[TechAssist] Re: Tektronix 485 Oscilliscope - Power Supply Cycling ON/OFF - FIXED
- From: Kevin <kevintv@xxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Fri, 25 Feb 2005 23:43:16 -0800
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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>>>>>
>>>>>Peter Neal
>>>>>Neal Electronics
>>>>>1905 E. Wm.Cannon
>>>>>Austin,TX 78756
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
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>>>>Peter Neal
>>>>Neal Electronics
>>>>1905 E. Wm.Cannon
>>>>Austin,TX 78756
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