Author Topic: HP 4274A LCR Meter - mini teardown  (Read 21120 times)

0 Members and 1 Guest are viewing this topic.

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #125 on: June 12, 2018, 09:24:01 am »
Ok, I try to measure the transistors. :) What level need there?

You have a table.
In bases Q ..... Q on the command table with logical levels.

 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #126 on: June 12, 2018, 09:29:13 am »
I not measured yet the U1 output voltages.

You wrote me * A3 TP2 8,4Vpp - OK *
I rely on it!

« Last Edit: June 12, 2018, 09:40:01 am by 3g57 »
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #127 on: June 13, 2018, 01:29:36 am »
Yes, it is. I confirmed :) Sorry I just mixed up.
I measuring the Q2-3-4. In progress.
« Last Edit: June 13, 2018, 03:06:47 am by MateKrisz »
 
The following users thanked this post: 3g57

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #128 on: June 13, 2018, 04:09:27 am »
I measuring the Q2-3-4. In progress.

Hi!
You need to go through the check on
cascades and set the required signal levels.
This is just the top of the A3.
Similarly, it is necessary to pass the bottom of A3.
Because they work synchronously.
I'm showing you on the screen.



Unfortunately I do not have a good file.
This is not all legible.

3g57
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #129 on: June 14, 2018, 06:07:50 am »
Hi,

I measured the Q2, Q3, Q4

Values:

Multi x0,01 x0,1  x1   x5
Q2 out after R24    -10,98 -10,98 -10,98 +6,4
Q3 out after R25    +6,4 -10,98 -10,98 -10,98
Q4 out after R26    -10,98 +6,4 -10,98 -10,98

I measured the DC voltage on A3 L2 and there is +11,2V

I measured on U5 14 pin the DClevel (for more pin need a little more space for checking, but I don't have)

x0,01 - -10,98
x01 - -10,98
x1 - -10,98
x5 - -10,98

In x1 position need + voltage or not?

Krisz
« Last Edit: June 14, 2018, 07:10:06 am by MateKrisz »
 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #130 on: June 14, 2018, 09:17:50 pm »
Hi! Krisz.
I watched.
This module has two common buses.
1- digital
2- analog
When you take measurements take it into account !!!
You should first of all make measurements of the signal levels at the input U7 / U6 / U5.
This way you can check the low and high levels of signals and compare with the table.
U7 / U6 / U5 create a signal level for the analog part
and send it to the keys Q2 / Q3 / Q4, Q10 / Q11 / Q12 / Q13 / Q14.
A high and a low level is better measured by an oscillograph. In DC open mode.!!!
Make a table for yourself.!
On your question:
Extender boards buy for yourself convenient.
If you want, you can wait for me next week, I can send
you need a file to make it.
This mine, but it is not high. There will be another, adapted for HP4275A




Check D-GND! So on the board?






________________________________








3g57
« Last Edit: June 14, 2018, 10:23:09 pm by 3g57 »
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #131 on: June 15, 2018, 03:00:28 am »
Hi,
Just a quick question. For the sake of clarity I ask it:
A-GND - A11 11-13L
D-GND - A11 7R

What are on A11 4R? (Bias Monitor RTN) It is same as A-GND?

I just checked the A11 board again and A-GND and D-GND and 4R are on common potential and connected to chassis. (All boards inserted)

Krisz
« Last Edit: June 15, 2018, 03:46:55 am by MateKrisz »
 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #132 on: June 15, 2018, 04:07:59 am »
1- The analog common bus typically supplies
operational amplifiers, etc.
2- The digital common bus usually supplies logic elements, CPU, etc.
They can communicate under certain conditions. As a rule, this is done
through the denouement.
At this device I watched 4 tires !!!!

You can find the answer to the second question in this diagram.
I painted her color.



Here the screening braid has its meaning.
It additionally performs an active role with a certain
connection. Learn. It is important.

Pay attention!!!! On the numbers in the triangle!
This is an example with the HP4275A



« Last Edit: June 15, 2018, 04:30:18 am by 3g57 »
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #133 on: June 15, 2018, 05:20:31 am »
Hi,

Here are the quick results:

Multi    x0,01     x0,1     x1    x5
U5-4     L            H        H     H   (U5 replaced)
U6-4     H            H        H     H
U7-4     H            H       H      H

High is +4V DC
GND A11-7R
It is good?

More results in progress.
I don't have numbers in the triangles on the schematic.

D-GND between A11-R7 and U8-10, U9-10, U10-10 are OK.

