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Everything posted by techknight

  1. techknight

    SCSI to Ethernet Adapter on New Hardware

    I actually use the ATXmega128A1U in our product. Sadly this chip even though powerful, is super sensitive to voltage glitches and flash erasure. Mine has a bootloader so I can do software updates, Even with tons of filtering, and the BOD enabled continuously with the thresholds set it, every great once in awhile i find a device that is stuck in a bootloader reset cycle and flash memory erased. Its weird. Only reason why the bootloader remains is I have the fuses set to make it read/write locked.
  2. techknight

    SE/30 PDS Adapter Epic Blunder

    Thats.... Stupid. usually its the other way around. your package is larger/heavier than the label. Thats odd...
  3. techknight

    Mac SE Monitor On/Off Switch

    you just need to tack a couple capacitors. 0.1uf ceramic/film, and 1uf electrolytic. across the VCC/GND lines directly at the chip. Also, a 5.6V Zener diode with the stripe side of the diode body soldered on the VCC pin, and other lead to ground. Then, put a 10 ohm resistor between the wire coming in from the switch, and the chip's VCC where all the above parts are attached. this will serve as a dump resistor if something were to overvolt or short causing the zener diode to clamp. You could go with the metal film non flammable type here. Maybe fusible type so it pops open if failure.
  4. I have an SE/30 motherboard here that belongs to someone else. It had a strange issue. it had black lines jumping around coming and going. UE8 was already changed and some other ICs swapped around by someone else. All the PALS are soldered in place, NO sockets! which that sucked. So, I decided to heat the PCB up and the jumping stopped, but it gave me a black line every 8th video bit. So i decided to buzz out all the connections to UE8, the PALs, and the VRAM muxes, all are OK. Then I decided to try the freeze spray approach. Hitting UG7 with freeze spray snapped the picture back in with no lines, no jittering. Perfect. But, it was a 341-0633 and all my SE/30 parts boards had the 341-0746 So I swapped out the pair, the 0633 and 0635 with the 0746 and 0747. Well, that stopped the raster from jumping around and the lines from flashing and going. But, my 8th video bit horizontally (like a UE8 failure) is still black and gone. So I thought, well since the other 2 PALs were the 6XX ones I went ahead and changed those out too so all 4 matched. Same thing. Its not UE8 because I can remove the ROM and I get zebra stripes with NO black line every 8th bit. So the scanning circuit works. Also towards the end of me screwing with it, I noticed the floppy disk ? icon was showing perfectly fine through the black line, as well as the mouse cursor outline. So its almost like an old arcade machine where the sprites are perfect, but the background has lines! That tells me its a VRAM write issue. maybe? I tried another ROM, another video ROM, and I sucked out and changed the VRAM and no difference. Even tried a different set of RAM, and tried my dougg3 ROM SIMM and same deal. This one is definitely got me stumped!
  5. techknight

    Mac SE Monitor On/Off Switch

    Wouldnt it have just been easier/safer to put a switch in the sweep supply at pin10 on P3? You will blow out that 74LS IC eventually doing it the way you are doing it. At minimum you need a Zener diode, a resistor, and capacitor filter network now at the IC. Just C23 alone isnt good enough anymore now that you have wires running half way to China and back, along with EMI generated by the switch, which is now closely coupled with the 12V line. All kinds of bad here. But hey, at least you tried.
  6. techknight

    Should it be recapped?

    looks like its nearly burned, so yea i would say that IC is shot. But that is the least of your concern. The bigger concern is the chain-reaction collateral damage potential that happened when the IC blew out. How many other parts went with it?
  7. techknight

    SE/30 PDS Adapter Epic Blunder

    Not sure of the feasibility, but it may be worth taking a few of those more badly damaged ones, and sending them to a Chinese reverse engineering house to see if the chips can be reverse engineered and the logic put into an FPGA or something.
  8. techknight

    512K Flup Flup Flup and Schottky diodes

    You cant reliably read Diodes in resistance mode. you need to use Diode check mode and check the voltage drop across them. Best test is out of circuit. (by removing them).
  9. techknight

    SE/30 does not boot

    Well, if it has one of those Quantum hard drives, its of no surprise this is happening.
  10. techknight

    LC575 screen

    Unless the thing has 50,000 hours on it and the CRT has gotten weak. its rare, but I have seen a couple computer monitors this has happened to. IBM PS/2 monitors being one of them, I have an IBM PS/2 monitor that the CRT has been worn into the ground. Has burn-in of course, but the emissions from the electron gun are so weak, turning up the brightness has severe color bleeding and blooming. Thats how you know the CRT is done for. Surprisingly, I found a NOS replacement. Havent changed it out yet though.
  11. techknight

    Apple 13" Monitor failing

    Ohh ok, thanks for clearing that up. These particular monitors are KNOWN for capacitor issues, so that is likely the cause. Sometimes the flyback housing can crack and start developing arcing points, but youll smell the corona it gives off if this is happening. More than likely though, you have bad caps, especially the two or three near the horizontal drive stage.
  12. techknight

