Re: 2247A Channel 1 issue

#80852

Thanks, thanks the info I was looking for. I started getting into the schematic last night I saw the path to U506. Will start checking it out.

Also notice just letting the scope run with the probe attached the attenuation factor jumps back and forth- correct / incorrect. Does not change with no probe attached so it is getting an intermitant signal.

KT

Show quoted text

--- In TekScopes@..., "Tom Jobe" <tomjobe@...> wrote:

Maybe start by looking at the #1 "Vertical Inputs" schematic to see the simple circuit which starts at the junction of R101, C101 and R105 for channel 1.
That junction point is connected to the readout ring behind the BNC connector, so you could test for continuity and shorting to ground, etc.
If you compared both ends of  R101 and R105 (Chan 1) with those of R102 and R106 (Chan 2) you might see if the readout voltage is getting that far.
If that looked okay, you could go to U506 and see if it arrives at pins 12 and 15 as you would expect.
With the scope on its back, you have excellent access to all of these resistors and U506 (16 pin DIP), with the blue outer cover slid back the width of your hand.
From reading the service manual, it appears that the readout signal gets changed to a digital signal at U506, but is a simple voltage up to U506.
tom jobe...

  ----- Original Message -----
  From: lldskjfoi
  To: TekScopes@...
  Sent: Wednesday, September 19, 2012 9:08 PM
  Subject: [TekScopes] Re: 2247A Channel 1 issue

  Some more checking shows channel 1 is not getting the code signal from the probe. Any idea on this circuit?

  KT

  --- In TekScopes@..., "lldskjfoi" <k.templin@> wrote:
  >
  > Hello everyone.
  >
  > Initial test show an issue with channel 1.
  >
  > Any direction on where to start?
  >
  > Channel 2 displays inputs correctly from the FG.
  >
  > Channel 1 displays 10 times the amplitude for the same signal.
  >
  > Example a 1 volt sine wave on channel 2 displays on the voltmeter function correctly at ~1v and 2 divisions at .5v / div.
  >
  > The same signal on channel one reads as ~10v. When set to 5v / div it fills two div.
  >
  > Thanks, KT
  >

Re: 2247A Channel 1 issue

Tom Jobe

#80851

开云体育

Maybe start by looking at the #1 "Vertical Inputs" schematic to see the simple circuit which starts at the junction of R101, C101 and R105?for channel 1.

That junction point is connected to the readout ring behind the BNC connector, so you could test for continuity and shorting to ground, etc.

If you compared both ends of? R101 and R105 (Chan 1)?with those of R102 and R106 (Chan 2) you might see if the readout voltage is getting that far.

If that looked okay, you could go to U506 and see if it arrives at pins 12 and 15 as you would expect.

With the scope on its back, you have excellent access to all of these resistors and U506 (16 pin DIP), with the blue outer cover?slid back the width of your hand.

From reading the service manual, it appears that the readout signal gets changed to a digital signal at U506, but is a simple voltage up to U506.

tom jobe...

?

Show quoted text

----- Original Message -----

From: lldskjfoi

To: TekScopes@...

Sent: Wednesday, September 19, 2012 9:08 PM

Subject: [TekScopes] Re: 2247A Channel 1 issue

?

Some more checking shows channel 1 is not getting the code signal from the probe. Any idea on this circuit?

KT

--- In TekScopes@..., "lldskjfoi" wrote:
>
> Hello everyone.
>
> Initial test show an issue with channel 1.
>
> Any direction on where to start?
>
> Channel 2 displays inputs correctly from the FG.
>
> Channel 1 displays 10 times the amplitude for the same signal.
>
> Example a 1 volt sine wave on channel 2 displays on the voltmeter function correctly at ~1v and 2 divisions at .5v / div.
>
> The same signal on channel one reads as ~10v. When set to 5v / div it fills two div.
>
> Thanks, KT
>

Tektronix parts and the 1410 Generator

#80850

Hi.

I have a working 1410 video signal generator, but I am thinking of scrapping it. I've pulled a few boards and of course it is loaded with great parts. I have not found any manual for this device, but I suppose there are a bunch of general purpose circuits in it.

