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Phillips 60pp9352/17
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rip1980



Joined: 11 Oct 2009
Posts: 8
Location: San Diego

PostPosted: Sun Oct 11, 2009 11:20 pm    Post subject: Phillips 60pp9352/17 Reply with quote

I took a broken Phillips 60pp93 off some one's hands and hoped to repair it in my spare time.

Would not power on, immediately suspected convergence ICs, as is common with these.

I got in to it and found that it did not match the schematic. Upon pulling the board I found both convergence ICs had been replaced previously. (I suspect more than once.)

Schematic calls for STK392-120 but unit had STK392-110 installed. Found 3 solder pads had been lifted by previous repairs (and so, question the competence.) Replaced as per the schematic with -120, genuine Sanyo.

Found 2 pairs of resistors for the red gun appeared to be open. These were NOT 6.8 ohm, but badly discolored from heat so have no idea what there were exactly, but did not match the other 6.8's in circuit. Schematic called for 6.8 ohm so replaced them with that.

Unit powers on now, Green and Blue guns work.

RED gun will flash with a HV ticking sound if I turn screen voltage UP. I took a video of this action if anyone needs it, I'll put it online. Turning it down stops the ticking and the gun stays dark.

I suspect that:

1) The resistors are too low, tripping a protection circuit or or otherwise dragging the HV down. What would be the effect of too little resistence here in a working set?

2) Weak cap in the HV section, but I'd expect that to be systemic (all guns).

Anyone have any insight to this or a working unit to compare to? Suspect resistors are pairs 3159/3160 and 3153/3154.

Thanks in advance!

A bunch of reference material, image filenames contain page number from PDF manual:





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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Mon Oct 12, 2009 9:51 pm    Post subject: Reply with quote

Have you tried swapping CRT boards to see if the problem follows the tube or the CRT board?
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rip1980



Joined: 11 Oct 2009
Posts: 8
Location: San Diego

PostPosted: Tue Oct 13, 2009 2:10 am    Post subject: Reply with quote

I have not.

I picked up today what is my best guess of what the original resistors were (630 ohm) and want to give that a shot and will try swapping CRT boards if it doesn't stabilize.

Original owner claims it just quit, no dramatics. Clicked off and never came back. But on the other hand, they never mentioned previous repairs which were obviously done. Maybe they were hoping to get something for it.

It's also hard to work from PD schematics, so printed out all the interesting bits on 11x17....if it's the gun itself, I'd probably just part out the chassis.

Thanks for the reply, will give it a shot.
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rip1980



Joined: 11 Oct 2009
Posts: 8
Location: San Diego

PostPosted: Mon Oct 19, 2009 6:13 am    Post subject: Reply with quote

Sorry I havn't been able to get around to messing with this until a today. Strained my back at workand hunching over inside the chassis wasn't a (good) option.

I tacked in the 630ohm resistors and got some stability. I did not have much time to mess with it, but I can get it to light up weakly turning up the screen voltage. It is very out of focus and convergence is way off, but is working and deflecting.

I made no attempt to dial it in until I'm comfortable I know what's going on. I rather not diagnose via smoke.

Turning up the screen voltage, it'll simply click and stop emitting, not cycling like it was.

Laying flat on my back, I was looking over the schematics. There are surge protectors on the CRT boards and one may have gone bad and/or I have might have a path between G2 and something, possibly deflection.

You advice on swapping CRT boards is spot on. I didn't get a chance to do that tonight, but will...while I have it out,I want toinspect it and see if theer are any tattletails (carbon tracks or anything)of something amiss.

Any opinion on how dangerous it would be to lift a leg on the surge protectors and power it up? Maybe after a get my meter on it and insure wedon't have some runaway voltage condition. I may very well be good and doing it's job.
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Mon Oct 19, 2009 3:01 pm    Post subject: Reply with quote

They should be 6.3 ohm resistors not 630.
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jts1957



Joined: 24 Nov 2008
Posts: 2472
Location: Far, Far Away

PostPosted: Mon Oct 19, 2009 9:30 pm    Post subject: Reply with quote

Thought he had ascertained were 6.8 ohms? Confused
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rip1980



Joined: 11 Oct 2009
Posts: 8
Location: San Diego

PostPosted: Thu Oct 22, 2009 3:52 am    Post subject: Reply with quote

OK...not mentioned before, but the reason I tried 630 is that's what they appeared to be, not matching the other deflection resistors. They also appeared to be original and not replaced.

Anyway, the higher resistance did let me weakly light the red tube with screen voltage before sagging out and dimming all the guns.

So tonight, I returned it to stock, 6.8 ohms.

I swapped the green and red CRT boards....the clicking (presumibly HV discharge) went away. The red tube would not light, turning the screen voltage up just sags out the other tubes.

However, I know the red gun works (had it running with the higher resistance.)

I'm pretty sure the red CRT was on well. I was surprised at no discharge clicks,
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rip1980



Joined: 11 Oct 2009
Posts: 8
Location: San Diego

PostPosted: Sat Oct 24, 2009 6:06 am    Post subject: Reply with quote

Ummm, it was late when I wrote that, but the last line should be I am pretty sure the CRT board for the red gun was making good contact.

So, thoughts on what it means to have the HV sag out when turning up the red screen voltage? (IE, the blue and green wil ldim and go black if you keep turning up red's screen voltage)

In my testing, I did NOT try putting the green screen voltage on the red tube.
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rip1980



Joined: 11 Oct 2009
Posts: 8
Location: San Diego

PostPosted: Sun Nov 01, 2009 7:57 am    Post subject: Reply with quote

My conclusion on this is it sounds like a short between Screen and ??

I have a couple ideas to try to recover the tube as I doubt i'll be able to get another one. Hopefully it'sjust a wisker or something falled into the neck of the CRT and I can shake it to someplace less trouble some.
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Sun Nov 01, 2009 6:39 pm    Post subject: Reply with quote

Start again. Green and blue work, you swapped green and red CRT boards and the green still works but red still doesn't?
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