Ekco TS 105 - UK Vintage Radio Repair and Restoration Discussion Forum

Freya · 1st Jul 2014, 10:28 am

This set was purchased just before Christmas 2013 from Beckenham, however it needed the help of a forum member to get it to me in Cornwall and it arrived around Easter time (thanks Steve).
Cosmetically it was fantastic with a tiny amount of veneer missing on the top edge, the chassis was untouched and the mains connector pins had a nice layer of corrosion build up.
The chassis is very easy to remove on these with just two nuts either side and side it out, complete with speaker (mine had been swiped at some point in the distant past)
Now I like the plug it in approach, so after snipping the mains filter capacitor and a gentle clean-up on the mains connector pins power was applied.... and a few seconds later a raster appeared. Normally this would disappoint me but seeing the quality and brightness of the CRM92 tube brought a smile, the raster had the usual issues after 65 years so I set about changing some capacitors taking time to re-stuff in the original cardboard sleeves. The line hold was a bit touchy so I swapped the line oscillator and video amp SP61`s around and this improved the lock.
The raster geometry was perfect but the set has two niggling possible problems, the first is highlighted in the video, link below. Now I have not seen this happen before and would like to know if it is due to a fault or just by design.
The second is a visible vertical line that is present slap bang in the centre of the screen, normally I would say this is due to ringing in the line stage but that occurs more to the left hand side.
http://youtu.be/j-ZIBCmS9Vw

Added a couple of reduced snippets of the line and frame sections

FERNSEH · 1st Jul 2014, 11:07 am

If the set had been a much later model I'd say that was a cross over kink. That is the first part of the scan energy from the booster diode is changing over to the line output valve. But that cannot be the case in the TS105 because although there is a PY31 diode in the line output stage, it is simply a damper diode across the scanning coils. Some of the flyback energy is feed back to the cathode of the 6P28 simply to boost the HT to that valve.
I notice that there is a 25mfd electrolytic capacitor in the cathode circuit of the line output valve, have you checked it?

DFWB.

Freya · 1st Jul 2014, 11:37 am

It has been changed with a new 22uF, all the resistors are well with 20%, two pieces of wiring had suffered with rot due to the wax dripping over. I had wondered about the scan coils but rejected that on the basis the raster ended up so well defined.
its had me scratching my head for a few weeks now

mark pirate · 1st Jul 2014, 1:29 pm

Quote:

but seeing the quality and brightness of the CRM92 tube brought a smile

How lucky can you get, a raster on first power up, and a good CRM92

Odd fault though, I too don't think the scan coils are to blame.

Mark

beltinge bore · 1st Jul 2014, 7:49 pm

I have a spare set of scan coils for a TS105 if you would like try them.When I was lucky enough to find a CRM92 in the Harpenden auction it had a set of scan coils "welded" to it so I fitted it with them.The tube turned out to be pretty good.Lovely little sets my wife even likes it.
Thanks to Stephen for making up the missing Radio selection bezel to finish it nicely.
That start up video is something I have never seen!
Hope to do a write up on mine soon.
Regards Steve.

DangerMan · 1st Jul 2014, 11:26 pm

Looking at the video of start up, the start up video just looks like the PY31 is slower in warming up than the 6P28. You wouldn't normally see this except that the EHT rectifier in this set is already warmed up because its heater is mains fed.
Maybe the PY is a bit tired, which could also explain the white vertical shadow shown here, or slow warming.
If you have a spare it's worth trying it or you can just temporarily put a silicon diode in parallel to see what happens. A UF4007 or similar fast soft recovery type will do. Even an ordinary 1N4007 might show what's going on.

I had exactly the same symptoms on a BV20 that had had a selenium EHT rec fitted, and the line o/p stages are very similar. A new PY31 cured all the symptoms including the ghostly vertical line.

Pete

Freya · 2nd Jul 2014, 7:55 am

Gold medal for Dangerman, well done Pete.
I put a new PY31 in quickly this morning whilst juggling the kids breakfasts and it has cured the rolling out issue.

