Which chips to buy

[Joad]

Hello guys, I am a fifteen year-old non-expreienced collector from Turkey. After buying a IIe for 40 bucks, and trading it with a PS4, I got a II Plus from an auction on eBay for 80 bucks plus shipment. The seller noted that he didn't test it. The power light was on, so I didn't imagine something like that to experience. Some chips needed to be reseated, so I did, but completely destroyed a RAM, and broke lots of legs of some chips, etc.. After resoldering legs, I got some pictures shown here. After some silly repairments, I completelyu destroyed lots of chips, and have no video. Which chips ı need to buy, or should I get a new motherboard/chips?

 

[Elfen]

Looks like you're learning your lesson - don't be a brute, take thing slowly and gently, and never force things if they are stuck.

You will need some contact spray cleaner to spray on the stuck chips.

You will need to put back that E0 ROM or it is not turning on (No AppleSoft BASIC, so on prompt or cursor). If you need to repair it, repair it. That requires some light soldering.

The RAM Chips are 4116s, you can get that anywhere. They are about $5 a chip or less.

The 74XX Chips can also be obtained anywhere as well. they are about $3 a chip or less, depending on the chip.

Don't worry about name brands. AS IS I see at least 6 different brand chips on the board, including 3 in the RAM Section alone. The RAM Chip speeds should be 150ns to 120ns (ex: 4116-15 or 4116-150 for a 150ns). The 74XXX series should be LS Series - 74LSXXX.

Places you can try for chips are Jamesco, Mouser, Newark/Element 14. There are other places to check but many including I consider these to be the top three.

When you get the chips, put them in gently, check the sockets first. If there might be a broken pin in it - get it out.

Post up a pic of the broken chips.

 

[Joad]

I will solder and try to put it back then, thanks. Can you make a proper list of the ones i need by the way?

 

[Elfen]

I remember your older post. You tested the board with some of the RAM missing? The Apple II can run on 1 row of RAM but the row has to be completely filled. If you have RAM missing on a row, it will display screen with jumbled characters because it thinks that the RAM is bad. So you can remove all the RAM and only fill in the bottom row to test the RAM 16K group (8 chips) at a time.

Any other cards came with your system? You will need a Language Card to have 64K; it goes into Slot 0 AND you remove 1 RAM Chip from the motherboard and put it on the Language card, then you take the ribbon cable from the card and put in into the RAM Socket on the motherboard. You need to know this if you remove all the cards and there is a RAM Chip missing - it is on the Language Card and you need to transplant it back on the motherboard or else it will error when you turn it on.

Q: (not asked on the other thread) Does the computer "Beep" when you turn it on? It means a lot whether it does or not.

 

[Joad]

I put the E0 back but still no video or beep which I think the lack of 74LS257s and 74LS138 causes.

 

[Joad]

Is there a way for me to send you a video?

 

[Elfen]

I will solder and try to put it back then, thanks. Can you make a proper list of the ones i need by the way?

It's right there on the board:

Row F  - ROM E0 needs to be fixed, there is no way to get that replaced as it is programmed.

Row F (again) - Far right on the socket, it needs a 74LS138

Row E (RAM Section) - 5 4116-15 RAM Chips. You can gently remove the current three and see if it turns on with just 32K after the 74LSXXX chips are replaced. If it does, put 8 RAM chips back in the motherboard to get the full 48K.

Row B - 2 74LS257 chips are needed in the board.

This is a total of 8 chips; 5 are RAM Chips, 3 are 74LSXXX chips. Should not cost no more than $20, perhaps a lot less. BUT I do not know what shipping will cost you.

So, when you get these in, and you still get a bad screen, you're half way there to fix it. It will take time (and money to buy chips) but it is doable. 

 

[Joad]

Thanks, do you know a website to buy those things?

 

[Elfen]

Read these links:

http://www.willegal.net/appleii/appleii-repair.htm

http://www.apple2online.com/web_documents/apple_iie_repair_guide.pdf(pdf download, it is for the IIe, but same rules applies.)

http://www.apple2online.com/web_documents/How%20to%20Repair%20&%20Maintain%20KB.pdf(pdf download for the Apple II)

http://www.toddfun.com/2012/05/28/apple-ii-plus-from-1982-teardown-repair-cleanup-and-demonstration/(with 2 videos)

 

[Joad]

I found a Turkish deal store, but it says SN74LS257N. Or on 74LS138, my dead chip says 74LS138N, but the website says HD74LS138P. Should I buy those or not

 

[Joad]

What about buying a working motherboard and replacing them with mine? A motherboard is for 56 bucks but the E0 thing is 46. http://www.ebay.com/itm/Apple-II-Main-Logic-BD-RFI-Motherboard-820-0044-D-606-X548-L-1979-Apple-II-/131563726492?hash=item1ea1cf269c

 

[unity]

Im so glad I did not ship you a 128k.

 

[Elfen]

Jamesco has the 4116 RAM:

http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?search_type=jamecoall&catalogId=10001&freeText=4116+ram&langId=-1&productId=41339&storeId=10001&ddkey=http:StoreCatalogDrillDownView

Jamesco IC Section, just put in the chip number to search:

http://www.jameco.com/webapp/wcs/stores/servlet/StoreCatalogDrillDownView?langId=-1&storeId=10001&catalogId=10001&categoryName=category_root&subCategoryName=ICs%20&%20Semiconductors&category=10

Mouser's IC Section, just put in the chip number to search:

http://www.mouser.com/Semiconductors/Integrated-Circuits-ICs/Logic-ICs/_/N-6j77x?P=1z0yhhsZ1z0yyznZ1z0yhfyZ1z0yrxkZ1yzxosoZ1z0z63x

Newark/Element 14's IC Section, just put in the chip number to search:

http://www.newark.com/logic

 

[Elfen]

The P in the chip number is fine. The important part is that it is a 74LS, not 74S, 74, 74HC, 74C, etc. LS means that is operates within a digital input/output of 5V. The 74C and 74HC are CMOS versions and operate at 3.3V, which would run hot on 5V and even burn out faster than a LS series, the others operate at other voltage ranges.

 

[miniMOJOman]

Im so glad I did not ship you a 128k.

Lol, I am sure there is a nicer way of putting that!

 

[Elfen]

Also, any letter before the 74LS is usually a company initials. Don't worry about as long as it says 74LS-what ever number you need, its the right chip.

Make sure it is a "DIP" (Or Dual In-line Package) - 2 rows of pins. Not one row ("SIP" - Single In-Line Package) or SMT/SMD (Surface Mount Technology/Device). On some online places will have this information and others not. Just make sure it is a DIP (usually by a picture on the site).

 

[Joad]

I bought the chips, and placed them but then a smell came from the motherboard. Now should I look for a new motherboard?

 

[david__schmidt]

I bought the chips, and placed them but then a smell came from the motherboard.

Uh oh - the magic smoke was released.  How sure are you all your replaced chips are oriented correctly?

 

[Joad]

Yeah, I checked each time I powered it on.