I just got into the multiburst board and there is fancy looking socketed package
  "TEK 155 0195 00"
Is this part of interest to anyone? I've searched the net for it and just three sites list it, one as a hybrid shaper circuit.

Studying this multiburst board makes me want to understand this instrument. Unfortunately there is no free documentation available. Any help or advice greatly appreciated. This one was made in 1985 and has all bays filled.

 - Tim

Re: 2247A Channel 1 issue

#80849

开云体育

Hi,

you should check, that there is no short on the "sensor" ring of the input which shows
the 10X signal. Normally the sensor, when open tells 1:1 probe and for probes
with 10:1 a.s.o. it is conncted via a resistor to ground !!!

Herbert

Am 20-09-2012 14:54, schrieb lldskjfoi:

Show quoted text

?

They on 10x non swtichable.

KT
--- In TekScopes@..., Pat-W9ZO wrote:
>
>
> I know it is probably silly to ask, but are you sure that the switch on
> one probe isn't set for the x10 setting ?
> PatM
> ============================================================
> lldskjfoi wrote the following on 9/19/2012 9:59 PM:
> >
> > Hello everyone.
> >
> > Initial test show an issue with channel 1.
> >
> > Any direction on where to start?
> >
> > Channel 2 displays inputs correctly from the FG.
> >
> > Channel 1 displays 10 times the amplitude for the same signal.
> >
> > Example a 1 volt sine wave on channel 2 displays on the voltmeter
> > function correctly at ~1v and 2 divisions at .5v / div.
> >
> > The same signal on channel one reads as ~10v. When set to 5v / div it
> > fills two div.
> >
> > Thanks, KT
> >
> >
> .
>

Re: 2247A Channel 1 issue

#80848

They on 10x non swtichable.

KT

Show quoted text

--- In TekScopes@..., Pat-W9ZO <malfam2@...> wrote:


I know it is probably silly to ask, but are you sure that the switch on
one probe isn't set for the  x10 setting ?
PatM
============================================================
lldskjfoi wrote the following on 9/19/2012 9:59 PM:

Hello everyone.

Initial test show an issue with channel 1.

Any direction on where to start?

Channel 2 displays inputs correctly from the FG.

Channel 1 displays 10 times the amplitude for the same signal.

Example a 1 volt sine wave on channel 2 displays on the voltmeter
function correctly at ~1v and 2 divisions at .5v / div.

The same signal on channel one reads as ~10v. When set to 5v / div it
fills two div.

Thanks, KT

.

Which Torx Size must I buy to refurberish someTM5000 Series Relais

#80847

Hi to All,

Which Torx Size must I buy to put into the very very small Torx Screws, used for the fixation of the 148-0128-03 Relais in e.g. a FG5010? Thank you in advance.

Greetings,

Egge Siert

Re: 2247A Channel 1 issue

#80846

开云体育

I know it is probably silly to ask, but are you sure that the switch on one probe isn't set for the? x10 setting ?
PatM
============================================================
lldskjfoi wrote the following on 9/19/2012 9:59 PM:

?

Hello everyone.

Initial test show an issue with channel 1.

Any direction on where to start?

Channel 2 displays inputs correctly from the FG.

Channel 1 displays 10 times the amplitude for the same signal.

Example a 1 volt sine wave on channel 2 displays on the voltmeter function correctly at ~1v and 2 divisions at .5v / div.

The same signal on channel one reads as ~10v. When set to 5v / div it fills two div.

Thanks, KT

.

Re: New to group - Just acquired a R7844

#80845

The funny part of the story is the pawn shop owner said he fired the employee who took the scope in for pawn when the owner did not come back to pay off the pawn and pick it up. He was convinced that he could never sell it and that was why it was not on the sales floor.

I guess its better to be lucky than good as they say! I have figured out how to use now and I love it.

