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Posts posted by DistantStar001

  1. So I'm not sure if this is the right place to put this since the monitor is technically a Mac accessory, but I use it with my SE, so here it goes.  


    I have a Mobius branded legal page monitor that has sat in a storage unit for the past decade.  I finally pulled it out and hooked it up, but all I got was was a small squiggle in the middle of the screen.  I turned it off and then back on again and now the monitor seems to have a power issue.  there's no smoke or flames or anything spectacular like that.  It jut powers on and off when I flip the switch and makes a chirping sound every time it does.  I know next to nothing about this monitor.  Owned it for decades but it never gave me a problem before, so I never had a need to crack the case.  


    As far as I can remember, the chirping sound is normal when it powers on (it's also synchronous with the power indicator light), but it seems to repeatedly fail and then try again.  Also the I noticed that if I leave it "on" the frequency of the chirping becomes slower.


    That's about all I know at the moment.  My first guess would be the capacitor, but I really don't know enough to be sure.

  2. 16 minutes ago, Daniël Oosterhuis said:

    It depends, I'd say. Try and see how sturdily it's still attached, or if it's easily knocked out of place. If it stays in place relatively securely, I wouldn't worry too much unless the Mac is often transported. If it does fall off easily, then maybe glueing it down with something secure, but easy to remove, like silicone glue or hot glue, might be a good idea. A few dots should do, and it should be relatively easily removable if the anode needs to be taken off for servicing again.

    It seems pretty secure (in that it doesn't come off unless I take it off), but I do move it on occasion.  So a few dots of hot glue sounds good for peace of mind if nothing else.  Thanks again.  :-)

  3. 15 minutes ago, Daniël Oosterhuis said:

    A dot in the middle of the screen usually means the deflection coil is not plugged into the analog board. Try fixing that first.

    THANK YOU SO MUCH!!!!  That did work.  Now I feel like bit of an idiot for overlooking something so obvious.  


    However, that little bit did break off.  Is that something I should be worried about?  Could the anode come loose or cause damage?  Or am I OK now, and can I finally sit back and enjoy my first (and favorite) Mac?

  4. So I might be SOL here, but I'm going to ask anyway (and hope for a miracle).  In an attempt to replace the fan in my SE, I detached the anode from the CRT so I could work on the board.  Everything went well.  The new fan works.  However, when I was reattaching the CRT, the tip from one of the prongs snapped off.  I only tested the for a second to see if it might still work but only got a single dot in the middle of the screen.  Obviously, I turned it off after that, and I'm not messing with it until I figure out a workable fix.  My question is can I remove and replace the flyback transformer on the board with a new one, or do I just need to suck it up and replace the board?


    If I can replace the transformer, then what is the part number I should be looking for, or what would make a suitable modern replacement?

  5. Update:


    First, Elemenoh, You were absolutely right!!!  I managed to get some 682 and 204 resisters, soldered them in (lost one since I suck at micro soldering) recapped the board, and plugged it in.  It powered on and booted, but no sound.  So I checked continuity and found a broken trace between R2 and Q1.  No problem.  I bodged it, plugged it in, and BONG!!!   I was very happy!! Then I rebooted and again no sound???  So I powered down and turned it off and back on again (I T Crowd stile) and still no sound.  I'm ashamed to say that it took me several hours to notice that there was a lot of white crud built up around the ram on the other side of the board.  I sprayed it with IPA and scrubbed it with a q-tip (did the same around the sound chip just to be safe).  Now it's back to its full functionality!!


    Thanks to everyone who helped me.  I'll try to post a picture of it set up and running when I get a chance. :-) 


    Oh, one more question:  How do I enter a 2020 date in System 7.5?  I keep trying, but it always reverts to 1920?  I don't seem to have this problem in 7.1 or 6.

  6. On 7/3/2020 at 6:59 AM, elemenoh said:

    Thank you!  I wasn't sure because of the font, but after comparing it to the pictures of my board, I think you're right.


    I think I'm going to check with my local electronics store first, but thank you for the link.  Now, one way or the other I'm getting my LC back!  :-) 

  7. I have checked them out, but I've had some trouble identifying the product I need.  I think the markings on the 582 indicate a value of 5.8 kΩ, however, the images on their site are unmarked.  Also, they didn't seem to have any stock from the results that came up.  I also checked out Mouser with no luck.


