Source for flyback transformer?

[clh333]

I have an SE/30 that I am in the process of restoring.  I bought it from an academic and it immediately displayed problems: jittery video.  On the advice of those who knew more than I, I sent the board out to be recapped.  Back from recapping and that much poorer, I find the video problem was not resolved by recapping the logic board.  In the meantime I have read Pina's books and now think the problem is with the analog board, probably the flyback transformer.

I would like to ask the membership for a recommended source for a replacement.  This does not seem like the sort of thing you want to buy off eBay.

Thanks for your replies.

 

[Johnnya101]

It could be the FBT, but try swapping or recapping your PSU and analog board first. Mine had some jittering, but it ended up being a bad PSU.

Are you hearing any weird sounds? Whining? Video collapse? That would point to the flyback. Any artifacting on the screen, especially when reading or writing to a disk? That would point to power supply. Does it only jitter when cold? Hot? Random?

 

[clh333]

No weird sounds, no video collapse to the point of, say, one vertical line or something; just a ragged and jumpy right-hand edge to the display.  Maybe a little variation in screen size on occasion.  This happens on startup (cold); I haven't left it on long enough to warm up fully because I fear a catastrophic failure.

I have a spare SE, "for parts only", that I could swap PSU and analog board from.  I believe they are equivalent?

Thanks for your suggestion.

-CH-

 

[Johnnya101]

Jittery right side display I think could be a loose or bad ground for the PSU and AB. Is the screw for the green wire tight?

And yes, they are the same.

Look up Dead Mac Scrolls PDF. It should be in there and youll see what Im talking about. This says that there is a sizzling though...

I was having a sort of similar issue with my SE/30. on cold boots, and only sometimes, the display would change in size and flash with white lines. It was a bad PSU. That could be your issue too (Unless someone else has something else to check). You probably should recap your AB and PSU soon though for best reliability.

 

[clh333]

Holy (smokes)!  I loosened each end of the PSU-to-chassis ground wire, moved it a little to break any oxidation and re-tightened.  Hit the power switch and the display is now stable.  Thanks!

I have a ~regulation-sized screen with grey background.  Cursor moves with mouse input.  Unfortunately the machine does not like the 800k OS 6.0.8 boot disk I am trying to boot from.  Disk issue or drive issue?

Thanks again,

-CH-

P.S.  I have a paperback copy of Pina's book, thanks.

 

[Johnnya101]

Yay! Glad that was a simple fix.

So its just stuck at a gray screen with cursor? Id say thats a memory check issue. Does it ever reach the question mark floppy icon? How much RAM is installed? 

If possibly, try creating another boot disk and trying that.

 

[clh333]

I get a chime immediately on power-applied.  I insert my boot disk and the machine spits it back out after a brief interval.  After that I get a disk-with-question-mark icon and boot proceeds no further.  I used this disk just the other day to initialize the HD of another SE I had been working on, and had booted yet another SE with it in the past.

The HD is a 2 Gb Apple from IBM; the original Quantum that was on this machine was toast.  The HD has been tested, verified and formatted on a Linux system but not initialized by an Apple OS yet.

I have 68 Mb on the board:  replaced all the original RAM with 4x16Mb SIMMs and 4x1Mb SIMMs with larger SIMMS in the first slots.

 

[Johnnya101]

68MB is a lot. My Quadra takes a full minute or two to do the memory check.

I still would try and make another disk if possible. System 6 or a system 7. Just something to verify it will boot. I had a system 6.0.5 disk I made and used it to install an OS for my portable. I tried using it with my SE/30 and it got stuck at welcome to Macintosh every boot. A new disk fixed that. Sometimes they just get corrupted.

 

[clh333]

From MacGUI I found an image of 7.1 as a set of 1.4 Mb disks.  I created Installer1 on a DSHD 3.5 floppy with a G3 desktop and tried booting the SE/30 with that disk, to the same result.  I verified the disk's viability by using it to boot another SE that had a superdrive and also verified my OS 6.0.8 disk with the same machine.  So there appears to be another problem limiting my ability to boot.  Additionally the video on the SE/30 has become unstable once again.  Oh, well, back to the drawing board.

Thanks again for your help.

-CH-

 

[Johnnya101]

Try swapping the PSU. Bet that will be your issue. The PSU outputting the wrong voltages could possibly cause no boot, and could definitely be the cause of the unstable display. It COULD be the logic board, I suppose, but that is not behind the unstable display.

When my SE/30 had a bad PSU, I would have an unstable display when cold, and also when booting to the ROM image I would get weird and random disk errors. It all went away when I replaced it.