Mac 128k help needed!

[Elfen]

If you have the radioshack desoldering tool (one of the few things they ever got right!), you can remove the chips quickly without ruining the traces. You just have to add a little solder to the joint with the bulb pressed and when the solder joint liquifies, release the bulb and the solder comes right out. It takes a little practice to use it but once you got it down, this would only take 40 minutes to unsolder all the chips at a few seconds per pin. Then you clean the board and inspect the traces.

 

[KenB123]

Wow that sounds awesome! I will have to get one of those! I will be able to use it for future things as well.

Thanks for the tip!

 

[KenB123]

Thanks for the tip! I just ordered one and I will let you guys know how it goes! It looks super useful!

I have another 2 boards also that I think are toast.

 

[techknight]

those things are difficult to work with, youll wear your thumb out quickly. Plus the tip isnt plated so it will fail in short order. 

ive had many of those, never again. Then I got a hakko 808. Best thing ever... 

 

[KenB123]

Oh great... Well it was cheep and I guess it will get the job done for just 1 chip that's all I need it to do (I hope)

 

[Elfen]

I use them all the time. Its  matter of practice. I'm sure there are Youtube videos out there on how to use it. It would take too long how to describe it here. But once you got it down pat, its simple.

 

[KenB123]

Yeah I watched a video on YouTube of someone using one. It shouldn't be that hard to do. I hope

Should I use flux with it?

 

[wilykat]

Famous last word ^^^^

Always is harder than it looks on your first few tries.  I've destroyed a few parts practicing. Thankfully junk electronics (old TV after you zap the CRT or old VCR) are common. 

 

[KenB123]

Ok I will practice on a junk analog first.

Thanks for the advice

 

[KenB123]

Ok I will practice on a junk analog first.

Thanks for the advice

 

[KenB123]

Ok I will practice on a junk analog first.

Thanks for the advice

 

[uniserver]

yup i think i still have like 800 4164's -samsung. 

i find that apple logo'd ram is the worst.

you should change them all.

i personally don't like sockets and don't see a need for them.

Once you change all the ram with some high quality samsung ram or equivalent,

the need to change ram in there will be something of the past.

The stuff apple threw in there was crap.

I also don't like upgraded 128k's, if you want 512k ram.. then get a 512k.

( but that is just me ) its your puter, its much more collectable stock.

especially an original Macintosh Mobo like that one.

Also, just adding higher density ram to a 128k, upgrading it to a 512k is not just a Drop in solution… You need a mux and some other parts, and a trace has to be cut as well.

I didn't check the link,  was the that a bulb solder sucker? 

As Elfin said,  if you add solder to all 16 pins and then get your iron in there and get that solder nice and melted all the way through the porthole.

once you pop it, it should slurp up that pretty good., afterwards you might want to take some needle nose and rotate each leg of the ram, because

there might still be some slight soldered surfaces.   

The nice thing about a desoldering iron is you can rotate while you are pulling the trigger and it sucks all the solder out really well.

Makes the task, much less labourous. Witch if you decided to change all 16 chips… is quite a task indeed.

if you just change that one chip.. you will be ok for a few weeks or months…  until the next one goes bad too.

then you will be doing this all over again.  Hopefully by then you have not misplaced all your supplies.

If anyone is interested in a owning a pretty good all-in-one desoldering iron, There is a pretty decent one on ebay for like 100 bucks free shipping.

http://www.ebay.com/itm/S-993A-110V-90W-Electric-Vacuum-Desoldering-Pump-Solder-Sucker-Gun-/161413419282?pt=LH_DefaultDomain_0&hash=item2594fd5112

I own it and its pretty decent. I like my hakko fr-300 much better, but those are 3x more. If you can get a Hakko 808, They are the Beastliest of all of them…  

i think. But even those have went up in price.

the hakko 808 with its V Twin Vacuum pumps on the end there. ITs like a mini Harley engine.

 

[KenB123]

Wow thank you for all of this useful information! Yes I remember reading that Apple branded chips were horrible and I guess I will change all of them then.

Yes I want to keep this thing as original as possible so I'm debating if I shoud use the sockets I have or just put the chips in directly.

Sorry for the delayed response but I was in school.

I hope I'm able to remove all of these chips just using the radio shack tool I ordered.

Thanks for the advice on adding solder to the legs first also and moving them with a needle nose prior to removing. This will be very useful and probably save me a lot of stress.

Thank you everyone on this forum providing me with all of this info it's really interesting and fun learning about all of this stuff!

 

[KenB123]

Wow I just noticed my triple post :0 my apologies on that. It's difficult to be using a iPhone to do all of this stuff haha. I will try to not do that again

 

[jsarchibald]

512K boards are easy to find, and most 128Ks ended up either having a 512K board installed or the RAM being swapped to accommodate 512K.  Handy in 1985, not so much in 2014.  Finding a 128K board in there means you have to keep it as one, but it sounds like you've already decided to do just that.  These things are starting to become harder to find, and original boards even harder again.

Sockets will also devalue the board, so I would just stick with your standard chips.  The best solution is to replace them all as they will continue to fail otherwise, but if you are happy to replace them if and as required, you should be fine.

Nice work!

 

[KenB123]

Yes I prefer having the original amount of ram I was surprised when I opened it to see it was not upgraded with a 400k floppy.

Thanks for the advice. I guess I'll just replace all of the ram chps without the sockets to prevent any future issues with it.

 

[Elfen]

Start with the bad chip first and then test the board and see if it works. If yes, then continue replacing the others. replace a couple at a time and test the board, this way if something happens you can check your work and do a fix before continuing. Nothing worse than replacing all the chips at once and end up with a Sad Mac and you do not know which ones are at fault. And take your time with it.

Recently I was working on a Raspberry Pi and its twin somebody decided to take their foot to them, crushing the USB Ports. I replaced the USB Port on one of them and it works fine, thing is, the Pis use Black Plastic USB Ports and I used White ports- which is a minor thing. But on the other Pi, I used have used too much solder and shorted out a pin or two on the Pi, though it booted up, it comes up with an error of "Overvoltage on Port 2" - one the USB Ports. The next day I desoldered the replacement USB port neatly, cleaned up the board, checked the USB traces to the chip and then put the removed replacement USB Port back in, being a little stingy with the solder this time. Now it works like the day it came out of the factory! I got these two Pis as a pair from Ebay for less than $20 each, including S/H. And they now got White Ports, LOL!

Lesson here? So solder wisely and only use enough solder to close the joint. Inspect you work on both sides and then continue to the next pin. For me, the I could only see one side of the Pi, but I left huge solder balls on each pin - a sign of too much solder used.

 

[KenB123]

Wow that's really smart! Thanks for the awesome tip!

 

[KenB123]

Hello everyone! While I'm waiting for the tools to fix the other 128k I have another 128k in need of attention. When I power this one on for the first 30 seconds to a minute or so it displays this pattern on the screen. Any ideas? I already replaced the caps with another questionable broken mac board and it started booting up quicker then it used to which took like 5 minutes to just not starting at all but it doesn't bong and boot when it's supposed to. Any ideas? I know jail bars mean bad ram but when it does boot it doesn't show any errors

 

[KenB123]

Also another thing to add is after the bars go away and the computer is warmed up I am able to restart it and have no problems.

It's just having trouble with the cold starts I don't know why.

All of my analog boards are working fine I make sure to test them with known working motherboard of a Mac plus.

Thanks everyone for all of your help!