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Old 24th May 2013, 03:29 AM   #381
locky_z is offline locky_z  China
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Join Date: Jun 2004
Location: XH
I think it is a bad relay contacts.
Try this script to test the relay contact.

Eout 30
Bout 2.5
for i=1 to 10
setRB 1
WaitRelay
GetADC
CurvePoint "1",i,Vrb
SetRB 0
WaitRelay
SetRB 2
WaitRelay
SetRB 3
WaitRelay
next
EndCurve "1"


I explain This script.
Click the image to open in full size.
This script test the RB1(6Kohm) relay.Before you run this script, you need connect a resistor between socket 'B' and 'E'. This resistor value and RB1 (6K ohms) is at the same class. Here I use a 2.2K resistor connect B and E.
Eout 30
Bout 2.5

Set B channel output 2.5V,E channel output 30V.
The test is loop 10 times,
In each cycle, system select RB1(6K), and measure the voltage on RB1,and display the voltage.Vbr is the voltage on RB1.
setRB 1
WaitRelay
GetADC
CurvePoint "1",i,Vrb

after measure the voltage, system will select another relay.
Statement "WaitRelay" is delay about 20ms in order to wait relay stable.
SetRB 0
WaitRelay
SetRB 2
WaitRelay
SetRB 3
WaitRelay


Statement EndCurve "1" show the result on screen.

If the relay contacts is stable, the value of "Vrb" is stable,It changes should be less than 0.02V.
From the result screen, you can check the Y-axis value on every point.
Attached Images
File Type: gif 1.GIF (4.3 KB, 215 views)
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Old 24th May 2013, 11:21 AM   #382
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Join Date: Oct 2011
Location: Tokyo, Japan
Hi Locky,

My kind thanks for your super support !

I have run the script and done in the following order:
- relay test 1
- transistor test
- relay test 2

The relay test seems to be ok, also after transistor test. The value drops not more than 0.015 volt in worst case.

However, the transistor test is still going bad (see attached graphic).

I made one mistake in previous message:
- when Rb = 6K : no problem
- when Rb = 500 : problems (Ic > 350 mA)

Also, problem start after 'calibration before measure' is selected. After one time problem, the problem stays. Perhaps a problem with calibration relay?

my great thanks for your help
Attached Images
File Type: jpg Relay Test 01.jpg (89.2 KB, 151 views)
File Type: jpg BJT Test.jpg (219.3 KB, 196 views)
File Type: jpg Relay Test 02.jpg (119.5 KB, 151 views)
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Old 24th May 2013, 03:41 PM   #383
locky_z is offline locky_z  China
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Join Date: Jun 2004
Location: XH
Click the image to open in full size.

This picture like J1 J2 J3 J4 contact wrong,
That script only test RB0, you can modify it to test RC0, but you need connect a 10~300ohm resistor to C and E.

Eout 30
Cout 2.5
for i=1 to 10
setRC 0
WaitRelay
GetADC
CurvePoint "1",i,Vrc
SetRC 1
WaitRelay
SetRC 2
WaitRelay
SetRC 3
WaitRelay
next
EndCurve "1"





But the picture not like J1 J2 J3 J4
Click the image to open in full size.
J6 is B Channel calibration relay,J7 is C Channel calibration relay.
You can select menu "Measurement->Curve Tracer",
Check the 'Calibration befor measure",
And click the "offset test" button
System will display the VBE/VCE/VRB/VRC offset voltage.
Normal the VBE/VCE/VRB/VRC offset voltage is between -0.010V ~ +0.010V.
If the offset voltage more than -1V~+1V, The two chips OP07 or the J6 J7 have wrong.
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Old 25th May 2013, 06:36 AM   #384
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Hi Locky,

Once more my kind thanks for your follow up.

I have run 4 tests (see attached):

- RC0 with 200 ohm: all within 0.02V (no problem)

- RC0 with 22 ohm: 0.045 / 0.036 / 0.027 V (problem ??)