Thanks and I will post some pictures later and do some tests on the PY31

1st Jul 2014, 10:28 am	#1
Freya Octode Join Date: Jan 2009 Location: Falmouth, Cornwall, UK. Posts: 1,991	Ekco TS 105 This set was purchased just before Christmas 2013 from Beckenham, however it needed the help of a forum member to get it to me in Cornwall and it arrived around Easter time (thanks Steve). Cosmetically it was fantastic with a tiny amount of veneer missing on the top edge, the chassis was untouched and the mains connector pins had a nice layer of corrosion build up. The chassis is very easy to remove on these with just two nuts either side and side it out, complete with speaker (mine had been swiped at some point in the distant past) Now I like the plug it in approach, so after snipping the mains filter capacitor and a gentle clean-up on the mains connector pins power was applied.... and a few seconds later a raster appeared. Normally this would disappoint me but seeing the quality and brightness of the CRM92 tube brought a smile, the raster had the usual issues after 65 years so I set about changing some capacitors taking time to re-stuff in the original cardboard sleeves. The line hold was a bit touchy so I swapped the line oscillator and video amp SP61`s around and this improved the lock. The raster geometry was perfect but the set has two niggling possible problems, the first is highlighted in the video, link below. Now I have not seen this happen before and would like to know if it is due to a fault or just by design. The second is a visible vertical line that is present slap bang in the centre of the screen, normally I would say this is due to ringing in the line stage but that occurs more to the left hand side. http://youtu.be/j-ZIBCmS9Vw Added a couple of reduced snippets of the line and frame sections Attached Thumbnails __________________ Stephen _________"It`s only an old telly" ___ Last edited by Freya; 1st Jul 2014 at 10:53 am. Reason: more info added

1st Jul 2014, 11:07 am	#2
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Ekco TS 105 If the set had been a much later model I'd say that was a cross over kink. That is the first part of the scan energy from the booster diode is changing over to the line output valve. But that cannot be the case in the TS105 because although there is a PY31 diode in the line output stage, it is simply a damper diode across the scanning coils. Some of the flyback energy is feed back to the cathode of the 6P28 simply to boost the HT to that valve. I notice that there is a 25mfd electrolytic capacitor in the cathode circuit of the line output valve, have you checked it? DFWB.

1st Jul 2014, 11:37 am	#3
Freya Octode Join Date: Jan 2009 Location: Falmouth, Cornwall, UK. Posts: 1,991	Re: Ekco TS 105 It has been changed with a new 22uF, all the resistors are well with 20%, two pieces of wiring had suffered with rot due to the wax dripping over. I had wondered about the scan coils but rejected that on the basis the raster ended up so well defined. its had me scratching my head for a few weeks now __________________ Stephen _________"It`s only an old telly" ___

1st Jul 2014, 7:49 pm	#5
beltinge bore Pentode Join Date: Dec 2012 Location: Herne Bay, Kent, UK. Posts: 233	Re: Ekco TS 105 I have a spare set of scan coils for a TS105 if you would like try them.When I was lucky enough to find a CRM92 in the Harpenden auction it had a set of scan coils "welded" to it so I fitted it with them.The tube turned out to be pretty good.Lovely little sets my wife even likes it. Thanks to Stephen for making up the missing Radio selection bezel to finish it nicely. That start up video is something I have never seen! Hope to do a write up on mine soon. Regards Steve.

1st Jul 2014, 11:26 pm	#6
DangerMan Heptode Join Date: Jul 2009 Location: Stoke-on-Trent, Staffordshire, UK. Posts: 719	Re: Ekco TS 105 Looking at the video of start up, the start up video just looks like the PY31 is slower in warming up than the 6P28. You wouldn't normally see this except that the EHT rectifier in this set is already warmed up because its heater is mains fed. Maybe the PY is a bit tired, which could also explain the white vertical shadow shown here, or slow warming. If you have a spare it's worth trying it or you can just temporarily put a silicon diode in parallel to see what happens. A UF4007 or similar fast soft recovery type will do. Even an ordinary 1N4007 might show what's going on. I had exactly the same symptoms on a BV20 that had had a selenium EHT rec fitted, and the line o/p stages are very similar. A new PY31 cured all the symptoms including the ghostly vertical line. Pete Last edited by DangerMan; 1st Jul 2014 at 11:35 pm.

2nd Jul 2014, 7:55 am	#7
Freya Octode Join Date: Jan 2009 Location: Falmouth, Cornwall, UK. Posts: 1,991	Re: Ekco TS 105 Gold medal for Dangerman, well done Pete. I put a new PY31 in quickly this morning whilst juggling the kids breakfasts and it has cured the rolling out issue. Thanks and I will post some pictures later and do some tests on the PY31 __________________ Stephen _________"It`s only an old telly" ___ Last edited by Freya; 2nd Jul 2014 at 8:11 am.