UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Television and Video

Notices

Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

Closed Thread
 
Thread Tools
Old 6th Sep 2014, 8:46 pm   #21
thermionic
Heptode
 
thermionic's Avatar
 
Join Date: Apr 2003
Location: Cornwall, UK.
Posts: 986
Talking Re: Philco upside down TV.

Quote:
Originally Posted by Heatercathodeshort View Post
I think Philco had a rethink with this model and decided to give it a better balance. They moved the speaker to the side and fitted another Plessey chassis suspended from the top.
When converted to ITA in 1955, you could view both channels at the same time. Regards, John.
I think you might have the 'StereoVision' model there, John......

SimonT.
__________________
The honesty of imperfection..........
thermionic is online now  
Old 6th Sep 2014, 10:01 pm   #22
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 9,145
Default Re: Philco upside down TV.

Quote:
Originally Posted by thermionic View Post
I think you might have the 'StereoVision' model there, John......SimonT.
Ha! ha! That is exactly what I was going to call it! Thought the aspect might have been a bit out so went for the twin channel option..John.
Heatercathodeshort is offline  
Old 6th Sep 2014, 10:19 pm   #23
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: Philco upside down TV.

Well that's the frame timebase sorted. The big surprise is that it was not the usual suspects C47 or C49 as correctly suggested by Simon but the 500pF mica capacitor C46.
One tends to forget about these mica capacitors, "they never go faulty" Well they do. Anyone who does radio repairs will often report that a mica capacitor has failed.
The line oscillator often fails in the Ekco TS88 and TS105 series TV receivers and the usual suspect is the 100pF mica capacitor in the miller transitron oscillator.

I supplied the Philco with signals from an Aurora converter , no results irrespective of which Band 1 channel was selected.
So I still the front end of the set to sort out.

DFWB.
FERNSEH is online now  
Old 8th Sep 2014, 12:44 pm   #24
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: Philco upside down TV.

More progress with Philco yesterday. Voltage measurements at the base of V1 (6F13) revealed that the cathode volts were to high irrespective of the setting of the RF gain control. The slider of the 10Kohm variable resistor is not making contact. For the time being the control has been bypassed to ground. Still no signals coming through from the Aurora just a very faint test tone on all channels.
Next, I turned my attention to the local oscillator. the voltage on C7A is too low, only 40V. R7 checks out OK as does C7A for leaks. It turned out that the adjustable iron dust core of the oscillator coil was touching the coil.
Centralising the core effected a cure, the volts on C7A have rising to 90V.
Still no signals though. Turned out that the tuning capacitor C6 was faulty.
That sorted pictures and sound are coming through, on channel 3!
I've retuned the set to the Birmingham frequency.
Anyway the good news is that CRT is excellent, it's one of the brightest Mazda CRM92 tubes I've seen for a long time.
There are still few jobs left to do. The sync separator function is bad, the frame and line hold could be far better. Also the HT voltage is low, only 175V. It should be in the region of 250 volts for this set. A replacemnt metal rectifier will have to be found.

DFWB.
Attached Thumbnails
Click image for larger version

Name:	Philco_0007.jpg
Views:	79
Size:	73.9 KB
ID:	97306  
FERNSEH is online now  
Old 8th Sep 2014, 1:07 pm   #25
Freya
Octode
 
Freya's Avatar
 
Join Date: Jan 2009
Location: Falmouth, Cornwall, UK.
Posts: 1,987
Default Re: Philco upside down TV.

I remember the tuning capacitor on my Ekco TC169 was faulty too, that kept me going for at least a week.
Good news on the tube.
__________________
Stephen
_________"It`s only an old telly" ___
Freya is offline  
Old 8th Sep 2014, 2:19 pm   #26
Colourstar
Octode
 
Colourstar's Avatar
 
Join Date: Feb 2006
Location: Ilkeston, Derbyshire, UK.
Posts: 1,397
Default Re: Philco upside down TV.

I'm looking forward to seeing photos of this set when David's done his magic. I don't think I've ever seen one working!

I have a Philco BT1840 that also uses this chassis. It certainly turned up in some very varied models.

