SMT Bandito Info/Build

[sinclairuser]

Started here
Looks to have come from here
Was experimental and not on Silverdogs website you had to ask via the contact form on the website


Someone was getting a reliable 37cm and an iffy 40cm on a 5 kopek. By using a different spec coil. Did mean to look up how big a 5 kopek coin was but never got round to it. (lost the link also )

Having said that depth is not what the Bandido II umax is about.

i was just suprised as i had not seen them, sd's shop is a bit sparse of late, wanted a hh kit and an idx kit but none in stock, i know he is waiting for idx boards, i just hope i have not missed the boat on the hh.

[Silver Dollar]

So I drew the schematic in Express so I can make mods to it;

[Silver Dollar]

Here's a pic of the transistor that doesn't fit showing how much pad you have to work with;



Here's what I got done so far. I found some small SMT 100uf caps.

[Silver Dollar]

I didn't know he had those too. Someone in another forum mentioned it and I emailed him and scored the last one!

I've been playing with the layout and might have some made one of these days but I didn't see much interest for
people buying some if I had some made.

I got the passive components installed today. The only ones giving problems are the big caps as I'm trying to use
surface mounts for them. I got 2 installed (220uf's) but might have to put the 100's on the back.

I have a 4066 but none of the other chips. I'd love to send and order and get this board going quick but I have to
wait for my SMT TGSL to get here so I only send one order...

I used some different values for a few parts as I didn't have the correct ones so my board might not be a good
one to compare to the original Bandito I have coming. By the way I've seen some Bandito's and Golden Saber's
selling on ebay for around $120. That's a good deal considering what it costs to make one.

[Koala]

when did silverdog sell these boards?, i check the shop weekly for anything new but seem to have missed these.

Started here
Looks to have come from here
Was experimental and not on Silverdogs website you had to ask via the contact form on the website


Someone was getting a reliable 37cm and an iffy 40cm on a 5 kopek. By using a different spec coil. Did mean to look up how big a 5 kopek coin was but never got round to it. (lost the link also )

Having said that depth is not what the Bandido II umax is about.

[sinclairuser]

when did silverdog sell these boards?, i check the shop weekly for anything new but seem to have missed these.

[Silver Dollar]

Well I was reading that Tesoro used a 3 turn because it was cheaper. The 10 turn is easier to tune GB with.
The GB is very sensitive. I'm not sure if you want to use shielded or plastic ones...

[Koala]

that's good that 0805 fit for the resistor will not have to redo them again

there is some logic to the caps 10nF and larger are 1206

small ones are 0805

works well for whats the most common at the suppliers

I have started to order all the hardware as that's what will take the longest to arrive. Had to go for a 10 turn POT could not find a 3 turn at a reasonable price. Hope the inductance of the wire wound does not cause any problem.

[Silver Dollar]

Well I can definitely say the resistors are 0805 the 1206's are too big! I squeezed a few in by
soldering one side and sliding it off the pad a bit to have access to the pad on the other side
but not recommended. Most of the caps are 1206 sized but some are smaller (10pf?).

The 3904 that has the wrong sized pads can be soldered but only 1/2 the leg is on the pad,
close enough, it's only to feed the clock to the 4024...

I tried using some 150uf SMT caps for the 220's, one worked but it's tough to get room for the others.

[Silver Dollar]

Well my board came in today so i'll try putting as many parts as I have on it
then see what I need to order. I have a SMT TGSL coming so want to order
parts for that too...

[Silver Dollar]

I'll bet the design was originally a Russian one and someone changed some things.
They changed the transistor pads but just missed one. I see hints of this in the
ground areas and some of the caps have smaller and larger pads layered on top
of each other. I get some complaints from a free gerber viewer because of some
of the changes and am not sure the layout guys would like it.

If I make more boards I may start over and put the pots along one side so you
can board mount them. And fix all the details problems at the same time.

Here's an attempt at moving the pots on the current layout;

[Koala]

think this will work

[Silver Dollar]

Oh ya I see it. I noticed the smaller outline but saw the value and assumed it was the same size.
I'd add jumpers if necessary or try to place it just right using the standard part. Ill have to fix that
on a relayout... Most likely a mistake should have been the same size as the others.

[Koala]

VT2 2N3904 top left of board between 4024 and 4066 tiny tiny transistor size there room on the board for a normal SOT-23

no 2N3904 in that size listed have to use an alternate part

[Silver Dollar]

Um it looks like 3904 and 3906 are the only transistors. Which one has a different pad size?

Some of the audio circuits are different on TGSL, usually to add a BD140 for more volume.
I've seen 1 MPSA13 or 2 transistor or 3 in the audio output stage. It looks like our layout uses
a 3904 and a 3906.

Here's a picture of the 3 possible configurations;