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Mitsubishi WS-55511 Problem

8K views 57 replies 4 participants last post by  GTvert90 
#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
 
#2 ·
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/for.../5600-crt-based-rptv-convergence-repairs.html
 
#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:
 
#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.
 
#13 ·
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?
 
#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
 
#17 ·
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.
 
#23 ·
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.
I have had the same convergence problem with a WS 55511. I replaced the convergence IC and the pico fuse A04 when it showed it was open. The TV turned on fine after everything was reconnected and I went to bed thinking it was fixed. The next day turned it on and the green light did the 3 second thing and kicked off. Pulled the board and the pico fuse was blown again. Now I'm trying to determine what is the cause of the short.

In reviewing the many posts on these models the above info was provided. When "verifying the supplies" is this an ohm check that you are referring to?

The resistors mentioned with the chip removed - I checked the 12 resistors pictured on one of the other threads that are adjacent to the IC and they checked out ok - however you mentioned the "yokes" needing to be disconnected. I have read this in the other threads but no description of the yokes. Any further info would be appreciated.
 
#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
 
#27 ·
Gtvert90:

I will post the picture of the resistors once I have reached the authorization limit to post. However in the meantime, the resistors that were mentioned on this model are purple in color, grouped together in two sets of 6 and are just in front of the IC chip. They are marked "3.9 ohms". I checked them with the IC connected and they measured 2.3 - lcaillo mentioned in a post that they may measure less when they are parallel so I assumed they were ok however this probably isn't correct since the IC was still connected. Any thoughts?
 
#26 ·
Thanks for the info - reading these posts and working on this set has been very educational. Of course I want to reach that point of a sense of accomplishment - when it is working!

I had removed the DM and inspected the 7 capacitors as mentioned previously. They were manufactured by "Jimenco" (sp?) that had put out some bad lots per other post but they weren't "bulged" but from your prior recommendations it would be a minor expense but wise move to go ahead and change them out.

Thanks again!
 
#29 ·
Check the schematic. If they are 3.9 ohm resistors and two are in parallel, this would be 1.95 ohms, adding a tenth for lead resistance and you are in the ballpark. I do not recall the values of every resistor in every set. They vary.
 
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