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Crumbtrail TV Forums: TV Equipment: Projection TV Forum:
RCA 52" convergence power supply dead

 

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HostileHST
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Mar 26, 2013, 1:00 AM

Post #1 of 48 (6130 views)
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RCA 52" convergence power supply dead Can't Post

I have the usual convergence issue as many do with the ITC222 Chassis and after re-soldering the fly back and checking FL231 fuse I was able to get it to converge, but then the power supply convergence power supply gave up and back to square one, fuses are still working.

Taking advice that Ron M. gave to another member, this is what I have so far:

Working on same board and tested my FET TP630 (TP30) using the method you've explained. G to D my meter starts out low then goes way up into the megaohms around 14meg last I checked. From D to S, meter is reading approx. 47kohm (explained by a smd resistor across those 2 pins). While I was at it, I tested from pin 3 of BP660 (BP60) to negative of BP665 (BP65) and didn't get any sign of life from my meter (nodda).

I pulled the FET completely out of the board. I soldered two wires into the circuit board, one where the S pin would normally go and other for D. With TV off, meter reads 346 volts, with TV on, it reads 322 volts.
Testing FET while out of circuit, the only reading I could get on my meter was 10mega ohms with my negative probe on the D and positive on S. Any other combination doesn't seem to do anything. I also made sure to short the pins to discharge it, something I watched on YT and also read after a google search.

At this time of posting, the mosfet no longer show squat on my meter. I am at a loss now with no clue if I messed the mosfet, if it was already bad or I need to be looking elsewhere for the problem. As usual, any help is appreciated.



Ron.M
Veteran


Mar 26, 2013, 3:12 AM

Post #2 of 48 (6124 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post


HostileHST;....

I'm not sure I'm going to be of much help...
I think I can help you get the power supply up & running again..
But if you have ANY convergence problems , I will not be able to help...
That chassis is one of the worst RCA ever made...
Not many techs are willing to mess with them...Unsure...
Sorry to be so blunt....Unsure....

OK ...
Let's see what we/you can do...

TP630 is getting what it needs for B+ ..322~346 , with no load...
Put TP630 back in the way it came out....
The meter you used to check the mosfet may not be the right way to check it...
The best way (Unless they are dead bang shorted) to check those is in circuit & under load...
Then read the voltage at pin #2 of LP50...
That's the transformer it hooks up to...
Do NOT read the voltage at "D" on the mosfet....
IF you get ~300 vdc , TP630 may be good...
Time to start reading secondary voltages...
On pins #11 & 12 , you'll see DP65 & DP75...
On DP65 you should read ~+53 vdc....
On DP75 you should read ~+15 vdc...
On pins #16 & 17 , you'll see DP70 & DP60...
On DP70 you should read ~-15 vdc ...
On DP60 you should read ~-53 vdc..
Note the polarity of the above voltages....
IF any or all the voltages are not there or low or ??? , you have a power supply problem...

Please post results...

THANKS....Sly...


Later...Ron.M....Cool...
Veteran & Retired TV technician


HostileHST
New User

Mar 26, 2013, 5:45 PM

Post #3 of 48 (6108 views)
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Re: [Ron.M] RCA 52" convergence power supply dead [In reply to] Can't Post

Last I checked several months ago, all output voltages were low, very low, but I will recheck anyways.

I am a bit lost on pin #2 of the transformer. I have never known them to be numbered, though it would make sense they should be. I also don't see any 17th pin, but that shouldn't matter cause I do know what diodes you want me to check and will do that today, I just don't know about pin #2 on the transformer. I assume pin #2 will be on the same side of the board that the mosfet is.

What I can do is check all pins on both sides of the transformer except the one to D on the mosfet as you indicate to NOT do that. Possible reason for that?

I will be using Ground for my negative lead coming off of the negative side of capacitor CP12A (CP612A for me). It goes directly to the negative side of the input power to this board.


HostileHST
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Mar 26, 2013, 6:24 PM

Post #4 of 48 (6103 views)
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Re: [Ron.M] RCA 52" convergence power supply dead [In reply to] Can't Post

Getting some seriously odd readings.
If I use a chassis ground, I get 200+ volts out of -15 and -53 and +15 +53.
If I use the ground (negative) from the main input power, the 346 vdc, the meter reads 116 vdc on average at both side of the four diodes you referenced.

If I use the negative off of capacitor CP665, I get virtually nothing on any of the outputs that should be -15 -53 + 15 +53.

