Home Theater Forum and Systems banner

1 - 20 of 58 Posts

·
Registered
Joined
·
58 Posts
Discussion Starter #1
Hey guys new here.

I have an open on F9A04 or 5. and High resistance on the other.

What IC part # do I need to order.

what size are the fuses.

I figure I'd replace both IC's while I was doing it.

Any help is great.

Thanks
PHil
 

·
Plain ole user
Joined
·
11,121 Posts
Your post was moved to a new thread to keep the forum better organized. I assume that you have the same model, but if not, please say so and I will change the title of the thread.

An open fuse should read a high resistance. An intact fuse should read a near short. These fuses are on the +/- 24V supplies that power the convergence IC (+/-) and the vertical output (+ only). The most likely cause for them blowing are the convergence ICs, though a vertical failure can take out the + supply.

This set uses the single STK393-110 output IC for the convergence. I do not recall the fuse values but they are marked on the fuse itself and on the circuit board, IIRC. I suggest using one of the suppliers in the thread here:

http://www.hometheatershack.com/forums/diy-repair-maintenance/4396-parts-distributors.html

B&D is good choice for you because they would have the fuses as well as the IC.

Read the first 10 posts here very carefully:

http://www.hometheatershack.com/forums/diy-repair-maintenance/5600-crt-based-rptv-convergence-repairs.html
 

·
Registered
Joined
·
58 Posts
Discussion Starter #3
Thanks for the reply.

I think I checked the wrong things.



Whats circled in green is what I checked thinking it was the fuse.

Upon further review and looking at the pico fuses online I believe what I circled in red to be the fuses.

Am I right?:time-out:
 

·
Plain ole user
Joined
·
11,121 Posts
Yes, your revised info is correct. The little green things are the fuses. The other is a diode.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #5
ah. so do I still need to check fuse resistance or do you just look?

I'm new at this can ya tell? lol
 

·
Plain ole user
Joined
·
11,121 Posts
No way to tell visually, you need a meter.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #8
Ao4 and Ao5 read open and Ao2 has low resistance.

Now I know you said open means they are good. But that just doesn't make sense to me. open should mean bad. Did you have a typo??


thanks
Phil
 

·
Plain ole user
Joined
·
11,121 Posts
No, open is bad, short is good. Read again.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #10
ah. Now that I think about it your right. I wasn't 2nd guessing you I was just making sure.

So F9AO2 had very low resistance.

seems like those fuses are good.

No need to replace them or IC right?

Now I need to test the rest of the fuses.
 

·
Plain ole user
Joined
·
11,121 Posts
F9A02 is on the audio supply I believe. Need to check the schematic to be sure.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #12
I'm not trying to get into this with you. I'm just trying to understand. Maybe I am the one using the wrong terminology.

When I say open My DVOM shows L or 1.

Which means there is no continuity which means the fuse is blown.

Now I believe the Ao2 fuse is good because it has continuity at .xx ohm.

the way I am taking what your saying is that if the fuse has continuity its bad.

Hopefully this will clear some things up.
 

·
Plain ole user
Joined
·
11,121 Posts
Sorry, I misread your earlier post and I missed the last one. Been sick in bed the last couple of days so not all here...

If the fuses are good time to regroup. Lets' start over. What is the set doing, exactly?
 

·
Registered
Joined
·
58 Posts
Discussion Starter #14
I never checked codes before I replaced the 7 caps So I don't know if it was the same code as before but its doing the same thing

plug in light flashes for a bit. then goes out.

Hit power light goes on for 3 sec or so then goes out.

Check codes and get 22. Short protect.

Now checking the pico fuses with my dvom.

F9A04 gives me a 1 value signaling it is open the fuse is blown.
F9A05 does the same.
F9A02 has a very low resistance about .08 meaning that fuse is good.

Or at least that how I see it.

This is where we got confused last time lol
 

·
Plain ole user
Joined
·
11,121 Posts
If those fuses are open you likely have a bad convergence IC.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #16
Alright good deal.

Anything else I should replace while I'm in there?

Already got the 7 caps on the DM board replaced.

Thanks

Phil.
 

·
Plain ole user
Joined
·
11,121 Posts
You need to change whatever else is bad. Sometimes resistors are damaged. You need to replace the fuses, verify the supplies at the chip, check the resistors with the chip removed and yokes disconnected, and repair any bad solder connections.

Read the first 10 posts of the convergence repair thread thoroughly, it covers all of this.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #18
two quick things...



I assume I should fix that solder. It was like that when I got there.

Its on the middle board. Where the one metal case screws down... I'll get a better picture of the thing i am talking about and post it up.

2nd question is that on my board the heat sink compound was kinda slopped on I figured it was like that from the factory. There was some between the heat sink and the compound. Is that needed or just excess?

Thanks.

Phil
 

·
Plain ole user
Joined
·
11,121 Posts
I see nothing that would be a problem in that image.

There is a discussion of proper use of heat sink compound in the convergence thread.
 
1 - 20 of 58 Posts
Top