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 13th Jul 2012, 9:17 pm   #1
stevitee
Diode
 
Join Date: Jun 2011
Location: Orpington, London, UK.
Posts: 9
Default PYE TT1 - First Transistor Portable UK TV

Good evening

I have just acquired this. Why, because I liked its looks and its very '60s'. All transistors (26) and a valve EHT rectifier. Got it home, adopted the gung ho approach and powered it up. Nice line whistle but no picture. Hooked up the Aurora and there was life, albeit just a thin white line across the screen. So, I think its another one of those sets that doesn't produce a raster unless a signal is present

I was unsuccessful in locating a schematic - there doesn't appear to be a Trader Sheet (not on my BVWS discs anyway) and nothing apparent on the interweb.

So, having worked out how to extract the chassis I noted numerous wax caps alongside the more 'modern' components. They were changed for new ones and some sort of a picture appeared. After various twiddling, the best I could produce was an image (of the Test Card) that was almost a 'negative' in appearance. Switched it off as I noticed one more cap that I had missed. That was replaced and when switching it back on again shortly after it had 'warmed up' there was (and still is) a loud buzzing from the speaker which didn't vary much when using the volume control. It sounds like the sort of interference experienced when an electric motor is running nearby. I have checked for any loose/touching connections and have re-checked all the joints soldered when re-capping.

I am embarrassed to admit that I am now stumped. I have heard this buzzing before when 'doing' a TV but I can't recall the cause or remedy.

Are any of you worthy folks familiar with this set (I have searched the Forum to no avail)? I would really appreciate sight of a circuit diagram and any information about this model - as I say there's nothing I can on the web so its all a bit of a mystery.

Any help will be gratefully received.

Many thanks.
stevitee is offline  
Old 14th Jul 2012, 12:41 am   #2
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,984
Default Re: PYE TT1 - First Transistor Portable UK TV

Info for the Pye TT1 can be found in the 1961/2 Newnes radio and television servicing book.
You have inspired me to bring down my TT1 to the workshop.
The frame timebase is free running.

DFWB.
FERNSEH is online now  
Old 14th Jul 2012, 8:40 am   #3
stevitee
Diode
 
Join Date: Jun 2011
Location: Orpington, London, UK.
Posts: 9
Default Re: PYE TT1 - First Transistor Portable UK TV

Thank you Fernseh, I am glad that I have inspired you to play with your TT1 too. Unfortunately, as luck would (wouldn't) have it, I only have one volume of Newnes and that is for 1959/60.

You wrote - ' the time base is free running'. Forgive my perhaps apparent ignorance but what is that statement telling me? Is is a statement of fact i.e the time base is of a type that free runs because that's how it is or it is free running but it shouldn't be. I am sure that you're being helpful but am I to presume that it IS a fault and if so what would be some clues as to the reason. I will check the time base circuit for 'duff' resisitors but with little knowledge of transistor technology and no circult diagram I shall be free running without a safety net....so to speak.

Many thanks
stevitee is offline  
Old 14th Jul 2012, 12:54 pm   #4
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,984
Default Re: PYE TT1 - First Transistor Portable UK TV

For starters, a picture of the Pye TT1.
The frame oscillator is free running in the sense that it does not need sync pulses to activate it. The set displays a blank raster when no signal is received.
Transistor V25 is the blocking oscillator and works in a conventional manner. The transistor conducts only during the flyback time and discharges the sawtooth forming capacitors C74 and C75. Frame repitition frequency is determined by C72, R74 and and the frame hold control R75.
The oscillator drives the V26 and V27 in a straight forward circuit.
It follows that to make a start on the restoration all those capacitors in the frame timebase should be checked or replaced as a matter of course.
The transistors OC72 and OC23 can still be found or the later types AC128 and AD149 could be considered as subsititutes.
The Pye TT1 is actually mentioned in the 1960/61 Newnes R & T serviving book.
I consider this to be an important historic receiver. It has a big 14" CRT, when around the same time it was made other manufacters were using quite small tubes for their transistor TV sets. Perdio and Ferguson used small CRTs.

DFWB.
Attached Thumbnails
Click image for larger version

Name:	PyeTT1pic.jpg
Views:	766
Size:	78.1 KB
ID:	68606   Click image for larger version

Name:	PyeTT1_1.jpg
Views:	580
Size:	47.7 KB
ID:	68607   Click image for larger version

Name:	PyeTT1_2.jpg
Views:	453
Size:	49.1 KB
ID:	68608   Click image for larger version

Name:	PyeTT1_3.jpg
Views:	431
Size:	62.5 KB
ID:	68609  
FERNSEH is online now  
Old 14th Jul 2012, 1:01 pm   #5
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,984
Default Re: PYE TT1 - First Transistor Portable UK TV

Here's a better shot of the frame timebase.

