[TechAssist] Re: Tektronix 485 Oscilloscope - Power Supply Cycling ON/OFF - FIXED
- From: Ed Gaidies <teltek@xxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Sun, 27 Feb 2005 00:57:53 -0500
Perry..
Same here.
But everyone approaches repairs to what they know.
As Wayne mentioned...I don't use it to full advantage.
-Ed-
Ed Gaidies
Tel-Tek Electronics
Est-1969
Ontario/Canada
teltek@xxxxxxxxxx
> From: Electric Medic <info@xxxxxxxxxxxxxxxxx>
> Reply-To: <techassist@xxxxxxxxxxxxx>
> Date: Sat, 26 Feb 2005 23:23:26 -0500
> To: <techassist@xxxxxxxxxxxxx>
> Subject: [TechAssist] Re: Tektronix 485 Oscilloscope - Power Supply Cycling
> ON/OFF - FIXED
>
> 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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>>>>>>>
>>>>>>> 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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