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Main => Monitor/Video Forum => Topic started by: rchadd on December 30, 2010, 09:08:58 pm

Title: K4600 vertical Collapse after incorrect of B and G yoke connections
Post by: rchadd on December 30, 2010, 09:08:58 pm

After I incorrectly connected the B and G connections on the yoke there was load buzzing sound and no picture when I turned the game (gorf) on. On correction now an expereincing vertical collapse of the display (a single horizonta line)

Any ideas on what is cause?

Did i fry any components or the kill the yoke/tube itself?

Any suggestions on where i should start looking?

is this monitor now officially dead?

Title: Re: K4600 vertical Collapse after incorrect of B and G yoke connections
Post by: Ken Layton on December 30, 2010, 11:42:31 pm

Probably damaged the transistors on the hor/ver (a.k.a. the "XY" ) card.

Title: Re: K4600 vertical Collapse after incorrect of B and G yoke connections
Post by: rchadd on December 31, 2010, 03:35:40 pm

thanks ken.

i will check out the schematics and order some new transistors.

any suggestions on specific transistor(s) that could be responsible?

Title: Re: K4600 vertical Collapse after incorrect of B and G yoke connections
Post by: Ken Layton on January 01, 2011, 01:01:51 am

The two heat sinked transistors on the hor/ver board.

Title: Re: K4600 vertical Collapse after incorrect of B and G yoke connections
Post by: rchadd on January 01, 2011, 09:33:56 pm

i guess those would be the transistors labelled V.OUT with doted circle around them on the schema? TR305 & TR306

would i also need to look at possibly replacing other V. transisitors? V.AMP or V.DRIVE?

unfortunately i do not have the monitor chassis local to me to verify the component naming.

Title: Re: K4600 vertical Collapse after incorrect of B and G yoke connections
Post by: rchadd on May 01, 2011, 08:51:00 am

Thanks for the advice Ken i have fixed the vertical collapse issue.

I tested the transistors using multimeter in diode test mode and it confirmed that tr305 and tr306 were bad.

the schema indicated that following codes for the transistors:

tr305   2SA490
tr306   2SC1625

I used a TIP31 instead of a 2SC1625 as i could not find supplier in UK.