Show quoted text

--- In TekScopes@..., "k4mt" <k4mt@...> wrote:

Hi All:

I just found a working R7844 with 7A26, 7A24, and two 7B85 plugins. I was in a pawn shop and saw it on a shelf in the back room. I asked the owner and he said it had been sitting there for 5 years and he did not know what it was.  He brought it down and I powered it up. Nice bright traces and ran a wire to calibrator output and all channels worked.

The best news is he wanted it off his shelf and asked me for an offer. Just for laughs I offered him $40.00 and he couldn't say yes quick enough. (guess I should have offered $20.00).

I have used scopes my whole life but not one like this. Am still trying to learn how to use it as I have no users manual. Was able to use it this weekend to troubleshoot my Ham radio PLL with a 60 Mhz output that my old scope could hardly see.  What a great piece of test gear!

TEK 1401A Spectrum Analyzer

#80844

Hi Everybody!

I recently bought a tek 1401A from Ebay (sans the tiny scope that goes with it. Alas.).  It lacks the battery/charger module but otherwise seems to be complete except for a missing fine frequency pot and multiturn knob.

It seems to have been much molested. I have already seen some transistors which have been stuck in the wrong way around. The power supply is dead but I managed to fix it. (Dead main chopper transistor, shorted 6.4 V zener shorted 22u cap in the +10V section )

If anyone has the same S/A and is working on it (or not|) I would like to join up with him and share my experience of the repair job.

I have collection of old Tek stuff and want to restore it to as close to original as posible.

Azzy

HP Agilent YIG 5086-7096 Mixer 5086-7059

#80843

Hi everybody,

A group of my students who are working on a broa band swept oscillator purchased a YIG oscillator on my advice. (Ebay)

I am unable to find the pinout of the YIG. It cannot be used. The unit is cosmetically sound and probably ( I hope) working

Its part number is 5086-7096.  When purchased, it came attached by a hard coax to, what is stated on the label, to be a mixer with part number 5086-7059.
All my search has to date yeilded no result. Could somebody help, please.

This is really important as the students have no access to any option. They cannot import something else as I collected it from the USA myself, by passing import regulations etc.
I will be extremely thankful for any information leading to its successful use. Also the mixer assembly which is probably useful too.
Thank you for the help.

Azzy

504, RM504, and other stuff in Boston

sipespresso

#80842

I have no affiliation with the seller.

-Kurt

correcting 5v supply on a 5110

#80841

I have this lovely collection of broken scopes. On one the 5v supply is off. If I understand the regulator circuits correctly this voltage is referenced to the other voltages, which are correct.

If the 5v is off (4.8v) should I be looking for shorted caps, drifted resistors and failed semis around the 5v regulator or is there some obvious thing I'm missing?

thanks again,

Jamie

Have you seen arcing around vertical output transistors?

#80840

I bought a 5111 on ebay for cheap and it mostly works but while working on it I noticed arcing around both vertical output transistors. I thought no big deal, probably just cold solder joints from heat cycling, right?

It would appear that the arcing is where the legs of the component enter the transistor. Has anyone seen this before?

It sure would explain the trace randomly jumping around on the screen a bit!

Jamie

Re: 2247A Channel 1 issue

#80839

Some more checking shows channel 1 is not getting the code signal from the probe. Any idea on this circuit?

KT

Show quoted text

--- In TekScopes@..., "lldskjfoi" <k.templin@...> wrote:

Hello everyone.

Initial test show an issue with channel 1.

Any direction on where to start?

 Channel 2 displays inputs correctly from the FG.

 Channel 1 displays 10 times the amplitude for the same signal.

 Example a 1 volt sine wave on channel 2 displays on the voltmeter function correctly at ~1v and 2 divisions at .5v / div.

The same signal on channel one reads as ~10v. When set to 5v / div it fills two div.

Thanks, KT

Or 475 (Network Analyzer) Re: Fun things to do with a TDS-360

JW

#80838

Phase and Mag?calculable from the relationship between the two traces:
?

?

(Poor man's net ana!)

de Jim?

2247A Channel 1 issue

#80837

Hello everyone.

Initial test show an issue with channel 1.

Any direction on where to start?

