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justez View Drop Down
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    Posted: 19 hours 22 minutes ago at 3:38pm
Yes, it was the blue transistor, which is wrong.
Repair Solved!






Edited by justez - 19 hours 21 minutes ago at 3:39pm
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Post Options Post Options   Thanks (1) Thanks(1)   Quote M K L Quote  Post ReplyReply Direct Link To This Post Posted: 22 hours 16 minutes ago at 12:44pm
Possibly. You can rule out a heater-to-cathode short in the tube by sucking solder off pin 11 (blue cathode). If blue remains the short is in the tube, otherwise it's in the blue circuit.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote justez Quote  Post ReplyReply Direct Link To This Post Posted: 22 hours 32 minutes ago at 12:28pm
Originally posted by M K L M K L wrote:

Originally posted by justez justez wrote:

On pin 9 of the socket with pin 6 of the desoldered flyback I have no voltage.

Of course. Now you just need to measure AC voltage at pin 6 of the flyback (with solder sucked off the pin).


Solved!
Thank you very much for your help MKL !!

I have noticed that pin 6 has continuity with the components but the track of pin 6 does not, and has a micro break.



now the image comes out saturated with blue and the cut off of blue to the minimum does nothing, maybe it is a transistor or the integrated circuit LM1203?


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Post Options Post Options   Thanks (1) Thanks(1)   Quote M K L Quote  Post ReplyReply Direct Link To This Post Posted: 22 hours 46 minutes ago at 12:14pm
Originally posted by justez justez wrote:

On pin 9 of the socket with pin 6 of the desoldered flyback I have no voltage.

Of course. Now you just need to measure AC voltage at pin 6 of the flyback (with solder sucked off the pin).
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Post Options Post Options   Thanks (0) Thanks(0)   Quote justez Quote  Post ReplyReply Direct Link To This Post Posted: 23 hours 4 minutes ago at 11:56am
Originally posted by M K L M K L wrote:

On pin 9 of the socket? How can you have any voltage there if you desoldered pin 6?

And if you meant pin 9 of the flyback why did you do that? You have already proved that output is fine (200V).


I understood that you wanted me to measure on pin 9 flyback.

On pin 9 of the socket with pin 6 of the desoldered flyback I have no voltage.

Before I had already measured that it had the voltages
+ 200V, -190V is present. (TP30 TP33)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote M K L Quote  Post ReplyReply Direct Link To This Post Posted: 23 hours 19 minutes ago at 11:41am
On pin 9 of the socket? How can you have any voltage there if you desoldered pin 6?

And if you meant pin 9 of the flyback why did you do that? You have already proved that output is fine (200V).


Edited by M K L - 23 hours 15 minutes ago at 11:45am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote justez Quote  Post ReplyReply Direct Link To This Post Posted: 23 hours 35 minutes ago at 11:25am
Originally posted by M K L M K L wrote:


You need to measure at the flyback pin. Not easy, I know. Try attaching an alligator clip to the pin.

I unsolder pin 6 and in 9 I have 63V (AC)

Edited by justez - 23 hours 34 minutes ago at 11:26am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote M K L Quote  Post ReplyReply Direct Link To This Post Posted: 23 hours 51 minutes ago at 11:09am
Originally posted by justez justez wrote:

I desolder pin 6 and measured pin 9 in the socket and I still have no voltage.

You need to measure at the flyback pin. Not easy, I know. Try attaching an alligator clip to the pin.

Originally posted by justez justez wrote:

What I have seen is that pin 9 of the socket has continuity with ground.
Perhaps there is the fault.

Pin 5 of the flyback is grounded and it's internally connected by windings to pins 6, 9, 10 (see the drawing in the schematics) so you're measuring the low resistance (like 1 ohm) of the winding in the flyback across pin 5 and 6. If you have other working chassis you'll see the same thing.


Edited by M K L - 23 hours 48 minutes ago at 11:12am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote justez Quote  Post ReplyReply Direct Link To This Post Posted: Yesterday at 10:02am
Originally posted by M K L M K L wrote:

Desolder pin 6 of the flyback and see if it has the correct voltage. if it doesn't the winding in the flyback is likely to be bad. Do you have the other voltages, +200V, -190V? If you have the heater voltage on the pin, check the parts that are connected to it: T1, R10, D1 on the neckboard, the test pattern circuit (that is superfluous anyway) and also the things you circled.


I have installed a new flyback that came from Diemen and the chassis still does not work.
T1, R10, D1 are ok
I desolder pin 6 and measured pin 9 in the socket and I still have no voltage.

+200V, -190V is present. (TP30 TP33)

What I have seen is that pin 9 of the socket has continuity with ground.
Perhaps there is the fault.