    As for seeking a donor board, I'm not sure what other boards might have the necessary.

  8. A sad update :-(


    First I wanted to say thank you so much to everyone who has tried to help me.  However, I must regretfully report that this is not going to be a salvageable Macintosh after all.  The corrosion to the analog board was far more severe than I had originally thought.  Several components were loose, and many of the traces and pads are falling off the board.  But the final nail came when I discovered a bent pin on the back of the CRT.  In my clumsy attempt to bend it back into shape the tube cracked and a piece of glass broke off, rendering any potential repairs to the analog board meaningless.   Maybe I'll come back to this someday.  But for right now, it's a parts-machine.  


    Its case and most of its innards are still in decent shape, so I'll probably salvage them for other computers.  


    I still have an SE with a single failed capacitor on its analog board, along with a bad hard drive.  So now that computer will be able to live on instead.  


    I haven't decided what to do with its floppy drive yet.  I still have my LC III that I'm repairing (I temporarily gave its drive to an SE for the moment), and the drives on my Mac II are a little mismatched.  So either would be a good candidate for a transplant.  


    The motherboard could be perfectly fine for all I know.  I did recap and clean it.  Unfortunately, however, I have no way to test my work at the moment.  


    As for the case, the upper center crew hole is completely shattered on the front part.  It looks to be some sort of corrosive damage that discolored the screw as well.  But structurally, and cosmetically, it should still be salvageable.  The back is a little yellowed and has a few scuffs, but is otherwise in good shape.  Who knows, maybe I'll find another beat-up old classic that could use a facelift.  Or I'll just sell the bits I don't use on eBay...


    All and all, this has been kind of a sad day for me.  I was really looking forward to getting this old Classic up and running again.  

  9. On 5/13/2020 at 2:48 AM, dochilli said:

    I have the same board (630-0395) and the values for it are in my above post.

    Cp 31 is 1000mF, 6,3V, 85°C


    On 5/13/2020 at 6:41 AM, superjer2000 said:

    I thought I had posted this before but couldn't find the post.  I compiled this while recapping~6 or so Classic/Classic II 110V boards.

    Classic Analog Boards.xlsx

    Thank you both for this.  I'm going to go over the entire board now and see if I can't get this thing to finally work!

  10. 4 hours ago, LaPorta said:

    There are different revisions with different caps. I ran into this as well. If you can give me the actual number of it, I can see if I have one.

    The part number for the board is 630-0395.  I Tried using the 630-0525 (220v international) as a reference since that's the most commonly documented, but it didn't work. 


    This isn't the first time I've run into an issue like this, where all the documentation for an American computer is for the international version of it.  Sometimes I'm lucky, and the two are somewhat interchangeable, and other times they're not.  PSUs are particularly annoying that way.  


    If possible, and just to check my work (since it's non-functional), is it possible anyone has a list of all the capacitor values with locations for this model?  I tried some schematics I found online, but for the life of me I couldn't find CP31, and there appeared to be other missing bits as well.  The good news is that I haven't done any damage.  It's just as broken as when I got it.

  11. I'm attempting to recap my Mac Classic's analog board and seem to have lost track of what goes where.  I'm not recapping the whole board just yet, only the ones that were obviously bulging or leaking for the moment as they're the ones that were the most obvious and problematic.  I've managed to get most of them done, replacing one by one, but I got distracted and now I can't find the proper values for CP11 and CP31.

  12. On 5/7/2020 at 8:20 AM, Fizzbinn said:

    Yes, there is a trace connecting them, confirmed with multimeter continuity check.


    Thanks.  I think I can bridge that between the resisters.  If I had to lose a pad, at least it was that one.

    On 5/7/2020 at 8:39 AM, LaPorta said:

    That incredible amount of crud around the legs of U1 should also be dealt with to make sure it isn't causing any issues.

    Yeah, I noticed that too.  I've been scrubbing this thing under a magnifying glass with alcohol and q-tips for a while now.  It looks a lot better, but it's clear that the caps leaked more than I had originally thought.  The damage isn't too bad, but R1 appears to be a casualty (not sure how though).  

