IIGS recognizes 5.25" drives but not 3.5" or smartport? Help?!

[spacecadet]

What if your problem all along WAS the "good" keyboard port. Or maybe even your keyboard itself. Maybe some kind of short. Can you now try the 3.5 inch drive in the motherboard with removed port and see if they detect?

 

Ok, tried that - still no dice. I'll try anything at this point if it's within my abilities.

 

Attached are pics of both motherboards and also the testing setup. Nothing looks weird, right?

 

The really strange thing is that I have basically two of everything - two motherboards, two 3.5" drives (plus the floppy emu), two power supplies. I've tested them all now in every combination and they *all* act this way. It's bizarre.

 

I took some measurements from my two power supplies:

 

PSU #1:

5V: 5.36

12V: 12.09

-12V: -11.3

-5V: -5.05

 

PSU #2:

5V: 5.65

12V: 12.77

-12V: -12.11

-5V: -5.37

 

Just for kicks I measured the voltage of the one removed battery and it was 2.96V, which is basically the full 3V it should be.

 

Obviously those PSU's are not completely on point, but are those numbers far off enough to cause a problem like this?

Edited May 4, 2017 by spacecadet

[Keatah]

The power supplies should be fine.

 

Care to post screenshots of your configuration/setup screen?

[eightbit]

The supplies look fine as Keatah said. And I'm sure you know what you are doing but I too would like to see shots of the config screen. I see no oddities with either board (except for the adb port and battery removed on one obviously). Did you use the Floppy EMU on both boards prior to this occurring? I hope the EMU is not somehow frying the ports....

Edited May 4, 2017 by eightbit

[eightbit]

Also, can you look closely at the 28 pin chip that says "IWM"? This is the floppy controller chip. Do you see any damage to this chip on either board? It is the chip a little left of the internal game controller port.

Edited May 4, 2017 by eightbit

[spacecadet]

The IWM chips look fine to me... I thought I actually took pictures of both but I guess I only got one, it's attached. They both look the same, though.

 

I'm also attaching a screenshot of my slot config.

 

 

Did you use the Floppy EMU on both boards prior to this occurring? I hope the EMU is not somehow frying the ports....

 

This thought had occurred to me... I am wondering if I should email the guy who makes them to ask if there's any way he knows of that that could happen. I don't expect him to do anything for me at this point (it's been more than a year since I've had mine) but if that's what happened, he should probably know it's a possibility and work on fixing it in future revisions.

 

I don't honestly know what else it could be. I did try the floppy emu on both boards. I don't honestly remember in what sequence, though. And I don't remember if the floppy emu was ever working on the second board several months ago, or if only the actual drives were. (I probably would have tried the floppy emu last, and if it didn't work, I may have thought the first board fried the floppy emu rather than the other way around.)

 

I also did have a dead battery in the second board, but I replaced it with the battery from the first board and there was no change.

 

[Keatah]

What is the model # of the drive you're using?

[Keatah]

I don't have my IIgs set up at the moment. And that really sucks because it's been a while since I played with the control panel. But..

 

Can you select (Your Card) for Slot 6? Just try it.. I know you have nothing plugged in there. And leave the 3.5 connected as it is now.

 

--or--

 

Can you change the STARTUP SCAN to a specific slot? Like Slot 5 for example?

 

I do remember from 1977/1978, one of the first things I learned, the Apple II scans slots backwards from 7 -to- 1. It's looking for Rom code to run.

Edited May 4, 2017 by Keatah

[Keatah]

Continuing on.. I believe the way you have it set up (in the screenshot above) is this.. The computer is scanning from 7 -to- 1, the natural order of things, and you can't change that order, but you can tell it to start at a different slot number.

 

Slot-7 is (Your Card), it is blank. So the computer is going to slot 6. You have it set to Disk Port. And it is seeing a Disk Port, which is essentially a vintage DISK II card not hooked to anything. The DISK II drive is pretty dumb. That's it's advantage. And it doesn't talk back to the controller saying it did this this or this. It only sends data. And I think your rig is waiting on data from a non-existent drive.

 

So change Slot 6 to (Your Card). The computer will see an empty slot and scan down to Slot 5 and start doing something there. Or tell it to start at Slot 5 itself!

 

Humor me and report back.

[spacecadet]

What is the model # of the drive you're using?

 

It just says "Apple 3.5 Drive". I believe it's the second one listed here: http://www.vintagemacworld.com/drives.html

 

Can you select (Your Card) for Slot 6? Just try it.. I know you have nothing plugged in there. And leave the 3.5 connected as it is now.

 

--or--

 

Can you change the STARTUP SCAN to a specific slot? Like Slot 5 for example?

 

I do remember from 1977/1978, one of the first things I learned, the Apple II scans slots backwards from 7 -to- 1. It's looking for Rom code to run.

 

I tried both of those things and again, no dice. The weird thing is it doesn't even spin up the drive. But it does provide power, because I can eject. But other than a tiny little scratch sound right when I turn the machine on, there's just nothing from a 3.5" drive, on either motherboard. And I have tried specifying the slot to boot from, and also tried setting slot 6 to "Your Card".

