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Found 13 results

  1. Hi there, it's my first post! Some time ago, the PSU in my IIsi suddenly turned itself off while running. Recently I opened it up to try and fix it and found 4 leaked caps on the secondary stage. The electrolyte had corroded through the legs and affected the solder mask and some pins on the bottom side. No unrepairable damage though. Cleaned the mess off, resoldered the oxidized wires and replaced the bad caps. Then tested the bare PCB on my desk with a fog light as load on the +5. It worked absolutely fine again: briefly touching /PFW to PSTRICL turned it on, touching /PFW to GND turned it off. After ten minutes it still worked fine, so overjoyed I put the thing back in its enclosure. Then tested again: /PFW to PSTRICL still turned it on, but as soon as I let the connection go, it turned off. Puzzled by this sudden change in behavior, I touched /PFW to GND to see if that would reset something. Or so I thought, because it wasn't GND -- I took the wrong hole in the connector and instead touched /PFW to -12... No smoke but then it didn't start at all anymore. My heart sank when I realized my mistake -- all my meticulous work, ruined by a single lapse of attention! About a minute later the main fuse F101 suddenly blew, completing the misery. I was quite upset by my stupid mistake and I'm still mad at myself right now... I later reverse engineered most of the main PCB and the daughterboard PCB. All parts on the main PCB seem to test OK, so I'm not sure why the fuse blew. On the daughterboard (https://cdn.pbrd.co/images/5dxpafFDF.jpg) I found three SMD parts with one open PN junction each. Alas Q1 and especially Q2 have such unclear markings that I can't guess what they are, thus halting my resuscitation endeavour. Hence my questions: Can someone identify Q1 and Q2? Their markings may be clearer on your own unit than on mine. Q1 may be "18" or "183". Q2 is very unclear but might be "13" or "132". Q3 is definitely "14" (etched) although it's not visible in this pic. Does anyone have a spare PSU for sale, or the daughterboard from a broken one? Converting a regular new ATX power supply to IIsi may just involve some rewiring and a logic inverter between /PFW and PWR_ON. Indeed I found this post: https://68kmla.org/forums/index.php?/topic/28901-microquadra-630/page-3 Is this approach known to work for a IIsi?
  2. Hi all, been a while since I last posted here, about the same time I tried to use my IIsi(s)... so dug them out but neither of them would power on. I would get a brief click, fan and light then they would power off again. Tried replacing the fuses, which might have done more harm than good since the guy sold me slow fuses by mistake which I stupidly tested anyway. after getting the right fuses they blew straight away. so did some continuity testing and found at least a couple of the zener diodes are allowing current in both directions, but there’s no way I know of to know their values. Wondering if anyone would happen to know what diodes are used at D302 and D305? See attached photo. Thanks in advance!
  3. JDW

    Modern PSU for the SE/30

    I need a new PSU for my SE/30, and it would be best if I got a modern one that supplies more power than the stock PSU. Any idea what ARTMIX could be using? (I doubt they made a custom designed power supply just for the SE/30. It certainly must be an off-the-shelf model, I would think.) http://www.artmix.com/hps_2009_EVO.html There are two +12V outputs, one being for the SWEEP. I assume these are isolated? For why offer two +12V output's instead of one powerful +12V unless they are needed to be isolated (to avoid noise issues)? I might be able to afford one PSU from ARTMIX, but I'd really like more than one since I have more than one SE/30. But at $200 a pop, that's too expensive, which is why I am posting here to see if anyone might know of a PSU that would fit inside the stock metal case and offer the same 4 outputs as the stock, but with higher current ratings. It's amazing to me that despite all the hundreds if not thousands of us who own and love SE/30's, you don't find any "rebuilt" PSUs for the SE/30 for some reason (outside ARTMIX). That implies that nearly every SE/30 owner on this planet is either using a stock PSU, or possibly a recapped PSU (which would not put out more power than a new stock PSU, which isn't designed for that many add-ons). The reason I seek a modern PSU inside the stock metal PSU enclosure is to cover any power requirement, regardless of the add-ons I add inside (HDD, PDS cards, etc.) I therefore look forward to hearing your thoughts. Thanks.
  4. Inspecting the Profile power supply board, I noticed a very burnt resistor that had cracked into two pieces. I'm having trouble identifying its value. Can anyone help me out? It looks like Brown-Grey-Orange-Grey-Brown? Thanks
  5. Hi everybody, I have just bought an iBook, model number M6497, without a power supply. The seller said he believed it was a 600MHz G3. I'd like to know the model number of the power supply so that I can go look for one. On the back of the iBook in awful grey on white (I think I need glasses), it is rated 24Vdc and 1.785A max. Can anyone help? Thanks, aa
  6. johnklos

