[TechAssist] Re: Tektronix 485 Oscilloscope - Power Supply Cycling ON/OFF - FIXED
- From: "majorthom@xxxxxxxxxxxxx" <majorthom@xxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Mon, 28 Feb 2005 21:53:11 -0800 (PST)
Scopes impress customers-if there were any
Neo
Jerome Silverman <greentron@xxxxxxx> wrote:
Sometimes I am using two dual channel scopes at the same time to see what is
going on. Always wanted a memoscope but they are too dear.
Jerry Silverman
Greentron Inc
4 Newland Ave Greenville SC 29609
Fax/Phone 864 232 3889
greentron@xxxxxxx
----- Original Message -----
From: "becyn"
To:
Sent: Monday, February 28, 2005 5:38 PM
Subject: [TechAssist] Re: Tektronix 485 Oscilloscope - Power Supply Cycling
ON/OFF - FIXED
> JEEZ! what do you guys do with the scopes? You must unplug them
> and put them back in the box after every use!
> Mine is just as handy as the multimeter, always on in standby mode...that
> is , single trace mode which basically kills the trace until I need to
> see it.
> One channel has a standard x10,100mhz probe on it, the other has an HV
> probe. Both are "grab and go", just like the multi...what setup time are
> you referring to?
>
> Jim McVey
> McVey Alltronix
> 327 Broadway
> Newburgh N.Y. 12550
>
> "If it doesn't play...
> CALL MCVEY !!!!!!"
> Factory authorized
> service for over 20
> major brands.
> 845 561 8383
> (Last of the Mohegans)
>
> Electric Medic wrote:
>
> >I'm Sorry, but I don't have time to hook up a scope everytime I change a
> >H.O.T. I only use our scopes for audio problems, and that is rare when a
> >scope is needed. I could drag out a service manual and all sorts of test
> >equipment, scopes, volt meters, display color bars, etc but if I can fix
the
> >unit without all of that, I will. Now if some field rep, or especially
the
> >newspaper comes by then I can hook the TV up to more equipment and really
> >make it look good, but not the norm. Pretty much if you change the cap in
> >the driver circuit especially on Sanyo's and solder up the driver
> >transformers you fix about 85% of blown H.O.t's. Except on the RCA's,
CTC195
> >and CTC197's where you usually have a bad flyback. On the 203's you
usually
> >have a bad solder conn. on the drive coil. I have never used a scope on
> >those and have fixed I think every blown H.O.T on every brand set I have
> >come across. As far as the Sony's if you check all VDR's and especially
the
> >6. something ohm resistor and do a good solder up of the horizontal
circuit,
> >q601 and q602 hold up just fine unless you had a surge of some kind, then
> >you might need the scope. We have three scopes in the shop and I use ours
> >mainly just with audio problems, never had too in low or high voltage
power
> >supplies. So, I guess we all do have many different ways of
troubleshooting.
> >
> >Perry Bower
> >Electric Medic
> >"It's Cheaper to Keep Her"
> >http://www.electricmedic.com
> >3850 Washington Road Suite 4C
> >Martinez, Georgia 30907
> >Phone: 706-8MEDIC4 (863-3424)
> >Phone: 706-863-3474
> >Fax: 706-863-2316
> >mailto:info@xxxxxxxxxxxxxxxxx
> >
> >
> >
> >-----Original Message-----
> >From: techassist-bounce@xxxxxxxxxxxxx
> >[mailto:techassist-bounce@xxxxxxxxxxxxx]On Behalf Of Gary McCartney
> >Sent: Saturday, February 26, 2005 9:55 AM
> >To: techassist@xxxxxxxxxxxxx
> >Subject: [TechAssist] Re: Tektronix 485 Oscilliscope - Power Supply
> >Cycling ON/OFF - FIXED
> >
> >
> >Every time I change a HOT or a flyback, I connect my scope to the HOT
> >collector and view the waveform as the set fires up. If I see something
> >abnormal, it gets unplugged in a hurry. I don't understand how anyone
> >can go on without using a scope. What about the Sony power supplies with
> >the shorted Q601- Q602, don't you check if the square waves are
> >symetrical at low AC before you fire up the set at 120V? Ripple in power
> >supplies? Proper horizontal drive? etc. etc. etc.