 

The only common denominator, other than the actual drives, is the Floppy Emu. Though I suppose one of the actual drives might be frying motherboards too. Floppy Emu seems more likely, though, just because it's less tested. I would think it would be common knowledge by now if those Apple 3.5 drives could spontaneously fry motherboards.

 

Anyway, thanks for your and eightbit's help to this point. I feel like this might have an unsatisfying ending, though...

Edited May 4, 2017 by spacecadet

[Keatah]

What is the model number of the 3.5 drive you have?

[Keatah]

And the only thing (about drives blowing up) that I'm familiar with is the infamous 74LS125 in the Disk II that can be damaged if the stake connector to the controller card is mis-connected. That and that that failure can damage the data on every floppy you insert. An easy $2.00 repair.

 

There's also something with the DuoDisk units that need a simple mod otherwise they zap disks on power on/off I think.

Edited May 4, 2017 by Keatah

[Keatah]

There's no model number listed? A9M0106?

[spacecadet]

There's no model number listed? A9M0106?

 

Well that's not printed anywhere on the drive externally, but it's got to be. All that's printed on the label is "Apple 3.5 Drive" and then a serial number. But it looks just like A9M0106 and the description on the site I linked to fits it perfectly. The only other drive that looks like that is a 1.4MB drive and mine are definitely 800K.

 

Edit: oops, yeah, it says A9M0106 in fine print.

Edited May 4, 2017 by spacecadet

[Keatah]

I'll assume that all the connectors are good and clean and continuity check from the motherboard solder points, through the connector, through the cable, and getting into the disk drive itself? Just a thought. But those are things I sometimes check on the bench. I still have a set of 5.25 (new style) daisy-chained drives that only work if you hold the connector a certain way. I'm not too sure if it's the controller card or the cable and its connection. I'm just sofaking lazy so I just push the cable this way and that way till it works.

 

Ok. Well I'm out of ideas for the moment and we seem to have thoroughly gone over all the "call-center" stuff. Maybe one of us will think of something else to try. If not then I could always take it into my lab and get down to individual parts and signals. Free of charge except some parts and shipping. Sometime in June I could have time.

 

I need to turn in for the night. I will be on here sporadically tomorrow and throughout the weekend.

[eightbit]

It really sucks that this happened to you...I really feel for you man. I don't suppose you have a CFFA3000 do you? If you did and can boot stuff you could at least confirm smartport assignments work properly...and even if the actual disk port is bad/blown the computer can still be usable. I got rid of all of my floppy drives after receiving the CFFA3000. I am not a IIGS software collector myself though...just like to play the occasional game or try the occasional application.

[Bloodnose]

joethezombie in this recent thread mentions some connection to the floppy with the VGC. He said he found some schematics to help trace problems.

https://68kmla.org/forums/index.php?/topic/27060-iigs-no-longer-seeing-35-drives-bad-vgc/

The thread is otherwise uninteresting in developing as a bitch-fest, and joe's solution was to replace the board.

 

But your issue is odd with the same behavior occurring between two boards.

 

Take a step back and try to see the issue from a new perspective.

 

Are your voltage readings stable, or do they wander? Are you testing with the connector attached to the board? Are you running any other computers powered-on (or anything with switching power supplies) on the same circuit? Old tech is very susceptible to feedback on the mains from cheap noisy switching power supplies.

[spacecadet]

Are your voltage readings stable, or do they wander? Are you testing with the connector attached to the board? Are you running any other computers powered-on (or anything with switching power supplies) on the same circuit? Old tech is very susceptible to feedback on the mains from cheap noisy switching power supplies.

 

The voltage readings are stable, and I'm testing disconnected from the board. (Should I test connected to the board? If so, how do I do that?)

 

I don't think I was running anything else on this circuit, but I'll double verify that today. I've tested at least the first board on a different circuit, though. But the second one didn't start doing this until I put it on this new circuit, so who knows. I'll check that.

 

Steve from BMOW got back to me with a really detailed email about what *might* happen with the Floppy Emu; he said there's a pin called /EN3.5 that was not used in earlier II's but is in the IIGS, which is why 5.25" drives could still work if that pin is shorted. But he says it could be shorted in the Floppy Emu, but he doesn't think that would actually damage a board. He suggested I test for continuity between that pin and any others, because there shouldn't be any. So I will do that today also.

 

Thanks as always for the help.

[Keatah]

Your DMM probes might fit into the white power-supply connector while it is plugged into the main board. If not, you can make an extension with a pin and some tape.. Measure voltage like you did before.

 

There is also the square white box to the left, which is likely wired in parallel to the main connector. This was to allow the IIgs mainboard to fit inside an Apple //e case and use its power supply. The voltages should be present there too. Easy to get at.

[spacecadet]

Ok, I tested the PSU on the board - it was easy using that extra set of pads next to the power connector.

5V: 5.01
12V: 11.71
-12V: -11.52
-5V: -5.06

That's on what I referred to earlier as "PSU #1", which is the PSU I really want to use because the other one has a broken power receptacle. I feel like this PSU seems slightly closer to spec anyway.