  13. 2 hours ago, Fizzbinn said:

    Not sure if you could do without R1 and R2 but here’s a pic of mine showing their markings:

    Thanks for this.  I've been Googling images and every picture I've found shows those resisters populated, but I was never able to clearly see their markings.  Now at least I know what to get.  My guess is that they are necessary and may have fallen off from corrosion, or they weren't as secure as they should have been and I inadvertently knocked them off removing the capacitor.  In either case, it seems that there is a trace in between connecting them.  If you have a multimeter, could you possibly confirm this?


    1 hour ago, Fizzbinn said:

    I’m a bit embarrassed how crooked those caps are

    Don't be.  If it works, that's all that matters.  You're already way ahead of me! :-)

  14. So I'm trying to recap my LCIII motherboard.  I managed to remove all of the old capacitors, clean all the pads (all of which survived) but I just noticed that the resisters at R1 and R2 are missing, and one of the pads at R1 seems to have fallen off.  The pads on R2 are still there and I cleaned them as well as the remaining pad at R1.  The board did work before all of this but would take forever to boot.  
    I don't know how long R1 and R2 have been missing, but I can't imagine that it's a good thing that they are.  The old capacitors clearly leaked but thankfully didn't corrode any of the legs on the ICs.  So do I have a problem?  Can R1 and R2 be repaired?  Do I even need to?
    Below are pictures of the board and a closeup of R1 and R2




    Edit: I was just looking at the closeup and now realize there appears to be some corrosion that I didn't see before.  Guess I'm going to have to go over this thing with a magnifying glass.

  15. I've been working on an Apple //e mother board for a while with no luck.  It worked when I got it, and all the ICs are socketed.  So I tried to use it to diagnose another malfunctioning board.  Unfortunately it didn't work, and when I reseated all the original ICs it stopped working all together (no video, no beep).  Finally I decided to give it a run through the dishwasher (figured that I couldn't kill a dead board) and now I get 12 horizontal bars across my screen, each 8 pixels tall.  This is the most life I've gotten out of this thing in months!  


    So far I've replaced all the RAM on the machine, the MMU, all the ROMs (Video, EF, CD, and Keyboard), as well as the CPU.  It's made no difference if the keyboard is plugged in or not, and I haven't been able to trip it into a diagnostic mode.  On a lark I popped in a known bad RAM chip and got a series of As and block on the screen.  I swopped out another good chip for bad and got Cs instead of As.  Then I hit Control-Open Apple-Reset, and that put the Cs back to As.  So I know that the computer can react to the keyboard, just not with known good RAM?


    Any ideas or suggestions?

  16. Short answer, No.  I tried this with an ESC key and found that not only the key itself was too tall for the //c board, but the orientation of the switch was vertical on that particular key as opposed to horizontal on the //c.  I'm not sure if that holds true for the option key, but in either case, it will stick out noticeably from the rest of the board.

  17. So I have two Apple 3.5 inch Unidisk drives. One works fine, but the eject motor doesn't push the disc out all the way, but I can live with that. The other won't work at all. When I connect it to my //e and insert a boot disc, the light flashes, then nothing. I've tracked the issue to the analog card in the drive, as when I swapped the drive itself between the two, the failure remained with the defective board. I've been poking at it with multimeters for months now with no idea what I'm looking for or luck in tracing the problem beyond the board.  
    I really don't want to throw this thing out. Aside from the high cost of replacement, this was part of my grandfather's //e, so there's a lot of sentimental value as well. So if anyone has a schematic, or any advice on how to trace the fault, I would be very grateful.

  18. It chimes after 10 to 20 minutes.  I figured that I would have to recap something, but my equipment is limited, and I've never dealt with surface mount capacitors before.  I haven't seen any sign of damage to the motherboard, but I know that the electrolytics used have a tendency to leak eventually.  The Good news is that the board was new-old-stock in the early 2000s and has only been used sparingly since.  

  19. So I have a Macintosh LC III (in an LC II case) that takes about 10 to 20 minutes to power up and boot.  Once it does, it seems to work fine, but if it goes more than a few hours without a power on, it just sits there spinning its fan for an increasingly extended period with nothing on the screen.  I've tested the monitor with my DuoDock and it seems to work fine, so I know it's the computer.  I'm guessing that it's a failing capacitor, the question is which one?

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