Philips 27PS55S/321 Startup Problem: Page 2


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Philips 27PS55S/321 Startup Problem

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ian33
User

Feb 4, 2011, 11:25 PM

Post #26 of 52 (2124 views)
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Re: [Ron.M] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

(have a rotten weekend)
ok tech ni shee
33ian comin soon lol

when times get hard the lord dont walk with me he carry me

Ron.M
Veteran

Feb 5, 2011, 4:25 AM

Post #27 of 52 (2117 views)
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Re: [ian33] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

aint33 i'm12;....

OK , you made an accusation....

Quote

if you get me banned just like the other ppl that put you in your place in the past.

Name some !!!! You opened your mouth , now back it up !!!!

Ron.M... Cool

....
Veteran & Retired TV technician

ian33
User

Feb 5, 2011, 3:41 PM

Post #28 of 52 (2110 views)
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Re: [Ron.M] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

i dont have time to go an read old post.you always have a problem with some ppl also i dont think they have a prob its jus u being the problem,are you gettin paid here? or is this your forum ,cause you always like to jump in

you can ban me al just make a next one if i have to no big deal

Ron.M
Veteran

Feb 5, 2011, 6:28 PM

Post #29 of 52 (2108 views)
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Re: [ian33] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

ian33;.....

Quote

i dont have time to go an read old post

Well , you had time to read them the first time...
So where's your memory ????
Or could it be you're a LIAR !!!!

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you always have a problem with some ppl

MORE BS....
PROVE IT !!!!..OR Shut the hell up !!!!

Quote

are you gettin paid here?

NO , all us wonderful techs here volunteer our time & expertise to help people including jerks like you at NO CHARGE !!!!

Quote

or is this your forum

NO , it is not....IF it was , you'd be gone in a New York second !!!...

Quote

cause you always like to jump in

I jump in for 2 reasons ONLY....
You're one of them.....

Ron.M.... Cool

....

Veteran & Retired TV technician

(This post was edited by Ron.M on Feb 6, 2011, 12:15 AM)

helixal
New User

Feb 5, 2011, 7:39 PM

Post #30 of 52 (2102 views)
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Re: [Ron.M] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

Back at the ranch. The last relevant post for the issue at hand is quoted here from above:

Here is what I found:

With the set plugged in, I noticed for the first time a chirping sound. It is so faint that I did not notice it earlier( or it wasn't there.) It seems to come from the middle area of the board, but I cannot locate it precisely.

1) with the set plugged in, I got 1.2V at capacitor 2561.

2) TV unplugged, resistor 3523 measured 100.6 ohms.

3) TV unplugged resistor 3532 measured :no deflection in the meter (If I short the probes together I would get a reading of 0 ohms. Here I get no reading on the electronic meter.) I assume the resistor is open.

Ron.M
Veteran

Feb 5, 2011, 8:56 PM

Post #31 of 52 (2100 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

helixal;....

I sincerely apologise for what is going on here...
Please note it's not all my fault...

jts1957 may or may not come back to this fray...
I don't think he'd mind a quick answer to your question...

3532 on my schematic shows 2K2...
That resistor IS open....

With that , I'm going back to watching.....

Good Luck.... Sly

....

later...Ron.M.... Cool

....
Veteran & Retired TV technician

helixal
New User

Feb 5, 2011, 9:36 PM

Post #32 of 52 (2095 views)
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Re: [Ron.M] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

Ron: That's what I said the resistor is open. So whats next? Will replacing the resistor fix the problem or is this a sign that there may be trouble elsewhere?

In getting a replacement what should I look for?
2200 ohms
tolerance?
wattage?

Thanks,

You and jts1957 have been most helpful.

Ron.M
Veteran

Feb 6, 2011, 12:05 AM

Post #33 of 52 (2090 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

helixal;....

I mostly jumped in here to 1st, to get you & jts1957 a manual , then to apologise for the fray...
I have a LOT of respect for jts1957 & would really like to let him run this....

Quote

Will replacing the resistor fix the problem or is this a sign that there may be trouble elsewhere?

You have probable major power supply problems....
That resistor feeds IC 7520....
IS there 3 red bands on that resistor or is it burnt up ???
Are you getting any voltage at the "Drain" of 7521 ???
You could be looking at an involved repair that may be best looked at by a reputable , trustworthy TV repair shop...
If you have Acrobat OR Foxit reader , when you open the manual you have a search feature that you can find parts etc with....
Look for a binocular type icon on the top of the page , click on it & enter the circuit reference number in the search box....
According to my manual 3532 is 2.2 K , 5% tolerance , 1/3 watt (1/2 (half watt) will work) , metal film (flameproof will work)....

If it's OK with you (or not) , I'd prefer to wait for jts1957 to assist you further.... Wink

...

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

....
Veteran & Retired TV technician

(This post was edited by Ron.M on Feb 6, 2011, 12:08 AM)

jts1957
Veteran

Feb 6, 2011, 12:31 AM

Post #34 of 52 (2083 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

If you have an older DVM and you have it set to the 2K (or less) range, you might be getting an erroneous reading. You could "float' one end of the resistor and retake measurement.

