Jump to content

Oberlehrer

6502
  • Content Count

    20
  • Joined

  • Last visited

  1. Oberlehrer

    Performa 475 power problems

    ...and as soon as my desoldering pump made contact with the power supply board I knew how wrong I had been about the caps probably not having leaked. A familiar smell permeated the air... Anyway, after recapping the power supply I got a chime; and with the "jumpstart" method I also got video. So far, so good. But of course I got one cap with the wrong height so the lid of the supply won't close. I'll probably recap the logic board as well while I'm at it.
  2. Oberlehrer

    Performa 475 power problems

    The Performa came without a PRAM battery. I was under the impression that without the battery it would chime but not produce any video; and that the "jumpstart" method would work for the missing PRAM battery (but not failing caps). I'm mostly irritated by the voltage breakdown; it's obvious that the computer won't boot when instead of +5V there are less than +2V. Anyway, a complete recap of both supply and logic board is probably in order.
  3. Oberlehrer

    Performa 475 power problems

    So I got myself a cosmetically very nice Performa 475 without a hard drive and without VRAM. It doesn't really turn on and I'd like to find out if this is a power supply problem or a faulty logic board. When switching on the machine it clicks/pops continually from the speaker; the LEDs in the keyboard blink with the same frequency. All voltages are very low (roughly 50% of the nominal voltages). The power supply seems to work when not connected to the logic board; I'm getting +5.3V, +11.1V and -4.5V. The power supply is a Dyna Comp model; I don't know if the Performa 475 came with other supplies as well. My thinking is that a short on the logic board would probably only pull down one of the voltages (and not all three). Neither logic board nor power supply are recapped though both don't show signs of leakage. Any ideas?
  4. Oberlehrer

    SE/30 recapping: sound chip question

    My point was: Is there a (known) reason why both audio channels use different values and types (1u electrolytic vs. 0.1u ceramic)? Just being curious here.
  5. Oberlehrer

    SE/30 recapping: sound chip question

    Any takes on this? I'm about to order caps this week; I'll probably stick to electrolytics. The lifespan of modern electrolytics is hopefully a bit longer so there's a chance I won't have to do it again in my lifetime. Removing the old caps worked quite well; not a single pad lifted. I tried the "twist with pliers" method first but found it a bit unnerving. So I stuck to the "cut off the top" method that exposed the leads and the plastic part at the bottom. That part was so brittle that it was disintegrating with little force, leaving the leads on the pads. Those were easily removed then.
  6. Oberlehrer

    Macintosh Portrait Display M1031

    That's a good question... I'll ring it out with a multimeter the next days. I also found this in the meantime:
  7. Oberlehrer

    Macintosh Portrait Display M1031

    Thank you for your comments and research. I've found the "Card compatibility an Video Output Tables" Apple Service Source; it lists the IIsi with 16 grays for the M0404 (which I assume is the same as mine): It also lists all Power Macs up to the 9500 as compatible. My guess is that this guide is from around 1995 and hence before the 4400 came out. Interestingly the 8100 is also listed as compatible but I couldn't get it to work with the monitor at all (so far). The IIsi plays nicely with a TFT and an adapter at 640x480, both grays and colors. So I don't really think it's a problem with the IIsi's graphics memory. I don't believe it's getting significantly better over time although I think the partial sync under 640x480 (as seen in the picture above) did not work immediately after turning it on. Perhaps I'll do a long-time test tomorrow.
  8. Oberlehrer

    mounting SE/30 drives on a different computer

    Update (but not solution to the original problem): The IIsi boots flawlessly off the 6.0.7 SE/30 drive (and is extremely fast...). When trying to boot off the other SE/30 drive I'm getting a "Happy Mac" for about one or two seconds and then the floppy drive icon with the question mark. My guess right now is that the system is incompatible or damaged.
  9. Oberlehrer

    mounting SE/30 drives on a different computer

    I assume there is no ID conflict. The drives are both on ID 0 (naturally I'm trying one at a time). The 8100 has two separate SCSI busses; I'm having the boot drive on one bus and the SE/30 drive on the other. SCSIProbe sees them fine as the only device on the bus (except the computer on ID 7 of course). I've also swapped busses. The SE/30 drives should be terminated (I know one is - it has three resistor packs installed); I've also experimented with another terminator at the end of the bus. As I wrote: the same setup works flawlessly with a drive coming from a IIsi. I wonder if that could be a driver problem? The IIsi drive has 7.1 installed, the 8100 runs 9.0.4. Could perhaps the driver on a 6.0.7 drive be incompatible here?
  10. The problem looks to me as follows: I'm trying to archive two hard drives coming from two SE/30. What I'm attempting to do is to connect them to the SCSI bus on my 8100, mount them and read the contents. So far this does not work. SCSIProbe sees the device (and is able to flash the LED on one of the drives) but can't mount them. Error message is "FAILED: Logical units not supported". I know that one drive definitely works; I was able to boot the SE/30 from it (I believe 6.0.7 was installed); the condition of the other drive is unknown to me (it spins up though). What's also irritating is the fact that the same setup on the 8100 worked very well with a drive from my IIsi. Any ideas? (I know this is not really a Compact Mac topic but I didn't know where exactly to post.)
  11. I have watched so far just the first 3 minutes. Is it accepted/veryfied knowledge that the Sony has a black switch and power connector and the Astec a white one? I'm asking because I'm having two SE/30's with Sonys and one has black components and the other one whites...
  12. Oberlehrer

    Macintosh Portrait Display M1031

    Some more pictures: This is how the monitor looks with 640x480. It's scrolling quite fast hence I didn't notice the "wraparound" of the Monitor control panel (the right part of it can be seen on the left side of the screen). Inside: Yes, it's made by Hantarex... Caps look generally good - not bulged and no signs of physical leakage (of course that doesn't mean that they're ok):
  13. Oberlehrer

    Macintosh Portrait Display M1031

    I had used this very monitor on that IIsi before, so I know that this combination works. It also seems as if there were a couple of different Portrait Displays: M0404, M1030 and M1031. The 13W3 cable is an Apple cable. The 4400 offers 640x870 resolution but the monitor won't sync to it. Here's another interesting tidbit: When booting the 4400 with the monitor connected I don't get a useful picture (as described). When I then connect my VGA monitor afterwards it has a hard time syncing (it obviously can't display 640x870) until it jumps to a working resolution (1024x768, I think). It will stay on grayscale though, and the monitor control panel identifies it as "Ganzseitenmonitor" (German for "full page display"). This tells me that the Portrait Monitor (and its properties) is correctly identified during startup.
  14. Oberlehrer

    Macintosh Portrait Display M1031

    Update: I can also get some sort of picture out of it with 1024x768 and 74.9 Hz refresh but not with any other refresh rates at that resolution. Surprisingly I also occasionally get something out of it at 640x480 and 60 Hz: a constantly and quickly scrolling picture that otherwise appears to be quite sharp and defined (more zoomed in than I would expect perhaps with 320 horizontal). That is not consistently the case, though - most of the time it's clear that there is some sort of picture but it's heavily distorted. It's as if the sync signals inside the monitor are all over the place.
×