Is there a single place I should ground to ensure I can give you proper reading for you?

I did not have the connector from the convergence amplifier hooked up or the one from the fly back power supply to see what readings I would get without any loads on the board. At this point I am unsure if it's even safe to hook those back up. On the other hand, it could be why I am getting such high readings since that side of the board doesn't have a true ground without the fly back connector hooked up. Will try with at least that hooked up and report back.

Sorry for such a mixed up post, have company coming over that will make it virtually impossible to concentrate on the TV. GRRRRR


(This post was edited by HostileHST on Mar 26, 2013, 6:29 PM)


Ron.M
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Mar 26, 2013, 7:19 PM

Post #5 of 48 (6097 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

  
HostileHST;.....

I do not have any service manual for the ITC222 chassis....
They are hard to find , if at all....
I'm using a Sams Photofact for RCA D52W20 which has a ATC221 chassis that appears to have the same or similar convergence power supply schematic..
That said;....

Pin #2 is where your 346 volts that goes to FET TP630 comes into LP50 (Power supply transformer)..
Use an ohm meter to measure from the "D" on FET TP630 to one of the pins on LP50....
Only 2 pins are connected to FET TP630..
One is for "D" & the other is supply...
Edit;.."D" goes to Pin #5 on LP50...
Measure Pin #2 as I asked & NOT at the "D"...
Reason is that there may be a huge signal there that could fry your meter...
Better safe than sorry...
Use the "Hot" ground at CP612A for your ground connection on your meter...
You are correct in using the ground at CP665 for the other readings...



Quote
Is there a single place I should ground to ensure I can give you proper reading for you?

NO ....There are 2 separate power supplies involved... They are isolated from each other , But , work together...
IF that makes any sense...

Sams PhotoFacts are a notch above garbage..}
Have everything hooked up & retake the readings....
THANKS...


Later...Ron.M....Cool...
Veteran & Retired TV technician

(This post was edited by Ron.M on Mar 26, 2013, 7:21 PM)


HostileHST
New User

Mar 26, 2013, 9:48 PM

Post #6 of 48 (6090 views)
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Re: [Ron.M] RCA 52" convergence power supply dead [In reply to] Can't Post

Totally get the two separate supplies, but working together part. One side is the input high voltage of the supply, other is the lower multiple voltage side only tied in together via the transformer and a optocoupler that tells the board to turn on/off.

As for my meter, it will read up to 1000 vdc and 750 vac.

Just tested pin #2 and it reads 320 vdc using LP650 (LP50) as the ground.

Voltages I get from the output are:

Pin: Voltage:
1 N/A (just meaning, of little use for now)
2 N/A
3 N/A
4 0*
5 0*
6 16vdc
7 Ground
8 Ground
9 Ground
10 -24vdc
11 0*
12 -1.5

* to low, generally under 1vdc, not worth writing it down

At the diodes by transformer, no voltages except -1.5 on DP660 (DP60)

Figured there was no point in rewriting down all the other diode numbers since they show nothing anyways.


Ron.M
Veteran


Mar 27, 2013, 3:32 AM

Post #7 of 48 (6086 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

 

HostileHST;....

SORRY abut the delay....

Took my dog to see the vet (10 mile drive , 1 way) & blew out a tire on the way back....

Then my daughter calls & she needs money (long story) , so I go out on the "donut" spare tire to wire her some moolah...(5 more miles , round trip)....

Back to out regularly scheduled program;....

Using CP12 as "Hot" ground , turn the TV on & read the voltage at "G" on TP30...
Should be about ~+4.5 vdc...
Use care when you use your meter there...
BEFORE you read the above voltage , please read the ohms to "Hot" ground from "S" on TP30...
Should read about 4.7 ohms...


Tomorrow , I'm going to have to resolve my tire problem...
This is the 2nd tire I've blown out in about 2~3 months...
I'm trying to find a used tire store that I can get a good deal on 4 tires...
So as a result , I may not be as quick to reply as I have been...

I will try to answer you as soon as I can...


Later...Ron.M...Cool...
Veteran & Retired TV technician


HostileHST
New User

Mar 27, 2013, 6:22 PM

Post #8 of 48 (6077 views)
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Re: [Ron.M] RCA 52" convergence power supply dead [In reply to] Can't Post

Completely understand about the tires on the car. We just replaced a passenger rear one, cost us $56 and that is for a tiny little Geo Metro, UGG.
Years ago, we bought a Baretta, blew a tire, replaced with new, another blew a few weeks are about a month later, replaced that tire. Finally had to take a $500 loan out on the car for two more tires. All said and done, it finally had all new tread and about a month later paid the loan off thankfully because we got our taxes back. I truly wish you good fortune getting tires, they should never charge so much for the things we need, but as they say, tiz life.

