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Service Manual

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Night Rider

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i have this tv model and it doesn't work for a few months. it's my grandfather's tv. i'm new on tv repairment and i study on it. so, i said that it is a reason to make my first steps knowing of course about the dangers. So, i asked if i can find just easy a service book for this model to start my "experiments". If you can help me i can find the CUC number when i'll go to the village, because i supposed that the tv model was enough. what is the CUC number Nigel? C.... U.... C..... ?
thanks.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Night Rider said:
i have this tv model and it doesn't work for a few months. it's my grandfather's tv. i'm new on tv repairment and i study on it. so, i said that it is a reason to make my first steps knowing of course about the dangers. So, i asked if i can find just easy a service book for this model to start my "experiments". If you can help me i can find the CUC number when i'll go to the village, because i supposed that the tv model was enough. what is the CUC number Nigel? C.... U.... C..... ?
thanks.
CUC is 'Compact Universal Chassis', it's the chassis number of the set, it's on the back near the model number, it should be CUC followed by four digits.
 

Night Rider

New Member
Sorry Nigel, the model is: T-55 730/5 and
the CUC is: 7301
I find and another number, i don't known if it is useful to you, here is:
GCA 47
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Night Rider said:
Sorry Nigel, the model is: T-55 730/5 and
the CUC is: 7301
I find and another number, i don't known if it is useful to you, here is:
GCA 47
CUC7301 is the number I need.

So what's wrong with the set?.

Assuming it's dead?, it's a VERY common problem, caused by a dry joint on C669. This cause the PSU to 'blow up' requiring a substantial rebuild, chip, transistor, six diodes, one zener, three resistors - and occasionally other bits as well!.
 

Night Rider

New Member
Yes it's dead. I want to measure the PSU but first i want to ask you first. Is there any service manual to attach me, because i want to known where i will measure. if you are sure about this problem show me only the PSU circuit with some voltages so i can know what i'm doing. C669 is a capacitor or something else? Don't laugh, i don't known very well about the numbers of some special tv components. As i remember this tv had another problem at the past and fixed by a technician, but after a month the tv was dead. The power led is off when i turn on the tv.
Thanks for helping me.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Night Rider said:
Yes it's dead. I want to measure the PSU but first i want to ask you first. Is there any service manual to attach me, because i want to known where i will measure. if you are sure about this problem show me only the PSU circuit with some voltages so i can know what i'm doing. C669 is a capacitor or something else? Don't laugh, i don't known very well about the numbers of some special tv components. As i remember this tv had another problem at the past and fixed by a technician, but after a month the tv was dead. The power led is off when i turn on the tv.
Thanks for helping me.
C669 is a capacitor, it's close to the switch-mode mains TX, and it's almost certainly blue.

You should also be VERY aware that the main electrolytic usually remains charged when the PSU dies! - it can give you quite a nasty shock!.

For a start, check if the switching transistor is S/C, it's the one on the heatsink.
 

Night Rider

New Member
Ok Nigel. i know about switch-mode PSU's because i constructed one at the past, for my lab. if i'll see a problem i'll tell you. thanks again!
 

Night Rider

New Member
And something else. I posted a topic to "Microcontrollers". "Problem with RF connection" is the subject. The problem that i had, i posted it at the past again and you give an advise. Can you, please see the post to give me an opinion, as i give more details for the problem?
 
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