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My old grundig is semi-dead

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t0nito
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Nov 7, 2013, 9:54 PM

Post #51 of 76 (1683 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

Wait Ron I think I screwed up probably had it on the wrong scale. I rechecked it in the 20M scale

E to C = INF
E to B = 10 MOhm
B to C = INF
B to E = INF
C to B = 4.4 MOhm
C to E = INF

BTW transistor is a BUT12A
Sorry about that.

(This post was edited by t0nito on Nov 7, 2013, 9:57 PM)

t0nito
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Nov 7, 2013, 10:06 PM

Post #52 of 76 (1671 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

Not sure if relevant but I get 360 VDC between pin A and B. Standby or on. Other than the LED display it seems there's no difference when switching between modes.

It so weird when the problem came it made a loud pop from the back, and when I turned it back on with the remote it made another loud pop but I don't see any component with the slighest trace of burning or charring...

(This post was edited by t0nito on Nov 7, 2013, 10:10 PM)

Ron.M
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Nov 7, 2013, 10:54 PM

Post #53 of 76 (1654 views)
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Re: [t0nito] My old grundig is semi-dead [In reply to]	Can't Post

t0nito:.....

When we find the bad part , we may see damage on it...
Not to worry right now....

Pin "A" goes to the collector of T661....
Pin "B" goes to the 360vdc source...
Pin "A" also goes to Pin "B" thru a winding in the transformer TR665...
So we have another mystery...
IF you have the right pins , there SHOULD be verrrry little reading between "A" & "B"...
Read ohms on a mid range between Pins "A" & "B" ...
IF you get a low reading , drop the range down till you get a lower reading...
IF you still have the original transformer , compare the SAME pins on it for ohms..
1 for the one in the TV & the other for the original..
According to your drawing in post #23 , I'm going to guess that "A" & "B" would be pins 1 & 2 ...
Even tho Pin 1 is shown as "ground" ???
Post readings...

At this time , T661 looks bad...
My manual has that as a BUT11A...
Probably subbed by previous tech...

Later..Ron.M... Cool

...
Veteran & Retired TV technician

t0nito
User

Nov 7, 2013, 11:07 PM

Post #54 of 76 (1653 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

There does seem have a discrepancy between the that drawing and the TV schematic, weird though, probably some mixup of the references on the site.

I'll be checking that tomorrow as it's a bit late here. I do have the original flyback, and fortunately I know it's working despite of it making a loud 15 kHz whine. (that's why I replaced it).

I'll be posting results tomorrow. Thank you Wink

Not sure this means anything but...

When the TV was working properly when it was in standby mode I could here a constant high frequency switching noise, it has always done that, and from I read it is normal for this particular chassis, I remember seeing this exact same model somewhere else doing this and at the time I thought it was the HV 15kHz noise so I found it weird at the time that it did that when in standby but now I know it was not the case.

It still does this now even with the fault, it just seems now that it won't leave standby mode even though the LED display says it's on. When I removed the transistor I plugged it in and that noise was gone.

Anyway the question is, based on this fact, wouldn't it be normal for this voltage to be contantly between A and B?

(This post was edited by t0nito on Nov 7, 2013, 11:20 PM)

t0nito
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Nov 7, 2013, 11:29 PM

Post #55 of 76 (1651 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

Just in case you wan't to get more "into" this TV, here's an interesting read about this exaxt same model:

http://obsoletetellyemuseum.blogspot.pt/2012/11/grundig-t51-4001-chassis-cuc34002.html

Also it seems to have the correct drawing for the transformer.

(This post was edited by t0nito on Nov 7, 2013, 11:32 PM)

Ron.M
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Nov 8, 2013, 12:25 AM

Post #56 of 76 (1638 views)
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Re: [t0nito] My old grundig is semi-dead [In reply to]	Can't Post

t0nito;....

Quote

When I removed the transistor I plugged it in and that noise was gone.

Which transistor ????

