Mitsubishi VS-5051 CONV Board


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Mitsubishi VS-5051 CONV Board

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BLF62
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Oct 19, 2009, 3:08 AM

Post #1 of 16 (2741 views)
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Mitsubishi VS-5051 CONV Board	Can't Post

Are the convergence circuit pico fuses that are referenced elsewhere on this forum part of the conv board or located near the big conv ICs? I see on the schematic some resistor looking components like R8E13 "F-1.8K". Is that a pico fuse with a 1800ma rating?

jts1957
Veteran

Oct 19, 2009, 2:50 PM

Post #2 of 16 (2735 views)
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Re: [BLF62] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

THINK

R = "ohms" (Resistor)
F or FU = Fuse

-------------------------
Location: Far, Far Away

Ron.M
Veteran

Oct 20, 2009, 1:42 AM

Post #3 of 16 (2728 views)
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Re: [BLF62] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

BLF62;....

Quote

Are the convergence circuit pico fuses that are referenced elsewhere on this forum part of the conv board or located near the big conv ICs?

They are NOT on the convergence board....See below...

Quote

I see on the schematic some resistor looking components like R8E13 "F-1.8K". Is that a pico fuse with a 1800ma rating?

Methinks you know just enough to be dangerous .... Sly

...
I have the service manual for that set & I could NOT find "R8E13 "F-1.8K" or
anything even close.... Unsure

....

The pica fuses for the convergence IC's are Z9A02 & Z9A03...
They are for the + & - 24 volt supplies....
They are near T9A00 which is the switching power supply transformer
located on the "Main" board......
They are little & usually black in color laying flat on the "Main" board...
They are rated at 5 amp each....
Depending on how severely the IC's are shorted , you will need to check the
other supply voltage coming off the flyback....
That will be R556 & R555 located near the flyback....
They are 1.2 ohms @ half watt each...
They are for the + & - 35 volt supplies...
According to my manual , the convergence IC's are STK391-020...
You need to replace BOTH....

Good Luck....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

BLF62
New User

Oct 20, 2009, 3:39 AM

Post #4 of 16 (2726 views)
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Re: [Ron.M] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

Thanks for the info Ron.M,
I have not worked on very many TVs, more instrument amps and guitar stuff.
Also I got the service manual online for 12.99 so who knows. It does seem like a lot of information is missing from it.

Paulpablo
Enthusiast

Oct 20, 2009, 3:51 AM

Post #5 of 16 (2725 views)
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Re: [BLF62] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

Ron , you are so nice to these layman folks!

Ron.M
Veteran

Oct 20, 2009, 6:47 PM

Post #6 of 16 (2717 views)
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Re: [Paulpablo] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

Paulpablo;...

I'll take this as a compliment...THANKS....

Quote

Ron , you are so nice to these layman folks!

That's real easy for me....
I'm non-discriminatory , non-biased & not bigoted or racist....
Even tho you & I have had a tiff or two , you appear to be about the same...
What some people on this forum definitely forget is that the name of this website is "TV-Forums.com".....
It is NOT "TV Technicians only.com" as some (maybe even you) would think....
Let's face reality...Money is VERY tight...
If you can help someone out here , HOW much does it cost YOU ????...SQUAT!!!...ZILCH...NADA...ETC....
Helping a newcomer here requires some finesse...
You should be able to determine their ability BEFORE you give ANY
potentially hazardous advice....That is NOT easy ....
My biggest fear is adviseing a greenhorn & he/she gets hurt.... Unsure

....
OR makes matters worse...

Regards....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

BLF62
New User

Oct 20, 2009, 7:55 PM

Post #7 of 16 (2714 views)
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Re: [Ron.M] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

I am not that GREEN,
I developed my own boards in cad for the Peavey Classic amps. A power tube board of my own design based on books from Kevin OConnor and others.
I understand the dangerous parts concerning loaded caps and ps sections.
As I am working on a 15 year old TV if I cannot fix it myself welll...................what would a layman say.
This is interesting because I have not seen this attitude anywhere else on the technical forums I wander into.
I thought I asked a decent question and Paul really did not answer it.
I'm sure someone will tell me the "SECRETZ" soonzzzzzzzzz or not.
I'm ordering the STK for like $8 vs $39 each locally.
I am not sure what to get for the picofuses...............

Ron.M
Veteran

Oct 20, 2009, 9:03 PM

Post #8 of 16 (2711 views)
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Re: [BLF62] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

BLF62;....

Be advised , you get what you pay for....
$8.00 is too cheap & $39.00 is highway robbery....
My advice is to get ONLY Sanyo replacements...
Here is a VERY good place to get them from:....

http://www.mcmelectronics.com/product/STK391-020

They are $10.59 each...

I've done bussiness with them in the past & they ARE reputable & back up their warranties....

Also the pico fuses:....

http://www.mcmelectronics.com/...C=&K=fuses&T=

Part # is;.. 28-0636 @ $3.69 each....
Scroll down a bit...
Looks like 5 fuses to that package....

OR if you want to spread the wealth around, try here:...

http://www.bluestar-online.com/...mp%20pico%20fuse.htm

They are $0.99 each...+ $9.00 s&h....

Now about your post:...

I HOPE some of that was meant for someone else & NOT me...
MY last post was aimed at Paulpablo & NOT you...

