开云体育

I have a 581A Tek scope I saved from the dumpster. It turns out that it doesn't trigger any signal at all.

Worth looking into it?

--
Christoph

Congrats. Do you also have a PG506 ? And SG503?

--
Christoph

Hi to All,


With several TM506A's it seems handy to me to convert the SG5010 for operating in one of these. The SG5010 has a provision to replace the GPIB/PLL Board a little more inside the enclosure.



But when powering it on through a TM506A it doesn't restart. Powering ít down was the only option. The Module was completely non-responsive with all Lights and Full Display on.



It seems that TM506A's have a partly connected transistor (Q3005). In TM5003 and TM5006(A)'s this transistor provides the restart voltage. Normal TM500 Power Supplies don't have this transistor. I always thought the SG5010 has a special Voltage Divider as a replacement for the restart voltage in case of working in a TM500 Power Supply. But this Divider didn't work as intended in a TM506A. Anybody who knows the ins and out of this Q3005?




Greetings,


Egge Siert


NOOT: the SG5010 does work in a 620-0057-00 (OCP5502 Power Supply), which is a Modified TM503B Power Supply (Lowered Voltages and GPIB Connections).

Hi Neil,

I think you' d better follow Raymond's advice. In diagram <8> you can see that U870 needs the -8V supply to establish Vee. You (and I) probably have no idea what consequences an absent -8V (so 0V I suppose?) has for this IC. So first of all search the causes of the failing power supply lines!
It is not always true that a -02 version is immediately "better" than a -01 version. Sometimes surrounding components have to be changed as well. IIRC a terrible example are the many versions for a vertical amplifier IC in the 7904 scope, with a list of corresponding component changes and calibration instructions. The 067-0049-02 was introduced in the 465 at S/N B301600 and it was the only change at that S/N. So it seems that replacement of -01 by -02 is fine.
BTW please mention whether you have an "early" 465 (below B250000) or "late" 465 (B250000-up). There were several modifications and you preferably need a manual that covers your S/N.

Albert

Hi to All,

Only a renewal of this Post in case somebody missed it.


Greetings,


Egge Siert

Hi again,

It seems that nobody on this forum has this device and.or its Instruction/Data Sheet. Of course I will pay for this information. Therefore this request again.


Greetings,


Egge Siert

Thank you for all the help!

After changing all the caps on the inverter and regulator boards, the voltages are perfectly centered as per the spec. limits. Ripple is 10x smaller. Traces are more crisp (lower noise)?

Now I'll try to calibrate it (never done it before).
Recently purchased TG501 for that purpose...

Thanks,

Maxim

More postings are becoming contaminated with "line noise" like "#yiv7938461022 #yiv7938461022 -- #yiv7" etc. I presume it is a de-html-ed version of the adverts at Yahoo! appends to each posting.

While that doesn't reduce the value of the information in the post, it does look ugly.

Can I suggest that before posting we delete the advert at the end previous message, rather than include it in the reply.

HiThanks to everyone for their comments and thoughts, very much appreciated.I've found a Tek 2200 series brochure and it lists the following differences:
100MHz bandwidth (2230), 60MHz (2220,2221)4K record length (1K/4K selectable for 2230)pre/post triggering (Point selectable for 2230)Cursors and Readout (2221,2230)Signal averaging (2221,2230)One reference memory location(2220,2221), three locations (2230)Expand, compress, reposition stored waveforms (2230)Dual Timebase (2230)26K extended waveform storage option (2230)
I have concentrated on the electrolytics for now, simply because of the failure mode. A year ago, if I used it every day it would work fine, if I left it a month it would take a few power cycles to get past the X once it had been on for a few hours. Now it mostly goes to the X. This all suggests degrading caps to me, but I could be wrong.?I had assumed that in the absence of CRT readout the X was a deliberate error state, but the comments about it maybe being an alignment aid also make sense.?I'm going to replace all the 5V and 8.6V caps in the next few days and will also have a closer look at the digital board jumpers in the 2230 manual.
thanksStuart

[Non-text portions of this message have been removed]

I'm sure you can just file a flat even with the shaft installed on the scope.

