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Hi, I have a problem with a Power Macintosh 5500 / 275. Nothing shows on the screen. It does the start-up chime and it might actually be working, but the screen is probably dead. There is no hard drive and no battery. Here is a video...

I am trying to repair a Power Macintosh 5500 / 275 Black. The main problem is that nothing shows on the screen. There is no HDD, but I thought that something should still show up. The screen never blinks or gives any sign of life. There was a chime before and the floppy drive seems to work. It...

Hi, I am thinking of acquiring a Sun Ultra 60 motherboard (only the motherboard). Is it possible to adapt an ATX power supply to power this motherboard? How is the standard used in Sun computers called? The manual says: DC output 350W (maximum) Output 1 +3.3 Vdc, 50A Output 2 +5.0 Vdc, 30A...

Hi, I have a sm124 Atari hi-res monochrome monitor that produces an annoying buzz sound. It does not matter if the Atari is working or not. What can I do?

Hi, I have this SYS68k/CPU-6A rev 4.4 board. It uses VMEBus. Can I make a computer out of it? And connect through serial port to it? If I can power it on and make terminal only computer, it's still something. I have no idea what OS can run on it. Specification: • 68000 CPU ( 8MHz) on CPU-6...

Somebody is selling a bunch of DEC PDP 11s. From the photos it looks like PDP 11 / 73. What can you do with this computer? What software can you try on it? Is it only accessible through terminal, so no graphics, right? Is it hard to install the RSTS OS. Is there software for it? I think...

Does anybody have the schematics for this power supply? I could not find one. My friend tells me that with the voltages I get there can be a problem with one of the transistors, but we need the schematics to understand it better. There are 3 transistors in general. Apple part number is 614-0028.

Hi, I have replaced the internal barrel battery of my Commodore 386 with a new coin 3V battery, but I still get CMOS error and the computer can not keep its settings. I am using a 3V battery which actually goes to 3.6V when measured with the computer powered off. It is 3.7 when the computer is...

Hi, I just bought an Atari 1040 STE. It works OK, I can access the contents of floppy drives, etc. But when I try to run a game, it starts restarting endlessly. One game said that the Atari is in high resolution and it can not change to medium. I have a mono chrome SM124 monitor. So this...

Hi, I am testing this computer without a monitor. I do not have experience with these models. It should be similar model to Apple LC III. When I switch it on: - it starts buzzing (from the speaker) - no sound/chim (I think it should make one) - the ventilator in the center of the computer...

Hi, I have an old PowerBook 180. After 10 minutes of use dark spots start to appear on the screen in the corners. First on the left and then on the right. Please see photo below: It is dark, but still kind of visible (like inverted color). What is it? How can I fix it?

Hi, I am using 2 x 3V coin batteries to replace the 4 x 1.5V for the real time click of my Amstrad 1640. It seems like the 6V reach the motherboard, but still it does not keep the date after complete power off. I also use a fuse and a diode (to block incoming tension from the motherboard and to...

Hi, The motherboard is this one: https://www.arvutimuuseum.ee/th99/m/C-D/30355.htm So this motherboard has 3 types of chips for the memory: - 44256 x 8 - 41256 x 4 - sticks with edge connectors x 4 I get 640 kb of memory which is weird I think. In the table below I have the 3rd configuration...

Hi, I managed to oil the stepper motor and the tracks for the head movement and now it does not give a floppy error 40. Still it does not work. When I try to access it from DOS it gives a read error: "Abandon, Retry, Fail ...". It is correctly configured in the BIOS as I have another one that...

Hi, I bought a French Sanyo MBC 555. The keyboard is azerty in French. On other computers (not Sanyo) this is not a problem. Usually you can use an azerty keyboard as qwerty with a default English DOS version. I do not have the original French Sanyo MBC disks. So everything is switched...

I got an IBM 5154 monitor not long ago. It kind of works, because I can see the POST messages, but the picture is moving horizontally. Is it the horizontal sync? Here is a video and pictures: https://1drv.ms/u/s!AsoOXKPKfQ6FgtslzuxtA6OPTPaGcg?e=2eLvhm I have capacitor C6 removed from the...

I have a 5160 XT 64-256 motherboard. Last time I tried to swap the CPU with NEC 12 Mhz one and it did not work. So I tried the original one and it still did not work. Motherboard appear "dead". Procedures done so far: - minimum diagnostics setup does not work. - the CPU is OK, I tried it on...

I have this disk Miniscribe 8450 xt. It is from an Amstrad 1640. It is disk on a card. It appears dead. The spindle motor never turns. The motor is not blocked. I am able to turn it. The one thing I noticed is that all film capacitors give voltage except for one near the power input. All...

Hi, I am trying to fix a Seagate ST-225 type 2 hard drive. It is a 20 MB drive. The controller is 62X0775 with 4 switches. Problem: the drive is reported by the BIOS, but programs can not use it. Programs report problem with MBR. The BIOS does not report 1701 error. It reports a 601 floppy...

Hi, I am trying to fix my monitor. It seems like the horizontal sync is not OK. Things seem to be at the correct height. The monitor is Olivetti CDU 1200 D12CS63, Toshiba , feb 1986 from Olivetti M24 computer. The video card is OK. Here are some photos and a video...