TV Forums

Free Games TV Forums

  Main Index FORUM
HOME 		Search Posts SEARCH
POSTS 		Who's Online WHO'S
ONLINE 		Log in LOG
IN 		Rules & FAQ RULES
F.A.Q.

Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Dead Sony KV-32TS36

 
First page Previous page 1 2 3 4 5 6 7 8 Next page Last page  View All


Ron.M
Veteran


Feb 2, 2014, 1:31 AM

Post #26 of 198 (1822 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
CRT_Fan;...

Welcome back....
I hope EVERYTHING went well for you..

A little refresher on my part (& maybe yours also) ...
Did you replace the H-Out transistor (Q591) with 2SC4927 or did you sub it ???
The 2 power supply transistors are 2SC4834s , right ???
With the yoke UNPLUGGED & CRT panel removed from the CRT;=>...
Did you test to see if the 2 power supply transistors get hot after a few minutes ???
Did you test to see if the H-Out transistor (Q591) gets hot after a few minutes ???
Please post results ....

Our next test will be to check the yoke...
I have a pix ready to go (1 of yours altered) as soon as you answer those 2 questions...
You will need a good black marker...

I will be back tomorrow AM & till Super Bowl starts..
After that , I'm offline for the day...


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


CRT_Fan
User

Feb 2, 2014, 5:31 AM

Post #27 of 198 (1813 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
  
> Welcome back.... I hope EVERYTHING went well for you..

I appreciate your concern Ron. After getting back I fell sick so it's been a rough month.

>A little refresher on my part (& maybe yours also) ...
>Did you replace the H-Out transistor (Q591) with 2SC4927 or did you sub it ???
>The 2 power supply transistors are 2SC4834s , right ???


No subs, but I guess I should mention I ordered a "2SC4927" but the part only says C4927 on it. Same supplier as the one that I blew up with the yoke attached.

Same thing with the power supplies: ordered 2SC4834, received C4834 (P code). From same supplier as last time.

I think that's normal, but I mention it anyway to be as precise as possible.

Now for the bad news...


>With the yoke UNPLUGGED & CRT panel removed from the CRT;=>...
>Did you test to see if the 2 power supply transistors get hot after a few minutes ???
>Did you test to see if the H-Out transistor (Q591) gets hot after a few minutes ???

I just now tested it with only the D board (and a couple subboards connected to it). I wasn't sure if it mattered, but I figured I'd put it all together and do the "everything but the yoke / C board" test tomorrow...

Well I left it on for 2 minutes but just as I went to disconnect and check the temperature, the high pitch sound stopped! Uh oh. I unplugged it and the HOT was very hot, not burning hot but painful if I kept my finger on it for more than a second. The power supply transistors were only a little warm.

Plugged it in again and still no sounds (no high pitch, no rough medium pitch, just the power standby clicking on).

I did some quick in-circuit measurements before I hit the hay. HOT has one short: B/E and E/B but I remember it was doing that before the sounds quit.

Power supply transistors have no shorts (in circuit). Did the +B test again and it passed so I think the damage is isolated to the horizontal section.

Is it possible I messed it up by leaving it on for 2 minutes without all the boards connected? The CRT itself is in another room so it was nowhere near the yoke or C board when I tested it this last time but the rear input panel and dynamic convergence board were off, as was the P board, whatever that does.



Not sure how much free time I'll have on Sunday myself, but lemme know what the plan is and enjoy the game tomorrow!


(This post was edited by CRT_Fan on Feb 2, 2014, 5:41 AM)


Ron.M
Veteran


Feb 2, 2014, 8:06 PM

Post #28 of 198 (1806 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
CRT_Fan;...


GET WELL !!!!..Wink..

Well , I was going to have you check out the yoke , but , based on this new info , it appears that the yoke is not involved...
Quote
I unplugged it and the HOT was very hot, not burning hot but painful if I kept my finger on it for more than a second.
Indicates bad flyback...
Locate & check C520...
470p @ 2 kv...
It should be a yellow or blue ceramic disc cap about the size of a nickel..
It should be near Q591....
See if there's any discoloration on the sides &/or the edges of that cap...



Quote
The power supply transistors were only a little warm.
Very GOOD !!!

Quote
Is it possible I messed it up by leaving it on for 2 minutes without all the boards connected?
NO !!!..
NOT in this case !!!..


