You might be able to some help and maybe a schematic from this group: http://groups.yahoo.com/group/TekScopes/ I was lucky and found my schematic at Boat Anchors a web site with lots of old obsolete service manuals and stuff. David Lessard Alexandria, Ontario, Canada mr_fixit@xxxxxxxxxxxx ----- Original Message ----- From: "Electric Medic" <info@xxxxxxxxxxxxxxxxx> To: <techassist@xxxxxxxxxxxxx> Sent: Wednesday, February 23, 2005 10:32 PM Subject: [TechAssist] Re: Tektronix 485 Oscilliscope - Power Supply Cycling ON/OFF - FIXED > I wish I could get my 2216 repaired. I bought it new in 1996 and it died > last year, no power. It is just sitting on a shelf collecting dust, I > thought it was a lost cause. You mean you all actually repair these? > > Perry Bower > Electric Medic > "It's Cheaper to Keep Her" > http://www.electricmedic.com > Check out the Electronic Repair Screensaver We created. More Images to come! > To download these Collections you must first install the Eyetide Viewer: > http://www.eyetide.com/download/?s=O3OfmSLHXygGHCv1W6Gz3Bgjtq3DNNMNdcKsYSVGC > "We're Number One Where it Really Counts, With our Customers" > 3850 Washington Road Suite 5b > Martinez, Georgia 30907 > Phone: 706-8MEDIC4 (863-3424) > Phone: 706-863-3474 > Fax: 706-863-2316 > mailto:info@xxxxxxxxxxxxxxxxx > "WE REPAIR WITH CARE" > > > -----Original Message----- > From: techassist-bounce@xxxxxxxxxxxxx > [mailto:techassist-bounce@xxxxxxxxxxxxx]On Behalf Of David Lessard > Sent: Wednesday, February 23, 2005 10:18 PM > To: techassist@xxxxxxxxxxxxx > Subject: [TechAssist] Re: Tektronix 485 Oscilliscope - Power Supply > Cycling ON/OFF - FIXED > > > They sure are, I couldn't have traced this short without one. The (- 5V) > power distributes everywhere. This was a great experience for me, now I'll > be able to service this thing forever...oh yeah...most of the parts are > obsolete now...forgot this thing is 30+ years old. You couldn't tell by the > way it works. > > David Lessard > Alexandria, Ontario, Canada > mr_fixit@xxxxxxxxxxxx > > ----- Original Message ----- > From: <majorthom@xxxxxxxxxxxxx> > To: <techassist@xxxxxxxxxxxxx> > Sent: Wednesday, February 23, 2005 10:05 PM > Subject: [TechAssist] Re: Tektronix 485 Oscilliscope - Power Supply Cycling > ON/OFF - FIXED > > > > Aren't schematics great > > Pete > > David Lessard <mr_fixit@xxxxxxxxxxxx> wrote: > > FIXED > > > > These things are built like brick sh*! houses. After acquiring a schematic > I > > discovered a shorted C852 (.47uf) on the attenuator board - PS decoupling > > capacitor shorting (-5V) to ground. All power supply current is monitored, > > shorts or excessive loads cause the power supply to shutdown. In this case > > the power supply was restarting, over and over again, about 3 times a > > second. While I had it opened I cleaned all the switches and > > potientiometers. Signals look better then ever. > > > > David Lessard > > Alexandria, Ontario, Canada > > mr_fixit@xxxxxxxxxxxx > > > > ----- Original Message ----- > > From: > > To: > > Sent: Tuesday, February 22, 2005 1:23 AM > > Subject: [TechAssist] Re: Tektronix 485 Oscilliscope - Power Supply > Cycling > > ON/OFF > > > > > > > I love these old TEK's > > > On and on > > > I'm replying because I have the complete S/M [1" thick]Maybe I send you > a > > schema of a cktif you like > > > Regards, > > > Pete I mennt the 475A:they are very similar,Pete > > > Wally Heise wrote: > > > David, > > > > > > I don't know if the 485 is similar to the 465 scope, but my 465 died > last > > > year. I traced the problem to the sealed high voltage module which is no > > > longer available from Tektronix. My scope would power up when I removed > > > this module, except no high voltage of course. I still have service > manual > > > but gave the scope to a friend. Hope that helps in troubleshooting it. > > > > > > Wally Heise > > > South Isle Repair > > > Isle, Mn. > > > sirepair@xxxxxxxxxx > > > > > > > > > > > > ----- Original Message ----- > > > From: "David Lessard" > > > To: > > > Sent: February 21, 2005 7:31 PM > > > Subject: [TechAssist] Tektronix 485 Oscilliscope - Power Supply Cycling > > > ON/OFF > > > > > > > > > > Hello All, My week just got tougher, my scope failed today. I may need > a > > > scope to fix my scope. When powered "ON" I can hear the power supply > > > cycling - on/off/on, etc. The rear fan starts to spin and panel lights > > start > > > to light up but only when the power supply is on for that brief 1/2 > > second. > > > Would anyone have a schematic of the power supply or tips. > > > > Thank you, > > > > David Lessard > > > > mr_fixit@xxxxxxxxxxxx > > > > > > > > > > > -------------------------------------------------------------------------- > > > --- > > > > Lost Password: > > > > http://www.tech-assist.org and select "Login Problems?". > > > > Email Archives: > > > > //www.freelists.org/archives/techassist/ > > > > > > > > > > > > > > -------------------------------------------------------------------------- > > --- > > > Lost Password: > > > http://www.tech-assist.org and select "Login Problems?". > > > Email Archives: > > > //www.freelists.org/archives/techassist/ > > > > > > > > > Peter Neal > > > Neal Electronics > > > 1905 E. Wm.Cannon > > > Austin,TX 78756 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -------------------------------------------------------------------------- > > --- > > > Lost Password: > > > http://www.tech-assist.org and select "Login Problems?". > > > Email Archives: > > > //www.freelists.org/archives/techassist/ > > > > > > -------------------------------------------------------------------------- > --- > > Lost Password: > > http://www.tech-assist.org and select "Login Problems?". > > Email Archives: > > //www.freelists.org/archives/techassist/ > > > > > > Peter Neal > > Neal Electronics > > 1905 E. Wm.Cannon > > Austin,TX 78756 > > > > > > > > > > > > > > > > > > > > > > > > -------------------------------------------------------------------------- > --- > > Lost Password: > > http://www.tech-assist.org and select "Login Problems?". > > Email Archives: > > //www.freelists.org/archives/techassist/ > > > -------------------------------------------------------------------------- -- > - > Lost Password: > http://www.tech-assist.org and select "Login Problems?". > Email Archives: > //www.freelists.org/archives/techassist/ > > > -------------------------------------------------------------------------- --- > Lost Password: > http://www.tech-assist.org and select "Login Problems?". > Email Archives: > //www.freelists.org/archives/techassist/ ----------------------------------------------------------------------------- Lost Password: http://www.tech-assist.org and select "Login Problems?". Email Archives: //www.freelists.org/archives/techassist/