Trying to save a Sony KV-M1411U - UK Vintage Radio Repair and Restoration Discussion Forum

ridgeracer · 28th May 2016, 5:36 pm

Hey guys, thought you might be able to help me.

Got a nice little 14 inch Sony Trinitron CRT today but it's arrived doing this:

https://www.youtube.com/watch?v=RiQ2Bn43a0c

Any ideas what could be the problem or is it a bin job?

As a side note the stand by light seems to flash twice once when you first turn it on and again 4 or 5 seconds later. nothing on screen.

HamishBoxer · 28th May 2016, 5:45 pm

Could be loptx failure code.Worth a check for drys and check the line transistor,I am not sure wether a duff cap can take it out as a long time since I had one on the bench.

PS Welcome to the forum.

ridgeracer · 28th May 2016, 5:56 pm

Yeah i think i will pop the board out and have a look at the joints. I'm not sure where the line transistor is? I'm fairly new to repairing CRT's I only just did the chassis on my arcade cabinet (flyback) so I'm a little blind currently with this one. I saw a thread on here about one and apparently the picture quality is close to a BVM/PVM so i really want to save it if possible.

Thanks for the warm welcome!

ridgeracer · 28th May 2016, 6:23 pm

ridgeracer · 29th May 2016, 11:04 am

I guess it's a bin job then

Maarten · 29th May 2016, 5:35 pm

Why would that be? These sets were mostly quite reliable and easy to repair.

The pictures in your above post are too small to see anything, however.

From the chirp when switching on or off (I think), it could very well be that the line output transistor is shorted. Dry joints on the driver transformer or elsewhere in the line output stage would indeeed cause this but apart from re-doing the soldering you would also need to replace the transistor. Start by measuring it in circuit for shorts.

John123 · 29th May 2016, 10:21 pm

Are you sure it doesn't need to be powered up by the remote or press of a channel button? I'm pretty sure the Sony I have will not switch out of standby from initial power up (via the mains on/off switch).

*EDIT* I just read that it's generating an error code via the LED. Definitely a fault, then! I stand corrected!

Marconi_MPT4 · 29th May 2016, 11:50 pm

Hi,
When LED error sequence flashes twice, it indicates the B+ over current protection (OCP) has activated and unit goes into standby mode. Generally, this fault relates to the B+ (120V) supply to the line output stage.

With the set powered off and a DVM set to ohms range, check resistance between pin 4 of T802 (FBT) and (for convenience) pin 11 (GND). If a very low resistance is measured then start checking transistor Q802, Diodes D801,802 and capacitors C807,825,805,806 for failure.

Cheers
Rich

ben · 30th May 2016, 9:00 am

If this is the set I'm thinking of (BE2 chassis?) change PSU secondary caps and PS801 N15 (probably open).

tri-comp · 1st Jun 2016, 1:00 pm

If you're wondering what PS801 N15 is it's the fuse (600mA) just above the horizontal driver transistor Q801 in the schematic.

No schematic ?
No problem, PM me with your e-mail address for a FOC pdf-copy.

28th May 2016, 5:36 pm	#1
ridgeracer Retired Dormant Member Join Date: May 2016 Location: Bristol, UK. Posts: 4	Trying to save a Sony KV-M1411U Hey guys, thought you might be able to help me. Got a nice little 14 inch Sony Trinitron CRT today but it's arrived doing this: https://www.youtube.com/watch?v=RiQ2Bn43a0c Any ideas what could be the problem or is it a bin job? As a side note the stand by light seems to flash twice once when you first turn it on and again 4 or 5 seconds later. nothing on screen.

28th May 2016, 5:45 pm	#2
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,935	Re: Trying to save a Sony KV-M1411U Could be loptx failure code.Worth a check for drys and check the line transistor,I am not sure wether a duff cap can take it out as a long time since I had one on the bench. PS Welcome to the forum. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

28th May 2016, 5:56 pm	#3
ridgeracer Retired Dormant Member Join Date: May 2016 Location: Bristol, UK. Posts: 4	Re: Trying to save a Sony KV-M1411U Yeah i think i will pop the board out and have a look at the joints. I'm not sure where the line transistor is? I'm fairly new to repairing CRT's I only just did the chassis on my arcade cabinet (flyback) so I'm a little blind currently with this one. I saw a thread on here about one and apparently the picture quality is close to a BVM/PVM so i really want to save it if possible. Thanks for the warm welcome!