Quote
I just now tested it with only the D board (and a couple subboards connected to it). I wasn't sure if it mattered, but I figured I'd put it all together and do the "everything but the yoke / C board" test tomorrow...
When you hook it all together , use CARE with the heavy red (HV) wire that goes to the side of the CRT...
There may be a charge on that wire since you powered up the TV...
It's enough to get MORE than just your attention !!!...Wink..
Ground the end of that wire to the tuner cover to discharge it..
I would like to know what voltage you are getting on the base of Q591...
Should read -0.3 vdc...
Use care when you read that...
The base is the pin (#1) on the left side as you face the transistor..
Let me know what all the results are....
THANKS...



Replacement transistors are OK...
Letters after generic numbers usually are not important...
The "2S" prefix is a given with these types of transistors & nothing to worry about...


Quote
HOT has one short: B/E and E/B
That is a very low reading due to an internal resistor between base & emitter & driver transformer circuitry....
IF you put your meter on a very low scale you should read low ohms with the transistor out of circuit that I see no need to do since you have B+ (~130 vdc) from the power supply to the flyback ...
Right ???..

I'll be online for about 3 1/2 more hours..


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


CRT_Fan
User

Feb 2, 2014, 9:15 PM

Post #29 of 198 (1803 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
>Locate & check C520... See if there's any discoloration on the sides &/or the edges of that cap...

Looks physically OK. Do you want me to check the capacitance? I can't get a reading without removing it from the board and it's small and hard to get to.

Unrelated: I was using a cap near the corner of the board as an easy ground and noticed that C522 was not connected securely so I resoldered it. Didn't seem to affect anything. It might have been barely connected before I bumped it. Oh, I measured it before I put it back in and got 48 nF.


Q591:

B: fluctuates between .001 and .000 VDC. Tried AC and got 1.61 VAC
E: 0 VDC
C: 134.8 which is exactly what +B measures on the FBT pin.

Ron, If there are any components you want me to check out of circuit, just post a list anytime tonight or tomorrow morning and I'll take the board to the lab tomorrow to work on.

Thanks for you continued assistance


(This post was edited by CRT_Fan on Feb 2, 2014, 9:17 PM)


Ron.M
Veteran


Feb 2, 2014, 11:36 PM

Post #30 of 198 (1795 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
CRT_Fan;...

Please bear with me as I try to rule out all the off-the-wall possibilities..

Quote
Looks physically OK. Do you want me to check the capacitance?
It shouldn't be all that small ...
It's a 2 KV cap...
It doesn't look that hard to get at...
According to the service manual , the cap sits in front of Q591 in what looks to be fairly spacious , but then , I don't have the set in front of me...
IF it's going to be a hassle , we can pass on this...

I'm concerned about the voltage at the base of Q591..
Seems to be a lack of H drive...

Find Q502 & take "B" & "C" readings...
"E" is ground..
Please take both AC & DC readings there...
THANKS..


I'll be back one more time before the game...


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


CRT_Fan
User

Feb 3, 2014, 12:43 AM

Post #31 of 198 (1793 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
Ron, here are the measurements for Q502:

B: -1.025 VDC .777 VAC
C: 117.3 VDC 81.9 VAC


Incidentally, several components in that region including Q502 look like they may have been replaced.


Ron.M
Veteran


Feb 3, 2014, 7:33 PM

Post #32 of 198 (1780 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
CRT_Fan;...


(Broncos got their ass kicked...Pirate..)

Q502 voltages appear to be OK....

But , I'm not sure about the base of Q591...


From post #27;...
Quote
I just now tested it with only the D board (and a couple subboards connected to it). I wasn't sure if it mattered, but I figured I'd put it all together and do the "everything but the yoke / C board" test tomorrow.
The way Sony has these boards hooked up causes problems...
When you read voltages that I ask for , I'd very much appreciate it if all the boards were hooked up , EXCEPT the connector that goes to the yoke...
Some of the panels are interconnected & you have signals & voltages going thru some of the boards..
So , lets re-read the voltages on Q591 WITH everything hooked up EXCEPT the yoke & the CRT panel OFF the CRT...
Retest the temperature of Q591 & the power supply transistors..
I don't know if any of this will make a difference , but , it's better to be sure..

Quote
but the rear input panel and dynamic convergence board were off, as was the P board, whatever that does.
The "P" panel has the circuitry for PIP..(Picture-in-Picture)..

Unsolder one end of R515 (0.33 2 watt) ...
Unsolder one end of R516 (47 ohms 1/2 watt(?)..
Both are in the base circuit of Q591...
IF you do this & have BOTH resistors with one leg unsoldered , you can now read the "B" to "E" resistance of Q591 without error..
It will be a LOW reading...