    -5 volts needed for...?

    Happy holidays, 68KMLAers! I have a nice Quadra 605 motherboard which I've recapped and did the resistor change to run at 33 MHz. Partly since the plastics have become so incredibly brittle, and partly because I don't have the capacitors needed to recap a power supply, I've decided to build this motherboard in to a small 1U rackmount case. I noticed that the whole motherboard takes 12 volts, 5 volts and -5 volts. I guessed that the -5 volts is probably only needed for the serial ports, so just to see I wired up 5 and 12 volts, and the system booted fine. There are two things I'm wondering: 1) I don't get any audio out of the speaker at all. This could be damage from the bad capacitors, it could possibly be damage from the recapping work, or it could be that it needs -5 volts for audio. Does anyone know if it needs -5 volts? 2) I plan to replace power supplies for a Quadra 610 (with 260 megs of memory and a QuadDoubler ) and a Quadra 630 (with 196 megs and a QuadDoubler), and ATX power supplies have -12 volts, but not -5 volts. I see from some projects, both here and elsewhere, that the Q630 doesn't require -5 or -12 volts and that the Q610 takes -12 volts. Can anyone confirm? I may just get some LM7905 regulators and feed them from -12 volts. It's always good to have working serial ports!
  7. I have a monstrous Attila the Mac 950 Quadra tower that is a fantastic machine. Works great with one strange startup quirk: Before powering on, I have to turn off the power to the machine (using a power strip on/off button), then on again immediately prior to powering up the 950. If I do this it boots 100% of the time, very reliably. If I DON'T do this power strip on/off step, the machine fails to boot properly and hangs with a grey screen at startup. Very reliably. BTW I didn't just stumble up on this startup workaround, I found a hint during my hours of googling vintage mac startup problems and going through my old mac reference books. But alas I have been unable to find the source of this tip, which might provide hints as to what's going on and what I can do about it. Replacing the PSU is one obvious option to try ... but perhaps it's the board that's faulty? Anybody here have experience or knowledge of this issue? Any suggestions appreciated. Thanks, Craig
  8. I have several working IIci macs and have been trying to get one in nice shape complete with a recap to set up in my working vintage mac office. Power supplies seem quirky and sometimes mysterious, so I thought I might post some of my observations here and see if any collective wisdom or similar experience might help guide my next steps. Back in December I did some testing to sort out which machine to have recapped. In testing, it seemed all 3 machines suffered from a strange symptom where the on-board power button had to be held down in order to sustain power. Strange. Anyone seen this before? The only thing I did after this testing was to use compressed air to clean them out some. I have 3 power supplies: 2 Delta and 1 Astec. Photos with testing notes attached. My newly recapped IIci is completely dead with both Delta power supplies. The other IIci motherboards work fine with these same PSUs, powering up with both the keyboard and the on-board power switch. One board lacks sound, which I'm guessing is a symptom of needing to be recapped. So the Delta PSUs seem fine, suggesting a problem with my newly recapped IIci. The Astec PSU works ok with one of the unmodified IIci boards, but with the other (which lacks sound) powered on once and then off once, never to be powered up again with the Astec PSU. Retesting this board with a Delta PSU and it again powers up fine. Oddly, the Astec PSU DOES power up my recapped IIci intermittently, and only with the keyboard. I have to press hard, sometimes twice but if I play around enough it powers up and then behaves fine. Strange stuff. What I conclude from all this is I have a problem with the newly recapped board, and I probably should recap the IIci which still boots cleanly with sound. Any insights on any of this appreciated. I have another strange PSU issue with a Quadra 950 which I'll post in a separate thread. Thanks all for taking the time to read this! Craig
  9. joethezombie

