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Blaupunkt Television HT help

R

Ren

Jan 1, 1970
0
Hi there

I have picked up a Blaupunkt MS 70-109VT-M Television Set.
When powering up all that was heard was a Tick Tick noise.
I traced the fault to a Transistor that was switching the the Line output
transformer.
This Transformer then feeds a separate High Tension Transformer.

I found that Transistor (BU508AG) was in shorted condition.
I found a suitable replacement (BU508A) which has a higher wattage/current
rating.

As soon as i had installed the BU 508A and made a few other checks of
surrounding components i energised the set.
Instantly the Screen lit up, and displayed a good picture of snow.
Shortly after (Only seconds) there was a Crack. Which only sounded like a
high voltage Crack..

Upon a close look at the HT transformer, I can see a Crack in the Caseing.
This is shorting or flashing over to the Line output transformer.

I havent lost the BU508A yet, probably due to the higher Current.Wattage
rating..

I was wondering, Whats my chances or options of getting a replacement
Transformer.
Is there a known equivilent ?.
I have no Circuit diagram or parts listing for this Tv, as will most things
i have a go at repairing.

Does anyone have an idea of what i could do..
The Set itself looks quite a styley set..


Thanks.

Ren (Nz)
 
J

Jerry G.

Jan 1, 1970
0
If you get in touch with the authorized parts dealer or Blaupunkt directly,
they can tell you where you can get the parts. You should use the factory
replacement parts for your set if you want to get it reliably working. As
for your fault, if you do not find the original cause of the failure, the
new parts will not last very long.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


Hi there

I have picked up a Blaupunkt MS 70-109VT-M Television Set.
When powering up all that was heard was a Tick Tick noise.
I traced the fault to a Transistor that was switching the the Line output
transformer.
This Transformer then feeds a separate High Tension Transformer.

I found that Transistor (BU508AG) was in shorted condition.
I found a suitable replacement (BU508A) which has a higher wattage/current
rating.

As soon as i had installed the BU 508A and made a few other checks of
surrounding components i energised the set.
Instantly the Screen lit up, and displayed a good picture of snow.
Shortly after (Only seconds) there was a Crack. Which only sounded like a
high voltage Crack..

Upon a close look at the HT transformer, I can see a Crack in the Caseing.
This is shorting or flashing over to the Line output transformer.

I havent lost the BU508A yet, probably due to the higher Current.Wattage
rating..

I was wondering, Whats my chances or options of getting a replacement
Transformer.
Is there a known equivilent ?.
I have no Circuit diagram or parts listing for this Tv, as will most things
i have a go at repairing.

Does anyone have an idea of what i could do..
The Set itself looks quite a styley set..


Thanks.

Ren (Nz)
 
R

Rainer F. Daltrop

Jan 1, 1970
0
IIRC MS70-109 is a Grundig CUC5860 chassis and it uses a HV tripler unit.
see if this picture fits it
http://w1.455.telia.com/~u45521011/images/Grundig/CUC_5860.JPG
See if there are any markings on that
'cracked' and 'arcing' part. BG2097-642-1001G or something would be my guess
that
comes to mind here. You need the exact part number and then we can dig up a
cross. Don't leave it working that way. You risc blowing the custom chips
in that set. And as for the original cause of that failure that Jerry
mentiones: I guess he knows that these tripler units do crack and/or short
out with age without any particular reason. But checkingthe voltage on the
supply to the HOT and changeing all small caps in the primary of the SMPS
should be advised.
If you feel unsure about it let a tech do it. Read the FAQ on safety issues
and discharging the CRT before replacing the tripler unit.

-Rainer
 
E

eddumweer

Jan 1, 1970
0
Check out before replacing the tripler with the BG2087 trippler
disconnected, if the set is switching on, and audio is present when
receiving a signal by aerial or cablesignal. If not, probably there could be
several faults by arcing.

Greetings Peter
 
R

Ren

Jan 1, 1970
0
Thanks Rainer, Eddumweer, Jerry G for your replies.

The Tripler that i have in this set is a BG 2087-642-1006 G.
With Blaupunkt TVs being very rear in New Zealand My first initial thoughts
on being able to get a replacement tripler for this set were thin. But after
checking
a local electronics wholesaler here in Nz, i see that they have the exact
one listed. At quite a reasonable price aswell.. $55 Nz..
....

