Philips K6 and K7 strange fault(s) - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

German Dalek · 19th Jul 2018, 9:25 pm

Giulio, here is more news.
Kris from Gent/Belgium wrote:
If the green field runs faster without signal, it will be by 99% sure, that the
hum comes from the power supply!
Background: without the vertical-sync the deflection runs a little faster,
50 Hz hum will run now faster over the screen.

Are you sure not to have a 60Hz problem with the DVD?

But as you said it runs on other TVs like the SABA. But it was told, that there
could be a problem with older TV sets, if they are powered with 60Hz PAL DVDs.

Good luck!
German Dalek

Giulio Maiocco · 20th Jul 2018, 6:25 am

Hey Thorsten,

Ok, I'll check the power supply too, Hanno recapped it, but maybe some wires broke during the transport, you never know what so many kilometers could do to a TV set.

The SABA T2500 is from 1968, so definitely not a newer set than those Philips! I could prove the point about the 60 Hz not being the case using the generator or connecting a digital converter for OTA reception to the modulator, what do you think about my idea?

Cheers my friend

Giulio

German Dalek · 20th Jul 2018, 4:27 pm

This will be fine.
If you post some pictures of the issue, just with another source,
the last readers will realize, that it is not a problem of your source.

Ciao,
German Dalek

Giulio Maiocco · 30th Jul 2018, 7:48 am

A little update about the K6...

We have colour bars, at least something resembling them!
Yesterday I reflowed quite a bit of the soldering in a specific spot on the PCB where bumping it did lot of strange things on the screen. There is still that dreaded greenish bar, but what I obtained is a little step forward. About the U630 discussed before, yes, the 4,43Mhz signal is present on pin 1, so this should be out of the equation

Best regards

Giulio Maiocco

Maarten · 30th Jul 2018, 2:14 pm

It looks like you're almost or even totally missing blue.

Giulio Maiocco · 10th Sep 2018, 4:16 pm

Hello everybody!

I'm well pleased to say that the K6 is finally alive and kicking as it should. As pointed before, the culprit was inside the U630 module and it was one of the small coils, the winding was hanging from the "surviving" hair thin wire. Fortunately it was possible to save the coil and now the rolling bar is gone, as an added benefit, we have the correct colour bar displayed.

About the K7, I haven't so good news to report. essentially it works, but without colour. I've started a wild chase thru the chrominance amplifier circuit, but, until now, no smoking gun.

Best regards

Giulio

19th Jul 2018, 9:25 pm	#21
German Dalek Hexode Join Date: Jan 2011 Location: Düsseldorf, Germany. Posts: 368	Re: Philips K6 and K7 strange fault(s) Giulio, here is more news. Kris from Gent/Belgium wrote: If the green field runs faster without signal, it will be by 99% sure, that the hum comes from the power supply! Background: without the vertical-sync the deflection runs a little faster, 50 Hz hum will run now faster over the screen. Are you sure not to have a 60Hz problem with the DVD? But as you said it runs on other TVs like the SABA. But it was told, that there could be a problem with older TV sets, if they are powered with 60Hz PAL DVDs. Good luck! German Dalek __________________ And now something completly different: MARC BOLAN, he was/is the real king of Pop Music!

20th Jul 2018, 6:25 am	#22
Giulio Maiocco Tetrode Join Date: Jan 2006 Location: Fossano (CN) Italy Posts: 71	Re: Philips K6 and K7 strange fault(s) Hey Thorsten, Ok, I'll check the power supply too, Hanno recapped it, but maybe some wires broke during the transport, you never know what so many kilometers could do to a TV set. The SABA T2500 is from 1968, so definitely not a newer set than those Philips! I could prove the point about the 60 Hz not being the case using the generator or connecting a digital converter for OTA reception to the modulator, what do you think about my idea? Cheers my friend Giulio

20th Jul 2018, 4:27 pm	#23
German Dalek Hexode Join Date: Jan 2011 Location: Düsseldorf, Germany. Posts: 368	Re: Philips K6 and K7 strange fault(s) This will be fine. If you post some pictures of the issue, just with another source, the last readers will realize, that it is not a problem of your source. Ciao, German Dalek __________________ And now something completly different: MARC BOLAN, he was/is the real king of Pop Music!

30th Jul 2018, 7:48 am	#24
Giulio Maiocco Tetrode Join Date: Jan 2006 Location: Fossano (CN) Italy Posts: 71	Re: Philips K6 and K7 strange fault(s) A little update about the K6... We have colour bars, at least something resembling them! Yesterday I reflowed quite a bit of the soldering in a specific spot on the PCB where bumping it did lot of strange things on the screen. There is still that dreaded greenish bar, but what I obtained is a little step forward. About the U630 discussed before, yes, the 4,43Mhz signal is present on pin 1, so this should be out of the equation Best regards Giulio Maiocco Attached Thumbnails

30th Jul 2018, 2:14 pm	#25
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,199	Re: Philips K6 and K7 strange fault(s) It looks like you're almost or even totally missing blue.

10th Sep 2018, 4:16 pm	#26
Giulio Maiocco Tetrode Join Date: Jan 2006 Location: Fossano (CN) Italy Posts: 71	Re: Philips K6 and K7 strange fault(s) Hello everybody! I'm well pleased to say that the K6 is finally alive and kicking as it should. As pointed before, the culprit was inside the U630 module and it was one of the small coils, the winding was hanging from the "surviving" hair thin wire. Fortunately it was possible to save the coil and now the rolling bar is gone, as an added benefit, we have the correct colour bar displayed. About the K7, I haven't so good news to report. essentially it works, but without colour. I've started a wild chase thru the chrominance amplifier circuit, but, until now, no smoking gun. Best regards Giulio