Date   

Re: tektronix 475 help ic part

Roberto
 

I ask the group if the part is # 155-0049-01C
and an update of 155-0049-01 of my failed tektronix 475 pc board a8
Roberto


Re: tektronix 475 help ic part

Roberto
 

On Tue, Jan 22, 2019 at 10:33 PM, Jim Olson wrote:


For Roberto and group I checked the boards I have and found these IC's
155-0049-01 : 466
155-0049-01C : 475
155-0049-02 : 466
I am guessing that they are all usable in the 475 the higher last dash number
is an upgraded part?
it should have been an updated version but I'm not sure 155-0049-01C: 475
Roberto


Re: tektronix 475 help ic part

Roberto
 

yes, I tried to search on eBay but without success
thanks
roberto


Re: 2236 trace fades at higher sweep speeds

 

I suggest that the "bright line" auto-trigger doesn’t fire often enough for the sweep to be very visible at fast sweeps.

So feed the 'scope a signal that it can trigger on that will put one or more cycles of signal on screen at a given sweep rate. I think you will find it make a *big* difference.

Cheers
David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of 8850hp@gmail.com
Sent: 22 January 2019 19:05
To: TekScopes@groups.io
Subject: [TekScopes] 2236 trace fades at higher sweep speeds

Issue: The 'scope has good intensity at long sweep times, but when I switch it to fastersweeps, the trace fades away.

Troubleshooting so far:
I purchased the 2236 on ebay, as having no trace, so I have no long history with this scope.
When it arrived, I was able to get a trace, on both channels. So far, I have replaced the
Power Supply capacitors, focus resistors, the LVPS voltages and ripple is within spec.
I do not have a high voltage probe, so I can't measure the HV power supply. The Grid Bias
has been adjusted as per the manual.
The trace is nice (focused) and bright at lower sweep speeds (0.2 ms), and slowly fades
as the sweep speed is increased. The beam stays focused, as it fades. Without an input signal the trace can be still seen at the highest
sweep speed (0.05us). With an input signal, the trace can no longer be seen when sweep speeds are 2us, or faster.
I'm looking for suggestions on where to troubleshoot further.
Is this a Z axis problem, or a tube problem?
I have searched the forum, and can find similar problems, but not one very close to this one.


Re: tektronix 475 help ic part

Jim Olson <v_12eng@...>
 

For Roberto and group I checked the boards I have and found these IC's
155-0049-01 : 466
155-0049-01C : 475
155-0049-02 : 466
I am guessing that they are all usable in the 475 the higher last dash number is an upgraded part?

Jim O

On January 22, 2019 at 1:14 PM "Roger Evans via Groups.Io" <very_fuzzy_logic=yahoo.com@groups.io mailto:very_fuzzy_logic=yahoo.com@groups.io > wrote:


It's the 'sweep logic' IC that controls A, B sweep, trigger and hold off. They turn up quite regularly on eBay, typically $20 or so plus postage to Europe. They are used in several of the 7000 timebases, eg 7B50A, 7B80, 7B85 and others, so you might be lucky and find a scrap timebase plugin but even scrap units seem to fetch quite high prices.

Regards,

Roger



Re: 465B: Basic Restoration Tasks List For Long Life?

bbortnick@...
 

Now that the pre-amp board is out, I have found that unscrewing the back plates of the pots is not so hard. Just don't break anything else nearby on the board whilst turning the screw driver!


Re: 465 minor repairs - help requested

bbortnick@...
 

Hi,
Can anyone supply a photo of the wiring near the back of the BNC's - where I have a photo of the possibly bodgy wiring?
I have added another photo of an odd bare wire soldered to the outside of the coupling capacitors. It did not appear to be connected to anything. What's it for?
I have since removed the amplifier board for repairs. So far need a new resistor - a 51ohm 1/4 watt. Does the type matter? Also the burnt out CH bulb (type 2200, 5v 60ma I believe - Here's the Monoprice part: https://www.mouser.ca/ProductDetail/560-2200.)
Thanks for the help!


