Have a 2467B. Suggestions please on very poor focus


Ronan
 

[Cross-posted to TekScopes2 and Tektronix]

Greetings!

I've acquired a 2467B, with no power-up error codes, but very poor focus. It has SN of BO50000+.

It's been in storage some years. I let it sit / powered on a couple days, same issue (as I expected). In the 2465B/2467B service manual, Preliminary Troubleshooting flowchart, I get past the 4'th step just prior to the PS test step, and now I have a decision to make.

Any experience with availability / sources of the CRT 154-0850-01 is appreciated -- having had some past experience with CRTs, and lack of diagnostics errors prior to the PS checks, time it has been in storage -- this "feels" like a soft/weak CRT. The traces don't appear to be distorted (rather are basically barely readable, totally out of focus).

As I assumed, I find no new / NOS tubes, I do see one seller on eBay/Greece -- they seem to go for between 75 and 300$ US. So, can be expensive.

As well, any ideas on the going price for a used 2467B such as this (unusable until the focus is fixed), is appreciated!

Opts 5H and 09.

There are no major cosmetic flaws, but the intensity control outer shell has fallen off.

Thank you !

Ronan
N. Cal.


Mark Vincent
 

Ronan,

Check the power supply voltages for d-c and ripple. The electrolytics, some resistors and several tantalums are known to give problems. Mr. Yachad of Condor Audio has a parts kit for the 2465/7 series with instructions. He will be glad to help you if you have questions. He is on this group. He is excellent with these series of scopes.

You can check pin 2 of U4310 to see if you have the -2kv. The heater supply can be checked at pins 1 and 14 of U4310 using a battery operated meter or VOM, e.g. Simpson 260, across the two pins to see if you have the 6,3VAC for the heater. Do NOT measure the heater voltage from ground to either pin 1 or 14! Pin 3 of U4310 should be about -2100V, Check TP4302 for -1100V, If these voltages are low, the power supply is suspect as it is common to both oscillator circuits. Replacing the parts in the power supply and elsewhere can make things work right that look bad before replacing. Your focus and dim trace likely will be right with the new parts. U4310 can be bad. The focus adjust should be from 0 to 15V on one side of R4435. Check the zeners, diodes and transistors in the focus circuit to confirm if any are bad. R4333 I will say is way out of tolerance. Mouser has radial types in 100meg. The 1/2W or 1W will work fine. The original carbon one could be 50, 60, etc. percent high or even open. The carbon one in my 2465B was 170meg. It was replaced with a new one. Here is the link for 1W types in stock: https://www.mouser.com/Passive-Components/Resistors/Film-Resistors/Thick-Film-Resistors-Through-Hole/_/N-7gz43Z1yzvvqx?P=1z0vkovZ1z0wsz3Z1z0wljo&Keyword=100+meg+resistor&FS=True. The 1/2W part number is: 588-MOX-300001006FE. The 1/2W is more expensive than the 1W.

The 2 100mfd decoupling electrolytics for the two oscillator circuits should be replaced with something like Nichicon ULD or UHE type. The kit mentioned above likely has these two in it. Mr. Y. can confirm this.

The RIFA caps are to be pulled out and replaced! Those I know are in the kit. Anyone on this group will attest to replacing these automatically/on-sight.

I hope you get this nice scope working right. It is a great scope.

Mark


 

On Tue, Jul 6, 2021 at 09:17 PM, Mark Vincent wrote:


Ronan,

Check the power supply voltages for d-c and ripple. The electrolytics, some
resistors and several tantalums are known to give problems. Mr. Yachad of
Condor Audio has a parts kit for the 2465/7 series with instructions. He will
be glad to help you if you have questions. He is on this group. He is
excellent with these series of scopes.

