Re: Tektronix 2335 Oscilloscope Repair
JW
<tm3ai497vrtb2dqku...@4ax.com>:
>
>
>I have a early 1980's era Tek 2335 here that is in need of repair. I
>know this is a somewhat scarce ruggedized military model, but it may
>be helpful if someone could tell me if there is a more standard model
>that this may be a clone of.
>
>I have many Tek service manuals, but not for this particular model.
>It would be great if I could troubleshoot from the manual of a
>slightly different model.
>
>Even advice would be helpful. The symptoms it displays are:
>
>Beam out of focus. Cannot sharpen, but does take some adjustment.
>Vertical adjustment does not work.
>Straight horizontal line, which does not change on Ch1 or CH2. No
>visible channel seperation.
>Does not respond to input of either AC or DC.
>Brightness varies with sweep frequency.
>
>I have another scope, so testing is not a difficulty.
Download the 86MB service manual here:
http://www.ko4bb.com/cgi-bin/manuals.pl?dir=Tektronix/Tektronix_-_2235
There's even a txt file with a possible solution for your scopes focus
problem:
http://www.ko4bb.com/Manuals/Tektronix/Tektronix_-_2235/Tektronix_2235_Poor_Focus_Problem_and_Solution.txt
----- Original Message -----
From: Jay Sario
To: TekS...@yahoogroups.com
Sent: Thursday, December 27, 2007 12:28 AM
Subject: [TekScopes] TEK 2235 no good focus
> hi to all,
> Would like to ask help from anybody. I recently got a used TEK-2235, I
> cant get a clear focus on the screen even if I rotate the "focus"
> knob, its always blurred. Hope anybody can share where I would check
> or what part to check...thank you and merry xmas to all.
Having a 2235 myself, I had found and saved this note from another
newsgroup:
>Between the hv multiplier (has CRT anode lead coming out of it) and the
>focus pot are two 1/2w resistors,510k ohm.Then behind the focus pot are
>four more 1/2w res,all lined up neatly in a row,also 510k ohms. These go bad frequently.
>Use carbon COMPOSITION type as replacements. The old ones change
>value,usually increasing in value.
Good luck! Adriano
JW
<fpeai4lc3tohrk1kh...@4ax.com>:
>On 20 Nov 2008 02:13:05 -0600 k...@netcene.com wrote in Message id:
><tm3ai497vrtb2dqku...@4ax.com>:
>
>>
>>
>>I have a early 1980's era Tek 2335 here that is in need of repair. I
>>know this is a somewhat scarce ruggedized military model, but it may
>>be helpful if someone could tell me if there is a more standard model
>>that this may be a clone of.
>>
>>I have many Tek service manuals, but not for this particular model.
>>It would be great if I could troubleshoot from the manual of a
>>slightly different model.
>>
>>Even advice would be helpful. The symptoms it displays are:
>>
>>Beam out of focus. Cannot sharpen, but does take some adjustment.
>>Vertical adjustment does not work.
>>Straight horizontal line, which does not change on Ch1 or CH2. No
>>visible channel seperation.
>>Does not respond to input of either AC or DC.
>>Brightness varies with sweep frequency.
>>
>>I have another scope, so testing is not a difficulty.
>
>Download the 86MB service manual here:
>http://www.ko4bb.com/cgi-bin/manuals.pl?dir=Tektronix/Tektronix_-_2235
Oops. I mis-read the model number. It's possible that the focus problem
may have the same solution, though...
JW
<creai4ho41b8i5dm3...@4ax.com>:
>Oops. I mis-read the model number. It's possible that the focus problem
>may have the same solution, though...
And if you get desperate:
http://yourmanualsource.com/
90 bucks though. Ouch.
Jim Yanik
>
>
> I have a early 1980's era Tek 2335 here that is in need of repair. I
> know this is a somewhat scarce ruggedized military model, but it may
> be helpful if someone could tell me if there is a more standard model
> that this may be a clone of.
No.there's the 2335,2336,2337;all one family.
An unusual scope,uses a lot of TEK-made ICs(sole source,NLA!),and difficult
to work on. Not a big seller like 465 or 7000 series.
I checked BAMA and one other manuals site,and neither had any of the 2300
manuals.
>
> I have many Tek service manuals, but not for this particular model.
> It would be great if I could troubleshoot from the manual of a
> slightly different model.
>
> Even advice would be helpful. The symptoms it displays are:
>
> Beam out of focus. Cannot sharpen, but does take some adjustment.
> Vertical adjustment does not work.
> Straight horizontal line, which does not change on Ch1 or CH2. No
> visible channel seperation.
> Does not respond to input of either AC or DC.
> Brightness varies with sweep frequency.
>
> I have another scope, so testing is not a difficulty.
>
>
--
Jim Yanik
jyanik
at
kua.net
JW
<l73ni410fqluctp7b...@4ax.com>:
>I finally set aside time and got inside the HV section.
>
>I found that the 2335 bears no simarity at all to the 2200 family as
>far as schematics and design.
>
>There are alot of specially made parts inside the HV section,
>including a thick film resistor combo.
>
>I may be able to bypass or jury rig something here, but I would need a
>copy of the schematic for the HV section. Are there any links to one?
Well, as I said before, yes. Unfortunately, it doesn't come cheap:
http://yourmanualsource.com/
Just be sure to ask them if it contains schematics before you purchase it.
There's some manual companies who sell service manuals without diagrams...
Jim Yanik
news:l73ni410fqluctp7b...@4ax.com:
> I finally set aside time and got inside the HV section.
>
> I found that the 2335 bears no simarity at all to the 2200 family as
> far as schematics and design.
>
> There are alot of specially made parts inside the HV section,
> including a thick film resistor combo.
>
> I may be able to bypass or jury rig something here, but I would need a
> copy of the schematic for the HV section. Are there any links to one?
>
> Many thanks in advance....
if you have no vertical deflection or positioning,why are you looking at
the HV section?
msg
> On 24 Nov 2008 23:30:01 -0600 k...@netcene.com wrote
<snip>
>
>> I would need a
>> copy of the schematic for the HV section. Are there any links to one?
>
>
> Well, as I said before, yes. Unfortunately, it doesn't come cheap:
> http://yourmanualsource.com/
>
> Just be sure to ask them if it contains schematics before you purchase it.
> There's some manual companies who sell service manuals without diagrams...
Posts like these continually appear and the answer is always the same, "buy
the manual"; if someone really does buy one, please consider scanning it and
posting the document somewhere for public download, perhaps the 'bama' site
or any other of your choosing -- help to mitigate the documentation problems
for older gear! Paper manuals will eventually become unavailable and businesses
selling copies may vanish as well; please help to make tech documentation a public
access resource.
Michael