I did Steve's suggestion of testing for shorts on the /EN3.5 pin, and found none anywhere. Not on the Floppy Emu, the ribbon cable, the connector, and not on the board connector either. Not on the physical drives. Nowhere.

 

Steve offered to look at my Floppy Emu so I think I'm going to take him up on that at this point. I don't really want to send it to anyone else to try because I don't want this to happen to anyone else.

 

The only other thing I can think is that maybe there's something weird about the way this PSU is delivering power that fried something on the boards... the time I first noticed this happening was around the same time I switched out to this PSU. But I don't know how to do further testing beyond just testing voltages. But I wonder if it's delivering a spike when it's first turned on. Or if one of the filter caps is not working properly or something.

Edited May 4, 2017 by spacecadet

[spacecadet]

I've got a lead on a new board from somebody in this forum, but before I get it and hook it up I do want to try to identify the root cause of this. Can someone tell me how I'd properly test for voltage spikes from the power supply with a DMM? Is it as simple as just holding the probes on the 5V or 12V rails while I power up the machine and watching the numbers? I just don't know how accurate that'd be and I don't want to electrocute myself either.

 

Steve also has one more idea for a test to run, which is to measure the voltage from pin 4 of the DB-19 connector with different drives (and the floppy emu) connected to make sure none of them are out of range. Since I couldn't find any shorts, I can only think the cause must be one of those two things (probably the latter - I can test tonight to find out).

[R.Cade]

Could both your 3.5 drives have gone bad, or the disks? Although disks are less likely since it should at least try to access them if they were bad...

[spacecadet]

Could both your 3.5 drives have gone bad, or the disks? Although disks are less likely since it should at least try to access them if they were bad...

 

Well the one longshot I thought of was maybe the power supply is spiking the voltage initially and that killed all three of my 3.5" devices. Maybe there's actually nothing wrong with the boards; maybe it's the PSU that fried the drives. But they all have power on all the pins they should, so that would seem really strange. Also, the Floppy Emu still passes its self check and it's getting power too. It seems really unlikely that any of them aren't working.

 

I've really only got two things left to try. One is really simple and that's just to check the PSUs for shorts. I just forgot to do that before, but that's a moonshot. I highly doubt I'll find anything there, but I just want to be as thorough as I can. I've checked them now every other way I can without taking them fully apart, and they seem fine to me.

 

The second thing, suggested by Steve at BMOW as his last idea, is to hook up an oscilloscope to pin 4 on the smartport connector and see if it's stuck in either low or high mode (it's supposed to be switching back and forth on boot to check if there's a drive there). If it is stuck, that would at least explain what's happening, though it wouldn't really explain why.

 

I've tested literally everything else multiple times now. I have no shorts, and I have good power everywhere, on the board and on the drives (and on the floppy emu). So I don't know what more I can really do.

 

When I get the new board I will absolutely test everything on it the same way before connecting anything to a) see if there are any differences to my current boards that would explain why my current boards are acting this way, and b) to give me a baseline to test again as I connect each component. I'm going to test with each component individually and only then start adding iteratively. If something does go wrong, then I should at least see what caused it. But hopefully nothing will.

 

You know, I try to be careful with my stuff but it is also possible that this is my fault. At least a couple of times I know I have unplugged drives from the computer when it was on. It's especially easy to do when it's taken apart like this, because there's just that one little LED to tell you that it's on, and the IIGS itself has no fans or other moving parts. So I need to be more careful about that.

[Keatah]

While not best practice, I've disconnected drive many times with the power on. However I've never (not recently) pulled out interface cards with the power on - anything can blow then as the angle of the card shifts and the contacts short power to the bus and all that!

 

I don't think there is a need to take apart the power supplies. They seem to be working fine. If they're sending spikes, you're only going to see that with a DMM with fast min/max feature or a scope.

 

If I was troubleshooting this I'd first verify the drives are good and can read/write a full disk. If they pass, I'd work backward to the IWM and SlotMaker chips. Checking the connections to the slots and ports. Then follow their connections deeper into the machine toward the processor.

[spacecadet]

Can somebody do me a favor and measure the resistance between pins 10 and 6 on the DB-19 connector on their motherboard? If you're looking at the connector from the back of the machine, that would be the top leftmost pin and then count 4 pins over from there to pin 6. If you're inside the machine looking at the back of the connector, it'd be the right-most pin and then count four over.

 

I'm getting 155 ohms on one board and 255 ohms on the other, which seems like it might be a short. Those same pins on the output ports of my two drives give me readings in the mega-ohms. I'm hoping this is the problem, but I need confirmation.

 

btw I do have a scope if there's anything anyone else can think to measure. I checked the power waveform and it looks fine to me on that connector, at least. I also didn't see any crazy spikes on bootup, though it does surge a little bit and then take a second to settle down, but the voltages don't look bad.

Edited May 6, 2017 by spacecadet

[Bloodnose]

I'm reading 4.5 KOhms, with image attached for you to verify pins numbers.