I've got a cracked L3 on a video overlay card. Actually 3 cards with this same part cracked in the same way. It's the tan colored blobber-job thing immediately left of the square Motorola thing.
The markings are:
SDL - 4105
TDK - y
Anyone know of a source to get this from? Not had any luck finding it yet, and I fear its a long obsolete part.
I'm not at home so I don't have access to all my esoteric and exotic parts suppliers bookmarks. I thought I'd get a heads up and get on the ball while I have a few moments. Been something I've been meaning to fix for a while.
http://www.applelogic.org/files/AVOChires.jpg
Hello Kearah,
thats really bad luck.....
and its also a unpleasent part of history in electronics too....
in the early years of the 80´s a lot of electronic engineers and companies faced overwhelming amout of "copycats"
from Taiwan and the engineers started protecting their work by using "custom parts" - often
manufactured by themselves with very tiny PCB´s and different kinds of 2 component "mixtures" adding
colored pigments to make them "nonvisible" and targeting to the aim if someone tries to copy then
also destroying such parts without detecting inside of the part.
Sometimes they even polished off the labels of the chips and then even covered the entire Interfacecard with that kind of 2 component stuff.
The disadvantage: Most of that guys never tested the changes that occured when using such "homebrew" mixtures....
some just crumbled off after years - and others after years started cracking apart.
Similar procedures also raised when the companies started to develop own "factory standards" that kept incompatible with other standards... famous examples: The IBM computers with the own interfacecards that couldn´t be used in any other computer, and similar behaviour by compaq and others.....
here we can face a result of that behaviour: no chance to get a replacement.... no correct documentation....
all just for protection against violation of patents....
hope you may get another card with another damaged part, so you might get this part in working condition by desoldering it....
seems that the specific mixture uesed at this "custom part" seems to crack by age and temperature ( similar
to nowadays stuff used at outdoor furniture that ages by UV-lighting and starts cracking and crumbling after 2 years....) - the only difference:
in former days it was the demand for protection against copycats - nowadays
it´s planned obsolesence because they want you to buy new furniture set after 2 years....
speedyG
Probably just have to break it open and see what it is and figure out what it does... It could be some simple combo-part. Also if there are schematics around for that board or another by that maker...
Hello Keatah,
did some small research ... of course a circuitplan is not availiable for download....
but at least the datasheet of the chip near to the components is availiable:
http://www.appleii-box.de/applefritter/TDA3301datasheet.pdf
unfortunatly there is no high quakity picture of the soldersice to view traces....
so it gets difficult to verify the connections... but it should be possible by trace follow up
to the TDA3301 chip to verify the parts and make conclusions to this drawing from the chip datasheet:
i´ve marked up some "special parts" that you might identify / verify....
please note the 3rd connection to the coils marked.... there is no data about that split offs.
I used red marking by same notation like used in the card.
sincerely
speedyG
Yeh, I was afraid of that, all the secrecy and lack of good markings.. I'll check the
actual boards in the next few days and trace it out.
In the past I've seen some of these boards have that hybrid inductor burned up - so maybe
it's electrically close to external inputs and outputs.
The part seems robustly built and looks like it was damaged by getting hit.
Hello Keatah,
up to my experience the problem with that kind of hybrid parts
is that the material has bad influence to the passiv abortion of the
powerconsumption ( the heat can´t be cunducted away from the part due to
no airflow at the parts themselves and then the heat keeps stored within the part .....
and after a while things get worse when the material used for sealing
gets hardened and one day the entire thing just cracks.....
when back to the card just for archive.... could you take a high resolution high quality picture
from soldering side and publish a link ?
thanks in advance....
sincerely speedyG
Yup. Should be about a week, maybe less. And thank for the data sheet schematic.
Keatah,
How about this?
http://www.mouser.com/ProductDetail/Panasonic/ECQ-E4105KF/?qs=FaGJejDeu%252b%2Fy%2Fa6s5CifsQ%3D%3D
Is it a Ceramic Capacitor?
Hope this helps.
Steven
Thx. But not quite. The component in question has 3 electrical connections. I was thinking of seeing if one of them can be repaired. Or perhaps dissected to glean more info.
Hello Steven,
in PCB´s in general Lxx indicates a coil.
in this case its a coil with fixed pickup ( third middle pin )... ( see shematic )
sincerely
speedyG
If Speedy's schematic analysis is correct, it's a delay line (SDL probably stands for S___ Delay Line). It is used in this circuit to keep the Luma and Chroma signals in phase.
The 4105 part of the marking is probably the model number.
I found an SDL-4301 online , which is said to be 400 ns. Hopefully there is a TDK SDL series data sheet online somewhere that covers the 4105. Worst case would be to either check delay on a working board with a scope or get a multi-tapped delay line and find the delay that works best.
regards,
Mike Willegal