You can check pin 2 of U4310 to see if you have the -2kv. The heater supply
can be checked at pins 1 and 14 of U4310 using a battery operated meter or
VOM, e.g. Simpson 260, across the two pins to see if you have the 6,3VAC for
the heater. Do NOT measure the heater voltage from ground to either pin 1 or
14! Pin 3 of U4310 should be about -2100V, Check TP4302 for -1100V, If these
voltages are low, the power supply is suspect as it is common to both
oscillator circuits. Replacing the parts in the power supply and elsewhere can
make things work right that look bad before replacing. Your focus and dim
trace likely will be right with the new parts. U4310 can be bad. The focus
adjust should be from 0 to 15V on one side of R4435. Check the zeners, diodes
and transistors in the focus circuit to confirm if any are bad. R4333 I will
say is way out of tolerance. Mouser has radial types in 100meg. The 1/2W or 1W
will work fine. The original carbon one could be 50, 60, etc. percent high or
even open. The carbon one in my 2465B was 170meg. It was replaced with a new
one. Here is the link for 1W types in stock:
https://www.mouser.com/Passive-Components/Resistors/Film-Resistors/Thick-Film-Resistors-Through-Hole/_/N-7gz43Z1yzvvqx?P=1z0vkovZ1z0wsz3Z1z0wljo&Keyword=100+meg+resistor&FS=True.
The 1/2W part number is: 588-MOX-300001006FE. The 1/2W is more expensive than
the 1W.

The 2 100mfd decoupling electrolytics for the two oscillator circuits should
be replaced with something like Nichicon ULD or UHE type. The kit mentioned
above likely has these two in it. Mr. Y. can confirm this.

The RIFA caps are to be pulled out and replaced! Those I know are in the kit.
Anyone on this group will attest to replacing these automatically/on-sight.

I hope you get this nice scope working right. It is a great scope.

Mark
Hi Mark,
Ronan's 'scope works fine, generally, as can be seen in his video. Except for the Rifa caps, replacement of components isn't "compulsory" and even risky if one doesn't have the experience and tools needed to do quality work.

Raymond


 

Ronan,
We're seeing the principal reason for my dislike of cross-posting.
You're getting responses from people who are unaware of what has been achieved and established already.
I fell into the same trap by responding on TekScopes after my responses on TekScopes-2.

Raymond


Siggi
 

On Tue, Jul 6, 2021 at 3:25 PM Raymond Domp Frank <hewpatek@gmail.com>
wrote:

Ronan's 'scope works fine, generally, as can be seen in his video. Except
for the Rifa caps, replacement of components isn't "compulsory" and even
risky if one doesn't have the experience and tools needed to do quality
work.
I'd love to see that video, if only for reference to my 2467.


 

On Tue, Jul 6, 2021 at 09:41 PM, Siggi wrote:


On Tue, Jul 6, 2021 at 3:25 PM Raymond Domp Frank <hewpatek@gmail.com>
wrote:


Ronan's 'scope works fine, generally, as can be seen in his video. Except
for the Rifa caps, replacement of components isn't "compulsory" and even
risky if one doesn't have the experience and tools needed to do quality
work.
I'd love to see that video, if only for reference to my 2467.
Siggi,
I already complained about Ronan's cross-posting. His main thread is on TekScopes-2.
Here's the link to the video:

**** QUOTE ****
The following files have been uploaded to the Files area of the TekScopes2@groups.io group.

/Ronan_2476B_display_demo/20210706_090713.mp4

By: Ronan <bass.woofer@gmail.com>

Description:
Demo of issue Ronan / 2476B with the finest focus I can get, while increasing the Readout Intensity from min to Max, the indicator LEDs flash as they do when I press "A/B Trig"
*** UNQUOTE ***

Raymond


 

On Tue, Jul 6, 2021 at 09:52 PM, Raymond Domp Frank wrote:


Siggi,
I already complained about Ronan's cross-posting. His main thread is on
TekScopes-2.
Here's the link to the video:
That quote doesn't work, of course.
This should:

https://groups.io/g/TekScopes2/files/Ronan_2476B_display_demo/20210706_090713.mp4

Raymond


Mark Vincent
 

Raymond,

Thanks for letting me know the status of is scope. I did not know he had a video. I also am not on either of the other two groups. I only went by what was posted here. I do not know his level of experience or ones around him to help in person. Checking parts to confirm one way or another is one thing provided you know how and what to do. Changing is another.

Mark


Siggi
 

On Tue, Jul 6, 2021 at 3:55 PM Raymond Domp Frank <hewpatek@gmail.com>
wrote:

This should:


https://groups.io/g/TekScopes2/files/Ronan_2476B_display_demo/20210706_090713.mp4

Thanks, that does work. I was looking for a video link in the thread and I
totally missed the file upload notification. The video is pretty grainy,
and recording the CRT tends to blow out the traces. Between the two, I'd
say this looks about the same as my 2467.

I'm also in agreement with you on the evils of cross-posting.