Mac SE/30: Scsi problems

[nvdeynde]

I recapped an SE/30 board yesteray but keep getting disk errors for the internal hard drive.

I got the board dead, with SimaSimac, so impossibe to test before.

Replaced all capacitors. The board posted but couldn't find the internal hard drive.

However if I boot with a floppy disk, the hard drive didn't appear to the desktop either but Apple HD SC Setup 7.3.5 could see the drive.

When I try to Initialise the drive with Appe HD SC Setup, I get the following:

- Format: OK

- Verify: OK

- Mounting Disk then takes a long time and gives "The Disk could not be initialized: Unable to Mount Volume"

When I try the TEST in Apple HD SC Setup, I get "Problems writing data to drive"

When I try FWB 2.06 Formatter: I get about the same results. I also gives a fault when trying to mount the volume.

What I have excluded ( = taken from a working SE/30 logic board and done the same procedure )

- The HDD: Formats fine on my other board - not faulty

- SCSI cable: is good

- Ram: swapped the ram modules from other board - no change

- Rom: swapped - no change

I'm doubting between the SCSI chip and one of the Bourns filters.

I hoe someone can point me to the solution.

 

[nvdeynde]

I have done some additional testing.

It doesn't boot from an external hard drive as well with OS 7.5.3 for an SE/30.

I get the same errors: doesn't recognise the disk, unable to mount

I have checked the 3x Bourns filters: all measure 54 Ohms pin-to-pin in circuit so I guess these are OK.

I'm thinkig for either a broken trace from the SCSI chip somewhere or a faulty chip.

I inspected the leggs of the SCSI chip under a magnifying glass and they look good, no visible corrosion.

Does anyone have schematics or picture where all the pins of the SCSI chip need to go so I can test them for continuity ?

It would save me a lot of time as sorting them all out myself would take several hours.

I hope it's not the SCSI chip as I don't have the equipment to replace it.

 

[trag]

Someone traced out the connections for the SE/30 SCSI chipped and posted them. You'll have to hunt for it though. You might also check the Wiki. It might be in there. But there was another SE/30 thread within the last few years about replacing the SCSI chip and then discovering that it was a corroded connection or trace.

Thought of a few search terms that would help. Here's the thread:

http://68kmla.org/forums/viewtopic.php?f=7&t=12985&hilit=SE%2F30+datasheet+53c80

Zuiko21 says he has a schematic showing the 53C80 connections somewhere around mid-thread, so you might try asking him about it.

 

[nvdeynde]

I have just finished testing all traces from the SCSI chip: not a single broken one xx(

I don't know anymore, it's just sad because it's a socketed version of the logic board.

Now I recapped another one and while it powers on: it can't find the SCSI hard drive at all: this one looks even worse as the previous board could at least find something.

Probably the end result will be the same xx(

These were 2x board I was recapping from a friend but he let them go too far: the was a lot of leakage from the capacitors on the PCB.

 

[uniserver]

could you try the drive in a external enclosure?

just for giggles?

it might be a power issue acutely, maybe the HD is getting almost enough power from the PSU, but not quite enough once the head starts seeking?

 

[nvdeynde]

could you try the drive in a external enclosure?just for giggles?

it might be a power issue acutely, maybe the HD is getting almost enough power from the PSU, but not quite enough once the head starts seeking?

I already tried an external enclosure: it's not working, same reslt: tried 3x 100% known good drives.

The PSU is not the issue as well as both PSU and Analog board are fully recapped as well.

PSU is stable, no drops or spikes in voltage as I logged both the +5v and +12v lines while testing.

Could it still be the bourns filter ? I don't think so because I measure 54 Ohms in-circuit between the pins, identical on all 3x Bourns filters.

I guess this is the right way to test them: correct me if I'm wrong.

I get +5v termination voltage on the SCSI connector, verified all traces from the SCSI Chip to the SCSI Connector, UL

I used this diagram to check all traces from the SCSI chip ( it was posted a while ago in another SE/30 Scsi topic ) :




I don't know anymore now. It's weird the SCSI chip can still see the HDD on the Bus, succeeds in format and verify but then TEST and Mount fail.