Here's how to read C520 without fully removing it from the board...
Desolder one leg cleanly...
Hook up one meter lead to the pin still soldered to the board...
CAREFULLY touch the other lead to the unsoldered leg to get a reading...
Make sure that that leg does NOT touch the foil on the board..


PLEASE post ALL results...

THANKS...Sly...


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

(This post was edited by Ron.M on Feb 3, 2014, 7:35 PM)


CRT_Fan
User

Feb 3, 2014, 10:30 PM

Post #33 of 198 (1773 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
   
I did one better and simply removed Q591 to get a full set of measurements this afternoon. It's a lot easier to take things out when you've got a solder sucker and other accessories available.

Resistance:
B/C: 2.04M .. C/B: OL
B/E: 3.07M .. E/B: OL
C/E: OL ..... E/C: OL

>It will be a LOW reading...

Since it wasn't, does this mean the HOT is bad? That's kinda what I suspected ever since the high-pitch sound stopped.

Diode mode:
B/C: 0.52V .. C/B: OL
B/E: .5~.8V .. E/B: OL
C/E: OL ..... E/C: OL

Also took out C520 while I was at it (in this case it isn't possible to lift a leg without taking it out the way it was mounted, which is why I didn't want to do it at home). I had trouble getting a reading at such low values, but I believe it is good. I compared it to another "471" cap found in a junk board and the reading was identical.

>So , lets re-read the voltages on Q591 WITH everything hooked up EXCEPT the yoke & the CRT panel >OFF the CRT...

So, like last time, you want everything connected except CN107, right? Even the FBT grey wire and anode cap connected? (And is that safe given that the FBT is "bad"?)


Ron.M
Veteran


Feb 4, 2014, 2:02 AM

Post #34 of 198 (1765 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
 

CRT_Fan;....

Q591 (2SC4927) may be bad...
Reason is that the datasheet shows a resistor from the base to emitter...
The datasheet does not give a value of that resistor...DAMM !!!
So , I'm leaning toward a bad Q591...
Which could explain the problem with the base voltage readng..
I suggest you get a new 2SC4927 & take ohms readings..
Do NOT do ANY of the following till you have a new transistor to compare with the one you have now...
Please do NOT install it till you post back with the readings...

***********************************************

Quote
So, like last time, you want everything connected except CN107, right? << YES!!
Even the FBT grey wire and anode cap connected?<<YES
(And is that safe given that the FBT is "bad"??<<FBT in doubt at this time...
I have some doubt about the flyback being bad...
That is why I was looking at the yoke till you posted Q591 was running quite warm/hot...
So , lets flip a coin ...LATER !!!..Crazy..


Old business;=>..

Unsolder one end of R515 (0.33 2 watt) ...
Unsolder one end of R516 (47 ohms 1/2 watt(?)..
Readings are "xx" ohms???
Do that before you hook it up for the temp test..

New business;=>...

When you check R515 , check the driver transformer (ohms) (T502) from the resistor leg that goes to the transformer...
Hopefully , you have Q591 out , the 2 resistors (R515/516) with one leg lifted off the board..
This way we get an accurate reading...

To make this easier on you , I suggest you do these tasks in this order;=>..
1)..
Check R515/516 , leave one leg unsoldered..
2)..
Check the ohms of T502 to chassis ground...
3)..
Solder the resistors back in...
4)..
Hook up ALL boards to the chassis etc , EXCEPT CN107..
Leave CRT panel off CRT...
5)..
Re-read voltage at base of Q591..
6)..
Run temp test..

Please post ALL info & test results..


THANKS...Sly..

Having fun yet ??

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


CRT_Fan
User

Feb 5, 2014, 1:05 AM

Post #35 of 198 (1753 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
I did some research and according to http://www.repairfaq.org/sam/deflfaq.htm the HOT must be bad because they say the damper on B/E should only be around 50 ohms so I guess something blew the resistor.

Reordered. Will measure this time!

> THANKS...Sly..

I should be thanking you!

> Having fun yet ??

Well, maybe not what I'd call fun, but certainly challenging, exciting (dealing with deadly voltages), satisfying (when/if it is finally repaired) ... even if it does end in failure it's still been educational and given me some confidence in working with CRTs. (I'm nowhere near ready to give up yet though.)


