GEC 5645 AM/FM radio

[Sideband]

I bought this set from a car boot sale a few years ago and, with hindsight, probably paid over the odds for it at £20. Anyway at that time I was just building up a collection of radio’s and after getting it home and doing some basic checks, found that it worked OK-ish but would need some TLC for reliable operation. It then ended up in the ‘to do’ pile. This weekend it had it’s turn.

This is a first-generation AM/FM radio and covers 88-100Mhz in addition to MW and LW. It uses seven Osram valves as standard with two Z719 (EF80) for the FM front-end, X719 (ECH81) as AM mixer and first FM I.F, W719 (EF85) as I.F amp, DH77 (EBC90) as AM detector, AGC rec and AF amp), N709 (EL84) as output and U78 (EZ90) as rectifier. Quite a standard line-up except perhaps for the DH77 and U78. The FM discriminator consists of a couple of GEX34 germanium diodes. Most manufacturers were using an EABC80 here but I suspect that there were some licensing issues because GEC were commited to Osram valves who didn’t have a suitable equivalent so GEC used what they had.

Having checked the set a few years ago, I knew it was basically working so now time to bring it up to standard. First clean out all the years of dust to find a reasonable chassis. All but one of the valves were original with the Osram lable (someone had changed the X719 for an ECH81), then set about changing the waxies. Once again these all checked as leaky and the Hunts Mouldseals were no better. For some reason, the tone corrector had been changed for a much higher value…it was a .047uF instead of .0047uF…maybe an error by whoever changed it or maybe they decided that the sound was too bright. Anyway I changed it for the correct value.

First test after doing all this showed the set to be working quite well. HT was also checked and found to be spot-on. I find that EF80’s struggle a bit at FM and this set tends to cut off completely just above 102Mhz. Following the alignment instructions didn’t help much other than to prove that the alignment was spot-on! I may try some EF184’s at a later stage but I don’t have any at present. AM alignment was likewise spot-on with just the minimum of tweaks on the MW aerial trimmer to peak it. I did find that AM tended to fade quite a bit but an ECH81 didn’t make any difference. After some voltage checks, I found the 68k screen feed resistor had gone up to about 90k with a tendency to drift higher with use. With this changed, things were much better and a quick check around the higher value resistors didn’t show up any other problems. After several hours of use, the radio does not drift off tune either on AM or FM.

Finaly the Bakelite cabinet. Once again the inevitable paint spots which cleaned of with dampened 000 grade wire wool. A good polish with several coats of beeswax floor polish restored a reasonable shine. The speaker cloth is not in the best of condition being somewhat frayed in places so I’ll probably change this at some stage. It cleaned up well and doesn’t look too bad from a distance of a few feet.

The pictures show the underside and there are a couple of views of the top chassis outside and inside the cabinet and then a veiw of the front. I think it's a very neat 'uncluttered' layout and very easy to work on.


Rich.

[Tazman1966]

Hi Richard.

A nice job. The chassis looks very clean indeed. What did you use?

Cheers,

[Sideband]

I just brushed all the dust off. The chassis came up just as it looks.


Rich.

[howard]

Well done Richard

I've not seen one of those sets before but it's rather nice.

Howard

[Sideband]

Originally Posted by howard

I've not seen one of those sets before but it's rather nice.

They turn up quite a lot on eBay (two in the last month).


Rich.

[Tim]

Nice job Richard. As you say these are easy sets to work on. ISTR there is a slight oddity with the tuning scale. It remains in the set and the pointer needs untangling from it as the chassis is removed.
There is also a paper backing to the scale which can become detached or discoloured.

[Sideband]

Originally Posted by Tim

ISTR there is a slight oddity with the tuning scale. It remains in the set and the pointer needs untangling from it as the chassis is removed.
There is also a paper backing to the scale which can become detached or discoloured.

The scale stays in the set but nothing needs untangling...the pointer and backing plate come out as one with the chassis. There is a paper backing that was slightly yellowed but it looks OK so was left as is.


Rich.

[ajs37]

Nice work Richard - I agree, they are easy to work on - I restored one just before Xmas last year and gave it to a friend of mine as a present. Can't remember too many details - I just remember changing all the waxies/ hunts, think I changed the output valve which solved a low volume problem - everything else was good. Cabinet came up good, with a polish (like you, I used beeswax).

Aesthetically, they are not my cup of tea - (that's why I gave it away!), but they must have been popular, as there are still quite a few of them around.

Cheers
Andy

[Robert Darwent]

Hi Rich,

Not a GEC model I've come across before, but it looks quite nice. You've certainly done an excellent job of restoring it. It looks really first class now, well done!

Regards