A1500 Floppy Woe

[scrappysphinx]

Hi Guys, i have just purchased my first big box machines in the form of 2 A1500's with monitor and external floppy drive for a tidy sum of £35 all in.
The first one was delivered this morning and the motherboard is an A2000 Rev 6.2
Anyway upon start the rom screen shows up fine so that machine appears to be ok however when i insert a floppy into either of the 2 drives it begins to read then returns to the rom screen.
Any ideas what to check first?
i assume that both drives wouldnt be dead but could i be wrong?
I read somewhere it could be a problem with the CIA chips, which ones are these?
I am collecting the other A1500 and monitor over the weekend so will be able to swap parts from one to the other to test.

[rkauer]

A1500 (and any other Amiga with ROM 1.3 or less) won't read FFS formatted disks.

Are you sure you are using a OFS boot disk, like Workbench 1.3 (or less) to test it?

[TheCorfiot]

Originally Posted by rkauer

A1500 (and any other Amiga with ROM 1.3 or less) won't read FFS formatted disks.

Are you sure you are using a OFS boot disk, like Workbench 1.3 (or less) to test it?

A1500 Was shipped with KS2.04 as standard, however I suppose it could have been downgraded at some point in it's life.

I agree with rkauer, Suspect Bootdisk ??

TC

[scrappysphinx]

Hey Guys, thanks for the reply's.

The machine has KS2.04 and i have tried WB 1.3 and 2.04 and it wont boot either. I know both disks work as i have used them with my A600 which a KS3.1 (i will move this 3.1 to the A1500 when i get the A600 out again).
Any other suggestions welcomed.

Mike

[cosmicfrog]

see if the external drive works in your other amiga if it dose plug it in 1500 hold both mouse buttons and boot off that prob be df2 if you have 2 drives already

[scrappysphinx]

Further investigation led to me swapping the two floppy drives with ones from an A500 and machine will still not boot. I will try the external floppy today as suggested by CosmicFrog.

[Fingerlickin_B]

What about jumper J301 on the motherboard?

It should be jumped for two internal FDDs or un-jumped for just one drive.

If you have it jumped with only one drive fitted the machine will still boot, but un-jumped means there is no drive sequence...no good if two drives are in the same chain I'd imagine.

Also, have you checked the jumpers on the drives themselves?

PZ.

[scrappysphinx]

Hey Fingers, J301 is jumped two allow the floppy drives and the jumpers on the back of the drives are jumped as ds0 and ds1.
I have unjumped J301 and plugged in a known working floppy drive from an A500 and still it begins to read the disk and then returns to the rom screen. I have also tried the external floppy drive and booting from df2 and still no joy.

[Fingerlickin_B]

Well man, we've now reached the limits of my knowledge I'm afraid, but surely one of the gurus on here will think of something.

Have you replaced the Kickstart ROM just to be sure of that anyway?

PZ.

[alexh]

Possibly a broken Paula chip?

[musashi5150]

I'm not saying it's the cause but Paula and CIA chips are involved in disk controlling. Might be worth pulling all the custom chips & CIAs and giving them a good clean? All the chip names are marked on the silkscreen.

Any battery damage or other motherboard fault you can see?

Could it be a dodgy PSU not supplying good voltage? Get you're meter on it

[scrappysphinx]

hey guys, i have replaced the KS2.04 with KS3.1
I have also pulled and reseated all chips. The guy i bought it off did say it may possibly be the CIA chip. Is the Paula chip the same as in an A500 or is it different for an A2000?

[musashi5150]

It's the same. A2000 & A500 are pretty much identical really.

[scrappysphinx]

New update:

CIA, Paula, Gary, Denise, Agnus, KS rom chips have all been swapped and machine is still doing the same thing. It will load to the rom screen but when i insert a KS1.3, KS2.04 or KS3.1 workbench disk it begins to load then returns to the rom screen.

Any more suggestions welcome

Mike

[alexh]

I am leaning towards musashi's suggestion that the battery might have leaked and eaten away at some of the tracks responsible for floppy disk access.

What condition is the area around the battery?

[scrappysphinx]

Hey Alexh, battery has been removed and there is no visible damage that i can see. I will take a photo in the morning and post for you to see.

[coze]

cable ?

[scrappysphinx]

Hey Coze, the cable is the only thing i haven't changed as i dont have another one long enough to test. But i am collecting the other A1500 on sunday evening and the cable will be the first thing to test!

[musashi5150]

But as you can't boot from DF2: it suggests the cable isn't the problem?

As alexh suggests I think it could be a dodgy motherboard trace to do with the floppy controller. Can't think what else it could be.

Just out of interest did you stick a multimeter on the PSU to check the voltages?

[scrappysphinx]

Hi Musashi, i havent actually got a multimeter and am not sure how to actually use one anyway. I will however swap the psu with the other machine i am collecting tomorrow evening and test again. I will upload photos tonight of the battey area but i cannot see any physical damage.