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SE/30 clock stopped.

S

SpaceFlightOrange

6502
Hi.
I pulled out my SE/30 that's been sitting patiently waiting for me to recap the PSU and analog board for about 6 months since the screen started glitching. so I did that, and it seemed to be working fine with a stable picture, and generally stable machine. though I did notice that the floppy port is missing the -12v which needs further investigation.

It was only this afternoon that I noticed the screensaver never started and on further investigation it seems the clock has stopped. it's holding the time and date, just not advancing. Is this a problem anyone has seen before? I've had this machine since September 2023, no battery damage on the logic board and it has been fully cleaned and recapped was working fine until today.

Thanks
 
So Further update. it seems that it is only stopped when the machine is running. turn it off, and the clock runs. Starting to think this is a software issue but I haven't changed anything in the last few hours.

Oh well, I'll keep investigating
 
Check traces from the RTC. I hope I'm not wildly misremembering here, but I think there's a 1Hz interrupt from the RTC that the CPU uses to keep time when the computer is running. When the computer is off, the RTC keeps time on its own - but when it's running, the OS only actually queries the RTC at boot time then keeps the time itself based on what I think is a 1Hz interrupt.
 
I would suggest checking diode D2, 5V from the PSU passes through it to the RTC chip when the machine is on.
If it's somehow broken, I could see it keeping the RTC chip from receiving power at all with the machine on.
 
Thanks both. I'll do that now. done all the other stuff, reset pram removed battery for an hour, booted off a floppy and checked instead of the drive, and no difference.
 
another thing I never mentioned is that when I removed the battery I put the board back in the machine and tested it. the clock was running (could seconds ticking over on the clock in the menu bar) and it ran for at least 3 mins because the screensaver came on. then when I returned to the desktop it had stopped. a reboot and a quick power cycle didn't have any effect. a longer power cycle (about 10 mins) had no effect. It tested the diodes D1 & D2 for comparison as they are the same part, and I think they are ok, but I need to check again as I'm questioning what I did (it's been a long week)
 
My IIfx did this right before it started death chiming. The clock would run….. sometimes, while the computer was on. After a few weeks it like this it died completely. This was 3 or so years ago, and I still haven’t figured it out. I know this doesn’t really help you, but I am very interested in what you figure out here.
 
Daniël said:
I would suggest checking diode D2, 5V from the PSU passes through it to the RTC chip when the machine is on.
If it's somehow broken, I could see it keeping the RTC chip from receiving power at all with the machine on.
Click to expand...
re-tested the diodes, and they seem fine. when off I can see about 2.8v getting to the RTC from the battery, and when on about 4.5v or so.
 
cheesestraws said:
Check traces from the RTC. I hope I'm not wildly misremembering here, but I think there's a 1Hz interrupt from the RTC that the CPU uses to keep time when the computer is running. When the computer is off, the RTC keeps time on its own - but when it's running, the OS only actually queries the RTC at boot time then keeps the time itself based on what I think is a 1Hz interrupt.
Click to expand...
checked this, it's coming from pin 43 of the UK12 VIA. when I probe this with my scope I got nothing. not sure what I'm supposed to see here, but I have continuity from pin 43 to pin 1 of the RTC.

At a loss now. I've just noticed on the schematic the the other lines to the same via for the chip select, data and the clock. I don't have a logic analyser to look at these, un fortunately.
 
The 1 Hz interrupt should pulse once a second when the system is powered up and booted to Finder. If it's not, the RTC may need to be replaced. (There is a modern replacement available, if that becomes necessary).
 
Arbee said:
The 1 Hz interrupt should pulse once a second when the system is powered up and booted to Finder. If it's not, the RTC may need to be replaced. (There is a modern replacement available, if that becomes necessary).
Click to expand...
ah, ok. so this is generated by the rtc chip? and is it necessary that it's booted to Finder? I didn't have a drive hooked up and was just testing at the disk icon
 
I don't know for sure if it's necessary to be booted to Finder, but that's the definitive test since you started out saying the clock wasn't updating.
 
Following. I have a similar problem with a Mac Classic, which has about a 1 in 5 chance of having its clock run upon startup and a 4 in 5 chance of it being stuck at whatever it's set to (either the default 1-1-04 at 12AM or whatever it gets changed to in the General control panel). I know the board has been recapped.
 
Scott Baret said:
Following. I have a similar problem with a Mac Classic, which has about a 1 in 5 chance of having its clock run upon startup and a 4 in 5 chance of it being stuck at whatever it's set to (either the default 1-1-04 at 12AM or whatever it gets changed to in the General control panel). I know the board has been recapped.
Click to expand...
This happened to a Classic I had. I don't recall the details, but here is the thread:

Classic: Clock won't run

So I just re-caped a Classic that I received from someone. Now, I have no idea if the clock worked before (didn't check), but currently something bizarre I have never seen before is going on: The clock won't advance time. I set the clock to the correct time last night, and it just stays where it...
68kmla.org 68kmla.org
 
LaPorta said:
This happened to a Classic I had. I don't recall the details, but here is the thread:

Classic: Clock won't run

So I just re-caped a Classic that I received from someone. Now, I have no idea if the clock worked before (didn't check), but currently something bizarre I have never seen before is going on: The clock won't advance time. I set the clock to the correct time last night, and it just stays where it...
68kmla.org 68kmla.org
Click to expand...
thanks for the info. I did check D2 and it seemed ok, but will recheck it. I do think it's the RTC chip in my case as I get nothing on the 1hz pin, so have ordered a couple of NOS replacements. Thankfully right now the RTC on my Classic is working fine.
 
I had a somewhat similar issue in a classic as well. I can't recall all the specifics but I do remember that probing the crystal it with my oscilloscope probe caused the clock to start running. It seems that these circuits are very sensitive to impedance (or maybe capacitance - I can't recall which and this is not my area of expertise). Anyways it seems that residual cap goo somewhere in the crystal circuit or left over flux can cause the circuit to not work properly.

I don't know if I ever went back to try to fix my issue and it might not be the same as yours given that your machine is keeping time when off, but I think it's still worth making the recommendation of making sure all cap goo from the timing circuit is cleaned and using some flux cleaner as well to make sure there is none left over from recapping.
 
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