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Author Topic: Tech Special: ICOM IC-271A with frequency drift  (Read 8560 times)

White Tiger

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Tech Special: ICOM IC-271A with frequency drift
« on: November 03, 2012, 01:00:59 AM »
Anyone have one of these with a similar problem? I bought this rig and the one problem the seller mentioned was frequency drift...

I checked the Interwebs and found that one reason for this was due to ICOM using plastic trimmer capacitors in the PLL/VCO & RF/YGR circuits - the fix is to swap out the plastic trimmer caps with ceramic ones (6pf, 10pf and 20pf's). I just can't seem to find out if this is something a novice like me can do...or if I need to take it to a real radio repairman (which means I no longer got such a "deal" on the unit).

Anyone have any information/experience with this fix?

Any help would be appreciated!
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gil

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Re: Tech Special: ICOM IC-271A with frequency drift
« Reply #1 on: November 03, 2012, 01:24:41 AM »
As soon as you mentioned that last time I suspected a capacitor issue... I can swap them for you Tim, but it's gonna cost you another hot chocolate...

Gil.

White Tiger

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Tech Special: ICOM IC-271A with frequency drift
« Reply #2 on: November 03, 2012, 03:36:38 AM »
Heheh, thats right, you did! and I'll take you up on it - what a BARGAIN!
« Last Edit: November 03, 2012, 03:39:23 AM by White Tiger »
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gil

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Re: Tech Special: ICOM IC-271A with frequency drift
« Reply #3 on: November 03, 2012, 12:55:45 PM »
When you buy the capacitors, make sure they are NPO types, which means more temperature-stable...

Gil.

White Tiger

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Tech Special: ICOM IC-271A with frequency drift
« Reply #4 on: November 03, 2012, 01:45:45 PM »
I bought the ceramic ones rated with a minimum range indicated (6pf, 10pf and 20pf) - but there was no mention of NPO?

The radio arrived today, haven't tried it - except the VFO, which appears to be a bit sticky...how does your VFO turn?

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gil

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Re: Tech Special: ICOM IC-271A with frequency drift
« Reply #5 on: November 03, 2012, 01:56:27 PM »
If they are the variable type, then forget what I said..

Gil.

White Tiger

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Tech Special: ICOM IC-271A with frequency drift
« Reply #6 on: November 04, 2012, 01:12:40 AM »
If they are the variable type, then forget what I said..

Gil.

Hah!

Wait...which should I forget...that they should be NPO or forget the offer to swap them out!?
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gil

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Re: Tech Special: ICOM IC-271A with frequency drift
« Reply #7 on: November 04, 2012, 12:18:24 PM »
That they should be NPO  ;D

Gil.

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Tech Special: ICOM IC-271A with frequency drift
« Reply #8 on: November 04, 2012, 12:58:20 PM »
Oh, whew...

....regarding the sticky VFO - does yours have "sticky" areas along the dial? Some owners have mentioned that the rubber gasket warps and causes the sticking - but I don't see any warping?
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WA4STO

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Re: Tech Special: ICOM IC-271A with frequency drift
« Reply #9 on: November 04, 2012, 02:02:51 PM »
Tim -- the IC271A is specified to use 6amps @ 13.8v DC while in transmit mode.

Here's the manual for it -- see Page one for specs.

http://www.hurderconsulting.net/radiostuff/ic271a.pdf

I've had a number of the multimode VHF and UHF icoms.  They are just fabulous for satellite work.  Only major thing now is getting some decent 144 - 148 mHz antennas up.

Wonder how far away the local two meter repeaters are for you?

Best 73 de Luck, WA4STO

White Tiger

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Tech Special: ICOM IC-271A with frequency drift
« Reply #10 on: November 04, 2012, 02:41:18 PM »
Tim -- the IC271A is specified to use 6amps @ 13.8v DC while in transmit mode.

Here's the manual for it -- see Page one for specs.

http://www.hurderconsulting.net/radiostuff/ic271a.pdf

I've had a number of the multimode VHF and UHF icoms.  They are just fabulous for satellite work.  Only major thing now is getting some decent 144 - 148 mHz antennas up.

Wonder how far away the local two meter repeaters are for you?

Best 73 de Luck, WA4STO


Thanks Luck!

There are four 2m repeaters near me - between 3.9 & 4.6 miles from my location.
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White Tiger

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Tech Special: ICOM IC-271A with frequency drift
« Reply #11 on: November 04, 2012, 05:27:21 PM »
I read the "power supply" section which says to use at least 6 amps, and it's maximum consumption is 6amps...but it also defines the external VDC power supply as the Icom IC-PS15.

When I looked on eBay I found that exact unit - BUT - it is listed as a 20 amp power supply....?

I have an external 13.8vdc, 10 amp supply - would it simply blow the fuse if I were to try to hook it up? I'd like to see if my "Tech Special" ...actually powers up!?
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cockpitbob

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Re: Tech Special: ICOM IC-271A with frequency drift
« Reply #12 on: November 04, 2012, 08:43:07 PM »
Tim,
The 10A power supply will be fine powering a 6A rig.  Even if the rig draws more than the 10A your supply is rated for, it shouldn't cook anything. 

gil

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Re: Tech Special: ICOM IC-271A with frequency drift
« Reply #13 on: November 04, 2012, 09:10:37 PM »
Yours doesn't have the built-in power supply? Mine plugs in directly in 110.. The only problem with it are the power switch that sometimes stops working (I leave it on and plug/unplug) and the RF gain button that seems to do nothing.. Otherwise, no sticky areas. That's probably the encoder being dirty. Easy to fix I'd expect. I really like the 271A because I didn't have to spend extra money for a tone board.. The 25W output is also a plus, compared with it's predecessors 10W.

Gil.

White Tiger

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Tech Special: ICOM IC-271A with frequency drift
« Reply #14 on: November 04, 2012, 09:35:23 PM »
Gil - No, it did not come with the internal AC power supply. that was an upgrade attachement. If you got one, then you got a good deal, they are difficult to source on eBay.

Yes, I agree, overall I'm really impressed with the 271A - and that it fell within my [strike]cheapskate[/strike], budget conscious ways - while being able to give me an all-mode local communication option.

cockpitbob & WA4STO thank you both for the excellent source information regarding the power supply!
« Last Edit: November 04, 2012, 09:38:11 PM by White Tiger »
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