I'll try to do those measurements you asked for tomorrow. One thing I'm not clear on:

> Hopefully , you have Q591 out

For step 1 & 2 sure, but does that also include step 5 or is that covered under "Do NOT do ANY of the following till you have a new transistor" policy? I.e. can I measure at Q591 Base solder point w/o the transistor installed or will that have to wait until the replacement arrives?


jts1957
Veteran


Feb 5, 2014, 3:05 AM

Post #36 of 198 (1747 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
Damper (when used) is C - E.

Quote
Well, maybe not what I'd call fun, but certainly challenging, exciting (dealing with deadly voltages), satisfying (when/if it is finally repaired) ... even if it does end in failure it's still been educational and given me some confidence in working with CRTs. (I'm nowhere near ready to give up yet though.)
Beware the 'Magic Smoke' too.


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


Ron.M
Veteran


Feb 5, 2014, 7:54 PM

Post #37 of 198 (1734 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
 
CRT_Fan;....

Step 1 , 2 & 3 can be done before you get the new HOT transistor...
As for step 5 ,
You can read that voltage there without Q591 installed...
We do not want to blow the new HOT ..
I'll need the reading..
Both R515 & R516 have to be soldered in..
Step 5A will be added after we get the readings from the new HOT & I'm sure you already figured out what it is....Wink..


If you are eager to tinker with the TV , I have some tests you can make while you are waiting for the new HOT:=>...
On the secondary side of the flyback , locate pins 6 & 8...
Coming off pin 6 look for D503...
It will be after R505 & L502...
Go to the negative side of the diode (Not the band end) & measure ohms to ground (Pin 7)....
Coming off pin 8 look for D502..
It will be after R501 & R510...
Go to the band end & read ohms to ground..
Then read the opposite sides of both diodes to ground..
Please post readings...

Look for IC501...
It will be opposite the flyback side of the board , a few inches toward the front of the chassis..
It is a small 7 pin IC & mounted on a heatsink....
Check & see if the front of the IC is there & intact...
No pothole...Wink....
THANKS...


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


CRT_Fan
User

Feb 5, 2014, 10:42 PM

Post #38 of 198 (1728 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
jts, Magic Smoke was not a factor in my poor reading comprehension there I assure you!

R516 50 ohms
R515 0.3 ohms
T502 < 10 ohms. The 2 legs on the other side of T502 were open circuits wrt chassis gnd. Between them I measured ~100 ohms.


D502 ohmage
2.69M |<| 1.2 wrt gnd
-1.2M |<| 1.3 w/probes swapped
1V |<| 0.45V diode mode

D503 ohmage
1.3 |<| -1.8M wrt gnd
1.5 |<| 2.98(M?) w/ probes swapped
2V |<| 0.45V diode mode

key:
band end |<| other end

I also measured Q591 without the transistor installed and the results were different but still not right I think. These are preliminary measurements NOT taken with all the boards installed (I'm thinking I will do that part this weekend) so they might not be useful.

Q591
B -0.025 VDC 2.89 VAC
E 0.000 VDC 1 mVAC
C 135V = +B
Power supply transistors were still only warm. I checked the other heat-sink mounted components and none of them were hot either.


IC501 looks undamaged.

Go ahead and send me more measurements to make if you like.


Ron.M
Veteran


Feb 5, 2014, 11:18 PM

Post #39 of 198 (1724 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
CRT_Fan;...

R515 & R516=OK...
T502 seems about right...
What does "wrt gnd" mean ???
Would that be "With Red To" ground ??


Quote
I also measured Q591 without the transistor installed and the results were different but still not right I think. These are preliminary measurements NOT taken with all the boards installed (I'm thinking I will do that part this weekend) so they might not be useful.
ALL boards , PLEASE !!!..

Quote
IC501 looks undamaged.
That rules out the Vert IC... Good...


Quote
Go ahead and send me more measurements to make if you like.
 That's it for now...

GOOD WORK !!!..Wink..


When the new transistor(s) arrive , post & I'll get back to you ASAP...


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


CRT_Fan
User

Feb 8, 2014, 7:48 PM

Post #40 of 198 (1705 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
> What does "wrt gnd" mean ???

wrt = with respect to, so black/common on ground. "Probes swapped" was red on ground in that case.

Q591 solder points WITHOUT transistor and WITH all boards and everything connected except CN107 (and a few unnecessary connectors attached to the front).

B: -.003 VDC .774 VAC
E: .06 ~ .08 VDC .171 VAC
C: 134.8 VDC

Power transistors were not hot. No sparking, crackling or other noises.

If you can think of any other measurements to make that need everything hooked up now is a good time.

