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Apple IIe, 80COL/64K memory expansion, time to buy and replace a chip?


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thread moved from

https://68kmla.org/forums/topic/62758-restored-apple-iie-keyboard-keys-not-working-which-options/

 

which started here

https://68kmla.org/forums/topic/62679-apple-iie-my-first-ii-after-many-macs-where-to-start-from/

 

I am proceeding with the restoration of my "new" Apple IIe, I feel very clumsy with this machine, I do not have experience at all.

 

The RAM test reports that the 64KB RAM on board is fine but the 80 column external RAM: the ESC+8 that is supposed to switch to 80 columns does not work.

I cleaned and pressed the two ICs with no luck.

 

time to buy and replace the IMG_20210413_212645.thumb.jpg.65254f954d28db4fac768fb55a0cc93c.jpgchip #2?

 

IMG_20210413_214406.thumb.jpg.e0a4dfe23032adece4cce458f0ed7d3f.jpg

thanks

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isn't de-soldering a better approach? I have the skills and tools, where are the pros?

ah, maybe it's a quick way to make a diagnosis? just pressing it on top a and run the test ...  still I do not have a spare MT4264-20, they sell it in set of 10

 

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20 hours ago, ironborn65 said:

maybe it's a quick way to make a diagnosis?

 

yes, to be honest, can't figured out how to read the information in your picture.

 

20 hours ago, ironborn65 said:

still I do not have a spare MT4264-20, they sell it in set of 10

 

To be honest those Mt chips are notorious for being unreliable, i will replace all of them to be in the safe side, or at least use sockets

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Cool, thanks @olePigeon, about the  RAM2E, I was wondering which applications can take advantage of configuration with more than 64KB :)

 

The second one, from the way I look at retro computing, is disturbing .... I'm more a Museum kind of "guy", but I understand there are several approaches, the importance is having fun :)

 

I'll try the RAM2E ...

 

 

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If you want OG parts, an original RamWorks tends to not be too expensive.  They were fairly common, and it uses cheap DIP RAM.  Database apps could use the RAM, but the most effective way to use it is to pair it with a RAM Charger.  It would then give you a semi-permanent 8MB RAM disk (just make sure the battery stays charged.)

 

I  like OG parts myself, but they're often prohibitively expensive.  An 8MHz ZipChip will run you $500 or more.  An OG 16MHz TransWarp GS will run you $1000.  So $200 for a real-time adjustable accelerator is OK by me. :)

 

I do draw the line at destructive upgrades, however.

 

Edit: If you have a SCSI card with DMA and a SCSI disk, it'll make good use of the extra RAM to speed up disk transfers.

 

Edited by olePigeon
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