Bush btv d91216b dead

[vinceroger69]

morning guys just picked one of these up still in the box looks great condition but the sets dead as in no led on the front so far i have tested both fuses ok disconnected the very small power board and tested output volages as per board spec none present except the 240 volts ac in i have now noticed a regular ticking noise about every 1 second coming from the yellow transformer between the hot and cold side i have checked the diodes for shorts none seem present at all can you advise me next step on trouble shooting please let me know the meter settings you want the items tested on the power board is a LS2202010 ver 4.0
same board as this shows you the specs etc cheers vince

[tom66]

Re: Bush btv d91216b dead

Does it tick with nothing connected?
Suspect startup cap or Vcc winding diode.

[vinceroger69]

Re: Bush btv d91216b dead

yes it does tom i have took this small power board out so i can test it. with nothing connected ticks away lol all capxon caps start up looks 22.uf 50v will go and look for one now pity i still dont have a esr meter yet but have got a capacitor tester just does not give esr which diode is the winding diode?

[vinceroger69]

Re: Bush btv d91216b dead

just changed the start up cap with a new one still the same just ticks away only power board connected.

[selldoor]

Re: Bush btv d91216b dead

Try it again with it all connected?

What voltage do you get on the BIG Cap - Meter on 600vDC - CARE High Voltage

[tom66]

Re: Bush btv d91216b dead

Also measure voltage across startup cap and let us know what PWM controller IC it uses.

[vinceroger69]

Re: Bush btv d91216b dead

will do your tests in a while (visitors just turned up with a faulty wii they have worked on lol want me to look at it whilst they wait lol) tom what pwm controller ic can you point out in the pic for me ? selldoor will also do your test cheers guys.

[selldoor]

Re: Bush btv d91216b dead

pwm controller ic can you point out in the pic for me ?

Its the 16 legged Ic on the back= U3

[tom66]

Re: Bush btv d91216b dead

Possibly not... may be U1... looks like one of those "tiny switchers" from STMicro.

[vinceroger69]

Re: Bush btv d91216b dead

just a question i have had to put this back together for now as i need a set of new multi meter leads (have a break in the wire somewhere lol) so will do more testing shortly but what i did notice that i thought one last time i would try to see if it would turn on and guess what red standby light came on flashed 4 times then snow and no signal screen so i thought i would turn it of and try again would not switch on. start up cap replaced with a new one. but by the mains wire going on to the circuit board there's a yellow oblong cap (the one with white glue on it) it also looks slightly discolored and maybe a little bulged at the board end? could this capacitor cause this issue? seems to go across the live and neutral wires. it seems it will turn on but very intermittently the person i got it from of free cycle said before it stopped working it had a sound hiss problem? never mentioned it never turned on.

[vinceroger69]

Re: Bush btv d91216b dead

this set does not have a on off switch at all basically you just press the little button on the top once to turn it on or by the remote control i did get the voltage on the large cap when it was on standby was 343 volts it never came out of standby so never tested it again just looked on ebay there must be a common fault with these sets one person has a pallet load of them for sale plus there's a few others for spares or repair with the same fault ie wont come out of standby but cant seem to find any fixes posted on the net.

[tom66]

Re: Bush btv d91216b dead

Have you measured Vcc yet?
This is a pretty simple power supply, only a few possible faults.

[vinceroger69]

Re: Bush btv d91216b dead

u1 primary side 6 legs looks like jk1 with a small 35 top right of chip
u3 16 leg ic looks like 08de60k tl494c
is there a service manual for these avalible tom there is one more ic i cant read the number of i have just spoke to the man i got the set of the reason why he gave it to me was the sound was crackling that that bad you could not hear the program you was watching also took ages to get to turn on. its a bush btvd9126b power board LS2202010 ver 4.0 there are loads in a job lot on ebay with this exact fault and also a few that wont come out of standby.

[selldoor]

Re: Bush btv d91216b dead

If you google tl494c there are images of it with some examples of circuits it is used in
which may be useful

[tom66]

Re: Bush btv d91216b dead

Looking at the design on this the TL431 drives the CFLs but that is independent from the main power supply.

[vinceroger69]

Re: Bush btv d91216b dead

a question i cant seem to find any manuals on line etc do you think the sound crackling issue could also be a power supply fault as the speaker connections are also on the small psu board. tom did you still want me to test vcc on the tl494c? pin 12 i think it is the cfls are working great thought the couple of times the set has fired up a odd one also seems to come on if left for a good few hours will turn on once then thats it?. still think its a power board issue?

[tom66]

Re: Bush btv d91216b dead

Test Vcc on the 6-pin controller IC on the primary, that IC is the source of all our power! (Or, at least all the TV's power.) If it's unstable you could hear crackling from the speakers.

[vinceroger69]

Re: Bush btv d91216b dead

its hard to read the id of it i can see the round indent on the corner the writing looks like square white box with a j in it then K1 WITH A SMALL 35 OR 36 in the top corner not sure which which pin is which this little 6 pin ic is about 3mm or 4mm so very hard to read anything on it.

[selldoor]

Re: Bush btv d91216b dead

Close up picture of it ?

[vinceroger69]

Re: Bush btv d91216b dead

used the otherhalfs glasses decently says j in a whie box then k1 then a realy small 35
been searching google for ages cant seem to find it this a link to the board specs i think http://cgesz.en.alibaba.com/product/...er_Supply.html
theres a joblot of these on ebay seems a common fault
http://www.ebay.co.uk/itm/31x-FAULTY...70970671028%26