Does anyone understand letter suffixes on 48 pin logic IC's

[62vauxhall]

Does anyone know if a CXA-1082BQ can be used in place of a CXA-1082Q in a CD player?

 

[orange]

Q: http://monitor.espec.ws/files/cxa1082bq-bs_880.pdf Ignore the first page of Asian language.

BQ: Google query https://www.google.com/search?q=CXA-1082BQ

There is a CXA1082BS as well as you may have noted...long 48 pin package.

Do you mean CXA1082A or just 1082?

Well, THAT's a little big.​

 

[62vauxhall]

Originally I obtained the number CSA-1082Q from the SM's parts list but tonight I looked at the actual part and is says CSA-1082BQ. So they omitted the "B" in the manual and the chip I bought today locally is the right one.

I must now watch YouTube videos repetitively of unsoldering and soldering techniques. I now know of a method called drag soldering and bought the de rigueur flux pen. If that's as easy as it looks, the hardest part will definitely be getting the old one off.

 

[orange]

You aren't familiar with surface mount?

 

[roccus]

There is really only one safe way to remove these without damaging the pads or having to put excessive heat to the board.... you need to have a metcal solder station with a fixture the size of the IC chip then use lots of flux hold the fixture square on the chip let it heat a bit the very gently start to twist the ship a bit there should be no resistance of the chip then wick the pads set new chip on I like to solder kiddy corner a leg on each side first to make it easy to align the legs with the pads another plus of the metcal is they are made not to apply to much heat... but a metcal is not cheap and the fixtures are a bit pricey as well I thought I was done with electronics and sold mine kicking myself in the ass for that now

something like this for the station..
http://www.ebay.com/itm/Metcal-Smar...903178?hash=item3ad02fe60a:g:TRgAAOSwYIxX5UZd

quad tips like this would be used they had many different sizes
http://www.ebay.com/itm/LOT-OF-2-NE...899423?hash=item3ad06ce05f:g:YikAAOSwmfhX6B2v

 

[62vauxhall]

Orange: Nope, never contended with one of these devices before.

Roccus: Thanks for the links but a specialized solder station ain't gonna happen. It was a stretch to afford a used Weller WES51 six months ago.

The YouTube videos I mentioned depict or imply that one of these devices can be re & re'd with a regular iron, a flux pen, solder wick , care and patience.

I think getting the old one off is going to be the hard part. One video I watched showed removal using what looked like a mini heat gun. I have nothing like that but I do have a big old soldering iron with a gigantic tip used for making stained glass windows. Since damaging the original chip further has little consequence, I am considering using it to heat the case of the chip. It may not work, the case may just melt and not conduct heat to the pins.

Another method was using flux and more solder along all four sides of pins. A very small screwdriver blade was kept at the ready at one corner and a standard iron's tip was worked back and forth across the rows of pins. Eventually the screwdriver blade was worked under the chip which gradually came away from the board. The leftover excess solder was wicked away and the flux mess cleaned off with IPA. This method looks plausible.

I am concerned about board damage and unsure if high or low iron temperature is better. When home, I will spend more time watching this because it's near useless doing that on my phone.

I am tempted though to try my big iron idea first.

 

[orange]

No, I would avoid that like term life insurance from a TV ad.

In this case go find an Elmer (helper/mentor in the ham sense) who can either teach you or just pay somebody to do it. This stuff is actually so old it's almost 'obsolete' and they don't make many of the read head assemblies anymore, according to Tasuke and others...so get some help learning or pay to have it done. The alternative is finding a working board or a different player. SMT is like Mars to a lot of people and you don't wanna meet Marvin the first time and have the project DIS-IN-TO-GRA-TED by a cranky spaceman.

 

[Billboard]

If you don't need the old IC, can you just cut all the leads and clean up the tailings with solder wick?

 

[roccus]

I don't like those heat guns for removing smt ic's it just take way more heat them I like to see if you do use one the you need to surround the chip you want to remove with kapton tape so that a joining components dont move around.... one way that might work for you but you have to be very careful and be sure the solder is completely melted is use an exacto knife to pry the lead up and do one leg at a time with a bit of a rest between lead to let the board cool down if you take your time you will get the chip off without damage to the board...

one mentioned cutting the legs.... not sure what size chip you are trying to remove but on micro chips the leads are so close together unless you have some sort of special cutters you can not get them under the chip or between the leads to cut them so you end up trying to cut several legs at a time this can be dangerous you can lift or damage pads

 

[orange]

If you don't need the old IC, can you just cut all the leads and clean up the tailings with solder wick?

No, it's SURFACE MOUNT TECHNOLOGY (SMT). It's not soldered in through the board. It's attached directly to trace points on the top or bottom of the board. This would also technically allow BOTH sides to have circuits independent of each other or joined at points through the board.

It also makes it really hard vs. conventional PCB construction, it's a special skill to master, much less design, as I understand.

 

[laatsch55]

Cut the leads then remove one at a time......what you're talking about doing will generate way to much heat on that board. After you have cut all the leads then just touch your iron to the pieces that are left, should come off attached to the iron...

