I am stupid and a digibete. Some years ago ]i posted a photo, but how? My photos dont have an URL, they are in my phone. How des itwork?
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After getting my AV9000 preamp up and working again, I was able to use the same technique to get a Marantz SR7400 receiver up and running again. It was throwing a "check pow5" error message, indicating a problem on the +5Vpower supply and I took it out of service a few years ago. Tonight, I pulled the PSU board and found five cracked solder joints on the bottom of the PCB - all of which were connected to ribbon cable harnesses. I reflowed each of them, put it back together again and it's back up and running without any error codes.
Thanks for posting about this. It seems to be more of a common problem than I knew about. I wonder how many receivers have been thrown in the trash for a simple fix like this? How visible were the cracks?
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Not hard to find, but you have to look carefully with a bright light and a magnifying glass. This one is more obvious than some of the others were.
I've also been wondering how many "perfectly good" receivers have been ditched because of a relatively simple problem like this. When this unit failed, I refused to ditch it because I knew it was something simple. I just didn't know what it was or where to look. Now I have a new thing to look for when repairing devices.
I've also been wondering how many "perfectly good" receivers have been ditched because of a relatively simple problem like this. When this unit failed, I refused to ditch it because I knew it was something simple. I just didn't know what it was or where to look. Now I have a new thing to look for when repairing devices.
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In the trade, and at the shop, we called them "ring joints", and I must have re-soldered tens of thousands of those little bastards over the decades.
It's the by-product of "wave soldering" on circuit boards, something rarely ever seen with hand-soldering/point-to-point designs - that's why "vintage" stuff lasted for so long without issues.
As for being a "relatively simple" problem, it sometimes caused catastophic failures, making the repair tedious and expensive.
I've also found that these types of cracks tend to appear on the larger joints, like connector posts such as you found. The wave soldering process made the electrical connection (for awhile anyway), but didn't deposit a large enough fillet for a good strong mechanical union. This problem has also been nearly exclusive to single-sided boards in my experience. Multi-layer boards with their plated-through holes are nearly immune to it, and worth the additional cost for this feature alone in my opinion.
Like wiseoldtech, this one little failure mode has paid a lot of bills at my shop down through the years, that's for sure.
Like wiseoldtech, this one little failure mode has paid a lot of bills at my shop down through the years, that's for sure.
Old-style double plated boards had issues with the tiny rivets used to bind the top/bottom foils.
Eventually, those rivets would lose contact with the foils and cause all kinds of havoc.
I must have seen just about every kind of service issue over 45 years in the biz.... my god I'm an old fart!
The ole "been there, done that, got the T-shirt" applies here. 😱
Eventually, those rivets would lose contact with the foils and cause all kinds of havoc.
I must have seen just about every kind of service issue over 45 years in the biz.... my god I'm an old fart!
The ole "been there, done that, got the T-shirt" applies here. 😱
I am pretty good at spotting bad solder joints.
One, I had a hard time to find was inside a car relay. On a VW Golf GTI the relay activating the fuel pump.
I had this damn pump failed a couple of time, finally stranded, had the car towed where they said, it needed a new pump and fit a new one. No car for few days and a stiff bill.
Few months, later, it failed again.
Then I had the car towed at my place, and stubbornly, debugged the damn thing.
Little by little, I arrived at the bug, it had to be inside the relay. I opened it and immediately saw a solder that had not fully flown so making a poor contact after many years unseen.
Intermittent failures are tough and costly in time and money.
Then I added a small switch at this relay to set it in a failed state when parked in not so safe places. They could hot wire the ignition, with no fuel, no way it could start.
BTW Beware of testing a fuel pump on a battery out of it's normal installation inside the fuel tank. This can be deadly
One, I had a hard time to find was inside a car relay. On a VW Golf GTI the relay activating the fuel pump.
I had this damn pump failed a couple of time, finally stranded, had the car towed where they said, it needed a new pump and fit a new one. No car for few days and a stiff bill.
Few months, later, it failed again.
Then I had the car towed at my place, and stubbornly, debugged the damn thing.