Quote

This is interesting because I have not seen this attitude anywhere else on the technical forums I wander into.

It's nice to see that I'm NOT alone with your observation & I concur...

Please keep us informed as to your progress ....
I HOPE the info provided helps....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

BLF62
New User

Oct 21, 2009, 3:18 AM

Post #9 of 16 (2704 views)
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Re: [Ron.M] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

Ron you and I are on the same page concerning the attitude issue.
I ordered for close to that price 11.99 ea for the STK parts with a guarantee of real Sanyo parts.

Thanks for your help!

Ron.M
Veteran

Oct 21, 2009, 3:35 AM

Post #10 of 16 (2702 views)
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Re: [BLF62] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

BLF62;....

Glad to see you're getting Sanyo IC's.... Laugh

.....

& you are VERY WELCOME!!!!.... Sly

......

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

BLF62
New User

Oct 21, 2009, 5:13 PM

Post #11 of 16 (2697 views)
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Re: [Ron.M] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

I am starting to understand this device better, the layout of PSs and signal and it is making more sense. As such I found some PS resistors on the signal board that have very poor solder joints and also similar on the DBF board. All the stuff I normally work on is AUDIO and this has some new and different circuits. But it does have a beauty after you stare at it a while. It "aint" mil spec but it is well made and lots of room between hot components.

Ron.M
Veteran

Oct 21, 2009, 7:47 PM

Post #12 of 16 (2691 views)
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Re: [BLF62] Mitsubishi VS-5051 CONV Board [In reply to]	Can't Post

BLF62;.....

Other than the fact that Proj TV's have a LOT of different circuits , the audio circuitry is a relatively small part of the unit...

Unless you know for sure the conv IC's are bad (ie,blown fuses) ,
check those connections as well....You "might" get lucky....
Also check those 1 & 2 watt resistors near the conv ICs for discoloration (Burns) & continuity....

Mitsubishi did make some decent big screen TVs...

Once again, GOOD LUCK... Sly

....

Later...Ron.M.... Cool

...
Veteran & Retired TV technician

BLF62
New User

Oct 25, 2009, 5:37 PM

Post #13 of 16 (2668 views)
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Mitsubishi VS-5051 CONV Board Update [In reply to]	Can't Post

Just waiting on ICs now. I was able to remove the FBT and go over all the boards. I found over 25 ready to fail solder joints mostly at resistors used in power supply sections of circuits. One resistor was so ready to go that it fell from the board while I was using a discharge probe to get at the bigger capacitors. I also touched up most all the plugin card headers and cleaned all the terminals. All of the places of ciscoloration and heat stress were limited to just a slight darkening of the PCBs no real physical damage.
After doing all this one thing really impresses me about this old set, all these connectors were easy to unplug not one single connector failed to be unplugged.

BLF62
New User

Oct 26, 2009, 11:19 PM

Post #14 of 16 (2654 views)
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Mitsubishi VS-5051 CONV Board Update [In reply to]	Can't Post

Got my parts in this afternoon. Was easy to solder and everything else was already to go.
Put it all back together and after several connector checks fired her up.

Yep it still works and YEP it still has the same issue.
One change is that I am getting this little convergence warble that looks like the convergence is about to line up.

any suggestions?

Ron.M
Veteran

Oct 27, 2009, 12:20 AM

Post #15 of 16 (2651 views)
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Re: [BLF62] Mitsubishi VS-5051 CONV Board Update [In reply to]	Can't Post

BLF62;....

"any suggestions? "

Quote

So I said "OK" and am now just using the forum or PMing someone with specific questions that is not bothered by PM.

Are you asking "me" or someone else????.... Crazy

....
Are you able to send pix ???....
Did you;..
Also check those 1 & 2 watt resistors near the conv ICs for discoloration (Burns) & continuity...post resistor #'s & values...
Depending on how severely the IC's are shorted , you will need to check the other supply voltage coming off the flyback....
That will be R556 & R555 located near the flyback....
They are 1.2 ohms @ half watt each...
They are for the + & - 35 volt supplies...
Did you replace these...Z9A02 & Z9A03...
Re-check those two for at or very near zero ohms...
I've seen those go bad just by soldering them in...

PLEASE reply on ALL of the above....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

BLF62
New User

Oct 27, 2009, 1:36 PM

Post #16 of 16 (2646 views)
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Re: [Ron.M] Mitsubishi VS-5051 CONV Board Update [In reply to]	Can't Post

Ron,
I did replace the pico fuses, the 2 conv ICs, most of the 100uf caps on the CONV board, and went over every solder joint, resoldering any that even began to look bad. That said there were lots of cold solder and fatigue cracks, like maybe 50. Some were so bad that just touching the component made it fall loose.

since posting yesterday, the following changes,
after I had the set on for say 15 minutes and went through the convergence it is working better than ever.
It seems to require a slight warm up period now.
There is a very small amount of grain that I had not noticed, however I am being very critical, perhaps trying to make this old set something it is not. Also since doing all this I have to remember that the picture is improved dramatically from where it was and the slight grain and other artifacts may have been masked by dirt and poor convergence.
I am going to just use it a week and re-evaluate and play with further settings adjustments but sparingly.
Thanks for all the help.

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