My_Ref Fremen Edition - Beta build/Fine tuning

[ClaveFremen]

 

[ClaveFremen]

Important

Bob,

remember to install J1 jumper on the bottom side (see attachment).

 

[bcmbob]

Will do, but please tell us again what it does and what happens without it. I know all of this stuff was covered on the development thread but sometimes it's difficult to track down. Thanks for your patience.

 

[ClaveFremen]

It carries V- to the regulator.

It is necessary becasue, otherwise, negative regulator would output 0V...

It must be soldered before big smoothing caps since it's soldered on the upper side of the PCB.

 

[bcmbob]

Done.



Thanks, Moving on.

 

[ClaveFremen]

 

[bcmbob]

Low profile caps mounted.

Hit a snag. My Mouser order didn't include 100uf caps for C102 / 202. Since this is a vanilla (base) build, can I use a generic (Radio Shack) substitute?

 

[ClaveFremen]

Use any good sounding cap sold by Mouser like Nichicon FW or KZ or Panny FM. 47uF 25V is good

Inviato dal mio LG-P500 usando Tapatalk

 

[bcmbob]

Dario, could you explain the flexibility in the range of values at C102 /202?

100uf/50V to 47uf/25V seems quite a spread.


"Inviato dal mio LG-P500 usando Tapatalk " ???

Glad to hear of your new phone. Google Translate relieved my fear that you were swearing at me

 

[ClaveFremen]

Dario, could you explain the flexibility in the range of values at C102 /202?

100uf/50V to 47uf/25V seems quite a spread.

The only important parameter is the voltage rating (25V and up), any capacitance between 47uF and 100uF will do.

Their only function is to ensure regulator stability but so far it seems to work perfectly also without them.

The RevC counterparts had the function to reduce ripple and impedance, this is not the FE case.

"Inviato dal mio LG-P500 usando Tapatalk " ???

Glad to hear of your new phone. Google Translate relieved my fear that you were swearing at me

My smartphone is over a year old... simply this time I've answered from bed (it was 1:30AM and I was trying to fall asleep...)

 

[bcmbob]

O.K. I have actually wondered if/when you got some time to sleep.

 

[ClaveFremen]

I've checked Mouser's shared BOM and it includes caps (Nichicon FW) for C102/C202 but in this moment they're not available, maybe this is the reason you didn't received them, Bob.

BTW It could be better this way, they're not so good for those positions, final BOM will have different caps (probably FG: 647-UFG1H101MPM)

Cerafines are very good caps for those position.

 

[bcmbob]

Thanks, I found some 100uf / 50V from the MyRef 1.3/1.2 builds. I'll add something better to my next order.

Here are the pics of all installed other than Heat Sinks, Relay. LM3886 (I think)

Please review.

FE-1

 

[bcmbob]

FE-2

FE-2

 

[ClaveFremen]

At a first glance it seems fine...

I can't read LM337, BC639 and BC640 markings, check them against silk screen (just to be sure ... ).

 

[bcmbob]

Same on both boards.

 

[ClaveFremen]

Seems fine

 

[bcmbob]

Just found a mistake

I mounted and trimmed R3 before attaching the heat sink so now the leads are too short. I remember one must do this with the LM3886 chips but I totally forgot it on R3. Luckily I have some double sided CPU heat transfer tape I can use till I get some new parts

 

[bcmbob]

Sockets filled, Relay in and LM3886 installed.

If you see something - say something,

 

[bcmbob]

Just one note on transformer wiring, since I didn't wrote anything about it.

The transformer should have double 25V (24V also fine) secondaries, let's say:

Secondary 1: green/yellow
Secondary 2: violet/white

They should be branched that way:

Green to AC1, Yellow to NAC1
Violet to AC2, White to NAC2

Please confirm.