SE/30 Very Unusual Screen Artifacts

take a complete working machine and swap in parts one at a time from the problem machine. Just a thought . . .

dan k

Dan, thank you for the reply. But as I wrote above in my original post, you can see that I swapped in a known-good WORKING motherboard and a known good WORKING analogboard. I also killed the HD and floppy to eliminate those variables. The only thing I didn't replace was the metal frame and plastic case, which have nothing to do with the problem.

Thanks.

and knowing how weird computers can be, Tried a different 'tube? As strange as it may be, that could be your problem.
I have seen stuff as simple as plugging in a USB Keychain, and the Network port goes out (still can't figure that one out...) and all oddities have happened in the electronic world. That's the only thing you can eliminate.
Just try the swap, and see if that is it.

I can't remember if the wire system going between the Analog/Power board has removable wires, but try a new wire set between the board and the PSU. I doubt that is the problem, but you never know...

While I didn't try to swap the CRT, I did change all the cables (I had a spare set of everything). Didn't solve the problem. And yes, I did plug and unplug several times, making sure each time the cables were securely locked in place.

Sorry I can't actually help with the specific problem though . . .

dan k

PS: if I sound at all snippy here, don't mind me. I'm just jealous 'cause you've got one of those TS adapters . . .

i agree, you've eliminated everything in the machine except the tube. it could be going bad and drawing too much current. any tube from a compact mac will work i think. just make sure to discharge it first!

Guys I pretty much knew it was NOT the tube, but per your advice I pulled the know GOOD WORKING CRT out of my Mac 512 and put it in my SE/30. It did not help. Nothing changed. I've now pulled it out and put it back in my Mac 512 and the tube works fine (much to be relief -- I was worried I might kill it).

Any thoughts in light of this now?

Thanks!

This is a known condition, called SimasiMac. Turn it on and let it sit there for up to 10 minutes... it may still boot. If not, check and clean connections between SIMMs (ROM-SIMM) and SIMM (ROM-SIMM) slots, and restart. If that doesn't help, check the battery. Replace it with a new one if voltage is low, and restart. If that doesn't work, you're gonna half to start replacing capacitors (C6 & C7). And there are still a couple more things you can do.

Thanks for the reply. I've not tried leaving it on for 10 full minutes, but I guess I can give that a try -- I didn't know "time" would cure SimasiMac. But what I can say is that I have reseated the ROM and RAM multiple times to ensure good contact. I though about using steel wool to clean the RAM & ROM contacts, but small parts of the steel wool would break off if I do that, and I might now be able to blow out all the particles even with compress air. I don't want a short, so I haven't used steel wool. But I can give a basic cleaning of the contacts with ethanol alcohol.

I've already checked the battery. It's a good one, testing at a solid 3.6v. I cleaned the battery contacts with steel wool (with the board upside down so the particles would drop down away from the board). So I know the battery contacts are good. I inserted and removed the battery multiple times, and I even tried booting without the battery in there at all. It didn't fix the horizontal lines problem.

As to the caps, I replaced them all a few months ago with good new electrolitics. I used hot glue to secure each cap (since they aren't SMD) to make sure they won't move and brake traces. Even so, I took a DMM last night and checked continuity on every lead from every cap to make sure the connections are good. I have an SE/30 motherboard schematic so I can see where the caps leads go to. No problems with broken traces from the caps.

I also soldered a 1k-ohm resistor (1.8W) across pins 7 & 15 of the sound chip as recommended on that repair mac website. I can't see why pulling up a pin on a SOUND chip would fix SimasiMac though. And the fact is, adding that resistor did not fix the horizontal lines problem.

I have also read about replacing the bourns chip (RP2), but I don't have one handy and I honestly do not see the logic behind that either. Looking at the schematic of that area, you can see that bourns chip is simply filtering the signals from the leftmost serial port and passing them through to another chip on the board. But if nothing is plugged into that particular serial port, the bourns chip is not used (from what I see) and therefore I cannot see how replacing the bourns chip would cure SimasiMac.

Any further thoughts in light of this?

Many thanks!

wow is all I can say...

but its time you just started swapping components - sounds like a bad mobo to me

I've been asking folks over at 68kmla the same thing. I put some more details over there for those of you who would like to have a read...

http://www.68kmla.net/viewtopic.php?p=74493#74493

Still at it? Well, maybe now is the time to put together an actual working test platform, as per my original suggestion. Ever think that perhaps some of those parts you've assumed to be good are in fact not? I can't even count the number of times I've "assumed" parts were good (as in - "well, it worked last time I checked") only to find those parts somehow gone bad since "last time I checked".

Proof the "working" parts, then test the suspect parts.

* sigh *

dan k

Sorry I haven't made the time to post my progress here. You can read the report I posted last night at 68kMLA here:

http://www.68kmla.net/viewtopic.php?p=74810#74810

Thoughts?

I had this problem with my Classic II's:

http://www.applefritter.com/kiwi/node/387

Don't know if it's related, but there are some fix suggestions there. I've seen the screen you get a couple of times. Once on an SE/30 and once on a Color Classic. I trashed both, silly me.

Actually, your photo looks quite different from mine. You clearly have thick vertical lines on your Classic II screen, mixed with some garbage artifacts. From what I understand there are thick and thin versions of these vertical lines. I've never found a good resource that tells the difference between thick and thin though. However, you definitely have the THICK variety. On an SE/30 vertical lines (thick or thin, I wouldn't know) means somethiing RAM related. I am not having any RAM related problems, so that would be yet another area of difference. The suggestions made for your Classic II in that thread are basically to replace the motherboard caps, which I already did on my board and that didn't fix the problem. But I think in your case, the stripes mean something RAM related and the garbage artifacts may have something to do with the capacitors or a loose socketed chip.

Thanks.