Sony TV blinking LED fault codes

[Richard Skeen]

A friend of mine has a Sony TV (model KV-28CS70U) which suddenly stopped working the other day. Every time he tries to turn it on, it turns itself off again, and the power/standby LED flashes red/green.

I thing the number of flashes is a diagnostic code indicating the type of fault, so I tried googling for a list (it's not in the user manual). So far, I've found several different and contradictory lists of fault codes, with no mention of which model they apply to.

By any chance, does someone has the information for this model to hand? Or, could anyone recommend a reasonably cheap source to buy the service manual for this TV?

Thanks, Rich.

[Adrian C]

From the service manual for KV-28LS60B same chassis (AE-6B) free on

error 00 Reserved 01 OCP ( Over Current Protection ) 02 Over Voltage Protection 03 No Vertical Sync 04 IKR Error at power on 05 IIC bus clock and/or data lines low at power on 06 NVM no IIC bus acknowledge at power on 07 Horizontal Protection 08 Tuner no acknowledge at power on 09 Sound Processor Error 10 Reserved 11 Scanrate Error 12 DAC Error 13 Backend Error 14 Dynamic Convergence Error 15 PIP Error 16

Eserviceinfo doesn't have the exact same model - but it may be close enough...

[Richard Skeen]

but got stuck at the point where a search didn't find the model KV-28CS70U - it's not shown as one of the models using the AE-6B chassis.

Tomorrow I'll count the number of flashes (forgot to write it down before) and at with any luck that should point in the direction of where to start looking.

Cheers, Rich.

[tony sayer]

OK so what in practice can you do to repair the fault these days?...

[Matty F]

Get a magnifying glass and examine every soldered joint on all the circuit boards. Particularly the joints that connect via solid wires to anything external to the board, and those to any large component. I have almost always found a dry joint is the cause of the problem.

[Adrian C]

>>> Tomorrow I'll count the number of flashes (forgot to write it down

It's an old CRT TV.

Lots of manuals also on Scribd. Search for "ae6b sony". Where would I be without the 'net?

A fix depends on access to tools, test equipment, understanding and ability to work with charged and live circuits etc...

has for that chassis, some documents and Windows flash applications that describe the circuit operation.

Though a replacement LCD TV is less than £200 these days, the challenge is still there not to spend that on a point of principle :-)

[DerbyBoy]

Though a replacement LCD TV is less than £200 these days, the challenge is still there not to spend that on a point of principle :-)

[Adrian C]

My Sony analogue widescreen 32" CRT cost me £1100 out of me pay packet in 2006, and there is a little investment here in TiVo gear (now going with AltEPG [1], no thanks to Virgin ...) that continues to fascinate. Could say I was an early adopter of that, and the many freeview set-top boxes that came and went.

Pity about the TV programmes though. I watch less and less as time goes on, and the last time I actually sat down and watched a film anywhere was probably six months ago. No time...

HD is really unnecessary here at the moment. Besides, I'd have to get shot of the TiVo which is kind of an 'over me dead body' activity.

[1] - - yep, a free EPG service for any TiVo that ye may dig up, lifetime or not. TiVo series 1 is far from dead.

[chrisj.doran%proemail.co.uk]

No personal experience since I don't get asked to mend things as often as in the past, but from what I keep reading over at sci.electronics.repair, electrolytic capacitors ain't wot they used t'be and are regularly found bulging.

Chris

[Richard Skeen]

On 01/06/11 10:54, Adrian C wrote: > On 01/06/2011 07:40, Richard Skeen wrote: >> A friend of mine has a Sony TV (model KV-28CS70U) which suddenly stopped >> working the other day. Every time he tries to turn it on, it turns >> itself off again, and the power/standby LED flashes red/green. >

The LED fault code is 4 flashes, "No Vertical Sync". However, googling suggests that this error can also be shown if there's a failure of horizontal drive, and that is what appears to be the case here.

There are two 0.47 ohm 1/4W resistors (paralleled) between the 135v B+ supply and one end of the primary winding of the flyback transformer. These are both open circuit. The other end of that winding goes to ground via the horizontal output transistor. So, hopefully the problem is simply that the transistor has failed shorted, blowing the resistors, as opposed to there being a problem with the flyback.

So, next step looks like finding a replacement 2SC5696-CA transistor.

Rich.