Intermittent right channel - back again

jbeckva said:
Definitely a great catch! I've also had those phx connectors disintegrate on other builds and ended up replacing them. Were there physical breaks in the traces that you could see??
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It sounded like the connector not the board.
 
jbeckva said:
Definitely a great catch! I've also had those phx connectors disintegrate on other builds and ended up replacing them. Were there physical breaks in the traces that you could see??
Click to expand...

That's where I thought the problem lay but the traces looked good under a magnifier.
 
WOPL Sniffer said:
It sounded like the connector not the board.
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Yes i would have agreed but somehow soldering a jumper to the connector's pin seems to have solved the problem whereas soldering to the trace pad conducted nothing. A bit of a mystery and I guess time will show if it goes intermittent again.
 
So this one is a mistery to me as well.
The phoenix connectors are all ok. The traces must be lifted off the board under the relays and connectors , although no sign of visible breakage on the traces, two were conductive with ohm meter but wouldn't pass any voltage. Go figure. In the end we jumped from the Phoenix pin the the relay pin soldering point on both and from the replay output to the binding post connection on Right only.

Hope it it works or it will get a new DCP board next look.

this board had two two pin and one three pin connectors. This connecting flexes when you tighten the screws. A one pieces seven pin connector is much more stiff and dose not put stress on the solder joint like the short ones do
 
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grapplesaw said:
So this one is a mistery to me as well.
The phoenix connectors are all ok. The traces must be lifted off the board under the relays and connectors , although no sign of visible breakage on the traces, two were conductive with ohm meter but wouldn't pass any voltage. Go figure. In the end we jumped from the Phoenix pin the the relay pin soldering point on both and from the replay output to the binding post connection on Right only.

Hope it it works or it will get a new DCP board next look.
Click to expand...

Sounds like a damaged via...
 
grapplesaw said:
So this one is a mistery to me as well.
The phoenix connectors are all ok. The traces must be lifted off the board under the relays and connectors , although no sign of visible breakage on the traces, two were conductive with ohm meter but wouldn't pass any voltage. Go figure. In the end we jumped from the Phoenix pin the the relay pin soldering point on both and from the replay output to the binding post connection on Right only.

Hope it it works or it will get a new DCP board next look.

this board had two two pin and one three pin connectors. This connecting flexes when you tighten the screws. A one pieces seven pin connector is much more stiff and dose not put stress on the solder joint like the short ones do
Click to expand...


Yup, I always support the board with a finger underneath when tightening the screws, keeps the board from flexing.
 
Via??

Hooked the amp up tonight and both channels are good. Hoping it doesn't return but historically, there were/could be long periods of working correctly between episodes of channel dropping.
 
62vauxhall said:
Via??

Hooked the amp up tonight and both channels are good. Hoping it doesn't return but historically, there were/could be long periods of working correctly between episodes of channel dropping.
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Mark this one solved!! I do not expect further issues with this board. However if it does it is going to get replace instead of repaired
 
BlazeES said:
The node point (pass-throughs spot) of a circuit from one layer of a printed circuit board to another.
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That is very interesting and if I understand correctly, confirms an observation I made when removing the relays for the first time.

What I saw, or thought I saw, was a tiny cylinder on a couple of the relay pins. Thinking instead they were liberal amount of solder, all was removed with the heat of the iron and flicking the tip along the length of the relay's pins.

I take what you say to mean there are such cylinders lining the hole which join traces on one side of the board to traces on the other? I can visualize now how such a feature is a design necessity of a double sided board.

Since the amplifier has been in my possession for quite a while before I removed the protection board for the first time literally days ago it does not explain the initial intermittent channel problem but it does explain why things got worse after I replaced the relays.

Could be perhaps there was a connectivity issue from the get go and replacing a presumed faulty relay compounded the problem.
 
I would like to see the procedure you used for removing relays. If not careful, they will have a BIG sweat joint remaining ( after solder removal but before relay removal) and you may have damaged the board where you can't see it (Maybe the plated-through holes). If you had to pry up the relay, you definitely damaged the board. If you saw remnants in the form of a solder cylinder on the pins of the relay, you damaged the board for sure. I do/did this for a living.
 
That would appear to be the case.

I have not confronted a board of this construction before. My "technique'" for removing the relays involved a handheld, spring loaded solder sucker and solder wick. Unfortunately neither on it's own or a combination of the two was successful in disengaging all pins of the relay. So yes, a further combination of heat and prying was needed to extract some pins from their holes.

As mentioned before, there was a pre-existing intermittent channel condition which it seems I exacerbated by removing the relay.
 
62vauxhall said:
That would appear to be the case.

I have not confronted a board of this construction before. My "technique'" for removing the relays involved a handheld, spring loaded solder sucker and solder wick. Unfortunately neither on it's own or a combination of the two was successful in disengaging all pins of the relay. So yes, a further combination of heat and prying was needed to extract some pins from their holes.

As mentioned before, there was a pre-existing intermittent channel condition which it seems I exacerbated by removing the relay.
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items like that relay are hard to remove easily. The best way to remove things like this is to sacrifice the component for the sake of the PCB. Frequent practice is to cut the top of the component away with Dremel and then dykes until you get down to each individual pin. Then a simple heating of the isolated pin and pin removal with tweezers is usually all that is needed. After that, solder suck the hole out.
 
I had to look that up, dykes in the context of tool and I saw....side-cutters. Never heard them called dykes before.

So would sacrificing a relay to preserve a PCB apply in all cases or just when a double sided board is involved?

I have a reason for asking.
 
That's what side cutters are called 99% of the time I've heard talk of side cutters.


2nd part, that depends. If your solder removal is adequate, you don't have to destroy the component. Even with a REALLY good solder sucker, sometimes you have to go Joe's route. If I am removing a component I want to keep I'll do the solder suck thing then "wiggle" the component. Not enough to separate a via or trace but enough to see if it's loose, if not I'll heat and suck again. At this point heat damage to surrounding components, traces and vias is possible, so I do it quick and leave the sucker on it longer to drag cooler air over the area. Gary, there really are no hard and fast rules, just observe how it's going and make the next call based on that.
 
Single sided boards are a breeze compared to double sided boards. Single sided boards I have had small signal transistors drop out on their own after solder sucking, two sided boards----RARELY. And when you have multi-layered boards it gets tougher because of the additional layers wanting to grab, and if the component leg touches any part of the tunnel, or hole, then as the area cools it will inevitably grab the component leg again. In those cases , a quick heat with a pull may do it, but if you have more than one leg do that it's almost impossible...
 
working one lead at a time and getting all the solder out, and using a popsicle stick use light lateral force and break the "sweat joint", but you must use a lot of heat on a component like that or you wont melt the solder on the opposite side of the board. Sometimes, TOO MUCH solder is applied during installation and it makes for difficult removal. Also, when installing a relay like those, I do NOT lay them upside down since gravity will pull some of that solder deeper than it needs to go. Laying the board 90 degrees to the work surface and put only enough solder to cover the pad................ Don't keep feeding it in.
 
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