> >
> >
> >
> >
> >Gary McCartney
> >
> >McCartney Electronics
> >Guelph Ontario Canada
> >Est. 1984
> >email: gary (at) number63.ca
> >
> >
> >
> >
> >
> >
> >
> >Kevin wrote:
> >
> >
> >>How would you test for shorted transistors, IC's and diodes? How would
> >>you test resistors that have changed value? I use my scope about once
> >>every two years. It is interesting how we all repair things in
> >>different ways. I guess it all comes down to what tools we feel
> >>comfortable using.
> >>
> >>Kevin Wilks
> >>Kevin's TV & Video Repair
> >>Penticton BC Canada
> >>kevintv@xxxxxxx
> >>
> >>
> >>-----Original Message-----
> >>From: techassist-bounce@xxxxxxxxxxxxx
> >>[mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of Al Gutz
> >>Sent: Friday, February 25, 2005 8:23 PM
> >>To: techassist@xxxxxxxxxxxxx
> >>Subject: [TechAssist] Re: Tektronix 485 Oscilliscope - Power Supply
> >>Cycling ON/OFF - FIXED
> >>
> >>
> >>My Tektronic is my main peice of test equippment.
> >>If I had to give up either scope or DDM, for me it would be DDM. I can
> >>measure voltage if needed with scope, cannot look at a waveform on a
> >>meter.
> >>
> >>Al G
> >>
> >>
> >>Ed Gaidies wrote:
> >>
> >>
> >>
> >>>Al;
> >>>Sorry to say...these days, providing you know what your scope should
> >>>show...and actually getting a Manual for scope traces..mine has
> >>>
> >>>
> >>gathered
> >>
> >>
> >>
> >>>dust.
> >>>
> >>>
> >>>
> >>>-Ed-
> >>>
> >>>teltek413@xxxxxxxxxxxx
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>>From: Al Gutz
> >>>>Reply-To:
> >>>>Date: Thu, 24 Feb 2005 22:11:16 -0500
> >>>>To:
> >>>>Subject: [TechAssist] Re: Tektronix 485 Oscilliscope - Power Supply
> >>>>
> >>>>
> >>Cycling
> >>
> >>
> >>
> >>>>ON/OFF - FIXED
> >>>>
> >>>>A new Tektronix TDS224 100 meg 4 channel with accessories runs about
> >>>>$5000, why not repair.
> >>>>Al G
> >>>>
> >>>>Electric Medic wrote:
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>>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=O3OfmSLHXygGHCv1W6Gz3Bgjtq3DNNMNdc
> >>>>>
> >>>>>
> >>KsYSVGC
> >>
> >>
> >>
> >>>>>"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:
> >>>>>To:
> >>>>>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 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?".
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> >>>>>>>
> >>>>>>>
> >>>>>>>Peter Neal
> >>>>>>>Neal Electronics
> >>>>>>>1905 E. Wm.Cannon
> >>>>>>>Austin,TX 78756
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>--------------------------------------------------------------------
> >>>>>>
> >>>>>>
> >>------
> >>
> >>
> >>
> >>>>>>---
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>>Lost Password:
> >>>>>>>http://www.tech-assist.org and select "Login Problems?".
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> >>>>>>>//www.freelists.org/archives/techassist/
> >>>>>>>
> >>>>>>>
> >>>>>>--------------------------------------------------------------------
> >>>>>>
> >>>>>>
> >>------
> >>
> >>
> >>
> >>>>>---
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>>Lost Password:
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> >>>>>>
> >>>>>>
> >>>>>>Peter Neal
> >>>>>>Neal Electronics
> >>>>>>1905 E. Wm.Cannon
> >>>>>>Austin,TX 78756
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>--------------------------------------------------------------------
> >>>>>>
> >>>>>>
> >>------
> >>
> >>
> >>
> >>>>>---
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>>Lost Password:
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> >>>>>
> >>>>>---------------------------------------------------------------------
> >>>>>
> >>>>>
> >>-------
> >>
> >>
> >>
> >>>>>-
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> >>>>>
> >>>>>
> >>>>----------------------------------------------------------------------
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> >>
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> >>
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> >>>
> >>>
> >>>
> >>>
> >>>
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>>--------------------------------------------------------------------------
> >>
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>
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Peter Neal
Neal Electronics
1905 E. Wm.Cannon
Austin,TX 78756
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