ST

On Thu, Mar 31, 2016 at 5:08 AM, edbreya@... [TekScopes]
<TekScopes@...> wrote:

I'm not sure what the mechanical situation is here, but if setscrew grip is a problem, and the shaft assembly can be taken apart, you may want to grind or machine a flat on the shaft, then use the common type setscrew. Another option is to drill a dimple in the right place on the shaft for a pointy-type setscrew to fit into, giving better torque without too much compression force.

Ed

[Non-text portions of this message have been removed]



------------------------------------
Posted by: edbreya@...
------------------------------------


------------------------------------

Yahoo Groups Links

On 30 Mar 2016 16:33:28 -0700, you wrote:

The trace brightens up very quickly and no dips that I can see. It starts to widen just a little when turned all the way up ( I de-focused the trace and did that very quickly. Turning the intensity up high makes my skin crawl. ~shivers~ )

So it is not a problem with the CRT. When they get old, the trace
becomes both dim and less well focused because of lack of emission
from the cathode.

There is another possibility with the CRT though. If the oscilloscope
has been in storage for an extended time, I think trace gas can
accumulate in the CRT. Operating the oscilloscopes for hours to days
may clear this condition.

This happed with my 7603 which was not used for 10+ years. A couple
of days of leaving it running with a bright but defocused trace made a
marked improvement in brightness and focus.

If you do this, for now I would only leave the 465B running while
supervised in case something happens.

I'm not sure yet if I would try that. You say precharge resistor? In parallel with the HV capacitor?

The high voltage capacitor goes to the high voltage test point and a
high value resistor, like 10M, goes between the open end of the
capacitor and ground. That way when the high voltage starts, the
resistor bleeds charge from the capacitor until it reaches ground and
it becomes safe to apply your oscilloscope probe or voltmeter.

The only other gear on the bench is the leader scope and my Keithley DMM. Also I did power on the scope in a different room when I first got it.

I Disconnected the vertical CRT leads and the trace curved a little but it showed no difference in thickness. The vertical pins on the CRT look a little crusty to my eye. I'm going to double check for noise on the LV connections to the CRT and then check the physical connections.

With the deflection plate leads disconnected, a slight curvature in
the trace is expected.

Hello everyone. I was recently given an early 465 scope. It has a trace and seems to work somewhat, but needs some TLC. I'm new to oscilloscopes, so bear with me if I say something wrong.


This is an early 465, so I've posted the relevant schematic in the photos section in case it is not freely available.


While checking the voltages at the power supply, I noticed that the +120 is high (+155). All other voltages are OK. Looking a little further, I realized that SCR Q1514 has just been totally removed by someone. Reading the circuit description in the manual, it appears that this SCR is there to provide overvoltage protection. It also says that if Q1514 is destroyed, the +120 V supply can rise to +160.


So before I place an order, would you guys think that the missing Q1514 is the cause of the higher +120 voltage, or did the higher voltage cause it to blow? Should I be replacing some of the other components at the same time?


Any assistance would be greatly appreciated.

I'm not sure what the mechanical situation is here, but if setscrew grip is a problem, and the shaft assembly can be taken apart, you may want to grind or machine a flat on the shaft, then use the common type setscrew. Another option is to drill a dimple in the right place on the shaft for a pointy-type setscrew to fit into, giving better torque without too much compression force.

Ed

That's awesome. I'm assuming the -02 is an updated compatible design so
would prefer that version. Ill reply off list with details. Thank you!
On Mar 30, 2016 9:28 PM, "jerry massengale j_massengale@...
[TekScopes]" <TekScopes@...> wrote:

Hi,

I have one 155-0049-02 and will check my cabinets tomorrow to see if i
have a -01. It would be $15 shiped to lower 48. respond off list to
j_massengale@...

