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-   -   Eastronic 6 Transistos (sic). (https://www.vintage-radio.net/forum/showthread.php?t=172313)

Avid_Nerdlinger 21st Oct 2020 6:40 pm

Eastronic 6 Transistos (sic).
 
4 Attachment(s)
Bought a tinny tranny for £7.99 off eBay. I was intrigued by the telescopic aerial on an AM only radio... it's not connected to anything, maybe the enclosure is used for FM versions as well. It was sold as not working, I found it did work through the earphone (2.5mm!) and after desoldering the speaker measured open cct. I tweezered the paper voice coil cylinder out and found the break on the coil was at the start of the winding so I wound it out enough to solder it and crammed it back on to the magnet. So now it works, the reception is as poor as you might expect and the speaker does click a bit when I can find a loud enough signal.

paulsherwin 21st Oct 2020 7:01 pm

Re: Eastronic 6 Transistos (sic).
 
Quite a few no-name Hong Kong LW/MW radios had pointless telescopic aerials in the 60s and 70s. Presumably the makers thought it would increase sales.

Herald1360 21st Oct 2020 10:31 pm

Re: Eastronic 6 Transistos (sic).
 
You could connect the telescopic to set 0V via a few turns wrapped round the centre of the ferrite rod. It probably wouldn't make things any worse.....

paulsherwin 22nd Oct 2020 12:30 am

Re: Eastronic 6 Transistos (sic).
 
Most of these cheap HK sets actually had reasonable performance, so if it's really awful then there's probably something wrong with it.

usradcoll1 22nd Oct 2020 4:44 pm

Re: Eastronic 6 Transistos (sic).
 
Quote:

Originally Posted by paulsherwin (Post 1302056)
Quite a few no-name Hong Kong LW/MW radios had pointless telescopic aerials in the 60s and 70s. Presumably the makers thought it would increase sales.

I thought, maybe it has a telescopic aerial because it has LW. It's strange that they use it for just decoration.
Very few radios in the US have LW, so I have little experience with it.
Always learning something new from this website. :wave:
Dave, USradcoll1

Avid_Nerdlinger 22nd Oct 2020 5:48 pm

Re: Eastronic 6 Transistos (sic).
 
1 Attachment(s)
Quote:

Originally Posted by Herald1360 (Post 1302121)
You could connect the telescopic to set 0V via a few turns wrapped round the centre of the ferrite rod. It probably wouldn't make things any worse.....

A Bambino-9 came in the post today (more on that to follow probably) and it has a detachable aerial so it might indeed be worth connecting this one up somehow. Bambino also came with cct diagram!

" if it's really awful then there's probably something wrong with it." it's pretty bad, I'll have a closer look, I didn't like the way the antenna coils were hanging off the ends of the rod and I could measure the electrolytic out of cct.

Herald1360 22nd Oct 2020 6:41 pm

Re: Eastronic 6 Transistos (sic).
 
If the aerial coils are hanging off the end of the rod, it could be worth adjusting the MW one for a peak response to a station near the LF end of medium wave and the LW one to peak up R4 LW. Certainly if they're wrongly positioned, sensitivity will be down. Use a few drips of candlewax or even a wrap of sellotape to hold them in position when tweaked.

paulsherwin 22nd Oct 2020 7:41 pm

Re: Eastronic 6 Transistos (sic).
 
Dave, a telescopic aerial is actually *less* likely to be useful on LW. If the aerial isn't completely cosmetic, it may have been added for SW use. These radios often covered BC and SW in markets where LW wasn't used.

The HK manufacturers were very focussed on the UK market in the 60s and early 70s though - it was the only significant part of the British Empire left then, and 1997 seemed a long way into the future.

Avid_Nerdlinger 23rd Oct 2020 6:06 pm

Re: Eastronic 6 Transistos (sic).
 