And now back to what we were doing.

Did those checks, first checking the ohms from hot ground to S and got 5.1 ohms and personally that sounds about right for 4.7ohm resistor with 5-10% tolerance rating (please do correct me if I am wrong).

Powering up TV, with all connectors in place, I again used hot ground then checked for voltage at G and get virtually nothing (varies at 0.0 to 0.1 vdc which isn't good by any means).

TW019 has already been replaced. The reason I mention this is according to part of the troubleshooting information I have, TW019 can cause convergence issues (our board, will fail to turn on). I still get the menu on the screen, granted even the menu now is hardly readable.

Just some history, I did originally get the convergence issue fixed just by resoldering the fly back and not once has the fl231 blown or any of the other two for that matter. I wanted to touch up the main filter board with fresh lead solder (preventive maintenance). Before I had done that, the board we are working on now wasn't getting near 300vdc, but was at least working or should say, the TV no longer looked 3D. I have checked many times to ensure I didn't short something but my theory is, by making the main filter board all fresh, boards that were still weak couldn't hang 10 with the power delivery from the main filter board. Sort of like replacing one piston with new rings in a car when the other cylinders are old and weak, doesn't always work out as planned. Bad analogy? I have more, but I am sure you get my drift.


HostileHST
New User

Mar 27, 2013, 6:40 PM

Post #9 of 48 (6074 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

Not sure if this helps, but thought it might help us both isolate the area of trouble by testing the voltage on the opto-coupler.

With TV off and using HOT ground for my negative lead, I got 14.72vdc.
With TV on, it initially reads 7vdc, slowly tapers down to around 6.5vdc and seems to hold around there.

I am guessing this should eliminate whether or not the TV is sending signal to the board to turn it on focusing attention to the high voltage side of the power supply you've been helping me with and a big help taboot Ron M.! I'm feeling motivated!


(This post was edited by HostileHST on Mar 27, 2013, 6:41 PM)


Ron.M
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Mar 27, 2013, 9:15 PM

Post #10 of 48 (6067 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

 
HostileHST;....

I will be leaving as soon as I post this for a tire search , so , I wont be back for an hour or so....

I'm using a Sam's Photofact service manual for RCA D52W20 , with an ATC221 chassis...
Hopefully the convergence power supply is close enough to yours...



Quote
TW019 has already been replaced. The reason I mention this is according to part of the troubleshooting information I have, TW019 can cause convergence issues (our board, will fail to turn on).

Where is TW019 at ????..
Would that be TW19 ???
IF so , I found it...
What troubleshooting information do you have & where did you get it ???

In the meantime;...

Let's rule out secondary shorts...

Go to the band end of DP65 & DP75...
Read ohms from there to cold ground...
Use CP665 for that ground...
Go to the plain end of DP60 & DP70 ...
Read ohms from there to cold ground...
When you first connect your meter to those points , your meter may show a low resistance , then climb up to a higher reading....
Wait for the reading to settle down & then record it...
OR you can momentarily short the diodes out to discharge any residual voltage..

Post as follows;...
DP65=xx vdc
DP75=xx vdc
DP60=xx vdc
DP70=xx vdc

Thanks....

Then , let's get the rest of the readings from the opto-coupler...
You have given me the reading from what appears to be pin #1 @ 14.72vdc.
However , you said you used "HOT" ground..
That pin's reading should have been at "Cold" ground (CP665)...
So , let's start with pins 1 & 2 @ cold ground....
Then read pins 3 & 4 at "HOT" ground , CP612 ....
Post results & I'll answer as soon as I can...

THANKS for your patience....Smile....


Later...Ron.M....Cool...
Veteran & Retired TV technician


HostileHST
New User

Mar 28, 2013, 1:55 AM

Post #11 of 48 (6063 views)
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Re: [Ron.M] RCA 52" convergence power supply dead [In reply to] Can't Post

Trouble shooting info was someting jt directed me to. Can't recall the site since my pc has had it's OS updated. I can send what I have, but last I read, you had dial up.

This is what I have so far on the diode tests:

DP665 initially no reading, then shows about 3 mega ohms then no reading again
DP675 after waiting for meter to settle, shows as 2.4K ohms
DP660 26k Ohm steady
DP670 24K Ohm steady

I can lift one let and test in diode mode of my meter if you like. Might help be more certain on those.