Q591 reorder not delivered yet. Maybe Monday.


Ron.M
Veteran


Feb 8, 2014, 8:02 PM

Post #41 of 198 (1702 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
 
CRT_Fan;...

THANKS for the info...

We're going to have to run another test when the new part(s) arrive...

Can't think of anything else we can do at this time...


Have a GREAT day & weekend...Sly..


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


CRT_Fan
User

Feb 10, 2014, 10:45 PM

Post #42 of 198 (1686 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
 

I only received one. Supplier issued a refund for missing stock.

Given that the last one went bad after a couple of minutes with the power on..

Code
Ohmage: 
 
E/B 22.8   B/E 22.8 
C/B OL     B/C 2.551M 
E/C 2.551M C/E OL 
 
Diode: 
 
E/B 0.021V B/E 0.021V 
C/B OL     B/C 0.511V 
E/C .521V  C/E OL

C4927 looks good to me.

I'm pretty busy right now so I might not be able to solder it in for a while, but go ahead and post the next test(s) to run and I'll do them when I have the time.

Thanks!


Ron.M
Veteran


Feb 10, 2014, 11:15 PM

Post #43 of 198 (1682 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
 
CRT_Fan;...

You may need another one after the next test...

Quote
Ohmage:
E/B 22.8 B/E 22.8 <<<There's our resistor !!!
C/B OL B/C 2.551M
E/C 2.551M C/E OL

Looking good...Smile...

When you are ready fot the next step , please post the day before you are going to do it...
THANKS...
This next step MAY take out the new C4927 you just got , so be advised...


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


CRT_Fan
User

Feb 13, 2014, 3:33 AM

Post #44 of 198 (1669 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
Hi Ron

I ordered some more, so I'm not too worried about losing this one.

I'll try to get to it tomorrow so please give me directions. thanks


Ron.M
Veteran


Feb 13, 2014, 5:48 AM

Post #45 of 198 (1664 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
    

CRT_Fan;...

This test is going to be tricky & risky...
Install the new transistor...
You'll have to read the base voltage QUICKLY !!!
Here's how...
Whichever way is easier to get at the base pin with the "-" probe of the meter..
From the top , IF you can read it there SAFELY , or from the bottom IF you can have the chassis in a stable position...
See pix below from the Service Manual..



Have the meter set to low dc volts..
We are looking for ~ -0.3 vdc...
With BOTH meter probes hooked up , turn the TV on for 2 seconds or less...
That should be enough time to get a reading...
IF & I mean IF you get ~ -0.3 vdc , turn the TV back on for about 15~30 seconds & then check the temp of the transistor...
IF it runs cool , do the test for a longer period..
Say 2~3 mins...

Please post results..

Thanks...Smile...


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


CRT_Fan
User

Feb 13, 2014, 11:16 PM

Post #46 of 198 (1657 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
Code
So far so good  
  
B  -0.311V  
E   0.046V  
C 134.6V  
  
These probably aren't useful:  
  
B 0.5 ohm wrt gnd  
E 0.2 ohm wrt gnd  
C 20k - 600k
Transistor Still not hot after over a minute.

Everything is still hooked up including black probe rigged to a safe ground point so lemme know what to do next.

EDIT
Couple more things to mention. It's possible that some of the connections weren't secure last time when I measured w/o the transistor so those measurements may not be accurate.

By the way I didn't leave it on for 2-3 mins because that's about the time range I think killed the other one so I am a bit skittish. Figured I'd report back first in case you've got some other tests to run before risking the destruction of the transistor.

Now that I've had a chance to look at the schematics, I notice the emitter voltage is about half of what it should be so there may be some other issue, unless that's due to the disconnected CN107?


(This post was edited by CRT_Fan on Feb 13, 2014, 11:53 PM)


Ron.M
Veteran


Feb 14, 2014, 12:21 AM

Post #47 of 198 (1650 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
 
CRT_Fan;..

OK , that's good news...
Previous transistor apparently WAS BAD from the git-go....Unsure...
Run the TV starting with 1 minute building up to 5 full minutes...
Let it cool in between cycles..
After each run , check the temp of the transistor...
IF it gets too hot , stop..

Quote
These probably aren't useful:
Yup , not needed anyway..


Quote
By the way I didn't leave it on for 2-3 mins because that's about the time range I think killed the other one so I am a bit skittish.
We have to find out IF the flyback is causing the transistor to get hot & blow...
We may lose this transistor in the process..


