Amiga 2000 Restoration and Floppy Header broken Pin

[Zippy Zapp]

Hi All,

The History: (If you don't want the history of the restore, skip down to Problem)
I pulled my A2000 out of my friends storage, last year, and it had not been used since about 1995. Of course the battery was not taken off and it leaked all over CPU and socket. I cleaned as best I could and polished CPU pins. (Those foam buffing sponges with 4 sides of different abrasive for manicure/nails removed the corrosion and restored shine to pins, it's amazing!)

Powered on: Black Screen. Tried removing chips and agnus (8375 in a DKB Mega Chip) to know avail. Was suggested it could be CPU socket, ordered replacements. I tested continuity across all traces that looked broken and all worked. All cpu socket pins worked testing against CPU expansion slot. Tried working CPU swap, nope. Had a feeling it was the Agnus so ordered new Agnus 8372A. Removed DKB mega chip and put the Agnus in direct.

Success! 2.04 ROM kickstart screen!

The Remaining Problem:
One of the pins on my 34-pin Floppy Header broke off with the cable. I removed it from the cable but not sure the best way to repair. I also don't have a known reliable pinout. It is the pin directly next to Pin 1 to the right. From the pinouts I have seen if they are correct it is Pin 3, Ground as the pins go up down not right left. It appears every odd pin is ground. Is this correct?
Also any ideas for repair? Is the pin needed and if so is there an alternate way of fixing with out de-solder and header replacement? Perhaps a lead pin from another header just a tad longer, wedged in there?
Thanks!

[hooverphonique]

usually, on 4-pin floppy headers, the two middle pins are ground.

[Zippy Zapp]

Originally Posted by hooverphonique

usually, on 4-pin floppy headers, the two middle pins are ground.

Hi, My bad I didn't note that it is the 34-pin floppy header on the motherboard, not the molex power connectors. Sorry.

[pandy71]

Single pin can be replaced but better to replace whole header (single pin will be hold by solder point i.e. higher mechanical stress applied to solder point).
Check schematics but one pin in header is removed (working as key to prevent incorrect plug position if plug have one hole filled).

[hooverphonique]

Originally Posted by Zippy Zapp

Hi, My bad I didn't note that it is the 34-pin floppy header on the motherboard, not the molex power connectors. Sorry.

aahhh.. well, yes, every other pin is ground (starting from pin 1).. on the floppy drive, pin 3 is used as key, and is thus removed.. Therefore it doesn't have to exist on the motherboard either..

[Zippy Zapp]

Originally Posted by pandy71

Single pin can be replaced but better to replace whole header (single pin will be hold by solder point i.e. higher mechanical stress applied to solder point).
Check schematics but one pin in header is removed (working as key to prevent incorrect plug position if plug have one hole filled).

Thats the thing, I can't be sure of the schematics or pinout as it seems different from a standard floppy...
Here is the link: http://www.l8r.net/technical/t-diskdrive.shtml

Originally Posted by hooverphonique

aahhh.. well, yes, every other pin is ground (starting from pin 1).. on the floppy drive, pin 3 is used as key, and is thus removed.. Therefore it doesn't have to exist on the motherboard either..

Fantastic. That is good to know. I didn't think to check the floppy connector on the drive. I know my other A2000 has all pins. When I saw the pin stuck in the ribbon cable I was a bit bummed. I will be connecting the floppy drives back in the mix later today. Getting the 2000 powered on again was first step. Doing one thing at a time down the check off list. Still have RAM Cards, SCSI Card and Accelerator to add in the mix testing one by one...

Why can't people take better care of storing computers? Especially when it is not theirs?

[Zippy Zapp]

Just an update on my progress and floppy connector. Every time I try to work on my Commodore's something in life throws me a curveball so I don't have time. Arrrrg.

Anyway just connected floppy DF0: only and keyboard and was able to boot to workbench after a few retries on floppy drive from read errors I don't think it is actually the disk itself as I wrote it not too long ago and it boots fine on other Amigas. I think it is the drive as it has not been used in 20 years!

Time to take it apart and give it a clean and lube drive screw and rails as it did sound like it was not so smooth...

As for the missing pin, it seems to work with DF0: Perhaps as others have said it is not needed. The floppy drive does not have missing pins as some have said that they do for key but none of my Chinon drives are missing pins. But perhaps that particular ground pin is unnecessary?

Anyway so far so good. It is now sitting on the work bench screen. Cool.

Now to check other components like RTC, Expansion slots and cards, etc.

[Zippy Zapp]

After deep cleaning and lubing drive rails and motor screw both drives are now working well. Thanks @ElectroBlaster for the petroleum jelly idea on the motor screw seems to have worked great all drives no smooth.

I wonder what they used on the motor screw from the factory? I didn't use too much just in case it decides to melt it shouldn't leave too much residue.

[bdb]

Vaseline is a grease (high molecular weight oils) left over as a byproduct of refining of crude oil into fuel. Were it to heat up beyond its flash or fire point, it would mean your computer is all ready on fire, otherwise, like all good chemicals, it would melt and act like an oil rather than a grease.

IMHO, for fast moving parts, a heavy oil would be better than a grease -- 3M's 3-in-one machine oil.

[Zippy Zapp]

@bdb,

Good information, thanks. I don't know how fast that motor screw turns but I don't think the stuff will fly off so easy. Below it is a metal part of the chassis with no electronics below it.

I just resurrected a non working Epson drive in a later model A500 and it did not need any grease on the drive head rails. Interesting enough is that on that particular model, it has a built in reservoir that was still holding a fair amount of grease, so I didn't need to touch it. Drive was made in 7/91 so 24 year old grease,

Both floppies on the A2000 are now working well too. Just need to solve the intermittent freezing and crashing that it is experiencing.

[EvilShiloh]

Originally Posted by pandy71

Single pin can be replaced but better to replace whole header (single pin will be hold by solder point i.e. higher mechanical stress applied to solder point).

I just had the same unfortunate luck. I could not get my floppy drive or my new GoTek drive to read a disk after installing the Gotek. Then I found the pin that broke off the floppy header stuck in the end of the cable. Thanks for the advice. . As soon as I get a 34 pin header in I be getting this done. The old A2000 will have to wait before we can play again.

[amiman99]

From my experience, and looking at the motherboard pictures, the missing 2nd pin in A2000 floppy cable is missing on purpose. You will also find a pin inside the cable.
This is made so you will not plug the cable in the wrong way.
I would say, leave it alone.

[Zippy Zapp]

I guess I should have updated this thread with more research. The pin is supposed to be missing and Commodore in its wisdom (?) decided to put the pin in the cable so you couldn't plug it in the wrong way. It would have been better to do what PC cables eventually did and block out the hole so no hole is there at all.

They created some confusion in so doing:

http://www.devili.iki.fi/mirrors/hay...docs/relax.txt

So, don't replace the header it's supposed to be the key.

Also as far as lubricating the drive I have learned a lot in 5 years and countless drives refurbed and boards recapped. There is some really good lubricant by Dupont called Molykote EM-30L. It is made for plastics and safe for metal and basically anything. It is like a thick cream and doesn't breakdown and seems to work great. Thanks to GadgetUK for finding that out. I have been using that and Silicone 3 in 1 for years now with good results.

As for the A2000 and stability. Apparently some of the corrosion got under one of the pins in the ROM socket and after replacing that and eliminating all remaining corrosion it worked great. It was important to bring all areas of corrosion down to the copper layer and then put on a coating to protect the copper.