    Apple Imagewriter II Restoration

    Welp, Another project on the table. Just picked up an Imagewriter II from Scott, And as expected, there are definitely a few things with these beasts that need attention. 1. You guessed it. Capacitors, Capacitors, Capacitors! A few of these just started to leak, while others appeared ok. But I decided to change every single one of them. Getting this little bugger apart is definitely NOT easy. it takes quite a bit of thought, but eventually i did it. First and foremost, Here is the driver board: This basically is the Power Supply/Driver board. few things to note here, the two Sanyo-Panasonic proprietary STK-based power output ICs. Made for toshiba of course with thier own part number, but ive seen and changed enough of these to know exactly what they are. The one on the right is the voltage regulator output IC, and the one on the left is the stepper motor driver output IC. This is the worrisome part, Even though these printers appaer to be fairly reliable, These power-pack ICs are definitely NOT known for reliability, So the first order of business is to recap this thing, and do some routine maintanance to keep these ICs cool and running under optimum conditions. Any slight variation, these ICs tend to fry themselves. If they do, well, its game over. These ICs were used notoriously in integrated stereo amplifiers, and projection TV convergence applications, and some old tube-type RCA sets used them in the power supply, and they were known for failure. Ive changed a plenty. So enough of that, You can probably see some spooge leaking from the left most tall capacitor, so they all gotta go! Removed the cap, and shown the leakage. Now here: I decided to remove the heatsink again, for routine service and mainanance of the STK power pack ICs. And the heatsink compound was dried and and crusty! Time to clean them up and re-grease the ICs. This will increase the service life drastically. Here is the shot of the digital control board for the printer, and all of its capacitors that need replaced as well. Again, one of these caps had some spooge too! and the solder joints on this board were really rickety. I touched most of them up already before I took this photo, but you can see clearly the ones I didnt and how bad they are. This is undoubtedly the result of being in storage/outside/basement where constant moisture, and heating cooling cycles took place causing metal fatigue. Had to be fixed! Oh and here is the undershot of the chassis: More to come! as I dive into the thing mechanically. I may even retrobright the case too, because it is piss yellow, Even all the way through the plastic in the inside as well, which further proves my theory of environmental storage.
  13. techknight

    Mac plus probing signal at J8 pin 1

    It could be. You would have to try a known good PAL from another logic board if you had one. otherwise, you would have to burn a new PAL which I dont think the bitstream files are out there for the Plus.
  14. techknight

    LC575 screen

    The trinitron CRTs are pretty much all the same. that CRT, (if its the same size) can fit in some of the other Apple Trinitron monitors of the same size. I know some of those displays were actually 13" but the CRT may still be the same.
  15. techknight

    Mac plus probing signal at J8 pin 1

    Your video signal is kinda weak. Might need to look into that. Check the CRT Neck board for a shorted video driver transistor, and/or check the logic IC on the analog board where the video is gated through. Also probe the video signal on the logic board as well. it seems as if the signal for the video is being damped for some reason.
  16. techknight

    Apple 13" Monitor failing

    I would almost need to see a picture of what your describing. CRT Monitors are very complex little devices and it can be many different things to cause those symptoms. Could be capacitors, could be the video amplifier IC, could even be the flyback itself.
  17. techknight

    Portable & SCSI2SD Questions

    Im worried. Changing the 9V batter should not have changed anything with the system turning on or off. All that battery is for, is when you slide the battery cover off, it switches into the circuit to keep the memory maintained. Until you slide the battery cover back on. the 9V battery servs no other purpose. So if changing the 9V battery made a difference, that tells me your battery latch switch is either bad, or the tab is broke off your battery cover. The portable wont last long in this manner.
  18. techknight

    SE/30 Video Section Replacement Parts

    As long as you match the LS for LS,. and F for F, you should be fine.
  19. techknight

    SCSI to Ethernet Adapter on New Hardware

    Good thing about using an ARM Cortex, you can get speed improvements of course, and then since the firmware is written in C, it should be fairly easy to port over without doing too much work, but you would have to replace the ASM routines though. Regardless, this is a really nice project Honestly, with a littel bit more cobbling, you can probably replace the ethernet PHY with an ESP8266.. and then use some of the WiFi driver development done by ants, combine the two, and you have one really badass product, with a wifi icon in the menu bar to boot! Then, if its miniature enough, it can be put inside vintage powerbooks, replace the internal HDD, and gain wifi support at the same time? HELL yes!
  20. Depends on how you comprehend the term "Upgraded" Because Upgraded could mean something as simple as just replacing the PCMCIA adapter with the upgraded newer version. It could go either way. There is a flash ROM on the PCB so anything is possible, but if the control IC itself is different, its hard to code around that.
  21. techknight

    TDK LC supply still clicking after recap

    @LaPorta Definite brain fart ol buddy... Check the opto-isolators.
  22. techknight

    Asanté EN/SC Setup?

    Depends on what website your trying to open. 90% of them are broken on browsers THAT old. You could try phils old radios. its a vintage site. But even then, its using SSL so dunno.
  23. Weird. my post disappeared.... I didnt see the pictures prior, they woudlnt load for me when I typed my message. So in the case of the expansion card, I dont know. My thought would be to remove it. But I do know the ROM generates an E code if it is unable to write to something.
  24. It can also do this if the power supply cant go into regulation. Like bad caps, open photo-couplers, etc..
  25. Dont think they exist, most of the time the monitors were engineered by other people and Apple rebranded them. So if you could figure out what they were "originally" you may have a better chance. However, your gonna need to do some troubleshooting regardless.