If resistor is good, check the condition of the horizontal output transistor (LOT=Line Output Transistor as they call it)(7460).

Could "chirping" be called hiccuping?

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

(This post was edited by jts1957 on Feb 6, 2011, 12:35 AM)

helixal
New User

Feb 6, 2011, 6:01 PM

Post #35 of 52 (2078 views)
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Re: [jts1957] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

JTS:

I am impressed by your understanding. You are right. I rechecked 3532 on a higher range and got 2260 ohms. I got a similar reading using an older analog meter. So it looks like that resistor is ok. I found (after a long hunt) the transistor 7540 clipped on the chassis. On the bottom of the circuit board, the terminals are labeled B,C,and E. The B lead (where it is soldered to the board) shows some brown/black residue that bubbled up - like it got very hot. The C lead shows a slight amount of this residue and the E lead is a nice clean silver in appearance. In the case of B and E the residue is right on the board - i.e. between the board and the solder bubble. The rest of the transistor looks fine - no signs of heat or distortion.

When you say "check the condition" do you mean what I just did i.e do a visual check or are there some measurements that I can take using my meter?

As far as the hiccups are concerned, I would say it is not hiccuping. It's a high pitched repetitive chirp.

jts1957
Veteran

Feb 6, 2011, 7:00 PM

Post #36 of 52 (2073 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

Google: Flux

Google: Checking/Testing transistors

From page 75 of pdf:
Set is dead and makes hiccuping sound
"Main Power Supply" is available. Hiccupping stops when L5561is de-soldered, meaning
that problem is in the "Main Power Supply"line. No output voltages at LOT, no horizontal
deflection. Reason:line transistor 7460 is defective.

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Location: Far, Far Away

helixal
New User

Feb 7, 2011, 8:01 PM

Post #37 of 52 (2057 views)
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Re: [jts1957] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

First of all my error. The transistor I tested was 7460 and not 7540. Yes the brown/black stuff could have been the flux but I did not see it elsewhere. Using the procedure I found at this web site:

http://www.electronics-radio.com/articles/test-methods/meters/multimeter-diode-transistor-test.php

I went through all 9 steps and got zero ohms on all tests. WITH the transistor still soldered in the circuit.

on 3 and 4 where it should have been open I got a deflection.

on 6 where it said I should get a deflection I did get a deflection in both cases.

on 7 and 8 where it should have been open I got a deflection.

I am tempted to say the transistor is not good.

jts1957
Veteran

Feb 8, 2011, 12:08 AM

Post #38 of 52 (2054 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

1) I assume you have an analog meter similar to one pictured on site (NOT a digital volt meter DVM).
2) You STILL have location numbers backwards.
3) Best to test any transistor "Out of Circuit."
4) http://www.mcmelectronics.com/...0Sheets/BU4508DX.pdf
As shown on datasheet this transistor contains a built-in damper diode and base-emitter resistor.

C=Collector / B=Base / E=Emitter
OUT OF CIRCUIT:
C to E = reads open one polarity of meter leads and a reading with the other polarity of meter leads. (with a "normal" transistor you would get open readings in both polarities)
B to C = reads open one polarity of meter leads and a reading with the other polarity of meter leads.
B to E = You'll read the built-in resistor value. (with a "normal" transistor reads open one polarity of meter leads and a reading with the other polarity of meter leads.)

Looking at the schematic you should notice that the base connects to a low value resistor and a very low resistance transformer winding along with the built-in resistor. The other end of the low value resistor along with the emitter and other end of transformer all connect to ground. Trying to obtain a meter reading will result in you reading the transformer winding - so is best to either remove completely or "isolate" two out of the three leads.

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

helixal
New User

Feb 8, 2011, 3:41 AM

Post #39 of 52 (2051 views)
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Re: [jts1957] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

1. I did use an analog meter.
2. Location numbers: we are dealing with transistor 7460 that's the one I measured.
3. I'll need to get a wick to get this thing out.

4. I additionally measured the resistance from the terminals of B, C, and E and ground (the chassis) and they all measured .3 or .4 ohms.

At this point I'd like to ask the question: If this transistor is bad would that alone account for the problem that I described in my first post i.e turn on getting progressively more difficult and finally unable to turn on with no picture, no snow, no sound and no reaction when pushing the power on button with no red LED illuminated?

jts1957
Veteran

Feb 8, 2011, 4:20 AM

Post #40 of 52 (2047 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

Yes it could. Be sure to resolder driver transformer (5461) solder joints.

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Location: Far, Far Away

helixal
New User

Feb 8, 2011, 11:58 PM

Post #41 of 52 (2039 views)
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Re: [jts1957] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

With the OLD transistor (BU4508DX) out of the circuit I made 6 measurements - all combinations of b,c, e and + and - polarity. All measurements were 0 ohms.