Krisz
« Last Edit: June 15, 2018, 05:26:07 am by MateKrisz »
 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #134 on: June 15, 2018, 05:57:03 am »
Hi,

Here are the quick results:

Multi    x0,01     x0,1     x1    x5
U5-4     L            H        H     H   (U5 replaced)
U6-4     H            H        H     H
U7-4     H            H       H      H

Krisz.
What is U5-4, U6-4, U7-4 ????
« Last Edit: June 15, 2018, 06:28:17 am by 3g57 »
 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #135 on: June 15, 2018, 06:10:43 am »
You need a level only U5 !!!
So far only at her entrance.
See the table.
Signal to U5 input
TLHT   - pin10
TLS#1 - pin8
TLM     - pin6
TLL      - pin4
Make a table for yourself when multiplexer is running.
« Last Edit: June 15, 2018, 07:16:40 am by 3g57 »
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #136 on: June 15, 2018, 06:32:34 am »
Here is the table:

Multi    x0,01     x0,1     x1    x5
U5-4     L            H        H     H
U5-6     L            L        L     L
U5-8     H            H       H      H
U5-10   H            H        H     H

U5-10 is U5-pin10
 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #137 on: June 15, 2018, 06:50:28 am »
Check. I'm not wrong.



This is the table.



Check now the levels at the output of U5, only relative to the analog common bus of 12L.
Make a table.!

p.s. I rely on your measurements.
If they are right, then you have a problem up to U5!
ATT does not work correctly. Therefore, further error.
It should also be taken into account that U5 controls the lower part of the circuit A3.
This will also be a mistake!


3G57
« Last Edit: June 15, 2018, 08:28:44 am by 3g57 »
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #138 on: June 15, 2018, 07:23:37 am »
Hi,

I measured again with same as your table.

Multi    pin10     pin8     pin6    pin4
x5        L            H        H     H
x1        H            H        H     H
x0,1     H            H       L      H
x0,01   H            H        H     L

But it is normal that the Hcur signal on the Bias monitor socket?

Krisz








 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #139 on: June 15, 2018, 07:29:30 am »
Hi,

I measured again with same as your table.

Multi    pin10     pin8     pin6    pin4
x5        L            H        H     H
x1        H            H        H     H
x0,1     H            H       L      H
x0,01   H            H        H     L


This does not correspond to the norm in the table!
So it does not work properly!
 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #140 on: June 15, 2018, 07:32:41 am »
But it is normal that the Hcur signal on the Bias monitor socket?

Understand the scheme!
I did not penetrate.

________________

Yes. Through the resistor R43

« Last Edit: June 15, 2018, 07:44:43 am by 3g57 »
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #141 on: June 15, 2018, 07:43:08 am »
Check the levels on U5 pin1, pin2, pin13,14?

I just asked the signal level at Bias monitor, never check this before.

But don't understand how not work properly the U5 when on Hcur socket the signal levels are correct.
 
 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #142 on: June 15, 2018, 07:48:24 am »
Check the levels on U5 pin1, pin2, pin13,14?
I just asked the signal level at Bias monitor, never check this before.

Compare the table and your measurements.

You have a problem up to U5 !!


At the output of U5, you have not measured.

p.s.  Yet. Read in the manual. Measurements must be made with the connected
TEST FIX. 16047 or without it ??  It is important!
« Last Edit: June 15, 2018, 08:28:14 am by 3g57 »
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #143 on: June 15, 2018, 08:30:26 am »
Hi,

I check the U8-9 levels?
I attached the fixture.

 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #144 on: June 15, 2018, 08:36:41 am »

I attached the fixture.

Once again, check the U5 levels after installing the TEST FIX. 16047
 Make a table.!
With U8 / U9 later.
« Last Edit: June 15, 2018, 08:39:20 am by 3g57 »
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #145 on: June 15, 2018, 08:39:10 am »
Ok, just a moment.
But the fixture, not original 16047, it is B+K Model TL89F1.
 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #146 on: June 15, 2018, 08:40:29 am »
Let it be for now. :-\
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #147 on: June 15, 2018, 09:08:28 am »
I repeated the U5 measure, and nothing changed.
The B+K fixture working with 4274A. Here is the article:
http://k6jca.blogspot.com/2017/11/replace-hp-16047a-test-fixture-with-bk.html
 

Offline 3g57

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ua
Re: HP 4274A LCR Meter - mini teardown
« Reply #148 on: June 15, 2018, 09:16:39 am »
Krisz!
Hence it is necessary to replace U8, U9, U10.
Install the sockets for them. It will be faster than checking !!!
You can not do this.
p.s. You can try, maybe they are good?
Perhaps the problem is up to them.

3g57
« Last Edit: June 15, 2018, 09:23:38 am by 3g57 »
 

Offline MateKrisz

  • Regular Contributor
  • *
  • Posts: 72
  • Country: hu
Re: HP 4274A LCR Meter - mini teardown
« Reply #149 on: June 15, 2018, 09:27:35 am »
 I hope! Tomorrow the first thing will be that I replaced them! :-) Thanks your help! 
Krisz
How test these ICs?
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf