Author Topic: SuperBug TV -> Motorola M7000 (Read 7159 times)

vernimark · « **on:** October 10, 2013, 07:55:29 PM »

Hi there,
I have a big problem with my SuperBug monitor. It's simply dead...
I started to control voltages and I can immediately see that I haven't any power greather than 73V. As you can see in the picture 150V is wrong.
I can suppose:
1)HVT doesn't wark at all
2) there is something wrong around HVT

Any idea? Any suggestion?

As suggestion I accept something like "I have something spare for you" also, working or not working (with a different problem obv.)

vernimark

PaulSwan · « **Reply #1 on:** October 10, 2013, 08:56:40 PM »

Your LOPT drive transistor (HOT) is not running/switching so you're seeing 73VDC just as DC on all LOPT low voltage windings, maybe?
If you have an oscilloscope, check if the HOT base is switching.
Paul.

vernimark · « **Reply #2 on:** October 11, 2013, 03:06:24 PM »

Dear Paul,
if I understood correctly transistor you mentioned is Q9 (7696).
I couldn't find any source for buying a new 7696. Do you have any info about it? I dunno, equivalents or online shops?
Tomorrow I'll check it by my scope but I think it has gone...

Thank you

vernimark · « **Reply #3 on:** October 11, 2013, 03:17:53 PM »

ok I found it.

7696 -> B2L -> NTE283...

I hope pinout is the same... 7696 datasheet doesn't exist. Or doesn't exist in my local google DB...

PaulSwan · « **Reply #4 on:** October 13, 2013, 01:26:46 AM »

It might not be bad, just not being driven by the oscillator circuit, hence the need to verify with a scope. You could also pull it out and test it.
But you might get lucky and it be just a bad HOT.
Paul.

vernimark · « **Reply #5 on:** November 18, 2013, 11:37:29 PM »

now I've HV.
after reviewing all Horiz. sequence till the driver I found a broken track! someone changed a capacitor burning the tracks all around. he tried to repair the damage but skipped one connection...

.. now I've another problem

vertical amplitude is not stable. I can see 12V are used for this circuit and in fact 12V are not stable just like the amplitude.

12V are generated through 75V with a couple of diodes, including one zener. Probably zener diode is faulty but I hadn't one for spare. Next post

vernimark · « **Reply #6 on:** November 19, 2013, 04:26:42 PM »

here a video of the described problem

http://youtu.be/1mw7pHhuUkQ

level42 · « **Reply #7 on:** November 25, 2013, 07:48:37 PM »

Looks a bit like a bad height pot.

vernimark · « **Reply #8 on:** November 26, 2013, 10:57:30 PM »

Quote from: Level42 on November 25, 2013, 07:48:37 PM

Looks a bit like a bad height pot.

my next w.e. is dedicate to close this issue

vernimark · « **Reply #9 on:** December 01, 2013, 02:11:47 AM »

Problem solved. 12v zener was faulty. Resto is complete, on few days i ll post all.pics

DarthNuno · « **Reply #10 on:** December 01, 2013, 07:51:55 AM »

Quote from: vernimark on December 01, 2013, 02:11:47 AM

Problem solved. 11v zener was faulty. Resto is complete, on few days i ll post all.pics

Please also schedule a video!

Good job!

vernimark · « **Reply #11 on:** December 01, 2013, 04:02:41 PM »

If i want to record for more than 2 seconds i need someone than help me with camera or play to the game. Or i have to buy glasses with camera inside like thesehttp://m.ebay.com/itm/200996724965?cmd=VIDESC

Etienne MacGyver · « **Reply #12 on:** December 01, 2013, 07:59:36 PM »

what about a tripod

vernimark · « **Reply #13 on:** December 01, 2013, 10:48:24 PM »

Good idea. Ok next w.e.

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