Arths Posted October 10, 2017 Report Share Posted October 10, 2017 (edited) Hey guys, Had an Apple IIc for almost 3 years but it did not came with a power brick. So I decided to buy a Toshiba charger transformed into a IIc power brick off eBay, the problem is when I'm turning on the computer the green power light is blinking and I'm not getting any startup beep. The disk drive is not running as well. Any ideas ? Best regards Edited October 10, 2017 by Arths Quote Link to post Share on other sites
bibilit Posted October 10, 2017 Report Share Posted October 10, 2017 What kind of PSU have you been sold ? Original item is 12 Vdc at 1.2 A Quote Link to post Share on other sites
Arths Posted October 10, 2017 Author Report Share Posted October 10, 2017 (edited) This is the one that I bought http://www.ebay.com/itm/221294478704 Maybe I'm not using the right cable for the other hand, I'll buy a new one and try again Edited October 10, 2017 by Arths Quote Link to post Share on other sites
xboxown Posted October 10, 2017 Report Share Posted October 10, 2017 This is the one that I bought http://www.ebay.com/itm/221294478704 Maybe I'm not using the right cable for the other hand, I'll buy a new one and try again What is wrong with the old fashion Apple //c original brick sized power supply? Quote Link to post Share on other sites
Juror22 Posted October 10, 2017 Report Share Posted October 10, 2017 The two that I could see in the photos were 15V. I would check the outputs with the a voltmeter. Quote Link to post Share on other sites
bibilit Posted October 11, 2017 Report Share Posted October 11, 2017 Or maybe something is faulty on the other side of the PSU. Quote Link to post Share on other sites
Elfen Posted November 19, 2017 Report Share Posted November 19, 2017 How is the Toshiba PSU connected to it? Check your connection and your PSU, I do not think it is strong enough to run a IIc. The IIc needs 12 - 15 volts, you can run off a Lead Gel Battery if in a pinch. It is a Power Hog. Check.this video out: Includes a pin out for the power port for you to verify. Quote Link to post Share on other sites
Arths Posted January 22, 2018 Author Report Share Posted January 22, 2018 (edited) Okay guys, sorry for the late response. I’ve been very busy for the last few months but finally got a my hands on a multimeter Well everything seems to be okay concerning the 15V power pins. I guess there must be something wrong with the internal power converter Interestingly enough it sometimes seems to be starting up, floppy drive led is solid red and I can hear the speaker cracking a little bit but nothing more.. Maybe dead condos ? Cheers Edited January 22, 2018 by Arths Quote Link to post Share on other sites
Arths Posted November 3, 2018 Author Report Share Posted November 3, 2018 Well, I’ve replaced the internal power supply as well.. same problem. I guess the computer is dead Quote Link to post Share on other sites
bibilit Posted November 7, 2018 Report Share Posted November 7, 2018 Hi, Keep in mind that the power supply is connected to the internal one : Not saying this is the issue, but as you have a blinking led some outputs are present... Quote Link to post Share on other sites
Arths Posted November 8, 2018 Author Report Share Posted November 8, 2018 I’ve replaced this one too.. Quote Link to post Share on other sites
bibilit Posted November 10, 2018 Report Share Posted November 10, 2018 have you tried without disk drive ? A short somewhere ? Quote Link to post Share on other sites
Arths Posted September 1, 2019 Author Report Share Posted September 1, 2019 On 11/10/2018 at 8:35 AM, bibilit said: have you tried without disk drive ? A short somewhere ? Sorry for the late response Yes I’ve tested without a disk drive and it still won’t boot. What should I check first ? Is there a place on the board where I can check that the voltages are the ones I shall receive ? Thanks for your patience Quote Link to post Share on other sites
bibilit Posted September 2, 2019 Report Share Posted September 2, 2019 I will run a multimeter, with no power connected, and see if a capacitor is not shorted. You have got two just below the psu connector and one above. Also a transistor nearby. Use the continuity test. Quote Link to post Share on other sites
Arths Posted September 2, 2019 Author Report Share Posted September 2, 2019 Thanks for your reply, I will try that as soon as I get home Already measured the 7905 chip and I’m getting voltage in expected ranges, is it a good sign ? Quote Link to post Share on other sites
bibilit Posted September 2, 2019 Report Share Posted September 2, 2019 Yes. The 7905 is the negative regulator. What about the remaining rails ? Quote Link to post Share on other sites
Arths Posted September 2, 2019 Author Report Share Posted September 2, 2019 (edited) 6 hours ago, bibilit said: Yes. The 7905 is the negative regulator. What about the remaining rails ? Here are my results Capacitors C57 shows zero C44 and C43 shows infinite when speaker is unplugged, .845 when it is Rails Thanks a lot Edited September 2, 2019 by Arths Quote Link to post Share on other sites
Arths Posted September 2, 2019 Author Report Share Posted September 2, 2019 Ok, RalfK from Apple Fritter asked me to test FFF and all I get is zero Quote Link to post Share on other sites
Arths Posted September 13, 2019 Author Report Share Posted September 13, 2019 Hey guys, Turns out it was the LM311N chip which was causing the blinking power light. Soldered a new one and blinking is gone but it still doesn't want to boot. Hooked the IIc using the composite output and here is what I get.. Sometimes I get scrolling characters instead like so Holding CONTROL-RESET makes the scrolling stop so I guess the CPU at least understands the keypresses. Any idea ? Thanks, Arths Quote Link to post Share on other sites
bibilit Posted September 13, 2019 Report Share Posted September 13, 2019 This is due to bad ram chips probably one or more chips imho. Piggybacking new ones can help Quote Link to post Share on other sites
Arths Posted September 13, 2019 Author Report Share Posted September 13, 2019 (edited) Might be a possibility, RAM chip are MT4264 right ? I've read online that I can also use 4164 chips. Edited September 13, 2019 by Arths Quote Link to post Share on other sites
bibilit Posted September 13, 2019 Report Share Posted September 13, 2019 Yes 4264-15 Quote Link to post Share on other sites
Arths Posted September 13, 2019 Author Report Share Posted September 13, 2019 Just now, bibilit said: Yes 4264-15 Mine uses TMS4164, must be an early revision of the IIc. According to this site, they should be compatible anyway. Ordered five chips from AliExpress, they should arrive in 2 to 3 weeks. Thanks for your advice Quote Link to post Share on other sites
Arths Posted October 7, 2019 Author Report Share Posted October 7, 2019 (edited) Hi guys, Just received the chips, tried piggybacking but that doesn’t seem to change anything. Maybe there are specific chips I shall try this method on ? If you have any idea, please let me know Thanks Edit : Piggybacking F18 makes horizontal white bars but that's it Arths Edited October 7, 2019 by Arths Quote Link to post Share on other sites
bibilit Posted October 7, 2019 Report Share Posted October 7, 2019 Problem is you can have more than one faulty unit. Sometimes not easy to troubleshoot, but a slight change can indicate the faulty chip Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.