Moving the LW coil made a noticeable difference, so much so I had to replace the clicky speaker with one off a Chinese kit MW radio I had previously ruined trying to convert it to LW... When I came to switch this on it wouldn't work until I had used some contact cleaner on the on/off switch - I wonder if the waterproof PVA I had used for gluing the clicky speaker back in gave off a vapour which coated the contacts... Moving the MW coil made no difference but the MW stations available here are very weak to begin with so possibly beyond this tranny's ability, I might revisit this next time I drive to the big smoke (Inversneckie).

Northyorks1 24th Oct 2020 1:40 am

Re: Eastronic 6 Transistos (sic).
 
2 Attachment(s)
Picked up the same radio a few months ago, with Paul Sound logo and MW/CB.

Ian

paulsherwin 24th Oct 2020 9:54 am

Re: Eastronic 6 Transistos (sic).
 
Interesting variant. You don't see many radios with CB coverage in the UK from that period, as it was illegal (and still is for AM). My guess would be that it's a model for the American market which somehow made its way here.

It explains what the aerial is for anyway.

crackle 24th Oct 2020 11:20 am

Re: Eastronic 6 Transistos (sic).
 
I think AM and SSB is now legal in the UK for use on the EU band

paulsherwin 24th Oct 2020 11:30 am

Re: Eastronic 6 Transistos (sic).
 
I stand corrected. I've never had much time for the CB thing.

Avid_Nerdlinger 25th Oct 2020 4:15 pm

Re: Eastronic 6 Transistos (sic).
 
1 Attachment(s)
I was able to find the sweet spot for the MW coil on the ferrite rod using an AM signal booster I stumbled across on my constitutional yesterday. For a bit of fun I videoed a demonstration of this signal booster, first MW then LW.

https://youtu.be/aT8Vo4VcdR0

https://youtu.be/yUZTzHhGTKE

Comparing this with a smaller HK AM radio Ingersoll XK-791 which works so much better, see photo, the ferrite rod on this one is only slightly shorter but is thicker, otherwise the component count looks similar. More evidence there is indeed something wrong with this one. By ear I'd say it has a poor signal-to-noise ratio so I'm guessing it's a problem with the circuit around the first stage transistor marked 901. I've no schematic for it but this radio should be simple enough for even me to reverse engineer. More to follow hopefully.

paulsherwin 25th Oct 2020 4:31 pm

Re: Eastronic 6 Transistos (sic).
 
It's actually likely to be something simple like a dirty wavechange switch. The transistors are probably general purpose types like the 2N3904 if you need to change them, though they might have 'Japanese standard' ecb leadouts.

Maarten 25th Oct 2020 7:04 pm

Re: Eastronic 6 Transistos (sic).
 
Hong Kong transistors might also use CBE layout (as opposed to European EBC).

buggies 26th Oct 2020 11:07 pm

Re: Eastronic 6 Transistos (sic).
 
I am surprised you had all that crackling noise out in the wilds - thought it might have been an electric fence at first but the top strand does not seem to be insulated - although it is separate from the mesh.

Avid_Nerdlinger 27th Oct 2020 12:25 am

Re: Eastronic 6 Transistos (sic).
 
Quote:

Originally Posted by buggies (Post 1303986)
I am surprised you had all that crackling noise out in the wilds - thought it might have been an electric fence at first but the top strand does not seem to be insulated - although it is separate from the mesh.

Fortunately it's not electric as I straddle it every day... I think the crackle you're hearing might be the wind whipping around my cheap compact camera, there is noise from the the radio as well but it's more of a white noise hiss.

"It's actually likely to be something simple like a dirty wavechange switch." - Good point. So I checked it but it wasn't dirty, at least I've now given the contacts a good polish and lube so it'll be good for another 40 years If I can fix it, I still haven't checked the electrolytics out of circuit, there's one decoupling the IF stages, that's next I think.

Avid_Nerdlinger 1st Nov 2020 6:46 pm

Re: Eastronic 6 Transistos (sic).
 
1 Attachment(s)
I'm putting this to one side for a while, it might just be a poor quality radio. I poked around it quite extensively, replaced a resistor which looked wierd and measured about 15% high in the IF section. Tried dropping in a replacement RF transistor off that abandoned Chinese kit radio. None of this made any noticeable difference.


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