With another new replacement transistor (NTE2353) alleged to be equivalent I got the following readings:

NTE2353: A GOOD NPN TRANS
should read:
_______________________ ___________________
B+ ----- C OPEN OPEN
B+ ------ E 45 OHMS OPEN
B- ------- C 22 DEFLECT
B- ------- E 22 DEFLECT
C+ ------ E 28 OPEN
C- ------ E OPEN OPEN

The B+ to E and the C+ to E readings don't mesh.
These readings don't seem to mesh with anyone's idea of a good transistor. The B+ to E and the C+ to E readings don't mesh.

Perhaps I am not understanding the meaning of the word "normal" In the above I took it to mean "good" for this transistor. Also it appears that in step 4 of the test that I quoted above for measuring a transistor there appears to be a typo: the second positive should read negative.

In any event it looks like my old transistor is fried. And the new one is a mystery.

helixal
New User

Feb 9, 2011, 4:51 PM

Post #42 of 52 (2035 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

The formatting of the table above got messed up. It should read;

Measured results of the NTE2353 transistor were: _______________________

B+ ----- C OPEN
B+ ----- E 45 OHMS
B- ----- C 22
B- ------ E 22
C+ ----- E 28
C- ------ E OPEN

In the same order as above a good replacement transistor should read (?):

open
open
deflection
deflection
open
open

The question is whether the NTE2353 is a proper replacement for the BU4508DX and are the measurements of it OK.

jts1957
Veteran

Feb 9, 2011, 6:00 PM

Post #43 of 52 (2033 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

Best to put in what you take out.
http://www.mcmelectronics.com/...XF-6YCFY64KgodYUUzCA

NTE Cross Reference info:
1 matches returned

Replace part.... With NTE part.... Product Line Data Sheets Notes
BU4508DZ ....NTE2636 Semiconductor

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

helixal
New User

Feb 9, 2011, 8:52 PM

Post #44 of 52 (2029 views)
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Re: [jts1957] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

The NTE was the only one I could get locally. I called NTE and they said it would be compatible even though they don't cross reference it. Do those measurements I took look reasonable for this type of transistor?

jts1957
Veteran

Feb 9, 2011, 11:15 PM

Post #45 of 52 (2024 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

Yes.

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Location: Far, Far Away

helixal
New User

Feb 12, 2011, 12:11 AM

Post #46 of 52 (1992 views)
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Re: [jts1957] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

WE HAVE LIFTOFF!

I replaced the transistor, re soldered the coil, held my breath, hit the on button and WOW it works. Comes on cleanly and stays on. A single inexpensive part did it.

jts1957: Your advice and guidance are awesome. Thanks so much.

Thanks also go to Ron for finding a service manual and other helpful suggestions.

While this set was down, I watched a 40 year old Zenith 19" color set. It's cabinet has never been opened by anyone. It has a terrific sharp bright picture whose colors are right on. It has a peculiarity however. You have to give it a tap on the side to get it to work. Think of Onslow on Keeping Up Appearances. At first the taps were light and infrequent but after a while you had to give it a real whack. Now here is where ian33 might come in handy. Willy-nilly soldering, just might, if you are really lucky, fix this problem.

Until next time.

Ron.M
Veteran

Feb 12, 2011, 12:22 AM

Post #47 of 52 (1990 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

helixal;.....

CONGRATULATIONS !!!!....

I knew you could do it.....

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Now here is where ian33 might come in handy. Willy-nilly soldering, just might, if you are really lucky, fix this problem.

ian33 is no longer welcome here & has been PERMANENTLY banned even tho he tried to return as "scope" (Banned again)....
He asked for it & he got it....
Your 40 year old Zenith most likely has a bad connection...
Not a big deal for an experienced tech to fix....

Enjoy the set.... Smile

....

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

....
Veteran & Retired TV technician

jts1957
Veteran

Feb 12, 2011, 12:24 AM

Post #48 of 52 (1988 views)
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Re: [helixal] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

You're welcome.

If you still have open , monitor how much heat is being generated by the new transistor. Unplug the set after running for 5 - 10 minutes and see if you can keep the BACK of a finger comfortably against the heat sink.

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

HBKMensa
New User

Feb 17, 2011, 12:42 AM

Post #49 of 52 (1978 views)
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Re: [jts1957] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

Take a look here for some links to good places to pick up electronic components for all models
http://www.youronlinelectronicstore.com

potcode
New User

Feb 17, 2011, 2:45 AM

Post #50 of 52 (1973 views)
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Re: [Ron.M] Philips 27PS55S/321 Startup Problem [In reply to]	Can't Post

i dont find ian33 approach was out of place,I usually help people over the phone and because am not there to see what they working with i will ask them to resolder these same areas he suggested.Cold solder joints cause alot of problems.With that said i dont think the HOT was the cause of the symtoms that was mention in the first post.The power problem was the HOT but the problems started with cold solder joints
which is most likely what cause the HOT to fail in that case
That post was like a war for what??

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