we did assembly , then send boards out to be wave soldered then we did final assembly with finished boards.

I never actually saw the process.

 

[swechsler]

When a PCB is assembled, they use a method called "wave, or flow, soldering. That turns out a very pretty solder joint which is difficult, if not impossible to recreate when servicing the equipment. They employed this stuff in a facility I worked at in the mid 70's.

Hmm, I didn't know they used wave soldering that far back. ISTR seeing pictures back when this receiver was new (1978) of a Pioneer factory (or similar) showing assembly line workers using soldering irons to assemble the equipment.

 

[the skipper]

Hmm, I didn't know they used wave soldering that far back. ISTR seeing pictures back when this receiver was new (1978) of a Pioneer factory (or similar) showing assembly line workers using soldering irons to assemble the equipment.

They might have there. I worked for an American company in '77 when I was exposed to this.

But, some assembly still had to be done by hand, such as wiring the sub assemblies together with wiring harness' and the components were still placed on the circuit boards by hand.