Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.electronics.repair
|
|||
|
|||
about mac plus
i baught an old APPLE - MAC PLUS computer . i pluged it to 230 v ac .
nothing happened . so i opened the cover . i saw the fuse inside it had burst . so i changed a onw 5 amp fuse . and i powdered it ON . i saw spark of fire in POWDER/SWEEP board . and again the new fuse had burst . i think some component had burst too. so please give me an idea to repaire it . OR give me the circuit ,so that i can verify it... |
#2
Posted to sci.electronics.repair
|
|||
|
|||
about mac plus
wrote in message ups.com... i baught an old APPLE - MAC PLUS computer . i pluged it to 230 v ac . nothing happened . so i opened the cover . i saw the fuse inside it had burst . so i changed a onw 5 amp fuse . and i powdered it ON . i saw spark of fire in POWDER/SWEEP board . and again the new fuse had burst . i think some component had burst too. so please give me an idea to repaire it . OR give me the circuit ,so that i can verify it... Isn't 5A a bit large for the fuse? You may have caused further damage by installing too large a fuse. These are not difficult machines to work on, just use standard switchmode power supply troubleshooting procedures to track down defective components. You likely have a shorted rectifier or chopper transistor on the input side of the power supply. They're notorious for cooking flyback transformers as well. |
#3
Posted to sci.electronics.repair
|
|||
|
|||
about mac plus
James Sweet wrote:
wrote in message ups.com... i baught an old APPLE - MAC PLUS computer . i pluged it to 230 v ac . nothing happened . so i opened the cover . i saw the fuse inside it had burst . so i changed a onw 5 amp fuse . and i powdered it ON . i saw spark of fire in POWDER/SWEEP board . and again the new fuse had burst . i think some component had burst too. so please give me an idea to repaire it . OR give me the circuit ,so that i can verify it... Are you sure it was a 230 volt model? If it had been imported from the U.S. it was 120 volt only. Look for Larry Pina's book "Macintosh Upgrade and Repair Secrets". Where are you, I can lend you the tools and books, but I expect you are not nearyby. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838 Visit my 'blog at http://geoffstechno.livejournal.com/ |
#4
Posted to sci.electronics.repair
|
|||
|
|||
about mac plus
Many years since I used to fix these. But some ideas, BP cap on the video,LM??? chip in the video, GI??? diode in the video, Mis-jumped 120v, dead EHT ,(the little ones would blow, and were replaced by a physically larger unit that was also used in the SE which lasted.These faults were so common that you could buy kits of parts to fix them for the 128k,512k,plus and SE, of which I am sure I still have a few. If you have, or know where I can get one of the flybacks for these that would be cool, I realized I have a 512 kicking around with a bad one, last one I bought was over a decade ago and the place is out of business now. |
#5
Posted to sci.electronics.repair
|
|||
|
|||
about mac plus
Geoffrey S. Mendelson wrote:
James Sweet wrote: wrote in message ups.com... i baught an old APPLE - MAC PLUS computer . i pluged it to 230 v ac . nothing happened . so i opened the cover . i saw the fuse inside it had burst . so i changed a onw 5 amp fuse . and i powdered it ON . i saw spark of fire in POWDER/SWEEP board . and again the new fuse had burst . i think some component had burst too. so please give me an idea to repaire it . OR give me the circuit ,so that i can verify it... Are you sure it was a 230 volt model? If it had been imported from the U.S. it was 120 volt only. Look for Larry Pina's book "Macintosh Upgrade and Repair Secrets". Where are you, I can lend you the tools and books, but I expect you are not nearyby. Geoff. Many years since I used to fix these. But some ideas, BP cap on the video,LM??? chip in the video, GI??? diode in the video, Mis-jumped 120v, dead EHT ,(the little ones would blow, and were replaced by a physically larger unit that was also used in the SE which lasted.These faults were so common that you could buy kits of parts to fix them for the 128k,512k,plus and SE, of which I am sure I still have a few. regards Andrew |
#6
Posted to sci.electronics.repair
|
|||
|
|||
about mac plus
Andrew wrote:
But some ideas, BP cap on the video,LM??? chip in the video, GI??? diode in the video, Mis-jumped 120v, dead EHT ,(the little ones would blow, and were replaced by a physically larger unit that was also used in the SE which lasted.These faults were so common that you could buy kits of parts to fix them for the 128k,512k,plus and SE, of which I am sure I still have a few. The SE flyback transformer also had a built in drain to remove any remaining charge on the CRT anode. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838 Visit my 'blog at http://geoffstechno.livejournal.com/ |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|