[Test-Equipment] Scope questions: OT for Tek?

[bonddaleena at aol.com]

Larry, thanks for the input.

First I need to make a large apology to you fine folks. I must (!!) have been tired when I asked my questions, because the scopes in question are NOT the same!

The Kenwood CS-2150 (with the trace problem), is exactly like my B&K Model 1590A. They are identical, 100 MHz scopes and the B&K works 100%.

The problems I listed are still correct for each model.

I figgered there was an attenuator problem on the Leader and looked around that area already. There are a lot of unique looking voltage divider parts, that are almost impossibe to see....

Like I said, the Leader works fine on Channel 2 and OK on Channel 1 as long as you stay at .1 V/div and down.......

ron
N4UE





-----Original Message-----
From: Larry Aamodt <aamola at wallawalla.edu>
To: bonddaleena <bonddaleena at aol.com>
Sent: Wed, Jun 29, 2011 8:24 pm
Subject: Re: [Test-Equipment] Scope questions: OT for Tek?


ron,
The vertical section of a scope often has attenuation for 
igher voltage "gain" settings and possibly amplification
or lower voltages.  My guess is that at .2V/div the
ttenuator is defective (open circuit) and hence no
ignal.  (often a fixed gain amplifier follows the
nput preamp/attenuator section to get the voltage needed 
o drive the scope full scale).  I have no specific
nowledge about Leader scopes.
  -Larry 
  WA0OSY
On Wed, Jun 29, 2011 at 07:30:01PM -0400, bonddaleena at aol.com wrote:
 
 Hi. I collect scopes (don't ask me why, some kind of sickness) ha ha
 
 I have a nice assortment, which includes a big 'ole LeCroy (350 MHz) to a 
mall Leader (15 MHz). I have done a refurb on them all and I am quite happy 
ith them all. This does not include 3 Tek 7623s which are driving me nuts, but 
hat's for another time.
 
 Here is my current 'problem'.....
 
 I have both a Leader LBO-526 and a Kenwood CS-2150 with different problems.
 
 I have NO doubt that both of these scopes are the same internally and 
xternally, except for the logos. Unfortunately, I have not been able to find 
ny type of manual for either.
 
 I'll start with the 'simple' problem.... The Leader.
 
 It works beautifully with a crisp display, but when I feed a signal to Channel 
ne, the display is non-functional at .2 mv/div and higher, In other words, 
sing the calibrator (or an external signal generator), I have a nice display 
ntil I start LOWERING the voltage/div. This is kinda opposite what seems 
ikely. .1 V/div (and lower) looks OK and .2 V/div looks like ground. Channel 
wo is fine.
 
 Next the .......... Kenwood
 
 Using the calibrator signal as above, and the exact same settings, the scope 
ooks like it is TRYING to work. I can see 'flashes' of light on the screen, but 
o traces. Pushing the "trace locator' produces a compressed, visible trace in 
he center of the screen, for each channel. I can use the 'position' knob to 
ove these traces up and down. However, when I release this 'finder' button, the 
races disappear and all I see are these low level flashes of light and I cannot 
ocate the beams. It appears (!!) they are off screen.
 
 
 Any Ideas?? The Leader problem is one that I can live with, since Channel 2 
unctions as expected at voltages of .2 V/div and up.
 
 Thank you in advance!
 If you wish, you can contact me off list:
 
 n4ue at arrl.net
 
 ron
 N4UE 
 
 
 
 ______________________________________________________________
 Test-Equipment mailing list
 Home: http://mailman.qth.net/mailman/listinfo/test-equipment
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Test-Equipment at mailman.qth.net
 
 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html