When I tested the opto coupler, it was on pin 3 and 4 that I tested for 14.4, thus why I had it it on HOT ground.

I'll test the other side in a few minutes since I took the board out of the TV to make it easier to take those diode readings.


HostileHST
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Mar 28, 2013, 1:57 AM

Post #12 of 48 (6062 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

Ooops, the TW019 I do believe would be TW19 for you, I've seen it somewhere as TW19 as well. It's located on the convergence amplifier board.


HostileHST
New User

Mar 28, 2013, 2:12 AM

Post #13 of 48 (6061 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

Here's what I got for the optocoupler using the correct grounding for each side of the opto:

1. 1.1mv
2. 2.4vdc, liked to vary, but it was right around there that it lingered
3. 0
4. 6.1vdc, again, like to vary a bit, but ultimately around that area


Ron.M
Veteran


Mar 28, 2013, 3:22 AM

Post #14 of 48 (6052 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

 
HostileHST;....


Quote
I can lift one let and test in diode mode of my meter if you like. Might help be more certain on those.

OK , you talked me into it...
All 4 diodes , please...



Quote
I can send what I have, but last I read, you had dial up.

What is it exactly that you do have ???
Depending on the file size , there are a few ways that could be done even tho I'm on dial-up...



Quote
1. 1.1mv
2. 2.4vdc, liked to vary, but it was right around there that it lingered
3. 0
4. 6.1vdc, again, like to vary a bit, but ultimately around that area

I made an OOOOooopppsss when I asked you for this info...
What I want is a set of readings with the TV off & another set when you press the power button....


THANKS.....Sly...


Later...(Thurs AM)..Ron.M...Cool...
Veteran & Retired TV technician


HostileHST
New User

Mar 28, 2013, 4:45 AM

Post #15 of 48 (6046 views)
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Re: [Ron.M] RCA 52" convergence power supply dead [In reply to] Can't Post

The testing I did on the opto was with the set on. I will have to do the test again tomorrow (Thursday) since it's getting late in they day now.

Will do on the Diodes, seems more practical for me and I don't mind one bit.

Tomorrow, I'll give you a list of what I have for schems, it's not much and largest file if I recall is about 2mb.


Ron.M
Veteran


Mar 28, 2013, 5:41 PM

Post #16 of 48 (6028 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

  
HostileHST;....

As Peter Falk's Columbo would say "One more thing"...

One more thing...
In one of my manuals , the Convergence power supply board has 3 connectors on it...
Two go down to the big board that has the flyback & 1 goes to the convergence amplifier board ...
To rule out any possibility of the convergence amplifier board having a short on it , disconnect BL660(?) that goes to the convergence amplifier board & turn the TV on...
See if you get any of the missing voltages from DP65 , DP75 , DP60 & DP70....

Please post results with the others....

A 2mb file will take only about 6 minutes for me to download...
No biggie....

EDIT:...
I suggest you do the tests in the following sequence;....
Check your diodes 1st;...
Resolder them back in...
Then read the opto volts &/or the diode voltages next...
This should keep any shock hazard at a minimum...

THANKS....Sly....

Later...Ron.M...Cool..
Veteran & Retired TV technician

(This post was edited by Ron.M on Mar 28, 2013, 5:48 PM)


HostileHST
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Mar 28, 2013, 7:15 PM

Post #17 of 48 (6020 views)
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Re: [Ron.M] RCA 52" convergence power supply dead [In reply to] Can't Post

I had already tested the board with the amplifier board unhooked trying to rule out a short on the amplifier.

I test all four diodes with one leg out of circuit, all 4 are good, while I was at it and since it was entertaining my 9 year old, I pulled one leg from ALL diodes, including zeners and all tested good. All tests were done with board no where near the tv, so no hazard there.

I retested the opto before the diode test, so far, I have yet to have a cap nail me, but wish me luck, it might happen! hehe.

Here is what I got from an ON/OFF test of the opto.

While TV is off:
Pin VDC
1. 0
2. 1.6 and varied within that area
3. 0
4. 14.7

Whiles TV is ON
Pin VDC
1. 0-1.1mv
2. 2.-2.4, doesn't seem to stablize
3. 0
4. 6.14-6.5 doesn't seem to stablize

All my schems say, ITC222 except for one that appears to be for the projection version that requires a lamp.

Let me know where to send those and I'll get right on it.


