My_Ref Fremen Edition - need help on PCB evaluation

[soongsc]

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.

 

[ClaveFremen]

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?

 

[soongsc]

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.

 

[soongsc]

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.

 

[ClaveFremen]

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...

 

[ClaveFremen]

Soemething like the attached schematic but I've some doubts...

 

[soongsc]

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.

 

[ClaveFremen]

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...

 

[soongsc]

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.

 

[linuxguru]

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.

 

[ClaveFremen]

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.

Siva, the flexible lead pitch cap you're using is in a public library? If so how it's called?

 

[linuxguru]

Siva, the flexible lead pitch cap you're using is in a public library? If so how it's called?

Dario - I modified an existing flexible-pitch outline from the Eagle parts library. It was either in the RCL library or the Wima library. I'll try to export that modified part data in some portable text format and post it here.

 

[ClaveFremen]

Payment collection

Since I don't want the Fremen Edition to be an endless work I've finalyzed the beta layout (attached) for production.

I'm waiting payment confirmation from the fourth participant, BTW I'l cover the extra cost if he pulls back so the import will be 29€ + shipping.

If the packet is less than 350g, shipping by Registered Mail will be:

Europe 9.50€
Worldwide (except Oceania) 12.50€

Add 4.50€ to have included 6 hard to find Elna RJH 220uF 50V, BAV99 and ZMY27.

Each participant should PM me with his PayPal account so I can send him the PayPal Invoice.

Thanks

 

[ClaveFremen]

Parts option

I must order for myself from both Mouser and Parts Connexion so I can order for partecipants too, if they prefer so.

Two things must be taken in account:

• we will pay the italian VAT (21%)
• shipping costs would rise to next weight (and price) range: 350g-1kg (18€)

 

[ClaveFremen]

Squalor joined the beta so the two PCBs will cost 27€

 

[regiregi22]

Just out of curiosity, where are you going to source the PCBs? If you don't want to say it in public, please write me down a PM.

 

[ClaveFremen]

I'm going to use makepcb for the beta run.

For the GB I'll probably use an Italian factory or makepcb again.

 

[soongsc]

Our local VAT is 5%. Normally buying through the web, not VAT is incurred. I wonder how it works in other places.

 

[ClaveFremen]

Our local VAT is 5%. Normally buying through the web, not VAT is incurred. I wonder how it works in other places.

Here in the European Union we must always pay VAT.

When ordering from another EU country we pay the VAT of that country (which can be slightly different but always around 20%), if the order is made outside EU we pay local (our) VAT and in most cases also customs duties.

 

[brianhutchins]

Hi Siva,

thanks

Your contribution will be precious.



It would be great!

which when tanslated means Dancing Salsa in the Umbu?