    SE/30 Sony Power Supply, Recapped

    From the album: Macintosh SE/30

    SE/30 Sony power supply after a full recap. Here's the cap list from DigiKey. It will not work for the Astec version. A couple of notes: 1. The "big guy" capacitor (620uF, 400V) is no longer made. The one in the list has a slightly higher capacitance at 680uF. The protection circuit (limiter) in the power supply can easily handle the negligible jump up to 680uF. Something very important, however: the legs on the replacement capacitor are not going to match the slits in the power supply board. I had to widen and lengthen the corners of the existing slits for the new capacitor to fit. I used a Dremel with a small abrasive bit to do this. I thought I'd taken a picture of the result, but apparently I was too excited to get the supply up and going and neglected to snap one! So, this is a picture of the completed board, so you can see the size difference and position of the capacitors. Very happy with this recap.
  10. joethezombie

    SE/30 Power Supply Re-Cap, bottom

    From the album: Macintosh SE/30

    Solder-side view of the Sony power supply. Contacts cleaned and ready for new capacitors.
  11. joethezombie

    SE/30 Power Supply Re-Cap

    From the album: Macintosh SE/30

    All capacitors have been removed from the Sony power supply and is now ready for the replacements to be installed. Copious amounts of electrolytic fluid has been cleansed from the board.
  12. Hi, I'm having some problems with a Quadra 700. The Mac only (now) boots when the power to the HDD is disconnected, and goes straight into the flashing floppy screen. When the HDD power is connected, the Mac does not boot at all - just a clicking sound comes from the machine. The PSU fan tries to spin too. I assume this is some sort of problem with the power supply - possibly not being able to supply enough power? Weirdly the whole machine was working fine yesterday, although it hadn't been booted in a long while before that. Is there something I can do to fix this? Has anyone experienced this before? Thanks very much.
  13. Did some recapping of boards and an LC Power Supply (PSU) today. I had a few successes here and there. Thus I post a few things I learned in recapping my first LC power supply though I am already used too such similar jobs. The problem I had was the size of the caps. Uniserver's webpage ( http://maccaps.com/MacCaps/Capacitor_Reference/Entries/1990/10/15_LC_I%2C_II%2C_III_Power_Supplies.html ) was very beneficial and informative to this cause, but this is only a partial recapping which is fine with me. The caps in the LC PSU are tall and skinny. The caps I got are short and fat, I did not take into account the physical size of the caps. The caps replaced are as follows, as per his website: 2 - 270µf - 25V - ELNA - Long Life Radial 1 - 270µf - 10V - ELNA - Long Life Radial 1 - 56µf - 25V - ELNA - Long Life Radial Though all of the caps should have been replaced, past posts ad discussions with him tells me that these 4 are the most problematic, and I found that they had all leaked in the LC PSU. But the LC PSU is very tight on space and the smell of rotten fish rose when I started deoldering. Furthermore I did not have a 270µf - 10V, so I another 270µf - 25V in its place. But again, the problem here was the physical size of the caps. One of the two caps I had to have standing on its long legs so its contact to the heat sink would be minimal. Another cap could not fit into the space the old cap was in so again, giving it long legs I was able to place it in the tight space. At least the LC PSU is working again, but I will have to recap it one more time with tall skinny caps that ae rated higher in voltage by a bit instead of short fat ones I used now. BTW - the dead PSU is now working again and a dead LC is now living once more!
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