DFWB.
Attached Thumbnails
Click image for larger version

Name:	PyeTT1FTB.jpg
Views:	435
Size:	62.1 KB
ID:	68610  
FERNSEH is online now  
Old 14th Jul 2012, 10:40 pm   #6
stevitee
Diode
 
Join Date: Jun 2011
Location: Orpington, London, UK.
Posts: 9
Default Re: PYE TT1 - First Transistor Portable UK TV

Thank you Fernseh, that is all very helpful information and now I understand the free running point. I have changed all the wax caps anyway and now that I have the circuit diagrams (thank you) I now have a map to follow, which will help.

I have been 'playing' with the set for most of the day and resolved the 'buzzing' that I mentioned. It was simply a wire that had come adrift. All resoldered and noise gone. I have a picture which is ok-ish. It locks and with a fair amount of fettling the contrast, sensitivity and brightness controls the picture is watchable. However, it is a bit 'soft', with a slow 'ripple' effect continually scrolling up the screen and the sound is distorted so I think I have some more work to do.
I took the case apart and removed the tube for a good cleaning including the plastic front screen and the side knobs which have been polished and the lettering re-done with a gold paint stick. It is all back together now and looks quite presentable. As you say an interesting set and not one that I have seen before.

I presume that it had an external telescopic aerial(s) and some sort of a front cover because there are two hinge connectors monted on the bottom of the front - your's has them too. Are you aware of either of these features and what the hinges are for?

Thanks again for the information.
stevitee is offline  
Old 15th Jul 2012, 6:21 pm   #7
Electrical
Hexode
 
Electrical's Avatar
 
Join Date: Jul 2008
Location: Gateshead, Tyne & Wear, UK.
Posts: 310
Default Re: PYE TT1 - First Transistor Portable UK TV

Hello Stevitee
Please find attached a PDF copy of the service information for the Pye TT1 television, from the 1961-62 volume of Radio and Television Servicing. The information includes a circuit description and set up notes. I hope this information will be of some help in your restoration of your receiver.
Regards Stan.
Attached Files
File Type: pdf Pye TT1 {RTS61-62}.pdf (701.5 KB, 310 views)
__________________
Junk accumulates to fill the space available.
Electrical is offline  
Old 15th Jul 2012, 6:51 pm   #8
Neil Purling
Nonode
 
Join Date: Jul 2005
Location: Hull, East Yorkshire, UK.
Posts: 2,031
Default Re: PYE TT1 - First Transistor Portable UK TV

That 'slow ripple' effect & the distorted sound: Check/replace the rectifier diodes, V12 & V13 and also look at the reservoir & smoothing electrolytics, C32& C33.
I have seen that problem before with a portable.
Neil Purling is online now  
Old 16th Jul 2012, 10:56 am   #9
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,984
Default Re: PYE TT1 - First Transistor Portable UK TV

The internal battery is an essential part of the power supply of these receiver,
it serves as a smoothing element and a stable voltage reference.
It is missing in my set so I'll have to make up a substitute battery pack or engineer in an alternative 10 volt supply stabilising arrangement. Of course it is lot easier nowadays to do circuit modifications but back in 1960 when the set was designed there was a limited number of specialised components available for the designers of transistorised TV sets.
The video output transistor presented problems. Special high voltage devices were not available. The TT1 employs a special CRT which can operate with only 15 volts of video. A few years later the AF118 became available.
Remember that the 1967 Thorn 2000 all transistor TV employed two stacked transistors in the RGB output stages. Of course that was from a >200 volts HT supply unlike the 40 volts video output stage supply in the TT1

DFWB.
FERNSEH is online now  
Old 16th Jul 2012, 11:19 am   #10
Studio263
Octode
 
Studio263's Avatar
 
Join Date: Apr 2007
Location: Hampshire, UK.
Posts: 1,514
Default Re: PYE TT1 - First Transistor Portable UK TV

Quote:
Originally Posted by FERNSEH View Post
I consider this to be an important historic receiver. It has a big 14" CRT, when around the same time it was made other manufacters were using quite small tubes for their transistor TV sets. Perdio and Ferguson used small CRTs.
Do any examples of the Ferguson "Transvista" survive? Looking it R+TV S it looked to be a more "complete" piece of work than the Pye set (it has a properly styled cabinet instead of a sheet metal box...) but yet it seems to be far more unusual.

Can it really have been so bad that BRC didn't make another solid state monochrome set (the 1590) until over 10 years later?
Studio263 is offline  
Old 16th Jul 2012, 12:40 pm   #11
stevitee
Diode
 
Join Date: Jun 2011
Location: Orpington, London, UK.
Posts: 9
Default Re: PYE TT1 - First Transistor Portable UK TV

Quote:
Originally Posted by valveman49 View Post
Please find attached a PDF copy of the service information for the Pye TT1 television, from the 1961-62 volume of Radio and Television Servicing.
Stan, thank you very much for this - it will be very helpful.
stevitee is offline  
Old 16th Jul 2012, 12:48 pm   #12
stevitee
Diode
 
Join Date: Jun 2011
Location: Orpington, London, UK.
Posts: 9
Default Re: PYE TT1 - First Transistor Portable UK TV

First of all, thank you to Neil P for those helpful points. I was going to look/check the smooothing caps but have just noticed that they are both 10,000 uf which is not the 'usual' size that I keep so changing them may be a challenge for a while. I do know (or was told) that the set spent most of its life being run off a lorry battery because the person who owned it lived in a house with no mains electricity (true!). However, the house was deep in the country. And, moving on to Fernseh's points, the battery is also missing from my set and the wiring that I assume was for the battery has been snipped/partly removed. Not sure that I'll go to the length of making up a 10v battery /substitute but I'll certainly follow up on the components suggested by Neil.