HostileHST
New User

Mar 28, 2013, 7:42 PM

Post #18 of 48 (6017 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

BP660 is needed to turn on the power supply. The PS/0n goes through the amplifier board via that flat ribbon that goes into the amplifier board, but I did as instructed anyways.

Without BP660 connected, nothing shows up on the 4 diodes.
With BP660 connected, I get:
DP675 -.57 vdc on the banded side
DP665 +1.3 vdc on the banded side
DP660 -1.9 on the blank non banded side
DP670 +.6 on the blank non banded side

What I can do for a test to see if the amplifier board is causing a possible short, it just run a ground and the PS/ON to the PSDF board, the board we are trying to figure out. Ultimately, no wire that powers the amplifier board will be hooked up to anything, aka no load, but at least the PSDF board will get a signal to turn on.

If I don't do something in the exact order, it's not to be rebelious, I don't always get the emails quick enough to head any warnings, but rest assured, despite how I go about things, I do take pre cautions and even then, it's not always enough.

Out of 25 years of being an electronics hobbiest, of all the times I've been nailed with electricity, the VERY worst was from the flash side of a digital camera and oddly enough, I knew about it, I was looking for it, but apparently it was looking for me and just about Pee'd my pants. Actually, I tossed the camera screaming words I won't repeat, lol.

Oh, another thing I wondered, could I clean all the secondary solder joint on the transformer to see if the secondary could be causing a short? sort of process of elimination, but I think I will try the PS/ON idea first to make sure it's not amplifier relate. Or I'll just wait to see what Ron M, the pro says, ya, I'll just wait for your input.


HostileHST
New User

Mar 28, 2013, 7:49 PM

Post #19 of 48 (6014 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

I should mention two things, your BL660 is my BP660, which is no big deal, I have at this point been keeping up with the difference in our schematics.

When I did the test with and without BL660 connected, I did it with TV on and TV off, TV on is the info I gave.


Ron.M
Veteran


Mar 28, 2013, 9:10 PM

Post #20 of 48 (6006 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

 HostileHST;....

Thanks for all the posted info...


Quote
What I can do for a test to see if the amplifier board is causing a possible short, it just run a ground and the PS/ON to the PSDF board, the board we are trying to figure out. Ultimately, no wire that powers the amplifier board will be hooked up to anything, aka no load, but at least the PSDF board will get a signal to turn on.

Sounds like a good idea....
I'm not sure that the "PS/ON" is available...
My schematic indicates that the convergence power supply is always on...
But , I'm curious as to how that test will work out....
Please post results in the thread....Thanks...


Quote
Oh, another thing I wondered, could I clean all the secondary solder joint on the transformer to see if the secondary could be causing a short? sort of process of elimination, but I think I will try the PS/ON idea first to make sure it's not amplifier relate.


What do you mean by "clean all the secondary solder joints" ???

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

Veteran & Retired TV technician


HostileHST
New User

Mar 29, 2013, 1:28 AM

Post #21 of 48 (5998 views)
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Re: [Ron.M] RCA 52" convergence power supply dead [In reply to] Can't Post

I did the test making sure I had ground and the PS/ON lines still connected from the conv. amp. board and get nothing from the PSDF board outside of the HOT side always having 320+ vdc to it. Several of the voltages I was initially getting from the board you've been helping with seem to be present on the amplifier board, as though it could be feeding voltage into the PSDF when I doubt it should be.

Repeating myself a bit on this line: Yes, the PSDF power supply always has it's high voltage present from the 320+vdc line as you've been putting it, the HOT side, but it's the PS/ON from the amplifier side that doesn't appear to read anything after the test I did. Confused yet, you ain't alone! What I am trying to say is, the voltages I was getting to the opto coupler don't appear to be getting there with the pins, -15, 15, -53, +15, 15, +53 disconnected from the circuit (and done in a way I can easily put it back together), nor any of the low voltages I was reading on the 4 diodes.

What I was thinking of doing was taking some solder wick and remove all solder from the secondary output transformer pins, making sure none of the pins touch the circuit board and see if I get anything through the transformer, ultimately, letting us both know if the hot side is putting anything out to the secondary cold side. I've been assuming up to this point, the HOT side is the high voltage side and the COLD being the multiple lower volt side, at least when you referred to ground, so I am just going with that lingo till I am corrected.

I plan to retest all this in a bit beings I have been distracted for most of the day and want to ensure I didn't miss anything. Then I will put all the pins I took out of the BP660 connector and retest for all the original reading before doing the test. I'll let you know, not that it really helps us out much, but doesn't kill me to try this or that.