28th May 2016, 6:23 pm	#4
ridgeracer Retired Dormant Member Join Date: May 2016 Location: Bristol, UK. Posts: 4	Re: Trying to save a Sony KV-M1411U Here are some pictures of the boards solder joints, some look very suspect to me but I will be honest I'm not an expert so... maybe you guys can tell me if there are any rough joints? http://s19.postimg.org/6vfnbyewf/201...8_18_12_16.jpg http://s19.postimg.org/qfu6eqfhr/201...8_18_12_25.jpg http://s19.postimg.org/6jy6z6ygf/201...8_18_12_32.jpg http://s19.postimg.org/fnwlzn01b/201...8_18_12_40.jpg http://s19.postimg.org/htqwu53hr/201...8_18_12_47.jpg http://s19.postimg.org/456beri7j/201...8_18_20_18.jpg http://s19.postimg.org/pu57imkfj/201...8_18_20_40.jpg http://s19.postimg.org/v4a69x4of/201...8_18_22_20.jpg I've done all the joints i thought looks a bit dodgy but still not working..

29th May 2016, 11:04 am	#5
ridgeracer Retired Dormant Member Join Date: May 2016 Location: Bristol, UK. Posts: 4	Re: Trying to save a Sony KV-M1411U I guess it's a bin job then

29th May 2016, 5:35 pm	#6
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,203	Re: Trying to save a Sony KV-M1411U Why would that be? These sets were mostly quite reliable and easy to repair. The pictures in your above post are too small to see anything, however. From the chirp when switching on or off (I think), it could very well be that the line output transistor is shorted. Dry joints on the driver transformer or elsewhere in the line output stage would indeeed cause this but apart from re-doing the soldering you would also need to replace the transistor. Start by measuring it in circuit for shorts.

29th May 2016, 10:21 pm	#7
John123 Heptode Join Date: Jan 2007 Location: Luton, Bedfordshire, UK. Posts: 891	Re: Trying to save a Sony KV-M1411U Are you sure it doesn't need to be powered up by the remote or press of a channel button? I'm pretty sure the Sony I have will not switch out of standby from initial power up (via the mains on/off switch). EDIT I just read that it's generating an error code via the LED. Definitely a fault, then! I stand corrected! __________________ Regards, John

29th May 2016, 11:50 pm	#8
Marconi_MPT4 Heptode Join Date: Mar 2011 Location: Dorset, UK. Posts: 521	Re: Trying to save a Sony KV-M1411U Hi, When LED error sequence flashes twice, it indicates the B+ over current protection (OCP) has activated and unit goes into standby mode. Generally, this fault relates to the B+ (120V) supply to the line output stage. With the set powered off and a DVM set to ohms range, check resistance between pin 4 of T802 (FBT) and (for convenience) pin 11 (GND). If a very low resistance is measured then start checking transistor Q802, Diodes D801,802 and capacitors C807,825,805,806 for failure. Cheers Rich __________________ To an optimist a glass is half full; a pessimist half empty; an engineer twice as big as need be! Last edited by Marconi_MPT4; 29th May 2016 at 11:58 pm.

30th May 2016, 9:00 am	#9
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Trying to save a Sony KV-M1411U If this is the set I'm thinking of (BE2 chassis?) change PSU secondary caps and PS801 N15 (probably open). __________________ Regards, Ben.

1st Jun 2016, 1:00 pm	#10
tri-comp Heptode Join Date: Oct 2008 Location: Aalborg, Denmark Posts: 903	Re: Trying to save a Sony KV-M1411U If you're wondering what PS801 N15 is it's the fuse (600mA) just above the horizontal driver transistor Q801 in the schematic. No schematic ? No problem, PM me with your e-mail address for a FOC pdf-copy.