Quote

Anyway the question is, based on this fact, wouldn't it be normal for this voltage to be contantly between A and B?

IF the transformer IS wound like it is in the schematic in the SM , NO !!!
The winding for that part of the transformer should read about 0.5 ~ 1.5 ohms...
There should also be 360 vdc at both A & B with the TV on or off...

See ya Friday.... Wink

...

Can not load the page;=>..
http://obsoletetellyemuseum.blogspot.pt/...hassis-cuc34002.html

I'm having a problem with that link.... Unsure

....

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

...
Veteran & Retired TV technician

(This post was edited by Ron.M on Nov 8, 2013, 12:29 AM)

t0nito
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Nov 8, 2013, 12:52 AM

Post #57 of 76 (1630 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

The main switching transistor T661.

That's odd the link works fine here!

Ron.M
Veteran

Nov 8, 2013, 1:33 AM

Post #58 of 76 (1628 views)
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Re: [t0nito] My old grundig is semi-dead [In reply to]	Can't Post

t0nito;...

Where is here & what are you using for a browser ???

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

Veteran & Retired TV technician

jts1957
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Nov 8, 2013, 5:25 AM

Post #59 of 76 (1625 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

Links works fine for me. VERY technical. In English & German. You're gonna love it. Wink

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

(This post was edited by jts1957 on Nov 8, 2013, 5:30 AM)

t0nito
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Nov 8, 2013, 8:28 AM

Post #60 of 76 (1621 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

Have you been able to open the link yet? I'm using chrome for a browser.

According to that site here is the pinout of that transformer:

Does the schematic make more sense now?

It's funny because the box where the transformer came has the reference of the first drawing written on it.

I'll give you the Ohm results later after work.

t0nito
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Nov 8, 2013, 1:45 PM

Post #61 of 76 (1618 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

Both transformers measured 4.3 Ohm between pin A and B.

Ron.M
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Nov 8, 2013, 6:45 PM

Post #62 of 76 (1607 views)
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Re: [t0nito] My old grundig is semi-dead [In reply to]	Can't Post

jts1957;....
I'm using IE-7 for a browser that periodically gives me problems...
You , I think have/use FireFox...
t0nito is using Chrome which I also have & will try later...
Thanks for the info.... Wink

...

t0nito:...
Well you cleared up one mystery..(with the transformer)...
Now we have to get this figured out....
From post #52;=>...

Quote

Not sure if relevant but I get 360 VDC between pin A and B. Standby or on.

IF you have one meter lead on Pin "A" & the other lead on Pin "B" & you are reading 360 vdc , something is rotten in Denmark...(NO offense IF you are in Denmark)..
You should read 360 vdc from either Pin "A" or Pin "B" to Ground , that being point "P" on the schematic..(Emitter of T661 will work fine)...
Re-check BOTH pins for 360 vdc to ground ....
Post results...

Quote

Both transformers measured 4.3 Ohm between pin A and B.

Both transformers should be OK....

Later...Ron.M... Cool

...
Veteran & Retired TV technician

t0nito
User

Nov 8, 2013, 7:59 PM

Post #63 of 76 (1603 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

I'm guessing that I can use pin D as ground?

If so PIN A is giving me 317V at the moment.

And pin A gives me something between 1090V, and 1110V I thought is was quite high, but then again the schematic says there's a 1.2KV capacitor connected to pin A.

Between A and B if i put black on B and red on A the meter goes bezerk showing jumping random numbers.

If I reverse the leads it shows 340V, it used to show 360 but maybe the grid voltage is fluctuating throughout the day.

Perhaps a false reading?

BTW: I'm in Portugal not in Denmark. LOL Wink

Can't you tell from the crappy english? Laugh

(This post was edited by t0nito on Nov 8, 2013, 8:12 PM)

Ron.M
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Nov 8, 2013, 8:18 PM

Post #64 of 76 (1596 views)
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Re: [t0nito] My old grundig is semi-dead [In reply to]	Can't Post

t0nito;....

