HMV 2705 in Vic Hallam cabinet 25/1/70

[RMDGuild]

I should probably have joined this forum five years ago when I purchased this venerable set. I think in a triumph of stupidity over commonsense I plugged it in to see if it would work! Fortunately not much happened! The degausser clunked into life and that was it. The main fuse perhaps is out, but I wasn't going to try the spare main fuse still in the envelope inside on grounds that if it were a problem further on in the electronics it would waste a good fuse. So it has sat in pride of place (probably my favourite acquisition of all time) not working for five years. Sometimes I open the doors and admire it! Ha ha! Anyhow, I have an old friend (ex Radio Rentals) who has managed to kick my 1963 Personal Fergie into life so perhaps we (he!) will have a go at this one. Any idea of common faults in this set which might render it currently lifeless? I was told by the seller that the tube was very low but even if it is, I understand there are some ways to revitalise it. How rare are these sets now...I haven't seen any on Ebay in the past five years and the gent who sold it to me said he hadn't previously seen one since 1996. Fortunately not long after getting the set I also found a catalogue with the set in it and the engineer pack in plastic wallet for the set. Any and all comments appreciated. Bestest.

[ms660]

I remember those goolie stretchers, Thorn/BRC 3000 chassis if I remember, chopper power supply.

Lawrence.

[RMDGuild]

Yes that's right! BRC 3000 indeed!

[dave walsh]

Smart set! I can't offer anything technical RMD but have you seen the-Can anyone identify this HMV TV Cabinet? thread posted by ryanbrownin on 24/7/15. 2705 pictures at p8*.

Dave W

[Cobaltblue]

Originally Posted by dave walsh

Smart set! I can't offer anything technical RMD but have you seen the-Can anyone identify this HMV TV Cabinet? thread posted by ryanbrownin on 24/7/15. 2705 pictures at p8*.

Dave W

This thread
https://www.vintage-radio.net/forum/...d.php?t=118284
Cheers

Mike T

[FIXITNOW]

have a look here lots off info page 3 and page 4

https://www.radios-tv.co.uk/vintage-...n-tips/page/3/

[RMDGuild]

Many thanks to all so far for your help...will have a look at these!

[thermionic]

Ahh, that brings back memories!

The HMV 2705 was my very first colour TV repair, at the age of 13. An old neighbour asked if I wanted their old TV to play with......!

I managed to convince my Father to help me carry the set back to our house, and it took pride of place in my bedroom / junkroom in the attic of my home. I had to make a return visit to the neighbour to collect the matching wooden stand.

On testing, the set didn’t do much except a brief buzz & hum at switch on. I discovered, more by luck than anything else, that the 100 Ohm dropper section on the top of the power supply module, was open circuit.

With this temporarily substituted, the set sprang into life, much to my surprise..... and joy! A new dropper was ordered and obtained from our local TV repair shop.

The CRT was not great, the picture had a pink hue due to a low green gun, but the set did provide me with many hours of enjoyment and a baptism of fire into the mysteries of colour tv technology.

Good luck with your set, you’ll find plenty of expert help here!

Cheers. SimonT.

[Welsh Anorak]

Hi!
Well, it's a 3000 series, and uses one of the first chopper power supplies which we either love or hate! That's the module on the top left of the chassis. Your problem probably is here. Ther's a red button on the back which might have tripped out indicating a short. These can themselves fail.
Basic fault finding starts here - is the dropper open circuit? Is the chopper transistor short circuit? The capacitors on the top will need changing anyway as they were pretty unreliable when these sets were current. If all's well, unhook the tripler and go from there.
The tube's original and will probably be soft. This can be boosted, but it might be worth trying to hunt a replacement - try the forum's wanted posts. An A63-120X will also do the job. However, that's in the future - let's get the old beast going first!

[RMDGuild]

Originally Posted by thermionic

Ahh, that brings back memories!

The HMV 2705 was my very first colour TV repair, at the age of 13. An old neighbour asked if I wanted their old TV to play with......!

I managed to convince my Father to help me carry the set back to our house, and it took pride of place in my bedroom / junkroom in the attic of my home. I had to make a return visit to the neighbour to collect the matching wooden stand.

On testing, the set didn’t do much except a brief buzz & hum at switch on. I discovered, more by luck than anything else, that the 100 Ohm dropper section on the top of the power supply module, was open circuit.

With this temporarily substituted, the set sprang into life, much to my surprise..... and joy! A new dropper was ordered and obtained from our local TV repair shop.

The CRT was not great, the picture had a pink hue due to a low green gun, but the set did provide me with many hours of enjoyment and a baptism of fire into the mysteries of colour tv technology.

Good luck with your set, you’ll find plenty of expert help here!

Cheers. SimonT.

Thank you very much - that's really helpful!!

[RMDGuild]

Originally Posted by Welsh Anorak

Hi!
Well, it's a 3000 series, and uses one of the first chopper power supplies which we either love or hate! That's the module on the top left of the chassis. Your problem probably is here. Ther's a red button on the back which might have tripped out indicating a short. These can themselves fail.
Basic fault finding starts here - is the dropper open circuit? Is the chopper transistor short circuit? The capacitors on the top will need changing anyway as they were pretty unreliable when these sets were current. If all's well, unhook the tripler and go from there.
The tube's original and will probably be soft. This can be boosted, but it might be worth trying to hunt a replacement - try the forum's wanted posts. An A63-120X will also do the job. However, that's in the future - let's get the old beast going first!

Many thanks - really helpful stuff! I've screenshot your message and the one above it to run by my ex-Radio Rentals pal next week as these sound like good starting points!

[1955APREN]

If all sections of the dropper are ok , on the top panel of the power supply right hand side , top
corner there is a large 30 volt Zener diode ( might be a metal one or a plastic one) . Measure the voltage on its cathode if it below 30volt even down to 28volts change the 1000uf 63v . If the voltage is 30v change the diode if you do not have a diode , as temporary test tack a 270k ohm resistor across the diode this will turn the delay transistor on resulting in the chopper transistor
turning on.
Hope this might help
Regards
Derrick

[RMDGuild]

Originally Posted by 1955APREN

If all sections of the dropper are ok , on the top panel of the power supply right hand side , top
corner there is a large 30 volt Zener diode ( might be a metal one or a plastic one) . Measure the voltage on its cathode if it below 30volt even down to 28volts change the 1000uf 63v . If the voltage is 30v change the diode if you do not have a diode , as temporary test tack a 270k ohm resistor across the diode this will turn the delay transistor on resulting in the chopper transistor
turning on.
Hope this might help
Regards
Derrick

Brilliant - many thanks and much appreciated!