I checked and ok: R237 c176 r242 d138 r245 T115 t116 c165 r232 c176 d150 r236 r240 r239 c160 c165 d141 r246 d139


Edited by justez - Yesterday at 10:35am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote M K L Quote  Post ReplyReply Direct Link To This Post Posted: Yesterday at 7:56am
Desolder pin 6 of the flyback and see if it has the correct voltage. if it doesn't the winding in the flyback is likely to be bad. Do you have the other voltages, +200V, -190V? If you have the heater voltage on the pin, check the parts that are connected to it: T1, R10, D1 on the neckboard, the test pattern circuit (that is superfluous anyway) and also the things you circled.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote justez Quote  Post ReplyReply Direct Link To This Post Posted: 21 Sep 2020 at 7:47pm
Originally posted by M K L M K L wrote:

Are you measuring on the pin coming from R35? Did you set the meter to AC? Is it a true RMS meter? Measure on both legs of R35 (one at a time, black lead on ground). If the correct voltage is only on one leg the resistor is open. If no voltage at all there must be something that pulls the voltag down. The flyback output that provides the heater voltage is also used for other things. We'll see later.


I had it in DC, I have put it in AC and I have the following measurements in r35 and it seems that it has tension in both legs but mV not V.
Does not go to 5-6 volts

On pin 9 the following voltage:



 R35 both legs.




Maybe something is wrong in this area



Edited by justez - 21 Sep 2020 at 8:15pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote M K L Quote  Post ReplyReply Direct Link To This Post Posted: 21 Sep 2020 at 5:05pm
Are you measuring on the pin coming from R35? Did you set the meter to AC? Is it a true RMS meter? Measure on both legs of R35 (one at a time, black lead on ground). If the correct voltage is only on one leg the resistor is open. If no voltage at all there must be something that pulls the voltag down. The flyback output that provides the heater voltage is also used for other things. We'll see later.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote justez Quote  Post ReplyReply Direct Link To This Post Posted: 21 Sep 2020 at 4:31pm
Originally posted by M K L M K L wrote:

Heater voltage (about 6.0Vrms) at pin 9 of the CRT socket?


on pin 9 of the socket I have between 4 and 5 mV
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Post Options Post Options   Thanks (0) Thanks(0)   Quote M K L Quote  Post ReplyReply Direct Link To This Post Posted: 21 Sep 2020 at 4:19pm
Heater voltage (about 6.0Vrms) at pin 9 of the CRT socket?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote justez Quote  Post ReplyReply Direct Link To This Post Posted: 21 Sep 2020 at 2:06pm
Today I got the high voltage probe.




I have measured EHT and I get 24.6KV, matches the flyback scheme
I have also measured TP27 and I get a correct square signal at 50V / 20us as it appears in the schematic.
In TP32 I still don't have a correct signal
Cry.



Edited by justez - 21 Sep 2020 at 2:07pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote justez Quote  Post ReplyReply Direct Link To This Post Posted: 17 Sep 2020 at 1:11pm
Originally posted by M K L M K L wrote:

It's the pulse signal that goes from pin 3 of IC104 and through T113, TH102, T114 to pin 1 of the flyback. All the parts and B+ can be good but if no pulse comes from pin 3 the flyback will not work.


Ok, I am going to check Tp23 and Tp27 with the oscilloscope and check the signal.
I have also purchased a high voltage test probe from Diemen.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote M K L Quote  Post ReplyReply Direct Link To This Post Posted: 17 Sep 2020 at 8:19am
It's the pulse signal that goes from pin 3 of IC104 and through T113, TH102, T114 to pin 1 of the flyback. All the parts and B+ can be good but if no pulse comes from pin 3 the flyback will not work.

Edited by M K L - 17 Sep 2020 at 8:20am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote justez Quote  Post ReplyReply Direct Link To This Post Posted: 17 Sep 2020 at 7:08am
Originally posted by M K L M K L wrote:

It's the horizontal drive that you should check. Without that a good flyback will never work.


In the horizontal section, check with the bulb to the HOT collector that B + (138v) arrived correctly
The horizontal transistor and the transformer measured them and they are ok.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote M K L Quote  Post ReplyReply Direct Link To This Post Posted: 16 Sep 2020 at 11:44am
It's the horizontal drive that you should check. Without that a good flyback will never work.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote justez Quote  Post ReplyReply Direct Link To This Post Posted: 16 Sep 2020 at 9:16am
Originally posted by gunblade gunblade wrote:

how is r240 looking?

r240 is ok.
In TP32 there is voltage one 27v but no square signal.
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