Author Topic: Recapped a NeoTec NT-27E, now it won't turn on (Read 3126 times)

Sarver Systems · « **on:** September 24, 2014, 09:06:25 am »

Ideas?

I am getting 110VAC to the plug, and the fuse is good.

I didn't adjust anything on the board, and the monitor worked before I capped it.

I triple checked each and every cap to make sure I put the right value in, and made sure polarity is correct.

No neckglow, no startup crackly sound.

I do get a bit of a buzz from the pincushion board now, which I don't remember getting before.

ed12 · « **Reply #1 on:** September 24, 2014, 11:24:29 am »

chk on the cold side of your smps for +26 and +125
these are your switched supply output's of interest

ed

Sarver Systems · « **Reply #2 on:** September 24, 2014, 05:33:04 pm »

Ed, I want to try what you are asking, but you're talking a little over my head.

I'm checking for 26VDC and 125VDC at what points?

ed12 · « **Reply #3 on:** September 24, 2014, 07:30:45 pm »

as pre page 4 of there service manual
which is to big to up-load

ed

Sarver Systems · « **Reply #4 on:** September 24, 2014, 08:53:01 pm »

Assuming the voltages check out, lets look at page 5 for a minute.

Step 5.2.3: Adjust R112 to set the horizontal deflection B+ (the connection point of R117/R424) to 113.5V.

So where exactly am I attaching leads?
Looking at the parts, R117 does not connect directly to R424. So I can't connect a lead where they intersect.

So am I supposed to connect 1 lead to R117 and the other to R424? If so, which side of each resistor?

Or maybe it means I can use R117 or R424 for one lead, and the other to ground?

I see, on page 11, bottom left corner where R117 is shown, there is a little arrow with DC written on it. I'm thinking this is indicating a test point. Correct?

ed12 · « **Reply #5 on:** September 24, 2014, 09:07:15 pm »

yes to the test point "pg11"
and 1 lead to cold ground
smps output ground,
NOT the smps input side
all the test point's will have that triangle on the print

ed

Sarver Systems · « **Reply #6 on:** September 24, 2014, 09:59:59 pm »

PG11?

ed12 · « **Reply #7 on:** September 24, 2014, 10:08:34 pm »

exacting tonight ?

>I see, on page 11, bottom left corner where R117 is shown, there is a little arrow with DC written on it. I'm thinking this is indicating a test point. Correct?<

pg=page

ed

Sarver Systems · « **Reply #8 on:** September 24, 2014, 10:12:50 pm »

Oh, pg is page. I'm sorry, I'm reading too much into it.

Hahahaha. Thanks, as always, for the help!

I'll report my findings.

Sarver Systems · « **Reply #9 on:** September 24, 2014, 10:13:32 pm »

What is "smps"?

ed12 · « **Reply #10 on:** September 24, 2014, 10:24:52 pm »

no problem
i was just poking at ya

smps=switch mode power supply

ed

Sarver Systems · « **Reply #11 on:** October 14, 2014, 10:34:01 am »

Bumping this to the top so I can find it when I am working on this monitor tonight.

Sarver Systems · « **Reply #12 on:** October 15, 2014, 08:26:00 am »

Made some progress!

Apparently during the move I snapped off the V-Hold (or maybe it was the H-Hold) pot on the remote adjustment board.

It called for a 5K, but all I had was a 10K. Set the the 10K to 2.5K (the middle point of a 5K pot) and solered it in.

Monitor fired right up!

But then it made a really high squaling sound, and blew up cap C19 off the pincussion board. Boy did that make some noise! I don't think my feet hit the floor more than once to get it unplugged.

I'll have to take some pics of the board.

So now the question is, what is the correct value of this cap?

I have the Neo-Tec manual, but it lists a bunch of caps that arent populate on my board, and a few of them are different values. The book is for 3 different models, so I assume the missing components would be for the other models in the book.

So, if anyone has a Neo-Tec NT-27E, can they take a look at the pincussion board and let me know the value and orientation of C19? You can see it without having to remove the chassis, its mounted on the outside, at the edge of the board.

My notes say I removed a 4.7MFD @ 50V.

mgb · « **Reply #13 on:** October 16, 2014, 08:07:59 pm »

C19 on the pincusion board shows as a 5.6uF 50volt bipolar in the scematic.

I read somewhere that its high freq

ed12 · « **Reply #14 on:** October 16, 2014, 08:27:15 pm »

it is in the horz sweep circuit
so bi-polar it is
i q the 50v in a high voltage sweep spot
i would tend to ramp the volt's up
but yes stick to bi-polar

ed

Sarver Systems · « **Reply #15 on:** October 17, 2014, 08:20:56 am »

I don't think I put a bipolar in that spot. My notes don't indicate that I removed a BP from the location.

However, if you're getting those specs from the manual, the manual is VERY wrong.

The manual shows caps and transistors on the board where there is nothing. I can see spots where they should be, but the spots are not populated.

If you've got an NT-27E sitting in front of you, and you're getting the specs from the board itself, then I totally trust you.

If you're getting the specs from the book, then I highly doubt you, just because none of the other specs are correct.

mgb · « **Reply #16 on:** October 17, 2014, 10:13:00 am »

I got it from the schematic and from ken Layton.
Schematics have been known to be wrong but I can't think of a time that ken has been wrong.

Sarver Systems · « **Reply #17 on:** October 17, 2014, 10:36:38 am »

Came from Ken? Now there is another reliable source that I would never doubt.

Consider it done!

C19 = 5.6uF 50volt bipolar

Sarver Systems · « **Reply #18 on:** October 30, 2014, 05:16:24 pm »

Mouser does not carry this value in bi-polar.

They do carry 4.7 and 6.8.

Suggestions?

Sarver Systems · « **Reply #19 on:** October 30, 2014, 06:16:43 pm »

Also, the board definitely has a polarity marking on it.

Sarver Systems · « **Reply #20 on:** November 03, 2014, 03:51:57 pm »

Any firther comments?

I purchased the following:

4.7 @ 50V BP
5.6 @ 50V
6.8 @ 50V BP

ed12 · « **Reply #21 on:** November 03, 2014, 05:00:17 pm »

stick with 4.7
even though it is bp
just as a rule follow the board..
as a bp it really dose not matter,just i do it out of doing it so many times

ed

Sarver Systems · « **Reply #22 on:** November 04, 2014, 08:44:58 am »

Just to verify, you want me to put in a 4.7 @ 50V BP in the location?

Sarver Systems · « **Reply #23 on:** December 10, 2014, 12:11:07 pm »

Recapped with the BP cap, and all is well.

mgb · « **Reply #24 on:** December 12, 2014, 11:03:24 pm »

Glad to hear it worked out.


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