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Post by darkarn on Feb 28, 2017 5:42:55 GMT
Ordered both relays from RS Online too, may be as fast as today due to its "same-day shipping from its global network of warehouses", more likely tomorrow though
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solderdude
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Post by solderdude on Feb 28, 2017 8:44:24 GMT
These are O.K., they are BC5x6B types.
Possibly the transistors on the board are still O.K. so I would replace the relays first and see if it works.
When the relay doesn't energize after about 30 seconds you can replace the 3 transistors near it.
When you have removed the relays you will have to suck out the holes.
Desolder litze will probably not work.
To heat all pins of the relay at the same time I use the following trick.
I take a short length of thick copper wire, the kind used for mains wiring in walls.
run that copper wire along all pins that need to be heated and cut it to that size.
Use one piece of wire, not 2 separate shorter wires.
Solder that onto each pin and apply solder in abundance.
Move the soldering iron (at least 30W) along that wire while keeping the wire in position so it doesn't 'swim' around in solder.
When everything flows and is heated lightly pull on the relay from the underside.
Position the PCB so you can reach the underside while heating the pins or ensure that it can drop out on its own weight.
Once it is out the solder in the holes must be removed.
A desoldering gun may help.
Another option is to heat the solder and blow it out with some force (mind hot solder splatters) or, a bit more tricky, drill out the holes with a small PCB drill. Ensure it is smaller than the through hole metalization.
succes
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Post by darkarn on Feb 28, 2017 14:45:25 GMT
Thanks, glad that those will work!
The relays will come in on Thursday so it will be a while before I can confirm if it is just the relays
If solder wick won't work, will a desolering pump work? (A desoldering gun is a bit expensive...)
I also cannot find copper wires but I think I do have what appears to be iron wires, will this be fine too?
Also just wondering, why are relays harder to desolder and need such techniques compared to "normal" parts? Is it due to them having more pins?
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solderdude
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Post by solderdude on Feb 28, 2017 15:20:36 GMT
yes, I meant a desoldering pump.
What I do is I heat the solder from one side and wait till the other side 'bubbles'.
Then quickly pull away the soldering iron and immediatly presse the desolder pump from the other side.
This should work.
When this doesn't work you can try heating it and blowing it out with compressed air (dangerous hot spatter).
If that doesn't work either drill out the holes but do not destroy the via.
All pins need to be heated at the same time + the board is much thicker this makes removal more difficult.
It is easy to heat 3 pins of a transistor at once but the relay pins are spaced far apart and all pins must be fully heated.
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Post by darkarn on Feb 28, 2017 16:49:56 GMT
My drill is way too big for these holes so I hope all I need is the pump (gotten a slightly bigger one this time)
And I am still unsure about the pins of the relay as I noticed that it is ok to heat and desolder one pin at a time for capacitors and resistors to remove them; unless I must have been desoldering stuff wrongly all these while and I should had heat all pins for capacitors and resistors too...
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solderdude
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Post by solderdude on Feb 28, 2017 17:48:02 GMT
With capacitors and resistors it is easy to desolder one pin at the time and pull on each side.
With the relay it isn't possible.
Also heating each pin and using braid or solder pump MAY work well if the solder hasn't penetrated deep in the vias.
You could always try that approach.
My experience, however, with desoldering parts like this is that some of the pins may appear to be loose but may still be soldered down deep in the via.
Pulling out the part may rip out the via.
The PCB is much thicker than most other PCB's which makes desoldering and clearing pad-via's more difficult.
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Post by darkarn on Feb 28, 2017 19:59:36 GMT
Ah ok, now I can see the concern, I will go search for copper wires as you recommended. If not, I will have to use those iron (?) wires And yes, I can feel how much sturdier the PCB is as compared to what I previously worked on; I felt a lot more at ease working on the Project Ember compared to other stuff as a result (or maybe too much at ease and thus made those mistakes!  ) |
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Post by jhelms on Mar 2, 2017 2:07:20 GMT
My advice on the relays since you have new ones on the way...
- Use a solder sucker to remove all the solder you can
- Use your iron to press on each pin and free it the best you can from sticking to the sides of the holes / use solder sucker once again to get everything out you can
- Use a pair of pliers, grab the relay and rock it back and forth until it breaks free (if you used the solder sucker properly and each pin is relatively free / the relay will come loose). If any pins break off, you can heat and remove them later. This destroys the relay but gets it out. I have little luck removing them in one piece and I consider them sacrificial
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Post by darkarn on Mar 2, 2017 7:34:29 GMT
Thanks! The relays should come in at any time so we should be able to see if this works out. And yes, I will replace both relays so if need be, I will cut them. I just hope this won't lead to other issues like lifted pads
Meanwhile, I noticed that one of the legs of B-IC1 is not soldered to its pads for some reason, should I solder that too? To clarify, the leg is still on the pad like the other legs, but there is a small hole on the pad unlike the other pads which already have solder covering them
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solderdude
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Post by solderdude on Mar 2, 2017 9:21:34 GMT
I would reflow all pins, also on the OPA551 when unsure.
I have had one amp returned to me because of oscillations on one channel.
Turned out the tab on the OPA needed to make better contact so added some solder.
Very hard to make that solder adhere and flow because all the heat applied simply is conducted away.
Probably need a big iron (used a 100W iron for this)
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Post by darkarn on Mar 2, 2017 10:12:31 GMT
Thanks! I am unsure how to reflow the pins for the OPA551s though; the pins look so close to each other that I fear that I may accidentally short them
Not to worry about my iron; I am using a variable temperature soldering iron
Also, the relays just reached my house and I have removed the old ones out. Time to see how this goes!
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Post by darkarn on Mar 2, 2017 10:54:46 GMT
New relays installed, both heaters are now working but still no sound and headphone protection LED not lighting up
I will replace the transistors next... after dinner
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Post by jhelms on Mar 2, 2017 15:47:01 GMT
Thanks! The relays should come in at any time so we should be able to see if this works out. And yes, I will replace both relays so if need be, I will cut them. I just hope this won't lead to other issues like lifted pads Meanwhile, I noticed that one of the legs of B-IC1 is not soldered to its pads for some reason, should I solder that too? To clarify, the leg is still on the pad like the other legs, but there is a small hole on the pad unlike the other pads which already have solder covering them It is soldered tight - it just does not look like the other pins as solder flows into the vias. Use a pick tool - pin will not move. Frans, I found the issue long ago where a few boards like the one you found did not solder all the way under the 551. This was resolved with the new IR oven and QA process. They are very, very well soldered  On the protection circuit, wait for approx one minute. Do you hear a click at all or any action on the relay? Wondering if the led was overheated at install? |
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Post by darkarn on Mar 2, 2017 16:16:45 GMT
I have not soldered the new transistors yet and here's what I see
I hear a click upon switching on but after that no more clicks.
I hear another click upon switching off the amp
The LED still lights up if I use a multimeter on it (the PSU is not plugged into the amp when doing this)
EDIT: I'll do the transistors tomorrow as my tension headaches are coming back
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solderdude
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Post by solderdude on Mar 2, 2017 19:51:34 GMT
The click you hear when switching on and off is the heater selector relay.
You need to replace the 3 transistors.
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