The Workbench

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

richtoy — Sun, 13 Dec 2009 13:32:54 GMT

I have an LX5500 that has these symptoms: -

The picture is ok when it first powers up (cold) but after a few minutes it gives a kind of echo on the left side of all images that varies in size with time. First it gets bigger and then it slowly (20 min) goes completely and the picture is good.

Here's a picture

Is this what you mean by this ?: -

"The MX has vertical stripes on the left, visible on dark surfaces like an echo, the stripes are a little bit brighter than the black background

Replace R36, 1K 1W, (next to L3)

Replace C18, 10nf 250V

Replace C16, 10nF 250V"

I have changed R36 and C18 but cannot find a C16 on either the circuit diagram, parts list or the PCB !! Changing the pair had no noticable effect.

I have also used freezer spray on the E/W drive IC and it's associted componenets (TR1 - TR3) and again nothing reacted.

All elcos have been changed.

Does anybody have any other suggestions?

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

jens m — Thu, 11 Jun 2009 12:30:12 GMT

hello die bogener!

two days ago my mx 4000 broke down and as i won´t get the spare parts til tomorrow (following your hints in the mx4000 thread), i started with my old mx3500, which broke down two years ago and wasn´t repaired, but replaced by the mx4000. my supplier had all the parts in stock, so i gave the 3500 a go.

your workshop is really great, made finding the fault and getting there so much easier!

the cap C12 on the mainboard was leaking and killed TZ8, which killed but12f in the powersupply...

thanks to your workshop the 3500 is working fine now again and tomorrow mx4000 will be the next on my workbench.

so, just wanted to say thanks, your effort is highly appreciated!

jens

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

nobby — Sun, 05 Apr 2009 11:44:17 GMT

Have you measured the voltages on the I2C bus to see if it is completely hung?

Neil

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

sjaak — Sun, 05 Apr 2009 00:33:32 GMT

Yes , but it won't start.

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

nobby — Sat, 04 Apr 2009 14:57:18 GMT

Have you tried starting it in service mode?

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

sjaak — Sat, 04 Apr 2009 08:18:06 GMT

Yes , and changed a couple of them.

I unsolder r158 on the nicam modul , but still no power up.

On the psu i measured 8 volt on c16 but nothing on c15.

On c11 nothing either.

I measured the 3 optocouplers etc.

On kathode D49 i have 8 volt.

If there's a short in the flyback trafo what should the psu doing?

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

nobby — Sat, 04 Apr 2009 04:43:42 GMT

Have you checked the caps on the NICAM board?

They are often troublesome.

Neil

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

sjaak — Fri, 03 Apr 2009 18:15:59 GMT

Hi there all,

I have a Beovision MX-5500 and it wil not turn on.

The standby led is on , and when you look at it closer you can see it flashing a little bit.

The tv is not responding to the controller.

I replaced the caps in psu en i cant find any defective components.

Can anybody help me with this or tell me were to start to find the problem?

Re: Workshop MX3500 MX5500 LX5500 How to repair and test this TV , common faults

nobby — Thu, 19 Feb 2009 07:29:23 GMT

Deflection IC is very prone to cracked joints.

Re: Workshop MX3500 MX5500 LX5500 How to repair and test this TV , common faults

Trens — Wed, 18 Feb 2009 09:06:11 GMT

I am repairing a MX5500. It fell onto the floor, but the picture was still right and the set was still working. A couple of weeks later the set showed a white horizontal line in the middle. I suspected a broken solder joint in or around the vertical deflection area. I found one at D26 (Diode?) and re-soldered it. But it is still giving me this white line. I could not find any other cracks.

Any ideas or suggestions that I might have overlooked?

For the diagrams: http://www.filedropper.com/beovisiontv

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

hiwi — Fri, 02 Jan 2009 10:06:40 GMT

Hi,

back to my MX5500.

i measured every voltage, 8V 12V etc on the RGB driver evereything looks good. Ground is ok as well. (Connected to the 2-Pin ground)

I have removed TDA3606, TEA8440 and TEA5640 and all elco's.

When I change R-Y with B-Y then i get a screen with red instead of green, so i suppose, that the videodriver an tube pcb have no problem the 3506 too.

OSD und Teletext are without any error.

On the TA 5640 the R-Y signal has 2.2V, the R-B 3.2V . The datasheet says 3.2 V for both, so this may be a problen, althougth when i change these lines, the scree becomes red. The Xtal is working, i have a clear 62,5hz Signal on Pin 15 on Pin 12 and 17 are the right voltages for Pal/Secam Mode (Vreg, that nearly 8V)

Do you have any suggestion, what to test next. is the error a problem of the Pal/RGB Modul or could it be a problem on the U-Board?

May be video switching or prblem with the sandcastle, the TDA 2579A?

Who should a correct CVBAS Signal look alike?

Best regards

Ralf

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

Die_Bogener — Fri, 02 Jan 2009 03:41:39 GMT

R6 consists of two resistors: PTC 40 + 1000 Ohm 265V. The 40 Ohm is a PTC. Is it burnt?

Martin

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

TonyK — Thu, 01 Jan 2009 18:56:46 GMT

Thank you for ansering Die_Bogener! I didn't found a topic about 4500 so I post here. The parts I wrote before and have replaced are from the mains filter board (picture). Do you know what value is the resistor R6 (mains filter)?

I'll replace the parts (from power supply) you told me after the weekend.

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

Die_Bogener — Thu, 01 Jan 2009 16:05:51 GMT

OK, this MX4500/5000/3000 has nothing to do with this MX3500/5500 workshop. It's a complete different design, no parts are compatible. This chassis was manufactured by Thomson, called ICC5, also used by Philips - Telefunken and many other companies. Just to make sure, that this information here does not fit to the MX3500/5500.

But try this:

Powersupply: Replace TP24= BU508A or S2000, check for insulation foil.

CP23 2,2nF 2000V (!!!! probably the reason for this defect...!!!)

CP04 100uf 25V

CP19 47uF 16V

CP24 47uF 100V

CP26 470uF25V

DP23 BY399

DP26 BA157

All parts are under the plastic cover. After that, there should be no blown fuse any more.

But... at least exchange some more of the caps. CP37 4700uF, CP32 1000uF and CP46 2200uF are the next to fail...

Very common on this ICC5 is also: TL31 BU508A or S2000, usually with a defect CL48 12nF1600V or CL44 440nF 250V. If there are vertical lines: RL44=56 and RL42=68 are gone...

Martin

P.S.: who gave you this part list? It does not fit at all to the ICC5 board...

Re: Workshop MX3500 MX5500 How to repair and test this TV , common faults

TonyK — Thu, 01 Jan 2009 15:39:02 GMT

It's a European model.