mojo2

[ian444]

> so what's your beef with silver plating? i'm all ears.

I find the easiest PCB's to solder have the HASL (lead) finish on the pads. Silver and gold basically need to be tinned and sucked dry first to ensure an easy solder job, in my experience. I know you like lead-free soldering, but the medical and aviation fields refuse to use it on reliability grounds. Lead-free is only used for consumer devices as far as I know. I dislike it (lead-free) in our hobby simply because I believe we are so small in contaminating the environment, compared to large corporations destroying the environment to make themselves some big money. Somehow, the politicians want the peasants to feel responsible for all the environmental damage, while the big companies strangle our resources for corporate profit. I am almost 50 years old, I can see through all the smoke screens now. When I was young, I used to wonder why my parents were so cynical....

[fumbles]

Ian,
I have heard it said that a cynic is a realist with life experience.
I have a few years on you and agree about the politics and about the pain of lead-free solder.

That said, I have found the Japanese "Goot" brand made by the Taiyo Electric Ind. Co. containing 3% silver and 0.5% copper to be a lot easier to use than many other lead-free solders, there are also silver loaded tin/lead eutectic solders available that are said to be very good to use.  I have just bought a small quantity of Cardas quad eutectic to try as many swear by it.

Yeo,
will there be another run of M3 spdif->eiaj boards at any time soon ?

[Paul N]

Hi Ian

I hate lead free too. I use this  tin/lead solder with 2% silver added.

http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/Soldering-Equipment/Solder-Fluxes/Future-HF-low-melting-point-halide-free-no-clean-cored-solder/60030/kw/

Not expensive, very easy to use, effective non corrosive flux, easily removed with e.g. isopropanol. In theory  silver loaded solder should always be used on gold or silver plated surfaces- such as the Mojo pcb!- as the joint can otherwise go dry.

I don't like the black Moojo boards- I found the eariler green ones were better made

Paul

[yeo]

hi guys

thx for sharing your experience with me.

and i hear you guys.

okay, mojo2 won't be silver plated nor gold plated nor lead free or whatever high tech plating. just regular tin plating.

i went for lead free as i believe very soon all exports to europe should comply with lead free regulations. i guess when the time comes, i could have another run using lead free.

also, using lead free, i believe is easier on my 2 girls' health (as well as mine) but then i don't think anyone did a study on the effects of inhaling tin solder? it couldn't be good too.

i could still use lead free solder i guess. the type i use has tin, silver and copper, low melting point and it's really easy to clean with isopropyl alcohol.

the spdif-eiaj board is being fabricated as we speak. and it's regular tin plating.

yeo

[ian444]

Sounds great Yeo, thanks!

[fumbles]

Yeo,
I appreciate your concern for your own and your daughters health.
I rather think that if the boards do not contain lead but only tin and you continue to use the solder you mention, which sounds very much like the Japanese one I found, then I would expect it would still comply with European ROHS requirements.
Could be worth checking at any rate.
The solder Paul N mentions is the leaded one I had heard recommended elsewhere, but is virtually impossible to find out here in the colonies, the nearest I have come across is a Swiss made one of similar composition but staggering cost, although buying from Rapid with a minimum export order of 25 GBP plus freight is no better, hence the Cardas experiment.

[milen007]

yeo, when is the expected date? my monica and mojo is dead ;( left alone too long and naked

good job yeo

[yeo]

hi fumbles

no kids of mine! these 2 girls work for me part time.

i'll send out for fab on wednesday. am out of town now and left the file in the other pc. 

if no mistakes, should be ready in 2 weeks.

yeo

[Paul_Hynes]

Hi Yeo,

Tin plating doesn’t age well. I found that within 6 months it was very difficult to solder due to oxide formation. I still have some of these boards and when I want to use them I have to clean the metal surface with brass wool and apply flux before they will solder properly. I now use boards with the copper coated with OSP, which is an organic compound. The OSP protects the copper and I have had no problems soldering boards that are two years old. I have been using lead free solder for years with no problems except for the tinned boards I switched to when the RohS directive took effect, which was not the fault of the solder. I use an OKI 90W temperature controlled soldering iron and this works very well with lead free 4% silver solder.

I agree that the legislation being forced on the European union is excessive. The way things are going many small businesses will be legislated out of business, with all the restrictions, extra expense and paperwork they are forced to do, to comply with the new directives.

Regards
Paul

[ToniM]

Hello all

there is no perfect material for pcb surfaces availible.

The best was hot air lead typical 10µ thick but only from a few companys availible in lead free
You can solder this for 2 Years without problems

Galvanic lead have a thickness of 1µ and are able to solder no longer than 6- 12 month

For nickel gold the same time

For galvanic silver the same

These surfaces have the problem that copper crystals diffund trough the surface and oxydice

Copper organic passivated is good but when you have areas on the pcb not soldered you have massive  oxydation after a few years

hope this helps

[ToniM]

Yeo

You need no lead free pcb for DIY products in Europe!!!This is the reason why a lot of companys sell their products as kits.
Lead free is only in finished consumer electronic product and industrial products.
Automotive, railway and aerospace are not under ROHS

greets Tony

[yeo]

hi tony

thanks a lot for your input!

now i'm more assured to go with leaded pcb. yes, i've been taken by all the media noise.

thx guys!

yeo

[Paul_Hynes]

Hi Tony,

I started using boards with OSP copper coatings in 2007 and I still have some of these original boards. There is no sign of any oxidation and they are soldering as well as when new. I have checked some of my board verification module build from this period and there is still no sign of oxidation on unsoldered areas. These earlier boards are around 3.5 years old now. They test fine electrically too.

Regards
Paul

[mikey1159]

The news that I have been eagerly anticipating )
Pls reserve 2 for me -for monica 2 and 3.
Thanks Yeo!
Mike

hi guys

lest you guys think i've gone off planet earth, i'm still alive and kicking. been to 3 countries the past 2 months and all this travelling is taking a toll on me.

finally back home but... lethargy kicks in... dang!

anyway, here's a rough but not ready pcb layout for mojo2.

changes from mojo:

1. slots for regulators. one for each channel of i/v stage, one for 12vdc, then feeds ccs2, then feeds 5v and 0.83v regulator. ditched the ccs + string of diode scheme.

2. incorporated the marvellous 3 transistor tweak by paul n. as you can see, due to space constraints, considering smd resistors here.


guys

any input? if you have any comments or changes to mojo you want to see, please highlight now.

hope to wrap this up this week and send for fab.

thx!

yeo
ps: anyone willing to proof read? of course, you'll get the mojo2 kit free.

[yeo]

hi guys

mojo2 pcb arrived few days ago. finally got it built up but my smd ferrites haven't arrived yet, so built without these for now.

one mistake! the 3 transistor should refer to 2 leds + 1 diode, i made a mistake and went to 1 led  + 1 diode, thus instead of seeing ~3v, the tda1545a current output pins see only 0.8v... too low and thus distorting like hell.

fixed this and it's okay. fortunately only the top layer needs amendment. i don't think this will cost much.

here's a pic. shown here are 7 regulators (ccs is a type of regulator too). i adapted audioslave to output ~18v and ~12v.

any comments?

yeo