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SE/30 freezes when trying to access a floppy disk


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Hiya !

 

My SE/30 started doing this yesterday: once you insert a floppy disk it access it twice , the hdd/trashcan/alias icons on desktop disappear and the system freezes. 

On reset the mac will eject the floppy disk.

I have a BMOW Rominator-II and it also freezes with the ROM/RAM boot options - so it's not something going on with the hdd-system setup. Already tried re-sitting cables and do a visual mobo inspection - all look good.

 

Any idea what this could be?

Thanks!

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I think some ram is bad - disabling 32bit mem-access (so 8MB is useable) does not freeze the system with rom boot

on normal hdd OS boot I get this error:

 

Sorry, a system error occurred.

"Finder" 

     unimplemented trap

 

will try with some new ram tomorrow unless someone else suspects something else :b&w:

edit: do I need ram with parity for the se/30?

Edited by keropi6k6
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  • 2 months later...

coming back to this I have not resolved the issue

I thought it was bad ram , but it wasn't the culprit

I even got a replacement floppy drive but it behaves exactly the same

one thing I noticed is that if I press the programmer switch I do get the command box working: I can type in it and mouse resumes moving

I did some basic troubleshooting on the mobo and found F3 blown (it provides termination power to external scsi/fdd ports) , replaced it but no change in behavior

 

Anyone has any idea why this happens? other than this the system works great and is stable....

thanks!

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On 4/4/2021 at 10:34 AM, keropi6k6 said:

coming back to this I have not resolved the issue

I thought it was bad ram , but it wasn't the culprit

I even got a replacement floppy drive but it behaves exactly the same

one thing I noticed is that if I press the programmer switch I do get the command box working: I can type in it and mouse resumes moving

I did some basic troubleshooting on the mobo and found F3 blown (it provides termination power to external scsi/fdd ports) , replaced it but no change in behavior

 

Anyone has any idea why this happens? other than this the system works great and is stable....

thanks!

Check the Filter IC Connected to the Floppy Connector....Check my Post on fixing a Mac SE SuperDrive....2 of this Filters where damage causing the unit to freeze. One of the filter IC is connected to the Reset and Interrupt Switch.  If the one connected to the Switches is bad, will send the interrupt to ground causing the machine to freeze(use a multimeter to trace the line to the correct IC from the switches). Verify  with a multimeter that the switches are working right. Using Ohms.  You can perform a simple test on the IC using a multimeter in ohms....test IC pins in pairs(Ex. Pin1 with 11), must be equal to 50ohms if I remember, except for first pair and the last pair(1-11 and 10-20). Check my post on that repair: 

 

 

 

 

 

mac-se30-logic_LI.jpg

Edited by MegaImg
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21 hours ago, MegaImg said:

Check the Filter IC Connected to the Floppy Connector....Check my Post on fixing a Mac SE SuperDrive....2 of this Filters where damage causing the unit to freeze. One of the filter IC is connected to the Reset and Interrupt Switch.  If the one connected to the Switches is bad, will send the interrupt to ground causing the machine to freeze(use a multimeter to trace the line to the correct IC from the switches). Verify  with a multimeter that the switches are working right. Using Ohms.  You can perform a simple test on the IC using a multimeter in ohms....test IC pins in pairs(Ex. Pin1 with 11), must be equal to 50ohms if I remember, except for first pair and the last pair(1-11 and 10-20). Check my post on that repair: 

 

thanks for the reply Megalmg! I will certainly check all 3 filters it's easy to do

the reset/interrupt switches work fine when pressed , reset does reset the system with no issue and interrupt brings up the command box (with the agility to unfreeze the system and mouse/keyboard once the floppy access kills it but I am unsure if you can ever go back using the system once the box appears, I am new to macs)

 

maybe those filters are going bad after all these years, nothing unheard of

the Mouser 652-4120R-601-201L part is indeed the correct replacement, right?

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On 4/5/2021 at 10:29 AM, keropi6k6 said:

I checked the switches and the 3 filters, I do not see anything unusual... all 3 filters behave exactly the same

 

9eqlydM.png

 

4WF86pA.png

 

it would be nice to be that easy LOL??

Great work checking up....mine was marking 45ohms on pin 7 and it was bad. The new IC Filters hit the 50ohms in all the pairs....I will verify the one connected to the Floppy port....do you have a FloppyEmu? Will be interesting if it happen with a external Floppy Unit.

 

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Posted (edited)
On 4/5/2021 at 7:15 PM, keropi6k6 said:

I have now also verified that the floppy connector pins go to the places that need to go, so there is no broken trace causing this behavior

 

interesting... if your filters were bad at 45ohms maybe mine are too?

sadly I do not have any external drive to check - but I did check a 2nd internal and a new ribbon cable (just in case)

I downloaded the SE/30 schematics and I checked that each pin is going the IC it is supposed to go -> but if said IC is good I cannot check 

the few inductors and resistors along these traces are also good
this is just making me sad :sadmac: I took my time and recapped the whole system some months ago and it just bugs me it does not work fully now

it started deteriorating , first 1 freeze with one floppy then it worked,  then a freeze next day with a couple floppies and now each time a floppy is used

 

http://i.imgur.com/5HxnoXRh.jpg

 

http://i.imgur.com/ucv5HLoh.jpg

 

http://i.imgur.com/OfmjlyTh.jpg

 

http://i.imgur.com/eGPHrZah.jpg

 

Edited by keropi6k6
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Allright, here is more weirdness ... any ideas what might cause this will be appreciated!

 

For the following the ROMBOOT option of the ROMINATORII is used, there is no hdd connected to the system as to take out of the equation any potential software issues

I have a blue SONY branded 1.44mb floppy disk, this one does not freeze the system at all whether it's MAC formatted or PC formatted

A Verbatim disk with the SAME data as the SONY floppy disk will freeze the system once inserted, as before the desktop icons will vanish and everything will seem unresponsive

so if I press reset or power-cycle the system and the verbatim floppy is written with some MACOS startup disk it will actually start booting from it, no freezes and weirdness reading works as expected :-/

 

does this make any sense at all?

just in case I reflowed the simm-rom and ram sockets but ofcourse this did not help at all :sadmac:

 

did gremlins messed with this system? LOL

 

 

 

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I have a video of this weirdness :

 

 

 

last disk is a verbatim one that just crashes the system

the previous disks are just random ones that have been used a bazillion times in various systems

it could worth noting that the 2 verbatim disks shown came from the same pack - the working one is a brand new and the crash one was used. 

no matter if the disk is PC formatted or MAC formatted or has a linux loader in it the SE/30 will freeze

if a OS startup disk is written in that disk the system will attempt to load and read stuff but eventually I will get a "bus error" message and that a reboot is needed

 

at least it is not doing it in all disks but it still is a possibility as it can happen with other disks not just the one shown in the video

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well it appears that any disks that do not work needed to be formatted in a macintosh and then they are fine

I did that to a couple that were freezing the SE/30 and now it's all good

I have no idea why, maybe something left from previous uses on the disk that crashed finder or something (which makes no sense if you write a disk image on them which theoretically writes over all sectors in the disk surface)

anyways... the end bw:) 

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