2236 trace fades at higher sweep speeds

Oliver Viitamaki
 

Issue: The 'scope has good intensity at long sweep times, but when I switch it to fastersweeps, the trace fades away.

Troubleshooting so far:
I purchased the 2236 on ebay, as having no trace, so I have no long history with this scope.
When it arrived, I was able to get a trace, on both channels. So far, I have replaced the
Power Supply capacitors, focus resistors, the LVPS voltages and ripple is within spec.
I do not have a high voltage probe, so I can't measure the HV power supply. The Grid Bias
has been adjusted as per the manual.
The trace is nice (focused) and bright at lower sweep speeds (0.2 ms), and slowly fades
as the sweep speed is increased. The beam stays focused, as it fades. Without an input signal the trace can be still seen at the highest
sweep speed (0.05us). With an input signal, the trace can no longer be seen when sweep speeds are 2us, or faster.
I'm looking for suggestions on where to troubleshoot further.
Is this a Z axis problem, or a tube problem?
I have searched the forum, and can find similar problems, but not one very close to this one.


Tektronix 1140A-- any interest?

Brad Thompson <bradthompsonaa1ip@...>
 

Hello--

I have a Tek "1140A Load Current Shunt Fixture", part no.
067-0764-00, which isn't documented but appears to be an
assortment of load resistors (some defective), switches and fuseholders.

If no one finds this of interest or value, I plan to use it to house a vacuum-tube curve
tracer project...
(http://www.dos4ever.com/uTracer3/uTracer3_pag0.html)

However, I'd feel remorseful if I dismantled this instrument only to learn
that someone in the group needed this item to complete a system or
a collection.

Please advise-- I'm a couple of weeks away from starting my project.

Thanks, and 73--

Brad AA1IP
or augment a collection.


Power Supply Extender Cables

JJ
 

Be careful when using the multi-wire flat rainbow color ribbon jumper cables with connectors already installed that you can buy on eBay for a few dollars to extend the 7000 power supply cables. I used them to extend the cables on my 7904 after hanging the power supply out the back end of the mainframe. I found 4 tantalum caps that were shorted on the rectifier board. After replacing the caps, things were working fine until about 5 minutes after power on when all hell would break loose in the low voltage regulator board power supplies and the trace would tear and go off screen. The cables worked well until I encountered the thermal problem - the low voltage regulator board's 54V power supply would have its ripple increase to about 6V after awhile, and all the other supplies would follow suit. TP1625 on the rectifier board would go from 40V to 125V. It should be adjusted to and stay at 40VDC (no plugins, etc) according to the Tek Power Supply spec.

I thought I had a thermal issue with another component but it turned out that the ribbon jumper that I used to extend one of the low voltage regulator cables (the cable that connects to the main board) was heating up to over 175 F according to my infra-red thermometer. After freezing the connector, the voltage went back down to 40VDC. Took me awhile to find it.
The Tektronix ribbon cables fit very tightly on the pins and the wire gauge is heavier - maybe 22ga or 24ga - whereby the eBay jumpers were 28ga and the connectors didn't fit anywhere as tightly on the pins - thus a high resistance connection.

I hope this helps someone.

John Justin


Re: tektronix 475 help ic part

Roger Evans
 

It's the 'sweep logic' IC that controls A, B sweep, trigger and hold off. They turn up quite regularly on eBay, typically $20 or so plus postage to Europe. They are used in several of the 7000 timebases, eg 7B50A, 7B80, 7B85 and others, so you might be lucky and find a scrap timebase plugin but even scrap units seem to fetch quite high prices.

Regards,

Roger


Re: tektronix 475 help ic part

Jim Olson <v_12eng@...>
 

Roberto I do not have my 475 book right now so need to know what is and which board it is on? I have a 475 disassembled for parts most likely I have it.