Ron.M
Veteran


Mar 29, 2013, 2:56 AM

Post #22 of 48 (5983 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

 

HostileHST;....


I'm a bit concerned about this reading...

Quote
DP675 after waiting for meter to settle, shows as 2.4K ohms


Disconnect the connector "BP660" & retest the ohms as you did before....



Quote
BP660 is needed to turn on the power supply.

NOT to question your judgment , but , from my schematics , the convergence power supply looks like it would be a running power supply the minute you plug in the TV...
Until I get the manuals you so kindly sent me , that's the way it looks to me...
I may change my mind after I see those manuals...
Also , there is NO "PS/0n" in my manual...
So , please be careful how you mess with that...
No need to make matters worse...


Quote
Repeating myself a bit on this line: Yes, the PSDF power supply always has it's high voltage present from the 320+vdc line as you've been putting it, the HOT side, but it's the PS/ON from the amplifier side that doesn't appear to read anything after the test I did.

This is where I lose it....Unsure...
I can NOT find a "PS/ON"...
Both power supplies will have the 320 vdc supplied...


Quote
What I was thinking of doing was taking some solder wick and remove all solder from the secondary output transformer pins, making sure none of the pins touch the circuit board and see if I get anything through the transformer, ultimately, letting us both know if the hot side is putting anything out to the secondary cold side.

That , IF it even worked , will not help us...
I can definitely tell you that the hot side is not putting anything out...
That's why you don't have convergence....Unsure...

I will PM you Fri AM....

Have a GREAT evening.....Sly...


Later...Ron.M....Cool...
Veteran & Retired TV technician


HostileHST
New User

Mar 29, 2013, 4:28 PM

Post #23 of 48 (5970 views)
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Re: [Ron.M] RCA 52" convergence power supply dead [In reply to] Can't Post

How can I add a photo of my board?

Pin 3 on BP660 is PS/ON and runs up to the optocoupler and yes, there will always be 320vdc on the high voltage side of the PSDF board as long as the TV is plugged in. I have been assuming, despite the hot side of the always having 320 vdc, the mosfet driver may not necessarily be turning on TP630 mosfet. I do realize that the transformer is getting 300vdc at one of it pins, but my knowledge on much of this is limited. I am more or less a monkey with a soldering iron and a "bit" of knowledge. Perhaps we should toss the PS/ON on the back burner and move on so neither of us blows a gasket (not at each other, but at this blasted TV).

I'll retest DP675 later in the day since I have an appointment to go to soon.

The down side to all of my schems is I can't find squat other than a block diagram with the PSDF board in it. No voltage info, nodda. JTS1957 was the one that graciously gave me a link to some site where you can download two files per day and I downloaded them and the one board we need a schem on is not there. No fault of JTS, but surely doesn't do us any good. Can you say GRRRRR, lol.


Ron.M
Veteran


Mar 29, 2013, 8:06 PM

Post #24 of 48 (5953 views)
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Re: [HostileHST] RCA 52" convergence power supply dead [In reply to] Can't Post

   
HostileHST;....



Quote
How can I add a photo of my board...

I will PM you with how to do it....




OK , you made a believer outta me with the PS/ON from the convergence amplifier board...
Once again , Sams s#!t for manuals struck again with a crappy schematic...
When you post the result on the diode , we'll go over what is going on & hopefully come to some logical conclusion..


Quote
Perhaps we should toss the PS/ON on the back burner and move on so neither of us blows a gasket (not at each other, but at this blasted TV).

I think you are begining to understand why a lot of techs will not work on these sets....Unsure...

jts1957 also sent me a link to the same site...
As you said , no schematics that could help...

Yes , I said GRRRRRRR a long time ago....Unimpressed...



Later...Ron.M....Cool....
Veteran & Retired TV technician

(This post was edited by Ron.M on Mar 29, 2013, 9:21 PM)


HostileHST
New User

Mar 29, 2013, 8:33 PM

Post #25 of 48 (5946 views)
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Re: [Ron.M] RCA 52" convergence power supply dead [In reply to] Can't Post

Retested DP675 with BP660 connector not connected and got:

On banded side it first reads 12k Ohms, quickly drops to 1.9 (ish) Ohms, the raises back up to around 2.4k ohms and pretty much stays in that range.

On the non banded side, it shows a solid .5 ohms.

Testing done with negative lead from meter to the cold negative side of the board.

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