Just another question..
Would i have done any harm by installing a replacement HOT of twice the
rated specification ?
The way i see it, the one i have installed can withstand more load.
BU508AG shorted, replaced with BU508A.

I will go through and replace all electrolytics around the SMPS just to be
sure aswell..
This wont take too long.

I have at this stage removed the cracked Tripler Pack. And removed the
outside casing revealing a nice black charcoal area where the coil has
blown.

So, it is safe to switch on the Set without a Tripler in Circuit.
If i do, this will let the set start up giving just Audio.?
Should i at this stage measure the voltage coming out of the Transformer
that would feed the Tripler.
What would a rough voltage be ?


Thanks once again for your replies.


Ren (Nz)
 
E

eddumweer

Jan 1, 1970
0
Hi Ren,

Normally I disconnect the wire between the transformer and the tripler, then
switch on the tv-set. After that and before ordering a trippler (if not in
stock) I check if I get audio on the tv-set. If I get audio, the controller
and the tunerpart will mostly be ok.

If not I will be suspicius because the arcing can damage the tuner,
microcontroller and the txt (videotext) by static electricity. During repair
in the trippler used chassis of Blaupunkt, Grundig and Siemens I see
sometimes the problems that the above mentioned circuits get bad. And then
you must know if the repairprice could be not to high.

Greetings Peter

Ren said:
Thanks Rainer, Eddumweer, Jerry G for your replies.

The Tripler that i have in this set is a BG 2087-642-1006 G.
With Blaupunkt TVs being very rear in New Zealand My first initial thoughts
on being able to get a replacement tripler for this set were thin. But after
checking
a local electronics wholesaler here in Nz, i see that they have the exact
one listed. At quite a reasonable price aswell.. $55 Nz..
...

Just another question..
Would i have done any harm by installing a replacement HOT of twice the
rated specification ?
The way i see it, the one i have installed can withstand more load.
BU508AG shorted, replaced with BU508A.

I will go through and replace all electrolytics around the SMPS just to be
sure aswell..
This wont take too long.

I have at this stage removed the cracked Tripler Pack. And removed the
outside casing revealing a nice black charcoal area where the coil has
blown.

So, it is safe to switch on the Set without a Tripler in Circuit.
If i do, this will let the set start up giving just Audio.?
Should i at this stage measure the voltage coming out of the Transformer
that would feed the Tripler.
What would a rough voltage be ?


Thanks once again for your replies.


Ren (Nz)
up
 
R

Ren

Jan 1, 1970
0
Thanks Peter.

I have since fired up the set without the Tripler in circuit, and dont get
any sound.. although. I cant be sure if the Television was tuned to any
local television stations.
I did try and connect a source via the Av in connectors, but still had no
sound.
Aswell as this, i dont have the remote control unit either.
I assume i press the Volume button , then the -ve and +ve buttons to raise
or lower the volume.
This is via the control panel on top of the Television.
One other thing i was unsure about was the c/s button ..

Anyway.. I have a replacement tripler coming.

As far as the output of the transformer is concerned, what value of voltage
should be coming out of this terminal ?


Cheers

Ren
 
R

Ren

Jan 1, 1970
0
Hi peter..


I have since received a new Tripler component, installed it, and as you
said.. I think the Tuner has been taken out.
At this stage , all i have on the sceen is a slight brightness with lines
running horizontally every 4cm..
It looks as though i will have to get hold of a Skematic diagram.
There is the occasional pop or crakle of Pink noise from the speakers.



Any ideas ???.
 
E

eddumweer

Jan 1, 1970
0
Hi Ren,

I have been looking, but no scematic drawing for this chassis here, if you
got an oscilloscoop, check the I2C lines, this is the communication between
the microcontroller, tuner and several other part's.

If you can't find it, I normally search for the datasheet's of the ic's and
so I find the I2C SDA and SCL lines. I thinks, knowing Grundig there are
more ic's who are using the I2C.

After all this was the reason I alway first disconnected the trippler from
the high voltage transformer.

Greetings Peter
 
R

Ren

Jan 1, 1970
0
Hi Peter..

I have managed to get hold of a Skematic diagram of the Set..
I will check those Rails as soon as i get back to the set.

I will post a message soon..

Thanks for replying..


Ren
 
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