ultrasparc
Active Member
Yes, sort of - like letting the heat sinks rest on the PCB, eliminating the load on the traces.
Repair PCB on SX-1080 power supply (AWR-152)
- Thread starter ultrasparc
- Start date
Yes, sort of - like letting the heat sinks rest on the PCB, eliminating the load on the traces.
I mean mount them to the amp heat sinks and run wires back to the power supply.
ultrasparc
Active Member
Right - and once I manage to get the power supply fixed, that element can be removed from the suspicious list.
For now I will try and find the best way to repair the solder pads.
I'm considering to glue a piece of neatly shaped wire around the pin holes, with some heat resistant glue.
This JB-Weld seems like a good choice for the job ?
https://www.amazon.com/J-B-Weld-829...al&ie=UTF8&qid=1471577672&tag=viglink28020-20
ultrasparc
Active Member
Ahh - that's creative
I suppose that could be done, but now that I have experienced baaad noise from runnnig wires across the PSU, I'm not tempted by that solution. Also I still need to fix solder pads for other components than the hot-running trannys.
I tested W B Weld's conductivity before I started using it in my STV-xH repairs, two 1" bare copper parallel wires in a puddle of it.
I don't remember how high up in voltage I went, but I had a digital microammeter in series with it and it registered nothing.
BUT that is NOT the way to do it.
Clean the trace to bare copper all the way down.
Bare wire wound around each component lead, following the trace.
Then solder it all together.
No glue involved. The component leads are the stability points.
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ultrasparc
Active Member
Argh, good point - didn't think of that
ultrasparc
Active Member
OK, not an issue then, but NO GLUE - got it
(I did manage to order it, though, should arrive tomorrow )The reason i even considered glue, is that the larger heat sinks I mounted on Q1 & Q4 are weighing them down, pressing/pushing the traces away from the board.
I will make new heat sinks for them from a PC CPU heat sink, that will rest on the surface, and follow your recipe to the point, Mark
ultrasparc
Active Member
Well, I actually think I got it fixed this time 
I prepped the traces to be soldered on, wrapped a piece of wire to pins where appropriate (Q1, Q4, Q5) or used the component lead to solder directly on the trace, where it could reach (R8, D10, D11).
Remounted the components and lit her up with great excitement. Thankfully there is now much more clarity and crispnes to the treble and much more response, and the bas is not as muddy as before.
So - the conclusion is that a beat up power supply can spoil the sound. This may be logic to some, but not to me.
Hopefully this has to be end for this recap-oddesy, that began more than 2 years ago.
Thanks to every one looked by and contributed.
I prepped the traces to be soldered on, wrapped a piece of wire to pins where appropriate (Q1, Q4, Q5) or used the component lead to solder directly on the trace, where it could reach (R8, D10, D11).
Remounted the components and lit her up with great excitement. Thankfully there is now much more clarity and crispnes to the treble and much more response, and the bas is not as muddy as before.
So - the conclusion is that a beat up power supply can spoil the sound. This may be logic to some, but not to me.
Hopefully this has to be end for this recap-oddesy, that began more than 2 years ago.
Thanks to every one looked by and contributed.
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petehall347
the brandy coffee man
well done saving the board .. it looked passed it to me by the burnt looking of it in the pics. i have done plenty of point to point repairs like yours but never attempted a burned looking board like yours .
ultrasparc
Active Member
Thanks!
Once I decided to get on with it, it actually wasn't too difficult. What I needed was the encouragement in general, and the precise description Mark (thanks, again Mark
) gave, that made it easy to do.I'm still surprised that the repair had such a great impact of the sound. Why would a beat up power supply influence the quality of sound ?
.
Thanks!
Once I decided to get on with it, it actually wasn't too difficult. What I needed was the encouragement in general, and the precise description Mark (thanks, again Mark
I'm still surprised that the repair had such a great impact of the sound. Why would a beat up power supply influence the quality of sound ?
Because I ASSUMED that all your power supply voltages were correct. Once the rebuild corrected it, I saw no documentation showing the original power supply voltages, nor do I now see what the repaired supply's voltages are. The initial conditions appear to be irretrievably lost.
I AM glad that the sound is now correct, that would have been a nasty troubleshooting session.
ultrasparc
Active Member
Well, all voltages are as they have been ever since I began 2½ years ago - both before and after this repair. The largest deviation from specs is that the 76 volts are 83-84 volts, and the 60V about 62-63 volts.
Thanks, so am I
- and I don't think I could have done without your advice I suppose this error must be very rare (damaged, and poorly repaired PSU) - I guess it could be written up in the checklist when trouble shooting poor sound.
- Has the PSU been repaired from fierce overheat, using jumper wires to compensate delaminated traces,
It isn't logical to me, that there should be any relation here - it's like checking the fuel filter in your car, if your
aircon doesn't work.
Anyway, I'm really happy with it now - and so I can start on the Luxman R1500, that I got as a temporary replacement, but which failed after a week
Watthour
Electron Rancher - JS3600
These can help for board repair:
https://www.amazon.com/200pcs-Through-Rivets-Grommets-Circuit/dp/B018RSXG66
https://www.amazon.com/200pcs-Through-Rivets-Grommets-Circuit/dp/B018RSXG66
what do you do about the extra mm's? Trim it off and flatten it?
I use these:534-23 (EYELET 1/16 X 0.093) , 534-24 (EYELET 1/16 X 0.125)
