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Rescued an SE from a life of being used to hold up a sign

Torbar

Well-known member
I was at a video game convention in NJ over the weekend(Funnily enough, it was actually called A Video Game Con), and at one of the booths there was a Mac SE with a sign taped to it saying something along the lines of "we accept trades" or something like that.  Long story short I ended up asking the guy if it was for sale, and we settled on $25 since it was untested because he didn't have anything needed to test it out.  I booted it up last night and it booted to the flashing question mark floppy icon, and emitted a smokey odor which IIRC is the flyback transformer, so I'll have to swap that out and look at the caps.

It's got the 800k disk, 20mb hdd, 1mb of RAM.  Might try to find the 1.4 ROM chips/SWIM chip, and a 1.4 floppy drive to upgrade it.  Also does anyone know if the flyback from a Mac Plus would work on it?

Overall the machine is in pretty good shape, little yellowing, and has the programmer switch installed

 

tanaquil

Well-known member
I wouldn’t.  You are eliminating the bleeder resistor if you do that.
Only if the Plus has an older flyback. As I recall the B and C variants both had the bleeder. The recommendation is usually to get the C if you can (because it’s the latest, I suppose). Most Plus machines I have seen have the C version, it’s the 512K and earlier that often don’t. 

Really a shame that replacement fly backs are so expensive now ($100 seems standard even for B variant). 

 

Scott Baret

Well-known member
Best thing to do for a failed flyback is to find a machine that got eaten alive by battery goop and pull the analog board/flyback from it. Not only do you get the flyback, you get a power supply, an analog board, some drives, and a speaker. There may even be other components on the board if the leak isn't too bad (chips, RAM, etc).

 

Torbar

Well-known member
Best thing to do for a failed flyback is to find a machine that got eaten alive by battery goop and pull the analog board/flyback from it. Not only do you get the flyback, you get a power supply, an analog board, some drives, and a speaker. There may even be other components on the board if the leak isn't too bad (chips, RAM, etc).
Yeah, probably the best idea actually.  Especially if I find a FDHD that was a victim of the maxwell bomb with the ROM/SWIM chips intact

 

techknight

Well-known member
So what makes you lead to the flyback? I dont see any troubleshooting steps so I dont know if the flyback is actually bad or not. It could be anything. 

if you get a raster screen with a blinking ? then the flyback is likely ok. 

Flybacks either work, or they dont. When they short internally, they go dead nearly instantly, and most of the time takes out the horizontal output transistor. 

 
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Compgeke

Well-known member
So what makes you lead to the flyback? I dont see any troubleshooting steps so I dont know if the flyback is actually bad or not. It could be anything. 


+1 for this. Smokey odor makes me think of maybe like burning leaves which tends to be something like a RIFA cap on the input filtering of a power supply letting its guts out. Especially if the system remained working throughout this whole endeavour. 

 

Torbar

Well-known member
So what makes you lead to the flyback? I dont see any troubleshooting steps so I dont know if the flyback is actually bad or not. It could be anything. 

if you get a raster screen with a blinking ? then the flyback is likely ok. 

Flybacks either work, or they dont. When they short internally, they go dead nearly instantly, and most of the time takes out the horizontal output transistor. 


+1 for this. Smokey odor makes me think of maybe like burning leaves which tends to be something like a RIFA cap on the input filtering of a power supply letting its guts out. Especially if the system remained working throughout this whole endeavour. 
I haven't done much troubleshooting yet(have a couple of other projects I'm working on first), but what lead me to the flyback is the dead mac scrolls.  Would definitely be good if it wasn't the flyback.  

What're your thoughts the best way to determine what the issue is?  Inspect the analog board and see if there are any bulging/leaking caps? and if I dont see any, power it on and try to get more of a sense of what's emitting the odor?

Thanks!

image.png

 

techknight

Well-known member
Take it apart is step 1. 

Then do a close visual inspection of all analog board components. Thats step 2. Both front and back side of the analog board, flyback included. 

Then power up and see whats going on. 

 
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