The 78xx regulator is has a standard pinout, see the datasheet: Pin 1 is input, pin 2 ground and pin 3 output. If you have soldered it in the wrong way around there will be no regulated 12V output. http://pdf1.alldatasheet.com/datasheet-pdf/view/9044/NSC/7812.html On 30/06/2017 10:01 AM, Terry Raymond wrote: > Hi Mike, > > If I could please get your email address I can send you a pic of > The regulator, and at your convenience. > > Terry Raymond > > On Jun 29, 2017 6:47 PM, wrote: > >> Are the Tantalum capacitors also called ceramic capacitors >> are they a kind of tan color fairly flat 2pins? >> >> The regulator is new. >> >> The axial capacitor you mentioned read 7V wasn't 9V I tried a different >> one, same 7V >> >> Terry Raymond >> >> On Jun 29, 2017 7:02 PM, "Mike Stein" <email@example.com> wrote: >> >> I guess left & right are relative; looking at U59 from the top with the >> mounting tab facing away from you the writing should be right side up and >> input and output are left and right respectively. >> >> Sounds like the 5V side of the supply/switch/etc. are OK but something's >> wrong with the 12V side all right if your measurements are correct; 16V >> sounds about right for the input but the output should be 12V. Either U59 >> is fried or you have a short on the 12V line causing U59 to shut down (or >> both); often the culprit is a shorted tantalum capacitor but I can't look >> at a C128 board at the moment to look for a likely candidate. >> >> m >> >> >> ----- Original Message ----- >> >> *From:* Terry Raymond <firstname.lastname@example.org> >> *To:* email@example.com >> *Sent:* Thursday, June 29, 2017 8:05 PM >> *Subject:* C128 power up >> >> Hi Mike, >> >> Reguarding my C128 power up issue. >> >> CAP-C106. Only getting 7V. I changed it but no difference. >> >> 74LS. All of these are almost 5V on the pins you mention. >> >> U59 REGULATOR-. The spec sheet I found on this describes it this way: >> LEFT PIN=OUTPUT >> MIDDLE PIN=GND >> RIGHT PIN=INPUT >> >> I took a measurement using the center ground and you said right pin is 12V >> Reading right pin=ZERO VOLTS >> LEFT PIN=16V >> >> Terry Raymond >> >> >> >> Message was sent through the cbm-hackers mailing listReceived on 2017-06-30 03:00:02
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