Mitsubishi VS-45603 Will not turn on


	FORUM HOME	SEARCH POSTS	WHO'S ONLINE	LOG IN	RULES F.A.Q.

TV Forums: TV Equipment: Projection TV Forum:
Mitsubishi VS-45603 Will not turn on

1 2

View All

Print Thread

Hazardsneon
User

Feb 1, 2010, 8:24 PM

Post #1 of 48 (8013 views)
Shortcut

Mitsubishi VS-45603 Will not turn on	Can't Post

I have a Mitsubishi VS-45603 and it will not turn on. I have found out that the 9 volt main on the signal board isn't getting power. Then, I found out that the 9 volt on the signal board is supplied by the 12 volt on the main and that isn't powered. Then, I traced out the circuit that turns the 12 volt on and off and it seems that the processor isn't sending out and "on" signal. What could make the processor not want to turn on the power???? This set was turning on perfectly until I recently put 2 new caps in the 9 volt main supply due to a shaking screen. I have double and triple checked that I have the polarities right. I've even tried turning it on with just the output cap in, just the input cap in and then neither cap in. Nothing seems to work. I've made sure I plugged in all connectors and that all the blade connectors are making contact. Please Help I really need to get this going. Thanks

Repair man
Enthusiast

Feb 2, 2010, 3:06 AM

Post #2 of 48 (8009 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

Here are some various repair solutions for that chassis I found in my notes ...

Change STRF voltage regulator.

Replace Q5A00,R566,C551 & R567.

REPLACE C957 820uf @ 180v ON MAIN BRD

Check for 10 vdc at pin 5 of IC502 if low, Check IC503 (Part # 270P704010 on the main PCB.

Check R529 .82 OHM 1/2 watt off pin 4 of flyback, if open check C411 2200 UFD @ 35V and IC 451 (Part # 270P064020) on the main PCB.

.

------------------------------------------------------------------------------------------

If you (or anyone reading this post) have any further questions or need clarification please feel free to contact me direct; you can find my email address by clicking on my user-name.

Learn Plasma TV Repair

_________________
Learn LCD TV Repair

Hazardsneon
User

Feb 2, 2010, 4:37 AM

Post #3 of 48 (8005 views)
Shortcut

Re: [Repair man] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

Awesome! I will be checking those components. Could you clarify which regulator the STRF regulator is? Thanks again!

jts1957
Veteran

Feb 2, 2010, 6:21 AM

Post #4 of 48 (8004 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

SMPS (Switched Mode Power Supply) Main regulator. Wink

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

Hazardsneon
User

Feb 2, 2010, 3:01 PM

Post #5 of 48 (8001 views)
Shortcut

Re: [jts1957] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

Call it a brain fart.... Thanks for your help. I will most likely be checking it out tonight after work.

Hazardsneon
User

Feb 3, 2010, 4:57 PM

Post #6 of 48 (7994 views)
Shortcut

Re: [jts1957] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

So I checked the parts listed and they all measured what they should be. Even if they are still reading the correct values should I replace them? Also, the output transistor Q5A00 wasn't shorted could it still have a problem? Pin 5 of IC502 had nothing on it so I will be replacing IC503. R529 was still there. I don't think I have a problem with the smps because I still have standby +12V. In reguards to Q5A00, I happen to have a part that is very similar to it but only a little less gain, I have a 2SC4125. Do you think that it would work?

Hazardsneon
User

Jul 6, 2010, 3:37 PM

Post #7 of 48 (7888 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

So, I replaced all of the parts listed above. I am still at the same place I was before. I really need to get this tv going. I have a slim budget otherwise I would just buy a new main board. I took a variety of measurements and they go as follows:
-Pin 5 of IC502 has 0 volts
-Pin 8 of IC502 has 0 volts (+28V supply)
-The +130V supply is at 0 volts
-The +34V supply is at 0 volts
-The +12VS supply is at +12 volts
-The +30V supply is at 35 volts
-The +32VS supply is at 112 volts
-The SHORT signal is at 0 volts
-The P-ON signal is at 0 volts
-The AC-OFF signal is at -13 volts

Please, I would very much appreciate some help resurrecting my wooden box. If you need a schematic to look at or other measurements I would be happy to provide you with them. Thanks

jts1957
Veteran

Jul 6, 2010, 7:51 PM

Post #8 of 48 (7885 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

Let's go back a second.

Quote

This set was turning on perfectly until I recently put 2 new caps in the 9 volt main supply due to a shaking screen.

Did you ever try it putting the original capacitors back in? Solder drips/splashes? unknowingly cracked the board or unplugged a connector?

Be careful which GROUND you are referencing for which voltage.

Do you have STANDBY voltages? Page 66 of SM. All reference COLD ground.
30 volts cathode D957;
12 volts cathode D972;
32 volts cathode D977.

I can find 2 lousy pdf's that appear to have been made from the paper manual, schematics have grayed over areas that scanned too dark and the person doing may have not scanned in the complete schematics.

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

Hazardsneon
User

Jul 6, 2010, 8:55 PM

Post #9 of 48 (7882 views)
Shortcut

Re: [jts1957] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

I haven't tried putting the original caps back in but I've left them out. Since they are only filter caps the effect will just make the 9V unstable and mostly make the screen shake. I've looked over these boards with a fine tooth comb and can't find any cracks or solder where it shouldn't be. I have been using the COLD ground for reference and I have all my standby voltages as follows:
+30 measured 35volts
+12VS measured 12volts
+32VS measured 112volts
The measurements that puzzled me was the 112V measurement on the +32VS line.
Do you know a good way for me to get you the service manual?

jts1957
Veteran

Jul 6, 2010, 9:19 PM

Post #10 of 48 (7879 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

32 volts is on the other side of R974.

