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Replacing Computer Chips on a 1541 Drive

Does the red light come on and stay on when the drive is first turned on? If so then the suspect chip would be in UC2. When you swap the chips the drive should then power up normally. If it does not then you either have 2 faulty 6522(which is not likely) or something else is wrong. If it does power up normally then the 6522 is faulty.

The difference between a faulty UC2 and a faulty UC3 is that when the faulty chip is in UC2 the fault appears when the drive is powered on. When the chip in UC3 is faulty the fault does not appear until a LOAD is attempted. So if one of the 6522s are faulty the symptoms will change. If the symptoms do not change then something else is the problem(or both 6522s are bad but like I said that is unlikely). So swapping the 6522s will either confirm the the 6522 originally in UC2 was faulty or tell you that you should look somewhere else.
 
Ok, I'll give it a shot. I hate doing it though because I have a hard time getting the chips out without bending their pins.
 
One possibility is that one of the socketed chips is not seated properly. Simply re-seating all the socketed chips might solve the problem but like you said, just make sure you don't bend any pins. If you are not comfortable re-seating all of them I would at least press down firmly on all of them.
 
Guybrush3pwood said:
Problem with swapping is that my drive exhibits symptoms that arise when both of those chips go bad, so I'm not sure swapping them would get me anywhere.

I'd love to buy your replacement chips, but without knowing which chips need replacing, I'm not sure what I could do except buy all of them, and that's not a very economical solution.
Click to expand...

Swap em... Got nothing to lose by trying, it's free.. Nothing ventured, nothing gained... ;)
 
Switched the chips. Now I get a spinning disc thing and a flashing red light instead of a solid red light.
 
Now you have enough parts to make one work.

What doesn't the II do? Is the head dirty?
 
Ok, forget the video. I type in a "load" command, the arm thing moves a bit to read the disk. I get "loading" on the screen. Nothing happens.
 
Ok, scratch that. Sometimes it reads...sometimes, it doesn't. Seems to be hit or miss. It started reading after I used some air duster to blow some crap out of the drive. I also blew on the head with the air duster. Also, the pressure pad looks...yellowed? Does this ring any bells?
 
Clean the head with isopropyl alcohol.

If that doesn't work, it needs an alignment.
 
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