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Old 2nd Oct 2018, 1:00 pm   #1
steve.collier2
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Default Icom IC-251E

Ive just taken posession of one of the Radio's I used to eye enviously as a penniless teenager when I obtained my Amateur licence.

considering its age it appears to have been well looked after, and came in the original packaging.

Its also got the benefit of having the Mutek front end fitted, which subsitites the pin diode switching with a low noise raly and also has a superior mixer circuit to the Icom design.

powered it up off 12V last night and it was picking up at good strength on a bit of wire in the kitchen

https://www.youtube.com/watch?v=K3zsLEckBAg


As a base unit they came with a mains power supply. these were prone to failure.
It came with a spare, that someone has started a repair on. looking at the construction, whilst good from an RF screening persepctive, Im sure enclosing the active bits of the power supply in a small aluminium "roasting tin" didnt do it any favours, it does smell of baked electronic components.

Ill probably repair them long term, and look at introducing some cooling ( they didnt have miniauture 12V PC fans back in the day ) , but enjoy the radio as is for now

Ive also included a pic of my new scope, with many thanks to John_bs
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Old 2nd Oct 2018, 1:01 pm   #2
steve.collier2
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Default Re: Icom IC-251E

more pics
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Old 2nd Oct 2018, 6:24 pm   #3
SiriusHardware
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Default Re: Icom IC-251E

A Proper Radio, with one physical switch or control for every function. Well done finding it.
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Old 2nd Oct 2018, 10:13 pm   #4
g4aaw pete
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Default Re: Icom IC-251E

Hello Steve

I have one of those, also with the Mutek board.
I also have two of the 6m variants. None of the three have suffered power supply problems, but they are getting-on a bit now.

Good luck with the psu repair.
This is the diagram of the IC551 psu, which I believe to be the same.

Regards
Pete
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Old 2nd Oct 2018, 10:59 pm   #5
steve.collier2
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Default Re: Icom IC-251E

Thanks Peter. IC1 looks “interesting” and unavailable . I wish you hadnt reminded me there was a 6M version to hunt down (last sunspot maximum was getting by with a PW MEON driven from an FT-757).
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Old 2nd Oct 2018, 11:06 pm   #6
g4aaw pete
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Default Re: Icom IC-251E

Just noticed there are no values on the circuit diagram.
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Old 2nd Oct 2018, 11:15 pm   #7
g4aaw pete
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Default Re: Icom IC-251E

Quote:
Originally Posted by steve.collier2 View Post
Thanks Peter. IC1 looks “interesting” and unavailable . I wish you hadnt reminded me there was a 6M version to hunt down (last sunspot maximum was getting by with a PW MEON driven from an FT-757).
There's also the 70cm variant.
But that's a step too far.
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Old 3rd Oct 2018, 7:55 am   #8
steve.collier2
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Default Re: Icom IC-251E

Thanks. of course I have a little black box that does all the bands but wheres the fun in that
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Old 3rd Oct 2018, 2:10 pm   #9
buggies
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Default Re: Icom IC-251E

Been my main rig since new - never had any problems with it so only just opened the manual to look at the PSU. Quick mobile phone pics attached for comparison with 551 circuit.
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Old 12th Oct 2018, 10:55 am   #10
steve.collier2
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Default Re: Icom IC-251E

spent a few hours on the case and panels.

It looks like a smoker has had it at some point.

the front panel and switches/knobs were very dusty and grubby.

Ive found that Cif bathroom foam works wonders for lifting dirt from hard surfaces, it does contain a small amount of ammonia, and Ive also got a tin of a wax polish type hard surface cleaner ( It was given to us when we got granite worktops ) works wonders also.

the Aluminium surround was quite oxidised, and has had a rub down with some 600 wet and dry wrapped around a pencil eraser to restore its brushed finish.

the rear panel idents still had the plastic film on from manufacture but was yellowed and lifting in places so this was carefully removed.
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Old 12th Oct 2018, 10:57 am   #11
steve.collier2
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Default Re: Icom IC-251E

more pics
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Old 12th Oct 2018, 11:18 am   #12
steve.collier2
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Default Re: Icom IC-251E

yet more pics
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Old 12th Oct 2018, 11:37 am   #13
Peter.N.
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Default Re: Icom IC-251E

Makes me wish I still had my FT101ZD.

Peter
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