Believe I located legible complete copy of manual, we'll see.

35 volts (audio) D974 cathode?
130 volts D971 cathode? Only IF K903 energizes.

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

Hazardsneon
User

Jul 6, 2010, 10:16 PM

Post #11 of 48 (7875 views)
Shortcut

Re: [jts1957] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

You are correct, I found 32volts on the otherside of R974. I thought I checked that but I must have been mistaken. There is not +130 or +35V audio. Thanks!

jts1957
Veteran

Jul 6, 2010, 10:35 PM

Post #12 of 48 (7874 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

Voltages on Q971 base & collector (when set is just plugged in & when you press power switch once)?

Voltage on pin #1 of connector KB (P-ON/PWR_ON)(when set is just plugged in & when you press power switch once)?

Do you have a variable power supply (0 to 12-30 volts @ up to an amp)?
Smile

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

(This post was edited by jts1957 on Jul 6, 2010, 10:35 PM)

Hazardsneon
User

Jul 7, 2010, 5:09 AM

Post #13 of 48 (7866 views)
Shortcut

Re: [jts1957] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

On Q971 the collector has 12.21volts and the base has 0volts on it. Pin 1 on connector KB has 0volts on it. I pushed the power button when I made the measurements and the values didn't change. I have a variable power supply. Thanks so much for your help!

jts1957
Veteran

Jul 7, 2010, 1:20 PM

Post #14 of 48 (7858 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

If you feel daring you "could" put 3 to 5 volts on the "right" side of R975 (NOT directly to the base of Q971). Relay should try to energize, at least.

Otherwise, go to IC706 and confirm pin #1 is 12 volts and pin #3 is about 5 volts.
Looks like pin #52 of IC700 should toggle with each press of power button.

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

Hazardsneon
User

Jul 7, 2010, 2:47 PM

Post #15 of 48 (7856 views)
Shortcut

Re: [jts1957] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

I will first confirm that IC706 has 12volts on pin 1 and about 5 volts on pin 3 and I will check pin 52 on IC700. After that I will try injecting the 3 to 5 volts. Thanks

Hazardsneon
User

Jul 7, 2010, 10:47 PM

Post #16 of 48 (7853 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

IC 706: Pin 1 has 11.35 volts and pin 3 strangely has 8.85 volts
IC 700 pin 52 was unresposive when the power button was pressed.
I injected about 4 volts on R975 and it energized the relay and supplied the +130V and the +35V audio but I still didn't see the guns fire up. Let me know the next move. Thanks

jts1957
Veteran

Jul 7, 2010, 11:15 PM

Post #17 of 48 (7852 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

Replace IC706.

You could remove the IC and place 5 volts from power supply on pin #3 to prove.

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

(This post was edited by jts1957 on Jul 7, 2010, 11:17 PM)

Hazardsneon
User

Jul 8, 2010, 1:58 PM

Post #18 of 48 (7842 views)
Shortcut

Re: [jts1957] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

That was it. I clipped pin 3 on IC706 and injected 5 volts from my power supply and it works! Thank you very much for your help!

jts1957
Veteran

Jul 8, 2010, 2:31 PM

Post #19 of 48 (7841 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

You're welcome.

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

Hazardsneon
User

Jul 13, 2010, 1:27 PM

Post #20 of 48 (7821 views)
Shortcut

Re: [jts1957] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

Alright, I changed out IC706 the 5 volt regulator and it turns on like a champ. Now........ I am trying to adjust the convergence and it is unresponsive. The convergence was next to perfect before this whole thing started and I wouldn't understand why either STKs would be blown. I haven't had a lot of time to look into this but even in the "Circuit adjustment" mode it doesn't do anything. The convergence is OK in the middle but the four corners are skewed. Are there connectors that could be unplugged that don't allow convergence but allow the TV to operate? I've replaced the STKs before and they have worked perfectly up until now. What can I check? Thanks!

jts1957
Veteran

Jul 13, 2010, 2:14 PM

Post #21 of 48 (7820 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

You have covered it pretty well. Double check that correct plugs are connected to the correct sockets. Stay out of SERVICE menu. Wink

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

Hazardsneon
User

Jul 13, 2010, 10:00 PM

Post #22 of 48 (7815 views)
Shortcut

Re: [jts1957] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

Back to the drawing board.... I can not get the convergence to change. The TV powers up every time now, I get into the convergence menu and I can't get either the red or blue to move. On the convergence screen, the words "red" and "blue" flash as though they are in action but the amps are doing nothing. Also, the green, which I can't modify in the advanced convergence menu, is distorted. I've checked and to the best of my knowledge, all of the connectors are in there respective spots. Where should I go from here? Thanks

jts1957
Veteran

Jul 13, 2010, 11:01 PM

Post #23 of 48 (7813 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

Start with the basics.
1) stay out of the SERVICE menu! Frown

2) convergence ICs have positive and negative 24 volts?

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

Hazardsneon
User

Jul 13, 2010, 11:40 PM

Post #24 of 48 (7810 views)
Shortcut

Re: [jts1957] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

I've been staying out of the service menu. I've only been accessing the convergence menu from the standard menu. There is no +24 or -24 on the STKs. Edit: There is also not +24 or -24 on the main board.

(This post was edited by Hazardsneon on Jul 13, 2010, 11:49 PM)

Hazardsneon
User

Jul 14, 2010, 1:13 AM

Post #25 of 48 (7808 views)
Shortcut

Re: [Hazardsneon] Mitsubishi VS-45603 Will not turn on [In reply to]	Can't Post

So, R520 and R522 are blown. What could have gone bad?

1 2

View All

Print Thread

Search for (options)

- Page loaded in: 0.19 s on (CGI/1.1)