Pin "D" looks OK...

You have the TV unplugged & T661 out of the set , right ???

Quote

And pin A gives me something between 1090V, and 1110V I thought is was quite high, but then again the schematic says there's a 1.2KV capacitor connected to pin A.

WHAAAAAAT !!!!
HOW are you reading 317 vdc , 1090 vdc &/or 1110 vdc on the SAME pin ????
Listen up !!!
Put the "-" (Black) meter lead on "P" ("D")..
Put the "+" (Red) meter lead on "B"...
Set your meter on AC VOLTS....
Plug in the TV & read volts with the TV off , then turn it on...
Post both readings...

BTW:...
Your English is just fine....
However , there may be a misuse of some of your wording that may be causing some confusion on this end...
No matter , we'll sort it out... Wink

Later...Ron.M... Cool

...
Veteran & Retired TV technician

(This post was edited by Ron.M on Nov 8, 2013, 8:23 PM)

t0nito
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Nov 8, 2013, 8:46 PM

Post #65 of 76 (1589 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

Oops sorry I mistyped.

Let me clear this up.

T661 was back in the board.

I'm taking new readings right now with T661 installed. Everytime I plug it in seems to have a different value.

Right now PIN A:

1120 VDC 540 VAC (with the meter flashing every second (???)

PIN B: 318 VDC showing 0VAC (???)

Without transistor:

325VDC on both PINS A and B.

Sorry about the confusion. My mistake for not reading thoroughly before posting.

Readings are the same both on and standby, as long as the set is plugged in, this is what I get. In fact, without T661 installed I don't even get power on the LED display, so I'm not able to tell if it's on or in standby but pressing on/off on the remote makes no difference.

And NOW there is 0V between A and B. Naughty me for putting back that transistor Blush

(This post was edited by t0nito on Nov 8, 2013, 8:58 PM)

Ron.M
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Nov 8, 2013, 9:47 PM

Post #66 of 76 (1579 views)
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t0nito;....

OK , NOW that we/you got that all cleared up , let's move on..
Those are the readings I expected in the first place...

NEW problem ???

Quote

1120 VDC 540 VAC (with the meter flashing every second (???)

Power supply IS trying to fire up !!!
So I think R641, C667 & IC655 may be good , before this happened;=>..

Quote

And NOW there is 0V between A and B. Naughty me for putting back that transistor

IF you have a meter lead (Red "+") on pin "A" OR pin "B" & the other lead (Black "-") on pin "D" with the transistor in & are reading 300+ vdc , then you are OK...
IF you are not , then you DO have a new problem... Unsure

..
IF not;=>...
Locate D621 at tha AC input...
Connect your meter's black lead to Pin "D"...
Connect the Red meter lead to the "+" side of the diode or the "+" end of C626..
That will be a big fat can lytic (150mfd @ 385vdc)..

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

t0nito
User

Nov 8, 2013, 10:01 PM

Post #67 of 76 (1577 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

Wait Ron, 1120 VDC showed a steady value, but when I put the meter to AC then the meter started flashing.

I had the - lead on pin D and the + to pin A with the transistor on the board when it gave those 1120 VDC, and the 300+ VDC on pin B.

It gave 300+ on BOTH A and B without the transistor.

I'm going to leave now, I'll continue testing tomorrow.

Thank Ron, for being so patient. Cool

Ron.M
Veteran

Nov 8, 2013, 10:39 PM

Post #68 of 76 (1567 views)
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t0nito;....

For tomorrow;...

I don't like the readings you gave for T661 (Post #51).....

Quote

E to C = INF
E to B = 10 MOhm
B to C = INF
B to E = INF
C to B = 4.4 MOhm
C to E = INF

Lets get a new one to try...

Later...Ron.M... Cool

...
Veteran & Retired TV technician

t0nito
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Nov 9, 2013, 2:40 AM

Post #69 of 76 (1565 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

What do you think, should I get a BUT12A or a BUT11A?