Steve
Colourstar is offline  
Old 8th Sep 2014, 3:41 pm   #27
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: Philco upside down TV.

Quote:
Originally Posted by Colourstar View Post

I have a Philco BT1840 that also uses this chassis. It certainly turned up in some very varied models.

Steve
Hi Steve,
Armed with all this servicing experience gleaned from the Defiant and my Philco I look forward to seeing your Philco on my next visit later this year.
The BT8140 has a very American appearance, even has a radio receiver.
You can imagine that there was a similar looking set Stateside.

The attachment shows small picture due to the low HT voltage.


DFWB.
Attached Thumbnails
Click image for larger version

Name:	Philco_0005.jpg
Views:	175
Size:	52.5 KB
ID:	97312  
FERNSEH is online now  
Old 8th Sep 2014, 4:06 pm   #28
Colourstar
Octode
 
Colourstar's Avatar
 
Join Date: Feb 2006
Location: Ilkeston, Derbyshire, UK.
Posts: 1,397
Default Re: Philco upside down TV.

Excellent David, that looks very promising.

Are you actually going to try and find another NOS rectifier or hide a sneaky diode & resistor combination somewhere, leaving the original finned device in situ?

Steve
PS- Yes, let's have a delve inside my Philco on your visit next month. It's almost a shame to disturb the cobwebs. It looks like something out of horror film in there. Quite appropriate that you'll be visiting around Halloween!
Colourstar is offline  
Old 8th Sep 2014, 4:13 pm   #29
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: Philco upside down TV.

Hi Steve,
I'll take a look upstairs, you never know there might be a good metal rectifier up there.
Incidently, the little Philco is one of the first sets to be worked on in my garden workshop.

DFWB.
FERNSEH is online now  
Old 8th Sep 2014, 4:57 pm   #30
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Philco upside down TV.

The infamous G1 cap.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 8th Sep 2014, 6:41 pm   #31
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: Philco upside down TV.

I removed the finned HT rectifier from this Plessey Mark 3? chassis. It was tried out in the Defiant. Guess what happened? Sparks and finally a bang, then the fuses blew. Accompanied with that familiar smell.

So I'll have to find another Westinghouse 14A96.

DFWB.
Attached Thumbnails
Click image for larger version

Name:	Chassis_0011.jpg
Views:	145
Size:	75.6 KB
ID:	97316   Click image for larger version

Name:	Chassis_0012.jpg
Views:	134
Size:	54.9 KB
ID:	97317  
FERNSEH is online now  
Old 11th Sep 2014, 8:25 am   #32
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 9,145
Default Re: Philco upside down TV.

Just fit a BY100 and a 30 ohm surge limiter David. Not worth stinking the house out attempting to get one of those old stink bombs to fire up [!]
If you can find an AUTOMAT rectifier from an Ekco, you will find it to be 100%. Problem is the length will not fit the Plessey chassis.
I had a look in my junk box and discovered this lovely little selection...I only keep them for old times sake.
I have a hilarious story regarding stinking EHT triplers but will save it for a more suitable thread. Regards, John.
PS Just tested the RM4 and the blue painted one and discover they are 'OK'. Your welcome to one if you want to do a bit of refitting. J.
Attached Thumbnails
Click image for larger version

Name:	Stink bombs..jpg
Views:	176
Size:	83.3 KB
ID:	97404  

Last edited by Heatercathodeshort; 11th Sep 2014 at 8:46 am.
Heatercathodeshort is offline  
Old 11th Sep 2014, 3:56 pm   #33
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: Philco upside down TV.

Hi John,
It turns out that the Westinghouse metal HT rectifier used in the Plessey Mark 1 and 2 chassis is different from the more common type 14A96 which can be found in many mid-fifties TV sets.
The Plessey Mark 1 metal rectifier is slightly longer than the the more common one. I'd guess that the reason for this is that the applied AC voltage is higher by 50 volts than the AC/DC mains receivers which operate on a much lower HT voltage, it's typically 190 to 200 volts DC. in those sets. The HT voltage is 250 in the Mark 1 and 2.
The metal rectifier in the Mark 1 has three more cooling fins compared with the 14A96.

DFWB.
FERNSEH is online now  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 4:08 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.