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Old 23rd December 2011, 11:34 PM   #221
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Quote:
Originally Posted by ClaveFremen View Post
I think you're right pointing out the lead free solder...

When TP boards were new the Zns leads mounted quite easily, after desoldering they don't fit unless you put some new solder in the empty hole and suck it with a vacuum pump.

Only after I've buyed a desoldering station I've managed to have those pads really clear...

Obviously I've always used leaded solder.

On the MINI2496 I've used lead-free solder and the only way to have a clean pad after desoldering is to wet the void hole with leaded solder...

I'm confident that the 1.27mm holes will help us with 1.0mm leads.
To get the holes clean enough, normally the pad is heated too much, that is why my through hole came out on the power resistor.
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Old 23rd December 2011, 11:44 PM   #222
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Originally Posted by soongsc View Post
To get the holes clean enough, normally the pad is heated too much, that is why my through hole came out on the power resistor.
I've desoldered several times quite all components on those PCBs and the only component that gave me problems were the big smoothing caps.

With leaded solder...

Anyway I think we're safe with 1,27mm holes, don't you?
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Old 24th December 2011, 02:57 AM   #223
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Originally Posted by ClaveFremen View Post
I've desoldered several times quite all components on those PCBs and the only component that gave me problems were the big smoothing caps.

With leaded solder...

Anyway I think we're safe with 1,27mm holes, don't you?
Lead solders are much better to work with.
In perspective, if the TP used 1mm and now you use 1.27mm then I would say it is okay for the majority caps out there.
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Old 30th December 2011, 03:11 PM   #224
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Dario,

I would like to propose more room on the board for C4. Possible enough room to fit the 1uF cap provided by TP is enough. I tried changing C4 to the same type cap of 0.68uF, it seemed to work charms like I anticipated.
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Old 30th December 2011, 05:12 PM   #225
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I would like to propose more room on the board for C4. Possible enough room to fit the 1uF cap provided by TP is enough. I tried changing C4 to the same type cap of 0.68uF, it seemed to work charms like I anticipated.
A 22mm cap?

It's not possible, maybe I can squeeze in a 15mm LS cap (MKP4 0.68uF is available in 15mm) but decoupling effectiveness would probably be lower...
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Old 30th December 2011, 05:48 PM   #226
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Soemething like the attached schematic but I've some doubts...
Attached Images
File Type: jpg 15mm.jpg (81.8 KB, 134 views)
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Old 30th December 2011, 11:29 PM   #227
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Originally Posted by ClaveFremen View Post
Soemething like the attached schematic but I've some doubts...
0.68uF is what I am testing on the TP board right now with th R7 change I made, it is MUCH better.
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Old 30th December 2011, 11:32 PM   #228
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0.68uF is what I am testing on the TP board right now with th R7 change I made, it is MUCH better.
As I wrote in the other thread I'll test too larger caps for C4, my doubts are not about the value but about the layout changes needed to use such value.

Every mm more between caps and LM3886 could be detrimental and/or reduce decoupling effectiveness...
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Old 31st December 2011, 05:31 AM   #229
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There are lots of tough decisions in layouts. I had to place C4 on top of the other two little caps beside it just enough room to slide in between the C1 and R3. So the leads are probably 2cm longer.
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Old 31st December 2011, 09:14 AM   #230
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Quote:
Originally Posted by ClaveFremen View Post

Every mm more between caps and LM3886 could be detrimental and/or reduce decoupling effectiveness...
15mm lead pitch is fine for C4 (with flexible lead-pitch options including 10, 7.5 and 5mm, all with one parts outline). In V1.4, I used 8x multifilar traces on both layers between C4 and the LM3886 power pins, but one thick stripline trace over a ground plane will also be fine.
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