Anyone with ideas as it would be a sad to give up on this board.

 

[uniserver]

maybe in this situation you need to sweat off that scsi chip , replace with another scsi chip?

i hear the SE/30 is known for having scsi chip issues...

 

[nvdeynde]

2x problems: I don't have a replacement SCSI chip, neither do I have a hot air rework station for removing the old chip and fitting a new one.

I really can't afford this kind of equipment for doing an occasional job, I whiched I could...

Do you have the right equipment and spare SCSI chips ? If so PM me what you would ask to replace the SCSI chip but I'm not convinced 100% that its the cause of my problems. I have never seen something so weird like this.

I have a 2nd SE/30 board with no SCSI at all but haven't tested the traces of the SCSI chip yet, I'm going to try that in the weekend.

 

[uniserver]

as long as you get some tin foil and make a cut it out so just the scsi chip gets the heat,

you can use a 22 dollar heat gun,

I just bought one and i love it. mcdermd uses his sometimes

You want to use some long electronics tweezers to pick up the chip.

use an iron to clean up the pads (if needed) , lay some flux down, then set the chip on there and melt it in.

I do have a extra scsi chip, it's on that board I got from CC-333

PS:

Last night I removed the FPU,(from CC_333's parts SE/30 Board) The CPU and the CPU socket, A ram Slot yes the heat gun rocks!

I got lazy and didn't mask the Battery Holder (when removing the FPU)… and it partially melted (so ya gotta be a little careful that air is super heated it)

I got my mouse pad a couple times there is now a couple big black spots. haha

I use 2 dead LC PSU's to raise the board off my desk/mouse pads.

 

[trag]

What machine have you tested the SCSI drive as good on?

I ask because your description is also consistent with a hard drive which has been formatted with incompatible formatting software. Kind of a long shot, but a possibility. What utility did you use to initialize the drives?

 

[nvdeynde]

I used my own working SE/30 to test the hard drive. It's definately not the hard drive or the formatter.

I tried multiple drives with Apple HD SC 7.3.5 and also FWB 2.0.6: both work fine in my good SE/30 when doing exactly the same, while they don't with the "problem" board.

Also the working HDD with os 7.5.5 from my good SE/30 does not boot at all with the problematic board. So I just swapped the logic board in my good SE/30 but no boot at all. It's polling the HDD but that's all.

 

[trag]

Hmmm. Frustrating.

Yes, I know that's not helpful, but an expression of camaraderie is the best I can do at this time.

 

[genie_mac]

Hi,

I'm in the process of trying to fix the SCSI on my SE30 as well, and found the original circuit diagrams incredibly useful (but that hasn't lead to any success yet ).

Don't know if you have them already but I found them here:

http://cdn.preterhuman.net/texts/computing/Apple_Schematics/SE-30%20-or-%20IIcx%20without%20NuBus/

Best of luck and I hope you get it sorted.

 

[trag]

I believe that board connection/trace/via issues are more likely to be causing problems than a bad SCSI chip, but just in case...

questcomp.com has the 53C80 available. They want $11.55 for it. However, if you order 4 or more the unit price drops to $5.775.

 

[uniserver]

I agree with trag, the SE/30 is just total crappy for rotted VIA's ///

Rotted Via's really annoy me!

i'v got one at home on my desk just waiting to suck up another 3 to 4 hours of my life

 

[genie_mac]

FYI I just fixed my SCSI problem, two bad vias were the cause. Seems to be a commong problem...two hours to fix and a wrecked head now....

 

[uniserver]

also watch this video, you can see how techknight got through his SE/30 scsi problem

 

[nvdeynde]

I checked all the pins of the SCSI chip, these are fine. However I didn't check every single pin of all the VIA's as this would take many hours.

I'm going to give up the board.

 

[genie_mac]

Don't give up!

Maybe leave it alone for a while as I know it can get very frustrating, but it would be a shame to dump it as you are so close