Re: PYE TT1 - First Transistor Portable UK TV
 

That looks a whole lot better, I take it you have replaced those dodgy preset pots?
I noticed the latches on the front, I take it the set has a removable lid over the CRT?
:beer:
Mark

Re: PYE TT1 - First Transistor Portable UK TV
 

Hi Mark,
I don't think the latches are used to fit an additional filter window. It's more likely a protection panel was supplied with the set to prevent damage to the moulded Perspex CRT safety shield.
The replacement frame linearity controls have solved the picture geometry faults.
Interesting to note that the circuit of the frame timebase output stage in the TT1 is very similar to the frame OP stage in the BRC 3000 series CTV.

DFWB.

Re: PYE TT1 - First Transistor Portable UK TV
 

The final stage of the restoration of this interesting receiver will be the provision of a 10.8 volt supply regulator. I have three choices: first, use nine series connected 1.2V 2.5A/hr NiCad cells. The cells can be installed into a box to replicate the original battery pack. The cells function as the voltage regulator when the set is operated on mains and car battery. Second, the all germanium transistor series regulator employing an AD149 transistor. The third option is a modern low dropout device like the LT1033.

DFWB.

Re: PYE TT1 - First Transistor Portable UK TV
 

Am I right in thinking that only option #1 allows running from its own internal batteries ? If so then that'd be my choice.

TTFN,
Jon

Re: PYE TT1 - First Transistor Portable UK TV
 

Hi Jon,
I'm also keen on the first option.
1.2volt 2500mA/H Sanyo NiCad cells are available from Conrad:

http://www.conrad-electronic.co.uk/c...omSuggest=true

Or from the same firm: NiMh 1.2volt 2400mA/H cells:

http://www.conrad-electronic.co.uk/c...=detview1&rb=1

DFWB.

Re: PYE TT1 - First Transistor Portable UK TV
 

Would one of those Akura DC regs work which they used in various mains/battery colour portables? Malc.???

Re: PYE TT1 - First Transistor Portable UK TV
 

Hi Malc,
the Baby 10 regulator? It's possible a spare one is out there somewhere. Certainly it would do the job.

DFWB.

Re: PYE TT1 - First Transistor Portable UK TV
 

Got one here, yours for the postage if you want it.

Re: PYE TT1 - First Transistor Portable UK TV
 

Should have them in stock here if you need one David.

Re: PYE TT1 - First Transistor Portable UK TV
 

Hi Bill, Hi Malc,
The TT1 was bought way back in 2005 at the Birmingham NEC. I was rather surprised the lack of interest in the set. Then Akura Baby 10 regulator module was considered at the time as a substitute for the NiCad battery. The idea was to use the set exclusively on the mains, but portability is what this set is all about so I'm still considering the battery option. The Akura regulator could still be incorporated into the circuit. It's a much better option than relying on the batteries doing the 10 volt supply regulation.

The Akura 10 volt regulator was still available in 2005.

Hi John,
presenting the Pye TT1 alongside the famous Masteradio.

DFWB.

Re: PYE TT1 - First Transistor Portable UK TV
 

Hi there
The Baby 10 regulator was available in 2005, but the original potted version had been replaced by third party discrete component units using, typically, an IC and a small transformer on similar metalwork. Some of these worked well and some didn't. The advantage of one of these is that you could open it up and experiment.
Glyn

Re: PYE TT1 - First Transistor Portable UK TV
 

Hi Glyn,
I'm assuming that the Baby 10 regulator delivers an output of 10 volts, but does it?

DFWB.

Re: PYE TT1 - First Transistor Portable UK TV
 

Good question. I don't think it did - I seem to remember it would give a stable output of around 11.6v and would do so with an input very close to that. Some of the alternatives wouldn't do that and would switch off if the battery voltage fell below 12v.
Goodness knows what was in the original three-pin block!
Baby 10, of course, refers to the screen size.

Re: PYE TT1 - First Transistor Portable UK TV
 

There was an article in Televison magazine May 1996 about the Nikkai Baby 10 colour TV regulator and how to build an equivalent using only a few components.

Download a scan of the article here: http://www.digifixltd.co.uk/pdf/NikkaiBaby10Switch.pdf

Since that article is now nearly 20 years old, I don't know if all the parts are still available to build it, but if they are, it should be easy. The Baby 10 regulator gives an output of 10.9v which should be OK for your Pye TT1.

Re: PYE TT1 - First Transistor Portable UK TV
 

There is a KT-706 DC-DC converter available on ebay that uses the same IC with almost identical circuit.

Re: PYE TT1 - First Transistor Portable UK TV
 

Link to a vendor in Taiwan: http://www.ebay.co.uk/itm/1pc-Switch...UAAMXQLw1Rzudg

DFWB.