IIe card can't read 5.25" disks?

[dzog]

Greetings Apple II friends. I am attempting to repair a IIe card I received in a lot. I recapped it and it seems to work OK, except for reading 5.25" disks.

My lack of Apple II knowledge and experience is hindering my debugging ability. 

I was able to get it to read a ProDOS 3.5" disk (via the host Macintosh) and run applications. No obvious issues there. But, reading a 5.25" disk just makes the initialization(?) noise and then fails. So, it's talking to the disk somehow. I've tried cleaning disks, 3x different drives, and a bunch of different disks, all the same result. I unfortunately don't have any other Apple II gear to test with. 

Is this a known Apple II failure mode of some sort? A failure of a certain chip on the board?

Any pointers are appreciated! 



View attachment Video.mov

 

[Realitystorm]

I assume you checked the drive model already to make sure they are supported?  https://support.apple.com/kb/TA47189

 

[dzog]

I assume you checked the drive model already to make sure they are supported?  https://support.apple.com/kb/TA47189

Yeah - they are all model A9M0107. As shown in the video, they make a satisfying noise but never seem to actually load any data. 

 

[bibilit]

IIRC capacitor goo can be present under the pds connector or even corrode pins. 

 

[dzog]

IIRC capacitor goo can be present under the pds connector or even corrode pins. 

Good call - I could just make out some unwashed goo/corrosion underneath the PDS slot near the cap. Hard to reach, but I poured in some vinegar, and also ran it through the dishwasher with detergent. Re-tinned the PDS pins with flux and a mini dab of new solder each. 

Haven't broken it worse yet  but still not reading any floppy disks! 

Is it interesting that the drive does do the "init" sound when access is attempted, but apparently will not read? Maybe I can get some sort of diagnostic software running via 3.5"/ProDOS; perhaps a disk copying software would lend some insights. 

 

[dzog]

I did get a disk copy program running via 3.5" ProDOS. This is what I get reading from a 5.25" drive with a disk inserted. Error on every read. The Red LED lights up on the drive, and every 8 blocks it makes a small noise. 



Video shows the behavior and the drive noise; apologies for the sad-sounding HDD in the background:


View attachment IMG_8550.mov

 

[AwkwardPotato]

Grasping at straws here:

In your recapping thread for this card, you posted a picture of the card after corrosion was removed w/ vinegar. That picture showed the component labeled SOMC1603, a resistor pack, and it appears that several signals going to the floppy port go through that component. Many of the solder joints on the resistor pack look dull/crusty; perhaps a bad connection on it is causing this problem?

 

[dzog]

That wasn't _quite_ it but it certainly led me down the path - thank you. 

We have victory!

First recap quickly became first IC remove-and-reflow and finally the hacky (but working) fix you see in front of you:





Sequence of events: 

- Retinned RP1 and a variety of other things to no avail

- Started testing everything with a multimeter

- Culprit! Cap goo (which I had thought looked so minor) opened a trace going from RP1 to the IWM. Barely visible damage near the junction.

- First attempt at fix (jumper from RP1 to IWM) first worked, then failed.

- Newbie debacle interlude: in a debug attempt, I tried to "reseat" the IWM with a heat gun (a $30 basic low/hi 250/350C one I use for heatshrink) instead of retinning with the iron like I'd be doing with the others. Oops, the chip slipped and now it's totally misaligned. Beat myself up a bit. Ended up removing IWM completely, cleaning off pads, and using solder paste for the first time to reflow. Paste is magic! But I used too much and had to clear 4 bridges, total PITA. 

- The fix was flakey as RP1's leg was corroded and weak. It soon fell off. Quite fortunately it's a simple 100 ohm resistor pack and I have plenty of resistors on hand. 

- Ultimate destination is one of the connector pins; wiring straight into there was easiest for me. 

It's not the prettiest thing in the world, but it does mean I get to play with Apple II stuff now

The happiest sounds: 


View attachment IMG_8565.MOV

 

[Realitystorm]

Glad you got it working, I've had a lot of fun playing with mine in my LC 475 (originally in a CC that needs a recap).

I've put together a partial guide for using the card that you might find useful

https://www.savagetaylor.com/2019/12/04/setting-up-an-apple-iie-emulator-card-in-your-68k-macintosh/

If you haven't already created ProDOS partitions, that should be a next step, it will give you a lot of flexibility for using the card.

I have 4 setup on my SCSI2SD

http://www.savagetaylor.com/2019/12/19/how-ive-setup-the-scsi2sd-that-i-use-in-my-lc-475/

 

[dzog]

Thanks for putting those helpful resources together

Fix is working reliably for a few days now. 

Eventually I think I'll want to make this board repair a bit nicer for the long-run - get a replacement resistor pack, redo the pad and trace, a nicer reflow on the IWM. But for now I'm just stoked to be up-and-running with it. And, heck, the "homebrew" look is a bit endearing