Jerry Massengale

-----Original Message-----
From: Neil Elver neil.elver@... [TekScopes] <
TekScopes@...>
To: TekScopes <TekScopes@...>
Sent: Wed, Mar 30, 2016 7:47 pm
Subject: Re: [TekScopes] Introducing myself and my Tek 465 Project

A cheap USB oscilloscope will work to check ripple however so will a
voltmeter set to AC mode.

What sweep IC are you referring to?

Thanks for the tip on ripple and testing with a voltmeter. I found that as
an option after some digging later but didn't know if it would be accurate
enough to make diagnosis.

The scorching hot IC is part number 155-0049-01 and called a 'sweep
generator.' Here's one source
but it seems to be unavailable from there and out of stock on another site
here: I believe it's
U870 in the manual and someone with a similar issue mentioned it here:



I've confirmed a dead -8 volts at the regulator so my next steps are to
test and likely replace the rectifier.But it's hard to keep up my
enthusiasm on careful part swapping if that IC is unobtanium. I'd be fine
fixing the power supply and waiting out availability but disappointing when
the part cross reference sheet has only 4 components that don't have a
common replacement!

Thanks for your help! I can tell after a half a day the brainpower in this
group is great and even if I have to put this Tek project on hold I'm sure
I'll get a working one soon.

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

Again. I got OCD bad about this.

I thought I had a viable glue/threaded insert repair going for my 1A4 var pot, it works well at room temperature but as soon as the scope warms up it loses grip.

This annoys me greatly. So I looked into the whole set screw thing, turns out there are many types...










I figure the cone point type would need less force to grip the shaft, therefore not putting so much force on the Delrin bond.



So now, off to finding cone point set screws and testing it. It looks like these might even help pots with the crack without needing a complex and unreliable hack.

Hi,


I have one 155-0049-02 and will check my cabinets tomorrow to see if i have a -01. It would be $15 shiped to lower 48. respond off list to j_massengale@...


Jerry Massengale

Hi Mac,
Since your response came so quickly, I couldn't resist to answer before going to sleep:

Barry describes (part of) his problem as follows:

Changing the vertical position of the trace definitely changes the height of the trace
as I move from bottom to top.

Only Channels 1 and 2 exhibit vertical linearity issues

The problem as described by you (Mac) from msgs. 89026:

My first complaint is the vertical channels 1 and 2 have a sawtooth noise on the trace.

Changing vertical position causes the sawtooth to appear and it grows as the trace is moved farther from center.

I interpreted Barry's description as a vertical trace compression problem, whereas in Mac's, I imagined a sawtooth superimposed on the trace with position-dependent amplitude. The compression (in CH1 and CH2) is the signature symptom for me to suspect U400. I don't want to make U400 into a scapegoat any more than necessary... -;(

Computer is going to sleep now, I'll follow within 20 seconds!

Raymond

My first post and description of the problem is in the archives as message number 89026,
dated Feb 23, 2013. The thread is 48 messages long and addresses the repair
and restoration of my 2465.

Thanks, I'll have a look tomorrow. It's 03:51 (AM) here...

Raymond

My first post and description of the problem is in the archives as message?number 89026, dated Feb 23, 2013.? The thread is 48 messages long and addresses the repair and restoration of my 2465.??

From: "hewpatek@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Wednesday, March 30, 2016 8:06 PM
Subject: [TekScopes] Re: 2465B U400 Availability?

? > I own a 2465 which exhibited non-linear vertical traces for Ch1 and Ch 2.

I traced the problem to failed -8 Volts from the LVPS. In particular, 1101.
I recapped and all was well. Still using the scope.

Thanks for that info, Mac. I based my response on what I remember of the (all too frequent) messages of vertical compression, from the middle increasing towards the top of the screen, for channels 1 and 2 only, as seen on this forum.
Did I miss your issue here?

Raymond



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That part is used in several early 7000-series time bases.
7B50A and 7B53A are examples. A while ago, while still available, these

plugins could be had for a few $$.

Thanks for the info - i may even buy a whole timebase to part out in the
worst case.

You may want to check the circuits around the IC before replacing because

it could be the victim of a failure, not the source.

Yes, i will be sure the surrounding circuits are perfect before plugging in
new. Thanks!