Jim O

On January 22, 2019 at 10:07 AM Roberto <iw5bsf@alice.it mailto:iw5bsf@alice.it > wrote:


I'm looking for how and failed ic part number 155004901 sweep ,
qservice he has no one
Roberto



Re: Unknown 545A plugin

C Smith
 

Not sure what u have, but I had a few of these clones bk in the day, and they were pretty much exactly like the text Tek CA plugin.
http://w140.com/tekwiki/wiki/Lavoie_LA-265-CA.
The other link shows, I think a very old Lavoie CA clone.
The ones I had were exactly like the tek plug-in, Spec's, manuals were about the same.
Wish I still Had! :-(


c smith
ka3bnn


tektronix 475 help ic part

Roberto
 

I'm looking for how and failed ic part number 155004901 sweep ,
qservice he has no one
Roberto


Re: Unknown 545A plugin

Bob Albert
 

I would guess LaVoie (sp?), who made Tek 500 series clones.
Bob

On Tuesday, January 22, 2019, 9:29:25 AM PST, iMac via Groups.Io <luispla=mac.com@groups.io> wrote:

Hi
The sticker looks pretty close.Probably is a Lavoie.
Thanks.


Re: Unknown 545A plugin

iMac
 

Hi
The sticker looks pretty close.Probably is a Lavoie.
Thanks.


Re: Unknown 545A plugin

Daniel Koller
 

Is this one of the Lavoie "clones"?  Others here might know exactly, but look on the wiki here:http://w140.com/tekwiki/images/d/dd/Lavoie_la-545-54b_2.jpg

You might send a photo to Kurt at the wiki page if there is not one up there already.
  Dan

On Tuesday, January 22, 2019, 12:10:38 PM EST, iMac via Groups.Io <luispla=mac.com@groups.io> wrote:

HI
Some time ago I bought a Tek 545A.Some days ago I start inspectig it before refurbishment and notated this strange plugin : PREAMP LA-545-54CA.
TekWiki has no info about it.Any ideas of the manufacturer?

There is a folder in the photos section.

Best regards from Spain.


Unknown 545A plugin

iMac
 

HI
Some time ago I bought a Tek 545A.Some days ago I start inspectig it before refurbishment and notated this strange plugin : PREAMP LA-545-54CA.
TekWiki has no info about it.Any ideas of the manufacturer?

There is a folder in the photos section.

Best regards from Spain.


Tektronix 2336YA Elapsed Time Indicator

Kevin Kolb
 

Where is the ETI on the 2336YA? I've looked in the operator and service manual but don't see it mentioned.

Thanks,
Kevin


Re: 2467B Trace flicker

 

In a previous post you described noise on the DIA signal and high frequency noise on the DI signal.  You have to quiet that noise before any other intensity measurements can be meaningful.  If DIA in noise free you can check the Z-axis by putting a test scope on The Z-Axis outputs (test points 65 and 66 in the service manual).  The Display sequencer and a few other parts CAN give you screen flicker but they don't put noise on DIA and they usually present other problems too.  So, if DIA is quiet, and test points 65 and 66 show proper waveforms with little noise in their amplitude, try other sweep speeds and see if the flicker "walks" across the screen.  
Step 1:  Obtain clean, noise free DIA signal.

On ‎Monday‎, ‎January‎ ‎21‎, ‎2019‎ ‎09‎:‎53‎:‎36‎ ‎AM‎ ‎CST, thespin@gmail.com <thespin@gmail.com> wrote:

Is there a good way to trace whether it's the z-axis hybrid, the display sequencer, or the front panel DAC subsystem?

On Fri, Jan 18, 2019 at 12:02 PM, victor.silva wrote:


Issues like you describe are usually related to a display sequencer (U650).
In my opinion I believe this is selected part.  I see many 2465Bs with the
display sequencer chip with a green thick magic marker line on it.
2445Bs do not normally have that mark on them.

--Victor

28581 - 28600 of 182379