Slots wont work

8 posts / 0 new
Last post
Offline
Last seen: 1 month 2 weeks ago
Joined: Mar 1 2019 - 04:38
Posts: 19
Slots wont work

 

 I have been getting my spare motherboard up and running over the last few weeks using an old ATX PSU and an arduino to interface a PS/2 keyboard.

Faults so far have been a failed 6502 (address bus all at 3.3V) and one 4116 ram chip (output stuck high) and now the board starts up and works fine. Ran a basic memory test and that looks good, can save and load programs . Loaded and ran galaxians from a wav file through the cassette interface so it cant have much wrong with it.

My remaining fault is, when I put a working disk interface/drive/floppy, it wont boot. The drive steps to track 0 then nothing more. Drive continues to spin.

 

Tried in slot 6 & 7, no change.

 

Any ideas ?

Offline
Last seen: 3 hours 26 min ago
Joined: Jun 18 2010 - 13:54
Posts: 159
Slots are working. If the

Slots are working. If the drive recalibrates to track 0 then at least part of the controller card is working.

 

If the drive continues to spin then it probably cannot read track 0 of the disk. This could be a bad disk, dirty head, fault on the analog card or controller card, etc. If you have another disk and/or drive you should try swapping them out first. If not, start with cleaning the head. Next you should check for proper voltages, disk speed, and reseat any socketed chips.

Offline
Last seen: 1 month 2 weeks ago
Joined: Mar 1 2019 - 04:38
Posts: 19
The interface card, disk

The interface card, disk drive and ProDos disk all work fine in my other machine so they are ok.

Unlikley to be voltage as im running the board off a 350W ATX PSU, but its certainly something to check.

As I am running a PS/2 keyboard, I dont have reset enabled at the moment, so I cant interrupt the boot process and see if I can read the interface Proms, but thats my next job to connect up the reset line.

 

Just cant work out why everything else on the board works  but a working disk/interface/floppy doesnt.

All part of the fun though.

 

 

Offline
Last seen: 3 hours 26 min ago
Joined: Jun 18 2010 - 13:54
Posts: 159
Since you have a working

Since you have a working machine, I'd first try to use that power supply just to eliminate your ATX PSU as the problem.

 

The PROM must be reading OK since you get the head stepper motion. If the problem really is the motherboard, it could be an issue with reading from the slot's DEVICE SELECT space.

Offline
Last seen: 1 month 2 weeks ago
Joined: Mar 1 2019 - 04:38
Posts: 19
Interesting developments

Interesting developments

 

Voltages all appear to be correct and dont dip or otherwise during device access.

 

DEVSEL and I/OSEL are active in the slot, all address and data lines appear active.

I then put the card in slot 1 and did PR#1 and prodos booted (well, it came up with a screen wanting 64k, so near enough), dos 3.3 boots (with a few complaints) and once running i can catalog the disk.

So, noisy bus i'm thinking now. Does RA01 terminate the I/O interface bus ?

The waveforms are messy, but no worse than most signals on machines of this vintage, but its hard to tell. Im probably getting reflections and that will be hard to see.

 

Two steps forward at least.

 

Edit, actually, booting from slot 1 is not at all reliable, sometimes Prodos will come up, Dos 3.3 will more often than not just sit and chunter, but its more active than slot 6. Strange.

Offline
Last seen: 1 month 2 weeks ago
Joined: Mar 1 2019 - 04:38
Posts: 19
Ok, I'm confused.

Ok, I'm confused.

 

With it almost working, I though I would try another Disk II interface I had about that didnt work in my working machine.

And it worked in slot 6, boots fine, Apex diagnotics running on it fine.

Put the original interface card back in the main machine, works fine in there.

 

So I seem to have some incompatability between two machines and their Disk interface cards. One motherboard is a Europlus and the other is a US ][+. I dont think there is a significant difference except a crystal and a couple of pads made/broke ?

 

Both interface cards came from the US, though they do look very different. One is much lighter and omits all the gold fingers that are not used, while the other is a much darker green and has every connector finger present, though I dont think they are essentially any different. They both appear to have 16 sector PROMS (though one is missing the yellow p5/p6 stickers) as they both read the same disks without error.

 

Well, I should not complain too much as they are working, but I would like to know why.

 

Also posted VCFED

Offline
Last seen: 1 day 19 hours ago
Joined: Apr 13 2006 - 22:28
Posts: 95
Oxidation Perhaps?

Have you tried putting the original Disk ][ controller card (the one that wasn't working) back into the new machine?

 

You may have had oxidation on the slot connector that can be "fixed" by the simple operation of inserting & removing a card from the slot a number of times. I had this very thing happen recently when I was restoring a Redstone Apple //e clone. A CP/M card refused to work in slot 4, but would work in slot 3. After numerous insertions & removals it miraculously started working, presumably because the oxidation on the slot connectors had been cleaned off.

 

Probably worthwhile spraying a little contact cleaner in slot 6 and 7 anyway to make sure the slot connectors are conducting nicely.

 

Cheers,

Mike

 

Offline
Last seen: 1 month 2 weeks ago
Joined: Mar 1 2019 - 04:38
Posts: 19
Polymorph69 wrote:Have you

Polymorph69 wrote:

Have you tried putting the original Disk ][ controller card (the one that wasn't working) back into the new machine?

 

You may have had oxidation on the slot connector that can be "fixed" by the simple operation of inserting & removing a card from the slot a number of times. I had this very thing happen recently when I was restoring a Redstone Apple //e clone. A CP/M card refused to work in slot 4, but would work in slot 3. After numerous insertions & removals it miraculously started working, presumably because the oxidation on the slot connectors had been cleaned off.

 

Probably worthwhile spraying a little contact cleaner in slot 6 and 7 anyway to make sure the slot connectors are conducting nicely.

 

Cheers,

Mike

 

 

I did think about that, have this a lot on our UCS3600 machines and ReyPak TI99 systems at work, reseating often gets them going again, and I think your probably right. But the card was in and out, being swapped several times. 

Will get some from work

Log in or register to post comments