Cap layout and board sure do look the same to me: https://macdat.net/cap_reference/apple/powerbook/180c.html
In any event, good luck getting it fixed!
In any event, good luck getting it fixed!
- VCF South West - June 14 - 16, Davidson-Gundy Alumni Center at University of Texas at Dallas
- VCF West - Aug 2 - 3, Computer History Museum, Mountain View, CA
- VCF Midwest - Sept 7 - 8 2024, Schaumburg, IL
- VCF SoCal - Mid February 2025, Location TBD, Southern CA
- VCF East - April 2025, Infoage Museum, Wall NJ
-
Please review our updated Terms and Rules here
Zenith Z-Note 425 Lnc Video Issues.
- Thread starter FParker
- Start date
Well, upon changing out the original chips for the "new" chips from my original board, everything has gone from bad to horrendous. No solder bridges, no shorts, no nothing. The chips must have been bad there too.
What on Earth am I to do? I can't get new chips; an unknown number of the old ones are bad. I really, REALLY do not want to give up on this computer. I've put in far too many hours to simply throw in the towel now. I guess I could just start swapping them out one at a time until I get a combination that works.
Alternatively, I could just buy the V53C104FK60L chips off of Ebay and pray they work.
EDIT: I know this is stupid, but would there be any way I could solder chip sockets to the solder pads? I think there's just enough clearance between the boards to allow for that. It would make the process of changing chips far quicker. As for the chips themselves, they're just through-hole chips with their legs bent underneath for SMD purposes.
EDIT 2: Belay that last edit, the feet on the chips would never be long enough to fit into the sockets. Back to soldering everything. I guess I need to check every chip, one at a time, with all the old chips. Hopefully I will be able to weed out the bad ones in the process.
Last edited:
GiGaBiTe
Veteran Member
Those are SOJ style ICs, but I don't know of any common socket that would fit those chips, because those specific chips are not designed to be socketed. While they only have 20 pins, they'd be classified as 26 pin devices, since there are 13 pins on each side, even though 3 of them on each side are not populated.
28, 32 and 40 pin SOJ sockets exist, but I'm not finding any 26 pin sockets. I'm sure there was probably a test socket made for that package type, but it's going to be decades obsolete by now, and difficult to find if any still exist.
There's the Retro Chip Tester Pro, but it's hideously expensive.
Retro Chip Tester Professional - IC Integrated Circuit Tester Pro | eBay
Find many great new & used options and get the best deals for Retro Chip Tester Professional - IC Integrated Circuit Tester Pro at the best online prices at eBay! Free shipping for many products!
www.ebay.com
$470 for the fully assembled version.
A cheaper method would be to find an old RAM module with similar memory chips and swap them out for the ones you want to test and use a PC to test them. If you find any bad bits, you can use the memory map to figure out which chip is bad.
Those are SOJ style ICs, but I don't know of any common socket that would fit those chips, because those specific chips are not designed to be socketed. While they only have 20 pins, they'd be classified as 26 pin devices, since there are 13 pins on each side, even though 3 of them on each side are not populated.
28, 32 and 40 pin SOJ sockets exist, but I'm not finding any 26 pin sockets. I'm sure there was probably a test socket made for that package type, but it's going to be decades obsolete by now, and difficult to find if any still exist.
There's the Retro Chip Tester Pro, but it's hideously expensive.
Retro Chip Tester Professional - IC Integrated Circuit Tester Pro | eBay
Find many great new & used options and get the best deals for Retro Chip Tester Professional - IC Integrated Circuit Tester Pro at the best online prices at eBay! Free shipping for many products!www.ebay.com
$470 for the fully assembled version.
A cheaper method would be to find an old RAM module with similar memory chips and swap them out for the ones you want to test and use a PC to test them. If you find any bad bits, you can use the memory map to figure out which chip is bad.
Sadly, I don't have access to any RAM modules that are like that. The depth of my old computer parts bin is shallower than a kiddie pool, so the best I can do is buy those similar chips. I sent an inquiry to a company that has them after reviewing the datasheet. Apparently, the V53C104 is a family of chips that, to the best of my knowledge, have the same pinout and traits.
Apparently, on the datasheet for the V53C104FK60L, 104F is shown to be the device designator, as opposed to 104N. The entire family is a 262,144 x 4 bit RAM. The FK60L runs at 60ns and is a low power design.
I don't see any reason why this wouldn't work, unless I am missing something (absolutely within the realm of possibility).
Last edited:
GiGaBiTe
Veteran Member
The "low power" design can be a gotcha. Does low power mean the IC was redesigned to use less current, or does it mean that it requires less voltage? In the FPM/EDO era, memory was starting to change over from 5v to 3.3v. On memory modules it didn't matter, because they just added level shifters. In memory chips directly on the board, it does matter because if you put a 3.3v chip in place of a 5v chip, it's going to die. It may work for a bit, but it won't be long before it burns up. To add to the complexity, there's a third wheel, 3.3v devices that are 5v tolerant.
Memory technology in the 90s was fun.
Memory technology in the 90s was fun.
From the looks of it, it's a five volt chip, and the L means low CMOS current needed for data retention.
I'll bet it was wild in the 90s to follow all this stuff as it was coming out. Such break-neck pace with development; it's truly incredible to ponder.
T-Squared
Veteran Member
Yeah, I'm not liking that memory chips like these are losing their ability to hold information. I have an S3 Virge that needs some memory, and it seems like the memory I got was just as bad as yours.
Why are they doing this? I'm assuming it's age related.
Another thing that frustrated the finding of these chips are the MOQs that a lot of distributors have. I don't need 50 of the same DRAM module, I need four. Such is life, I suppose: endless frustration.
GiGaBiTe
Veteran Member
There are numerous failure modes, but the most common would be electron migration, atmospheric contamination, or manufacturing defects. Electron migration can cause shorts or breaks in the circuitry in the die, atmospheric contamination can cause oxidation of the die and destroy it, and manufacturing defects can be imperfections or errors in the etching process that make the die susceptible to failure later on. Some manufacturers are more likely to have failure than others, like early Micron memory chips have extremely high failure rates, likely due to manufacturing defects.
You can try asking for samples, just say you need 10 or 20 for a prototype and offer to pay for them and shipping. Some manufacturers are open to doing that, I've had to do it before when sourcing hard to find components.
There's the Retro Chip Tester Pro, but it's hideously expensive.
Retro Chip Tester Professional - IC Integrated Circuit Tester Pro | eBay
Find many great new & used options and get the best deals for Retro Chip Tester Professional - IC Integrated Circuit Tester Pro at the best online prices at eBay! Free shipping for many products!www.ebay.com
$470 for the fully assembled version.
Only when you buy it assembled.
Contact the developer http://8bit-museum.de/rct and you will get the board with an pre-assembled ATmega for approx. 60 USD. It uses standard components for maybe 50-60 USD.