EDIT: Well I ended up ordering a BUT11A since that was the original part.

(This post was edited by t0nito on Nov 9, 2013, 2:34 PM)

t0nito
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Nov 20, 2013, 9:21 PM

Post #70 of 76 (1550 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

Hi Ron, I FINALLY have the BUT11A values are as follows on the 20 M scale:

B to C = INF
B to E = INF
C to B =9.5 MOhm
C to E = INF
E to B = 14.75 MOhm
E to C = INF

(This post was edited by t0nito on Nov 20, 2013, 9:22 PM)

Ron.M
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Nov 22, 2013, 12:40 AM

Post #71 of 76 (1543 views)
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t0nito;....

Sorry about the delay , but I'm having computer problems that I've been battling for about 2 weeks....

Those readings on the new transistor look better that the original...
Here's what we're going to do...
1st;..
On the flyback , unsolder the wire that goes to the trippler from the flyback...
2nd..
Check the value of R523...
Comes off the emitter of T521...
Should read VERY low resistance..(0.12 ohms)..
3rd...
Install the new transistor in the power supply..
4th...
Have your meter set to +DC volts on a range of 200 vdc & ready to go & hooked up to the anode of D514..
Use R523 for ground..
D514 comes off pin 15 or "L" of TR665 transformer..
5th...
With the meter hooked up as I said , turn the TV on & look for a quick pulse , OR better yet a steady +200 vdc..
6th...
Please post results...

I have some errands to do Friday , so my responses will be erratic....Sorry... Unsure

...

Later..Ron.M.... Cool

..
Veteran & Retired TV technician

t0nito
User

Nov 22, 2013, 10:44 PM

Post #72 of 76 (1534 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

In Reply To

Quote

1st;..
On the flyback , unsolder the wire that goes to the trippler from the flyback...

done

Quote

2nd..
Check the value of R523...
Comes off the emitter of T521...
Should read VERY low resistance..(0.12 ohms)..

Reads about 0.2 ohm

Quote

3rd...
Install the new transistor in the power supply..

done

Quote

4th...
Have your meter set to +DC volts on a range of 200 vdc & ready to go & hooked up to the anode of D514..
Use R523 for ground..
D514 comes off pin 15 or "L" of TR665 transformer..
5th...
With the meter hooked up as I said , turn the TV on & look for a quick pulse , OR better yet a steady +200 vdc..
6th...

Meter jumps to around 5V then back to zero when unit is plugged in.

Turning it on with the remote makes no difference.

(This post was edited by t0nito on Nov 22, 2013, 10:46 PM)

Ron.M
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Nov 22, 2013, 11:26 PM

Post #73 of 76 (1529 views)
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t0nito;.....

Thanks for what you did...

So much for expertise...
Time to go on an Easter Egg hunt... Unsure

...

...

Put the original flyback back in & re-try what you just did...
Read the voltage at D514...
I'm lighting candles , saying prayers , sent a email to the Pope requesting a Novena & High Mass , contacted the Dali Lama , etc , for some really great Karma...

Good Luck.....

Later..Ron.M... Cool

..
Veteran & Retired TV technician

jts1957
Veteran

Nov 23, 2013, 1:20 AM

Post #74 of 76 (1526 views)
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Re: [Ron.M] My old grundig is semi-dead [In reply to]	Can't Post

You forgot to page (in no particular order): Doctor Who, Marcus Welby, M.D., Dr. Kildare, Dr. Henry Jekyll, Dr. Moreau, Dr. Frankenstein, Doctor McCoy and Doctor Dolittle. Tongue

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

Ron.M
Veteran

Nov 23, 2013, 6:58 PM

Post #75 of 76 (1522 views)
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Re: [jts1957] My old grundig is semi-dead [In reply to]	Can't Post

jts1957;....

In case you hadn't noticed , I'm dealing with HIGHER POWERS ....

Have a GREAT day & weekend... Sly

...

Later...Ron.M... Cool

...
Veteran & Retired TV technician

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