Once again, thank you all
stevitee is offline  
Old 16th Jul 2012, 4:39 pm   #13
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,984
Default Re: PYE TT1 - First Transistor Portable UK TV

Quote:
Originally Posted by Studio263 View Post
Do any examples of the Ferguson "Transvista" survive?
I believe that one Ferguson model 743T "Transvista" is known to exist in the UK. The line output stage of the 743T differs from the Pye TT1 in having one output transistor, a Mullard N7D, later to become the AU101. The TT1 uses two 2G221 transistors. I notice that the Ferguson uses an OC170 for the video amplifier.
Certainly the Ferguson looks a better product compared with the Pye which has a "prototype" look about it.

DFWB.
FERNSEH is online now  
Old 16th Jul 2012, 4:59 pm   #14
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,984
Default Re: PYE TT1 - First Transistor Portable UK TV

The Ferguson 743T. http://www.freewebs.com/405tv/galleryno2.htm

DFWB.
FERNSEH is online now  
Old 28th Jul 2012, 8:34 pm   #15
stevitee
Diode
 
Join Date: Jun 2011
Location: Orpington, London, UK.
Posts: 9
Default Re: PYE TT1 - First Transistor Portable UK TV

A quick update on my post dated 16 July. I duly replaced the rectifier diodes with modern equivalents (courtesy of Maplins) and the smoothing caps (by using two 4.7k uf 'strapped' together in each case). The result has been a good improvement but its a far from perfect picture which I will put down to Fernseh's observations about the lack of a 10v battery and its inherent stabilising attributes. Essentially, I am quite pleased. It is watchable. Thanks everyone. I'd like to post a couple of snaps of it but haven't established how to do this yet.
stevitee is offline  
Old 28th Jul 2012, 8:47 pm   #16
stevitee
Diode
 
Join Date: Jun 2011
Location: Orpington, London, UK.
Posts: 9
Default Re: PYE TT1 - First Transistor Portable UK TV

I have now created an album in my profle so I think if you follow this link https://www.vintage-radio.net/forum/...hp?albumid=416 you can see the set.
stevitee is offline  
Old 28th Jul 2012, 11:03 pm   #17
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,984
Default Re: PYE TT1 - First Transistor Portable UK TV

Hi Stevitee,
You are getting good results from your set, a good start with it's restoration. Still no results from my TT1. The CRT heater was lit for a while, then a smell of burning and the set went dead.
I'll place the set on the "to do later" pile.

DFWB.
FERNSEH is online now  
Old 5th Sep 2012, 10:51 am   #18
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,984
Default Re: PYE TT1 - First Transistor Portable UK TV

The TT1 looks a positively crude affair when compared with the 1960 Zenith 19" portable TV set. In fact I believe this set was announced as ready for sale in the US in late 1959.

DFWB.
Attached Thumbnails
Click image for larger version

Name:	ZenithTV.jpg
Views:	390
Size:	37.1 KB
ID:	70409  
FERNSEH is online now  
Old 6th Jan 2016, 3:40 pm   #19
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,984
Default Re: PYE TT1 - First Transistor Portable UK TV

I thought it would be a good idea to have another look at this set. Well it seems because the voltage regulator was missing, the DC supply to the receiver was too high. The set was designed to operate from 10 volts. Something like 15 volts was being supplied to the receiver. You'll recall the NiCad battery serves as the voltage regulator.
The first casualty seems to be one of the 2G221 line output transistors, it has a emitter to collector leak, the meter reading is 75 ohms.
The set is full of OC171 transistors so there could be a likelihood that many of them will have the metal whisker fault.
This not going to be an easy restoration. What's more it's a difficult chassis to work on.

DFWB.
FERNSEH is online now  
Old 6th Jan 2016, 6:17 pm   #20
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,984
Default Re: PYE TT1 - First Transistor Portable UK TV

Ten volts from the bench power supply has been connected to the line oscillator and driver stage. The line oscillator circuit is working at 10Kc/s. The correct 15 volts P- P waveform is present at the collector of the line driver transistor V34, a Mullard OC23.
Without the line output stage the current drawn by this receiver is a very modest 0.5amp @ 10volts.
The circuit diagram was posted up #7 by Valveman.

DFWB.
FERNSEH is online now  
Closed Thread

Thread Tools



All times are GMT. The time now is 2:17 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 - 2022, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.