Telefunken chassis 618 problem (english)

Hello everybody.

I found this site while I was looking for help for my Telefunken TV set with 618 chassis and I hope someone could help me.

When TV is turned on, it pumps 3 times and then goes off.

I did following: resoldier all cold joints
Changed all elcos in secondary part of power and line stage
Checked all diodes in secondary part of power and line stage with ohm-meter as well as most of transistors (marked as TL)
Exchanged line trafo

Asfter no success, I began to disconnect each secondary line to see which one is problematic. I found that:
- when RF17 (3R3) which goes through vertical deflection is removed
- or when BL55 connector is removed (vertical deflection coil)
- or when BG36 connector is removed (connection of vertical deflection to NS module)
TV turns on and works fine (except that picture is flat horizonztal line) and measuring on U5 is about 21 V.

While everything is connected and TV pumps 3 times, U5 voltage jumps up to 30 V while pumping.

If I disconnect any other secondary line or any other load of U5 while NS deflection is connected, TV will not turn on.

Can you help me as I ran out of ideas for repairing. Please, answer in english.

Thank you all in advance,

Ivo Andreis

Hello again and thank you for your reply.

After disconnecting BL55 and putting 60W bulb at U2, TV switched on and remain working (it was not pumping anymore) and bulb lights. Any other suggestions?

And yes, when pumping, TV pumps 3 times in about 3 seconds.

OK, I will replace it this evening and let you know the results. Thanks.

Hello again. I Replaced DL21, DL22, RL21 and still same thing. I would like to make following conclusion:

- If tv turns on and bulb is lit connected at U2 while deflection coil is disconnected, power supply is OK. Am I right?
- If TV fails to turn on with vertical deflection connected it is either error in vertical deflection circuit or this circuit is too much load for U5 and problem is somewhere else.

How big load is vertical deflection, and what could be disconnected from U5 so that it could be enough to supply deflection circuit (if not in error)? NF part is completely out, teletext module too (if they are using U5) and still TV is pumping. Also, NS deflection module has U5 too, and, when disconnected, still pumps.

TEA register that there is somewhere excessive current leak and voltage raises above it's values and shut off TV so I think it is good, and cost almost as value of TV).

Yours, totally hopeless, but never-give-up

Ivo

One explanation please. I cannot locate CL70. Where is it located, arround what part at schematic diagram?
By removing LL32 you mean just part which is connected between pin 4 of DST and DL21, DL22 and CL22 or whole LL32?

Hello again. Finally some progress is done. After removing part of LL32 TV switched on perfectly. So I put another DL21 X((now there was not anything beside it what could be wrong) and changed RP42 (who has 3 instead of 1 ohm) and TV worked!!!

But I ran across another problem: TV is on, and on screen I have a lot of about 20 cm thin parallel lines in red, green or blue color jumping randomly on screen. Picture is same weather it is on tuner (no antenna connected), AV1 or teletext. Just a lot of those thin lines jumping randomly at whole screen. Sound from speakers is noise while on tuner, so this is good.

Thank you all so far for helping me.

And yes, i put ESM 740 G2 instead of G1 which was originally inside - what is the difference between them?

Amazing thing is that ESM which was in TV is taken from another working TV (Nordmende Galaxy). Galaxy was working with it and Telefunken not. This was the reason why I didn't suspect it until yesterday evening. But now Galaxy and Telefunken will get new one. I will check cable from trafo to screen. According to HR Diemen 'The book' I have right line trafo for this chassis. However I will do more work this evening with it and let you know. Could I use for test purposes cable from Galaxy? This cable has no ground wire comming from screen connector and Telefunken has one. Cable could become loose inside of connector after endless turning of board. But as I was looking at the end of cable, wire goes at plastic piece together with ground wire and I am not sure if this could be dissasembled and fixed. I will certainly let you know the results. And I will not give up!

Thank you all,

Ivo

Now here is what I found: I dissasembled white plastic box at picture tube board where focus wire comes in and i found that two little springs of screen grid and focus were clogged (rusted?). I cleaned them and after that jumping thin colored lines was gone and now I have black screen (like when TV is on AV with no signal). There is no snow on it. Is it step back or forward? Any suggestions?

Ivo

Well, now it is time to make another conclusion:

If I turn G2 to right, whole screen becames brighter, but no return lines. BUT, if I disconnect BL55 (vertical deflection coil) I have one thin bright line in the middle of the screen. Does it mean that white box on picture tube board is OK? I tried with second picture tube board from donor TV and result is exactly same. If white box is defective, would this line still be visible without BL55, eg. does showing of thin line without BL55 means that white box is OK? Also picture tube itself is good as I switched whole electronics to donor (spare) TV with same chasis and results are same.

OK, I will check video board and resolder it as well as chassis.
I was looking at archive and found discussion started at 02.02.2004. (put '618 regenbogenbild' in 'Forum durchsuchen' field) for which I think could be related to my problem. As I don't understand language very much :(, could anybody tell me was that my kind of problem and what was solution (if any) described.

If I got straight line in middle of screen while no vertical deflection connected, could I say for sure that E/W deflection circuit is correct as line goes from beginning to the end of screen. One thing that comes to my mind as I am writing this: while vertical deflection is disconnected, would I be able to shrink horizontal line with trimmer <-> (horizontal size) and actually see shrinked line? If this is possible, is it proof for functionality of horizontal deflection circuit including TDA4950 and it's components?

I definitelly started process of elimination of circuits :D. I am out of mental and any other power and will continue work tomorrow.

As usual, thank you all for help so far.............

Ivo