- RC0 with 12 ohm all within 0.02V (no problem)

- VBE/VCE/VRB/VRC offset voltage: all within +/- 0.001 V (no problem, although Vbe (black) a litlle in the beginning, and Vce (blue) a little at the end)

Do yo see any problems? Should I replace any of the relays?

many thanks,
Ozzy
Attached Images
File Type: jpg RB0 test with 200 ohm.jpg (101.0 KB, 8 views)
File Type: jpg RB0 test with 22 ohm.jpg (282.7 KB, 9 views)
File Type: jpg RB0 test with 12 ohm.jpg (90.7 KB, 8 views)
File Type: jpg VBE-VCE-VRB-VRC offset voltage.jpg (149.3 KB, 11 views)
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Old 25th May 2013, 09:25 AM   #385
locky_z is offline locky_z  China
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Join Date: Jun 2004
Location: XH
I think the RC0 relay contact no problem.
But at post #381,the script only test the RB1 relay contact, no RB0,
You can run the follow script to test RB0 relay contact.
Before run it, you need connect a 100~1K resistor to B and E


Eout 30
Bout 2.5
for i=1 to 10
setRB 0
WaitRelay
GetADC
CurvePoint "1",i,Vrb
SetRB 1
WaitRelay
SetRB 2
WaitRelay
SetRB 3
WaitRelay
next
EndCurve "1"
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Old 25th May 2013, 12:06 PM   #386
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Location: Tokyo, Japan
Hi Locky,

See results attached (with 200 Ohm). Max voltage swing (red line) is 0.01 V.
Attached Images
File Type: jpg RB0 test.jpg (186.9 KB, 18 views)
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Old 25th May 2013, 01:16 PM   #387
locky_z is offline locky_z  China
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Join Date: Jun 2004
Location: XH
From this result,There are nothing wrong with RB0 relay contact.

Use another script to compare RB0 & RB1
Connect a diode(1N4001) to B & E, (B+ E-), and run this script

Eout 2.5
for i=3 to 30
Bout i
setRB 0
WaitRelay
GetADC
CurvePoint "1",Vbe,Vrb/CurrentRB

setRB 1
WaitRelay
GetADC
CurvePoint "2",Vbe,Vrb*12/CurrentRB
next
EndCurve "1"
EndCurve "2"

Click the image to open in full size.

Normaly the result as black, If some relay contacts wrong ,It will have some spiked (such as red).
Attached Images
File Type: png 1.PNG (21.1 KB, 163 views)
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Old 25th May 2013, 01:51 PM   #388
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Location: Tokyo, Japan
Locky,

I did the test with a 1N4002 diode, and it shows good results (no problems).

I tried a NPN Hfe-Ic BJT test again, but the problem is still there. It seems multiple relays are clicking at the same time when the problem happens. I tried different positions of the transistors in the socket, but no difference.

Thanks for your super support
Attached Images
File Type: jpg RB0-RB1 comparison test.jpg (270.2 KB, 19 views)
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Old 25th May 2013, 02:43 PM   #389
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Location: ISRAEL
Did you try reloading the software again??
When i get unexplained errors,i always extract a new folder from the zip and start a fresh program. It worked for me most of times.
Also, try to restart the tracer board...
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Old 26th May 2013, 01:32 AM   #390
locky_z is offline locky_z  China
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Join Date: Jun 2004
Location: XH
Try using a different combination of resistors(RB/RC) to measure hfe-ic curve, to see if a problem occurs.

Try to use a same transistor and use different RB/RC combination to measure the curve
1.RB=1360K RC=1K
2.RB=91K & RC=1K
3 RB=91K & RC=75
4.RB=6K & RC=75
5.RB=6K RC=4.55
6.RB=500 RC=4.55

Then observe the measurement results to see if there spikes.
If the spike at the begining of curve,It is normaly.
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