[mr.beam]

Killed my PG tonight while making fine adjustments to the DEF board, suddenly the pj switch off, then few seconds later on again, the red LED at the DEF board named D 023 beginns to light, and the pj switch off again, then on and off, so on.....! What happened? I noticed, that the cooling ripps at the DEF board was hot! Is the STK chip grilled????

Please help, what happened? What to do that locate my problem?

Thank you,

Daniel

 

[Boilermaker]

Daniel,

If you will do a search, you will probably find that you have lost your horizontal outout transistor. Were you trying to adjust the picture width?

 

[mr.beam]

Thanks Boilermaker,

yes I adjusted picture width, but not to much, I think there was enough space to the edges. Why did this killed the horizontal out transistor? Is Q5209 the H OUT transistor, its an 2SC4288A??? Will test it! What else could be wrong, because if I pull all conections to the DEF PWB, nothing changed, the pj switch off and on......did I killed more? All looked so perfect on the tubes faces before it switched off! I was so happy, that I centered the blue with the green, but suddenly it happened!

OK will check the Q5209 in the H.DEF OUT area! What else should I test??? Is the big IC the STK79315A OK? The red LED 023 is on when pj powered up, what does that mean?

Thank you,

Daniel

 

[Boilermaker]

Yes - It is the 4288. There is a procedure in the service manual to properly set the width. All you will need is a VOM.

 

[Tinman]

Do NOT sub the 4288A! Make sure you get the same one again, if it's bad. Too many people blow these out by getting "just a little more" out of the Horizontal size. You MAY have popped D30 in the powersupply as well, but it's rare. D30 feeds the deflection board.


Marc

 

[stefuel]

For those who insist on cranking the H-Width pot, if your going to do it, make only slow and small adjustments.


Chip S.

 

[deronmoped]

Couple of other things on the H-pots. There is a H-out pot, do not get that confused with the H-width, they are pretty close to each other. Also if you turn up the H-width you should max out the H-width (amplitude) on the remote first, because if you have the H-width (amplitude) set to zero on the remote and you max out the H-width pot, then turn up the H-width on the remote that could cause problems.


Deron.

 

[Tinman]

NEC tutorial no.4:


Turning the H-width pot is very helpful in improving your soldering skills.


Marc

 

[mr.beam]

Thank you all for help and advice!


Mark,

will check D30 on PS-B PWB too. I think its the 4288, because D 5023 lit (red LED on DEF PWB), while powering up, so this means the Horizontal defl. is in trouble!

Yes Marc good chance improving my solder artwork



So will be back with some BBQ transistor's, bon appetito!

Later,

Daniel


The beer is cold!

 

[mr.beam]

Yep, its the 4288A, reads 1,1 ohms in all directions! With what brand should I replace it, either a TOSHIBA or a PMC. Get both here in Berlin. I noticed that the transistor was already changed some time ago, so in was the TOSHIBA!

What about the driver two 2SK752, or the other transistors on the cooling ripps, could they got grilled too???? I pull out the D 5206 near the 4288, measured it, but it is OK! So it wents in again!

Thanx for help, will drive to Berlin now, and buy some 4288A!!!!!


Daniel


The beer is cold!

 

[Tinman]

Buy the Toshiba. Do NOT substitute.


Say Hi to Berlin for me, I was born there.


Marc

 

[mr.beam]

Hi Marc,

live in Berlin since 1984, first WEST, now all together, great town, so the music and life......got the TOSHIBA today , will solder it, hope the PJ will work with again! And nothing more to change???

Then will do the service adjustments page 5-28 in the 9PG service manual with my Hameg scope connected to TP 4003, but at the 10PG only 0,83Vpp not 1,3Vpp is to be adjusted with VR4002 V-HEIGHT! I think that I did adjust VR4002 wrong before! Without my scope, just with feeling....

Perhaps you want to visit Berlin sometimes, then you are welcome in my house!

Thank you,

Daniel


The beer is cold!

 

[mr.beam]

Please help!

Changed the 4288 with a fresh Toshiba, reistalled the board, but then all the same, red LED 023 light, Pj switch off after a few seconds, and a few seconds later switched on again, and so on..... I checked all voltage from power supply, all OK, supply is OK!!! So pull out the DEF PWB again, and noticed the H Out transistor 4288 is burned again! What had I done? I put all pots to mid, but it was burned again?! Need realy help, have one good 4288 left, but what to do not to burn it again???????

I checked the driver and the other main transistors, all OK, the diodes, all OK! May I have killed the deflection coils? Why is the H out transistor toasted again?

Please help,

Daniel

 

[stefuel]

Mid point is probably not what you want. That pot is very sensitive. It would be best if you remembered where it was prior to moving it. I'm sure you noticed how little adjustment it took to make large changes in raster size.


Chip S.

 

[Tinman]

Turn that pot up only 1/4 to start. Less, even.


Marc