Author Topic: half a screen help  (Read 12560 times)

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Offline kjn4685

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Re: half a screen help
« Reply #50 on: September 25, 2014, 01:23:25 am »
To 126
 

Offline tautech

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Re: half a screen help
« Reply #51 on: September 25, 2014, 02:00:41 am »
Please post the 2 transistor part numbers that are in your scope. (H-Final output)
2S*****??
All markings please.
Carefully post them, all numbers plus any letters that might be separate to identify Hfe range.

OR good photos if you can.
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Offline kjn4685

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Re: half a screen help
« Reply #52 on: September 25, 2014, 03:06:03 am »
Ok this is the 4 trans on the board. As you see that I have changed 2 trans they are the ones at the bottom of the pic. here is a pic. I hope that this will help you guys see what is going on.
« Last Edit: September 25, 2014, 03:45:41 am by kjn4685 »
 

Offline tautech

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Re: half a screen help
« Reply #53 on: September 25, 2014, 03:51:20 am »
From your picture:
2 x 2SA1360 Y PNP Hfe 120-240 (still in PCB)(you previously posted wrongly as c1306)
2 x 2SC3423 Y NPN Hfe 120-240 (shown removed)
Datasheets attached.
Although the datasheets list both transistors suitable for "Audio Frequency Amplifier Applications", they are used in a Video output stage.
If the manufacturer made this change from the schematic you have, you are best advised to seek the same transistors for replacements.

As you have substituted the NPN's and not fixed the fault, you need to check/replace the PNP's.

The NTE373 is not the best substitution match for NPN 2SC3423 but should be OK to test with, then replace.
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Offline kjn4685

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Re: half a screen help
« Reply #54 on: September 25, 2014, 04:15:08 am »
A 1360 pnp is vcbo -150 v. -150 v -5 can you tell me what is the difference between  + or-
« Last Edit: September 25, 2014, 04:20:29 am by kjn4685 »
 

Offline tautech

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Re: half a screen help
« Reply #55 on: September 25, 2014, 04:22:23 am »
A 1360 pnp is vcbo -150 v. -150
Correct.
Use the full name: 2SA1360 Y
If you have to get a substitute make sure it is at least -150 V rated.
Some datasheets do not show the voltage as -V, only V but PNP is the important bit.  ;)
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Offline tautech

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Re: half a screen help
« Reply #56 on: September 25, 2014, 05:35:24 am »
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Offline kjn4685

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Re: half a screen help
« Reply #57 on: September 25, 2014, 05:56:54 pm »
Again I thank you very much. I also appreciate the information that you sent me. I will do what you said
Lou
 

Offline kjn4685

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Re: half a screen help
« Reply #58 on: September 27, 2014, 03:30:35 am »
Now I have another scope. So will you guys tell me how to hook the too scope together and test my old scope to fix it. If anyone could help me I would be appreciate any help
Lou
« Last Edit: September 30, 2014, 03:38:00 am by kjn4685 »
 

Offline kjn4685

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Re: half a screen help
« Reply #59 on: September 30, 2014, 12:28:11 am »
Hi there again I seen on the forum this octopus circuit board. It has a 12v ct transfromer at 300 ma. I have a 12v ct at 3a is the anyway I can use it. If so do I need something to reduce the amps.
 

Offline kjn4685

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Re: half a screen help
« Reply #60 on: October 02, 2014, 02:29:07 am »
I need help with my oscilloscope agian. I need to know after I hook up the too scopes what am looking for.
 

Offline tautech

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Re: half a screen help
« Reply #61 on: October 02, 2014, 07:32:24 pm »
Have you replaced the PNP output transistors?
http://www.vyrian.com/part.php?part=2SA1360-Y%28Q%29

There is no point in testing the scope except the sweep that I expect is working fine.
It will be a sawtooth waveform that varies with the timebase setting.
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Offline kjn4685

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Re: half a screen help
« Reply #62 on: October 02, 2014, 07:53:57 pm »
I have already ordered the transistors. And again I thank you. You don't know how much this helps me
 


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