 

[62vauxhall]

Thanks all. The idea of cutting leads seems a good one. I'll rummage around for something to use. I have some small cutters that I think may be small enough but not exactly sharp so will think about what to use to fix that. At the moment, they close with no gap but they're dull.

Might also have an old watchmaker's tool my dad used to cut springs but I haven't seen that in years. Would not have tossed it so it must be here somewhere.

 

[62vauxhall]

There's a local parts store that has a fair number of tools and devices for electronics repair so I bought the smallest pair of cutters they had. Only $6 (from China) but small as they were, not small enough for this job. I intended dealing with each of the 48 pins one at a time, but since they are tiny and closely spaced, the snipping action pulled the foil away from the board. Since those traces are about half the thickness of a mosquito wing, I tried another method.

One of the videos I watched showed inserting a thin wire behind the "knees" of the pins and after applying liberal amounts of solder to maintain heat by liquidity, gently pulling the wire, disengaging the pins from the tabs. This worked well for the most part but 2 or 3 more foil traces were pulled off. I thought maybe a very small gauge wire jumping from pin to a remote solder point would work but the pins are so fragile and the between space so small, this cannot be acomplished.

So my experiment is over. I'll keep the CD transport and remove the stupidly expensive transistors I put it and dispose of what's left. I'll keep the box/remote/manual because ya never know.

 

[roccus]

There's a local parts store that has a fair number of tools and devices for electronics repair so I bought the smallest pair of cutters they had. Only $6 (from China) but small as they were, not small enough for this job. I intended dealing with each of the 48 pins one at a time, but since they are tiny and closely spaced, the snipping action pulled the foil away from the board. Since those traces are about half the thickness of a mosquito wing, I tried another method.

One of the videos I watched showed inserting a thin wire behind the "knees" of the pins and after applying liberal amounts of solder to maintain heat by liquidity, gently pulling the wire, disengaging the pins from the tabs. This worked well for the most part but 2 or 3 more foil traces were pulled off. I thought maybe a very small gauge wire jumping from pin to a remote solder point would work but the pins are so fragile and the between space so small, this cannot be acomplished.

So my experiment is over. I'll keep the CD transport and remove the stupidly expensive transistors I put it and dispose of what's left. I'll keep the box/remote/manual because ya never know.

Sorry to hear I tried to tell you... I did pc board rework and repair for 3 years for a company 90% of the work I did was on SMT boards literally 100's of pc boards came across my bench that were damaged by the line solderers trying to fix a goof up they did only to end up ripping pads and tracers I seen all the tricks they tried to use... when one of the line girls would damage a 5 6 9 or 15 hundred dollar pc board they would panic in an ISO controlled environment it's like they could just toss it or hide it as every board had a serial number and a paper trail so they would quietly bring it over to me and I would just put it on my bench in with all the rework boards and quietly repair it and return it to them I took care of the line girls and they took care of me bringing fresh baked goodies and coffee to me.... they called me DR. Ray lol

hope I got all my spelling right perry!!!!!!

 

[62vauxhall]

Sorry to hear I tried to tell you... I did pc board rework and repair for 3 years for a company 90% of the work I did was on SMT boards literally 100's of pc boards came across my bench that were damaged by the line solderers trying to fix a goof up they did only to end up ripping pads and tracers I seen all the tricks they tried to use... when one of the line girls would damage a 5 6 9 or 15 hundred dollar pc board they would panic in an ISO controlled environment it's like they could just toss it or hide it as every board had a serial number and a paper trail so they would quietly bring it over to me and I would just put it on my bench in with all the rework boards and quietly repair it and return it to them I took care of the line girls and they took care of me bringing fresh baked goodies and coffee to me.... they called me DR. Ray lol

hope I got all my spelling right perry!!!!!!

Yes Dr. Ray, you did indeed and in hindsight your's would have been the best option.

I think I overloaded on looking for solutions plus I was looking for the quickest method. I had the idea that prolonged heat application would harm the chip. Why I was worried about that I don't know because as far as I knew it was f*cked anyway. Not having dealt with one of these before, I truthfully did not think it would be possible to unsolder and lift pins one at a time but I see now that it could have been done.

Well, another loss goes on the experience side of the ledger.

 

[roccus]

Yes Dr. Ray, you did indeed and in hindsight your's would have been the best option.

I think I overloaded on looking for solutions plus I was looking for the quickest method. I had the idea that prolonged heat application would harm the chip. Why I was worried about that I don't know because as far as I knew it was f*cked anyway. Not having dealt with one of these before, I truthfully did not think it would be possible to unsolder and lift pins one at a time but I see now that it could have been done.

Well, another loss goes on the experience side of the ledger.

I hear you we do screw things up that is what makes us smarter in the end

 

[orange]

I got a mid 80s Sony or two spare and no chips needed. Just fix the tray sensor so it doesn't open and close immediately. Works fine otherwise. If you really want it, I can work out Pony Express across the border maybe. Just take it.