Amiga hardware info, help and support with a focus (but not limited to) North American NTSC experiences. Open to all.
User avatar
JEY08
Bath, MI

by JEY08 posted Thu Dec 20, 2018 8:45 am

intric8 wrote:Hrm... I spy an A4000. And original Marble Madness disk! ;)


Yes, also an A3000.
User avatar
JEY08
Bath, MI

by JEY08 posted Thu Dec 20, 2018 8:53 am

Maybe this should be a separate thread but I've noticed something about the A1000 drive.

I was having trouble reading disks I created with either Supercopy Pro and PC drive, or created with the A3000 or A4000. Disks were double density since that's all that's available now. They'd read o.k. sometimes but usually not. I also tried the single density drive of the A3000 with the same result.

Originals from CBM or games like Marble Madness were were read o.k. by the A1000.

I have an external drive I bought shortly after getting the A1000. So I hooked it up to the A3000 and then used it to create disks for the A1000. Disks created that way are read without problem by the A1000 even with the double density disks.

Not sure what's going on.
User avatar
intric8
Seattle, WA, USA

by intric8 posted Thu Dec 20, 2018 9:38 am

All Amiga floppy disks should be 880KB double-sided double-density. Although IIRC the 4000 had some sort of weird support for HD, too. And most disks can be read (even PC ones) if you have the right software.

However, I have once seen where a machine (like an A1200) running 3.1 might make a floppy and a 1.3 machine didn't like it - which never made sense to me except that some A1200 FDD drives sucked. If the ADF was 1.3, that never made any sense to me but I do recall having odd experiences like that and always chalked it up to poorly made hardware.

Do the disks that can't be read format OK? If you simply format a disk, then move it over to the 1000 (without anything on it) does the 1000 accept it, or think it to be bad, too?

The fact that your external can write it to disks, though, (I'm assuming full ADFs) and the 1000 reads them every single time is a head scratcher. Makes it sound like the disk drives on your pro machines might have issues.

This is not an answer, but if I want to write disks for my A1000 I always use my A2000 (which has the same OS). Works flawlessly.

That's a lot of rambling. Wish I had a eureka thought up there.
User avatar
JEY08
Bath, MI

by JEY08 posted Thu Dec 20, 2018 10:08 am

I wouldn't be able to tell by just formatting. The A1000 has trouble with the higher track numbers if they're written by the A3000 or A4000 drives or the PC drive. The error only shows up after reading about half the disk. It's only happy with the external single density drive.

I can read PC formatted disks o.k. with both the A3000 or A4000.

I can also read disks created by the A1000 o.k. on the other machines.

I remember having this problem before if I used PC preformatted disks in the A3000. It seemed like I could never completely erase the old tracks.
User avatar
JEY08
Bath, MI

by JEY08 posted Thu Dec 27, 2018 7:54 pm

I decided to try repairing the original front memory that quit working.

Here are rust stains in the front cover from the memory board shield showing that it was under water.

Front_Mem_Cover.jpg
Showing rust on cover


There are 8 ceramic capacitors and one tantalum capacitor on the board. They all tested good.

I don't have a way to test the memory IC's so I replaced all of them. To my surprise it is now working. :)

Here's the repaired board with one of the old chips in front.

Mem_Front.jpg
Repaired board


The reason I was surprised it worked was because of a mistake I made. Removing the IC's is difficult because I didn't have enough room to clip the leads. That meant heating all of the leads at the same time to remove them.

So I used a hot air rework station to do that. However when they designed the board they used thermal reliefs where needed except for the power planes where they connect to the IC. Without a thermal relief the ground plane sucks the heat away and makes it difficult to melt the solder on both sides. So you have to get the board hot enough to melt the solder.

To do that I first baked the board at 90 deg C for a couple of hours.

You normally should bake a board to remove the moisture when using a hot air rework otherwise the steam can create very high pressure inside the IC's. Especially for moisture sensitive ones.

That was the mistake. I should have baked it at 125 C for 48 hours. There was more moisture absorbed into the PCB that I realized.

So the board blistered in one spot as you can see on the right side of this photo.

Mem_Back.jpg


I was fortunate that it didn't break any vias when it blistered. I'm happy it works in spite of my mistake.

Who is online

Users browsing this forum: No registered users and 2 guests