Little by little, I arrived at the bug, it had to be inside the relay. I opened it and immediately saw a solder that had not fully flown so making a poor contact after many years unseen.
Intermittent failures are tough and costly in time and money.
Then I added a small switch at this relay to set it in a failed state when parked in not so safe places. They could hot wire the ignition, with no fuel, no way it could start.
BTW Beware of testing a fuel pump on a battery out of it's normal installation inside the fuel tank. This can be deadly
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Thanks.
The relay coil is activated by a transistor, the disable switch opens this connection ( not at the big current given by the relay contact to the pump ).
This car whith a gas injection engine has a safety feature. The fuel pump is disabled when the engine is not running. This is taken care by a simple electronic at this relay, detecting pulses given by the ignition system.
The relay coil is activated by a transistor, the disable switch opens this connection ( not at the big current given by the relay contact to the pump ).
This car whith a gas injection engine has a safety feature. The fuel pump is disabled when the engine is not running. This is taken care by a simple electronic at this relay, detecting pulses given by the ignition system.
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I had a faulty relay in a VW once... You just plug in a normal relay so it runs all the time, safety be damned. Maybe this post belongs in the "stupid" thread. To be 20 again lol.
If it came down to that or being stranded and needing to be towed with no money to pay for it, guess which I'd chose? 🙂
It's nice to not be a flat broke kid anymore but I certainly looked better then.
It's nice to not be a flat broke kid anymore but I certainly looked better then.
The Peugeot 205 GT1 1.9 that I had some years ago also had a troublesome relay on the fuel pump.
As a safety feature, the relay would cut the fuel if the engine was stopped or if the car was upside down !!
Peugeot wanted over £100 for the part. The local supplier only £35 for an identical part.
.
As a safety feature, the relay would cut the fuel if the engine was stopped or if the car was upside down !!
Peugeot wanted over £100 for the part. The local supplier only £35 for an identical part.
.
There was the story about the dummy that missed the part about using a SPENT .22 shell. He allegedly shot himself in the leg, leading to a car crash.
Dumm Blond experiments done in my youth revealed that when a .22 was fired outside a gun barrel, the lead bullet doesn't move far, but the brass does. It will penetrate a pair of jeans far enough to make a big bruise, and maybe draw a little blood, but not cause a serious wound......yes you can set off a .22 round with a big magnifying glass and the Florida sun.
There were people who used all sorts of creative fuse replacements, the most common was good old aluminum cooking foil wrapped around the dead fuse.....
One of the usual replacement part companies (Mallory maybe?) made a "universal" replacement pot for console TV sets that needed long shafts. The pot came with a hollow shaft that was about 2 1/2 inches long with rings scored around it so it could be snapped to the needed length. One of the discarded pieces was just the right size for a good "No-Blo" fuse.
I used one of them to sniff out an intermittent short in the fan speed switch in the air conditioner in my 1965 Pontiac Grand Prix. After blasting the partially dead switch into total charcoal, my AC had only one speed, high. It was Miami Florida, so a perfectly acceptable compromise.
The fuel pump fuse in my old VW got so hot once that the plastic melted off of it and fell on to the floor mat. Not long after, I rewired the pump direct from the battery (fused) using a second relay driven by the original pump circuit.
Then there was the car my auto teacher was driving one time... Bad fuel lines or something so he was running it from a 4 litre Jerry can under the hood connected directly to the cam driven fuel pump lol
Then there was the car my auto teacher was driving one time... Bad fuel lines or something so he was running it from a 4 litre Jerry can under the hood connected directly to the cam driven fuel pump lol
That particular hack made regular appearances in the shop at the local music store where I worked for many years. Eventually the bench tech got into the habit of yelling, "Oop - foil on the fuse," to which the rest of the shop would reply, "Foil on the fuse!!" followed by varying intonations of disappointment in our fellow man.
I do miss that place sometimes...
Gas can under the hood connected directly to the fuel pump....That was a handy trick at skying resorts when one got stuck with the fuel line clogged by frozen humidity. Service station nearby were used to provide a piece of hose and whatever suitable can from the trash bin with enough gas to drive down at warmer temperatures.