 Channel 2 displays inputs correctly from the FG.

 Channel 1 displays 10 times the amplitude for the same signal.

 Example a 1 volt sine wave on channel 2 displays on the voltmeter function correctly at ~1v and 2 divisions at .5v / div.

The same signal on channel one reads as ~10v. When set to 5v / div it fills two div.

Thanks, KT

Re: San Diego 7934 and goodies

Rob

#80836

Why do these deals always come around someplace far far away from Louisiana.

If I knew someone in San Diego I might even consider having it shipped here.
Shipping would likely cost more than the asking price for the bundle....
sigh...

At least I can hope a member of this forum lives close and gets it 
Rob

Show quoted text

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf
Of sipespresso
Sent: Wednesday, September 19, 2012 1:09 PM
To: TekScopes@...
Subject: [TekScopes] San Diego 7934 and goodies

I have no affiliation with the seller.  I emailed them an confirmed that
they are asking for $160.

-Kurt

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

Yahoo! Groups Links

Re: New to group - Just acquired a R7844

Rob

#80835

*laugh* well I was/am impressed..... scoring my all-time favorite... with
prudent plug-ins to boot.. 

As I re-read the title and my post; some of my responses may be a bit
cryptic to someone very new.

Bama is here:

Tek-wiki is here:

and Dave is here:

Again, you did a great deal.
Rob

Show quoted text

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf
Of larrys@...
Sent: Wednesday, September 19, 2012 8:12 PM
To: TekScopes@...
Subject: RE: [TekScopes] New to group - Just acquired a R7844

"Rob" <rgwood@...> wrote:
You got a great deal. Rob, you have a gift for understatement.  Wow!  That would have been a good
price for a couple of the plugins.  Congrats!
-ls-



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

Yahoo! Groups Links

Re: New to group - Just acquired a R7844

#80834

"Rob" <rgwood@...> wrote:
You got a great deal. Rob, you have a gift for understatement.  Wow!  That would have
been a good price for a couple of the plugins.  Congrats!
-ls-

Re: 2213 no trigger

#80833

hi David,
thx for the tip! i will check this as soon as possible (couple days out of town). i check tp444 before with ext. trigger and that was very small compared to the input signal. don't know the exact amplitude but much lower.
probably back on saturday. tjeenz.

Show quoted text

--- In TekScopes@..., David <davidwhess@...> wrote:

I would start by looking at TP444 (middle of schematic 4) which should
be a duplicate of the trigger input signal as selected by the source
and coupling controls.  At the very least, there should be a 60Hz sine
wave at that point when the trigger source is set to line.

Then I would check pin 2 of U460B which should be a duplicate of the
tri.gger level voltage as set by the trigger level control.  In Auto
mode this voltage will be between the peak levels of the trigger
signal but in normal mode, it should be between +0.65V and -0.65V.

It would be nice to have a nicer scan of the service manual.  I
extracted and cleaned up schematic 4 from the one available online:



On Tue, 18 Sep 2012 11:00:41 -0000, "tjeenz" <tjeenz@...> wrote:

Hi,
Have a trigger problem with a 2213 tektronix.

In auto and line trigger i have a baseline. In norm not. Also ext. trigger fails (signal from function generator 4v pp and ch1 on 1v/div)

cannot get still image to see frequency, amplitude is ok. with signal on one of the channels, trig in auto i can almost get still image if freq is low enough with var hold-off. trig-level does nothing. Also the trigger led never blinks.

Checked all p.s. voltages. Are ok (no ripples), but according to service manual there should be some specific resistance on the voltages. These are way too low in my scope:
8.6v   114 ohm at tp500=	58 ohm
+8.6v   95 ohm at W975	=	16 ohm
+5v     330 ohm at W985	=	16 ohm
+30v   905 ohm at W965	=	16 ohm
+100v 12.5 kohm at W966	=	16 ohm

so i guess something is wrong somewhere. checked the big capacitors in the p.s, for 30V and +8.6V, both were in spec.

Are these resistance values in the manual a good reference for finding the faulty area?

regards, tjeenz