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Hi Raymond,

Yes I'm using a 1GHz bandwidth scope at 5GS/s. I've also tried looking at the output on a spectrum analyser, seems the largest peak is at 800MHz with many other harmonics of 200MHz/5nS.

I am thinking you could be right, someone's maybe 'got at' this unit and tried adjusting the filter and made it worse... I'm going to make up an extender board so I can try adjusting it as per the service manual.

- Keith

BTW the pulse amplitude specs are on page 1-1 in the Service Manual. TG501’s I’ve seen easily meet those specs.

Raymond

On Tue, Jan 28, 2025 at 05:13 PM, Keith wrote:

I'm wondering if it is CR515 or something else. If I measure the amplitude
(Vpp) I see:
10nS - 1.480v
5nS - 0.820v
2nS - 0.724v
1nS - noise (10mV or less)

I'd expect the 5nS output to be similar to the 10nS (and slower) markers?

Hello Keith,
You don't mention which RTM3000 you're using. They start out at 100MHz bandwidth but from your amplitude info, I guess that's not your model...
Do you have a TG501 service manual?

I haven't experienced nor read about a failed CR515.
It has always been (one or a combination of) expecting to see the 1ns pulse on - say - a 100MHz BW 'scope, incorrect filter adjustment, not using the correct (1ns only) output of the TG501, trigger problem, bad/intermittent contacts on the PCB, leading to incorrect filter adjustment. The 1ns adjustment has a big influence. Maybe someone using the wrong 'scope has been in there before you?

I just checked one of my TG501's

On a Tek 7904/7A19 (500MHz nominal BW):
10ns 1.5V
5ns 1.1V
2ns 0.9V
1ns 50mV

On a Tek 7000/S-4 sampling 'scope (<=75ps nominal rise time):
2ns 1.05V
1ns 0.35V

If no other explanation, try filter adjustment, following the service manual. It's not difficult, *if* you have the right 'scope...

Raymond

That new meter scale looks great!

Get service manual.

Check all LV PS voltages.

Follow HV PS and CRT checks and service.

Most likey HV mult, high R resistors, HV transformer.

Unlikey that CRT is bad.

Jon

I'm wondering if it is CR515 or something else. If I measure the amplitude (Vpp) I see:
10nS - 1.480v
5nS - 0.820v
2nS - 0.724v
1nS - noise (10mV or less)

I'd expect the 5nS output to be similar to the 10nS (and slower) markers?

Hello all,

I’ve been searching for repair information regarding a Tektronixs 465 oscilloscope and found this interesting website.
So, I just registered and like to introduce myself.

I’m Wilfred, 62 years old and living in the Netherlands.
My interests are electronics, in particular restoring the good old tube televisions and radio’s, Oldtimer cars and general technical things.

Recently I found a Tektronix 465 scope in a fairly good shape, with some issues though, but in a working condition.
The 100:1 attenuator on channel B needed replacement, capacitor C1552 as well.
Anyway, at some point I noticed that the beam was intermittent blurry due to the astigmatism.
Astigmatism could be adjusted but not within reach of the potentiometer.
It was even so that the scope reacted strange when I turned the potentiometer to one side, the illumination of the small light bulbs went too dark and also the beam disappeared.
Voltage on the grid seems to be okay, 0-110 V depending on adjustment.

I’m afraid that the picture tube has an shortage issue between grids, but like to know from the members experience if this would be he case indeed.

Thanks a lot for any reply and have a great day !

Wilfred

On Mon, Jan 27, 2025 at 02:06 PM, zenith5106 wrote:

I have it and just scanned it.
It is here for a while:

If someone wants to upload it to TekWiki, go ahead.

Fantastic ... thank you!

I just became aware, that I - erroneously - answered on a very, very old thread.
However, the subject - 502A HV transformer offerd on ebay - might be interesting to some members here.

--
Stefan

Hello Martin,
there is one 120-0150-00 in the German ebay, .
It is expensive and looks not very good (aged/damaged in storage?) - but might be never installed - look at the cables.

--
Stefan

On Mon, Jan 27, 2025 at 01:49 AM, vk2bea wrote:

Does anyone have a scan of "24X58/2467B GPIB (Option 10) instrument Interfacing Guide

I have it and just scanned it.
It is here for a while:
If someone wants to upload it to TekWiki, go ahead.

/H?kan

My headache is gone. There was a problem with the cable between the voltage sensor and the scope.

The signal source in my case is a R&S radio test set. This is connected through an insertion voltage sensor (R&S URV5-Z2). After a frequency change I've compensated the ripple manually on the test set with the reading of the rf-voltmeter (R&S URV5).

Using a 1GHz scope (RTM3000) which should be able to see it.

wich scope are you using to see the 1ns pulse?, I think that you need a 1ghz scope if I recall correctly. I have a TG501, with a 500Mhz scope (TDS5054) I don?t see the 1ns pulse, but with the 7s14 it works.

On Mon, Jan 27, 2025 at 1:06?PM Sigur?ur ?sgeirsson via groups.io <siggi=
[email protected]> wrote:

Hey Neil,

I believe the 50Ohm resistor is in the top left corner of this picture:
/g/TekScopes/photo/12814/163755/Ceramic%20substrate.

I should note that the easiest way to diagnose these from the outside is to
measure the DC resistance from BNC center to shell. In DC coupling, 1M it
should be a megaohm within 1%. In 50Ohm coupling it should be 50Ohm.

The GND coupling on these attenuators is "faked". Essentially this engages
AC coupling, 50Ohm termination and 100X attenuation, which attenuates the
input signal through the pre-charge resistor against the 50Ohm terminator,
and then by a further 100X.

It is possible that what you're observing is that the first relay is not
making contact to DC couple the signal into the attenuator, in which case
you'd see an effective infinite DC resistance.

Hey Neil,

I believe the 50Ohm resistor is in the top left corner of this picture:
/g/TekScopes/photo/12814/163755/Ceramic%20substrate.

Siggi

On Mon, Jan 27, 2025 at 9:51?AM NEIL YUENGER via groups.io <nyuenger=
[email protected]> wrote:

Correction, I am only referring to the 2465 scope.
I incorrectly mentioned a 2245 which I do not own.

Since it's being used as a frequency multiplier, I expect it's a step-recovery (snap-off) diode. If I had to improvise, I'd try a varicap diode because I heard that they have some step-recovery behavior.

FWIW,
Dave Wise

________________________________
From: [email protected] <[email protected]> on behalf of Keith <keith@...>
Sent: Monday, January 27, 2025 9:32 AM
To: [email protected] <[email protected]>
Subject: Re: [TekScopes] 152-0536-00 hot carrier diode

Appreciate that Miguel but that's for 33, I just need 1!

Appreciate that Miguel but that's for 33, I just need 1!

On Mon, Jan 27, 2025 at 08:22 AM, Keith wrote:

Hot Carrier,

152-0536-00

CR515 152-0536-00 SEMICOND DEVICE:SILICON,HOT CARRIER,4V 80009 152-0536-00

In case anyone is interested, I have created artwork to replace my faded 130 L-C scale.

/g/TekScopes/photo/300288/3879649

I cut a 26SWG brass backing plate, preferring to keep my original for another day.