[TechAssist] Re: Tektronix 485 Oscilloscope - Power Supply Cycling ON/OFF - FIXED
- From: becyn <becyn@xxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Mon, 28 Feb 2005 17:38:01 -0500
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 <alg@xxxxxxxxxxx>
>>>>Reply-To: <techassist@xxxxxxxxxxxxx>
>>>>Date: Thu, 24 Feb 2005 22:11:16 -0500
>>>>To: <techassist@xxxxxxxxxxxxx>
>>>>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: <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
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>--------------------------------------------------------------------
>>>>>>
>>>>>>
>>------
>>
>>
>>
>>>>>>>---
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
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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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>>
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>>>>>>Peter Neal
>>>>>>Neal Electronics
>>>>>>1905 E. Wm.Cannon
>>>>>>Austin,TX 78756
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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>>
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