Quote
I notice the emitter voltage is about half of what it should be so there may be some other issue, unless that's due to the disconnected CN107?
Yes , it IS due to CN107 being disconnected..
The yoke & flyback work together to get ~30 KV (+other voltages) for the CRT & deflection to operate..
With the yoke being disconnected , you are only getting about 1/2 the HV.

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


CRT_Fan
User

Feb 14, 2014, 2:19 AM

Post #48 of 198 (1644 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
>Previous transistor apparently WAS BAD from the git-go

I think I only got one from that seller. The reorders are definitely from someone else.

>We have to find out IF the flyback is causing the transistor to get hot & blow...
>We may lose this transistor in the process..

No problem.


90 sec - warm
2 min - warm
3 min - warm
4 min - warm
5 min - might be warmer, but still not hot to the touch

I entertained myself while watching the stopwatch by taking FBT measurements. Probably useless w/o the yoke connected, but no harm in posting them.

Code
                 Actual        
(1) C     134.6 = Q591 collector        
(2) +B    134.8        
(3) 200V  134.8        
(4) H1    182.5        
(5) H2    182.5        
(6) -15V  0.024        
(7) E     0.011        
(8) +15V  -0.001        
(9) 27V   0.001        
(10) ABL  8.43        
  
B .945 VAC        
E .124 VAC        
C 197.7 VAC
What's next? Leave it on longer and longer? Yoke test?

EDIT - more testing will go here

6 min - the screw was hot but cooled down quickly, transistor itself only warm
8 min - about the same, maybe a little bit warmer on the transistor
10 min - definitely getting hotter, especially the screw, but transistor body is still "warm". Cools down quickly from touching it.

Still measuring about -.3 V on B.

15 min - about the same. Screw is very hot but cools down quickly when I touch it. Transistor body warm.

20 min - I don't know... still -.3V though.

30 min - transistor itself was definitely hot the first time I touched it, but the second time it was down to warm. Still -.3V.

I don't know. It took an hour or two before the set died the first time, so I can't say for sure it's not going to blow up eventually.

Let's not forget that way back when I first replaced Q591 and I put the C board on the yoke and plugged everything in it blew up right away.

I don't mind running it for a few hours or until it keels over, if you want me to do that tomorrow.

Time for bed...


(This post was edited by CRT_Fan on Feb 14, 2014, 4:25 AM)


Ron.M
Veteran


Feb 14, 2014, 7:31 PM

Post #49 of 198 (1626 views)
Shortcut
Re: [CRT_Fan] Dead Sony KV-32TS36 [In reply to] Can't Post
    

CRT_Fan;....

In the future , do NOT read any voltage on the collector of Q591 OR pin #1 on the flyback....
I'm surprised you haven't BLOWN your meter by now..
Luckily , the yoke being disconnected may have saved it...
On the next step , you WILL blow the meter IF you read at those locations...
There normally is about a 5,000 volt pulse on the collector & pin #1 of the flyback IF everything is working OK..

30 mins & transistor is warm & did NOT blow indicates flyback , wait for it , ....................Good !!!......(So far !!!)..
It looks like we are going in circles here...
I suspect that part of the misdiagnosis was due to bad "new" transistors...

OK , let's go for the jugular..Shocked....
Plug in the yoke ONLY & leave the CRT panel OFF the CRT ..
Hang it in space away from the neck of the CRT & other wiring & metal...
Turn on the TV & be ready for a FAST disconnection from power...
Have your hand on the AC cord & be ready to jerk it outta the wall or where ever you have it plugged in...
IF you hear ANY any sustained hissing , crackling , or POPs , unplug the TV IMMEDIATELY !!!
It is normal for BRIEF crackling when the TV is first turned on..
However , NO POPS or hissing allowed...
IF you hear ANY hissing , crackling , or POPs , try to determine where they were coming from..


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

(This post was edited by Ron.M on Feb 14, 2014, 9:13 PM)


jts1957
Veteran


Feb 14, 2014, 8:19 PM

Post #50 of 198 (1623 views)
Shortcut
Re: [Ron.M] Dead Sony KV-32TS36 [In reply to] Can't Post
What's an "ANY any"?

Who ya calling 'POPs'?

Happy St. Patrick's Valentine's Day


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

(This post was edited by jts1957 on Feb 14, 2014, 8:21 PM)

First page Previous page 1 2 3 4 5 6 7 8 Next page Last page  View All
 
 


Search for (options) - Page loaded in: 0.15 s on (CGI/1.1)
0