We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissible in your locale.

Author Topic: ICOM AD-55 power supply output voltage adjustment  (Read 3544 times)

Offline alpard

  • Sr. Member
  • ****
  • Posts: 267
    • View Profile
ICOM AD-55 power supply output voltage adjustment
« on: October 14, 2020, 1808 UTC »
Hi All

I checked my ICOM AD-55 output voltage, and it is 20V.
This is too abnormally high voltage I thought.

Is there ways to lower the voltage on the AD-55?

« Last Edit: October 15, 2020, 2236 UTC by alpard »
ICOM R71E, Lowe HF-225, YAESU FRG100, TECSUN PL-330, PL-320, XHDATA D-109, D-808, MSi001 SDR, AOR AR3030, Sangean ATS803, ATS-909X, Antenna= Random Wire+ATU, Active Miniwhip

https://twitter.com/RadioPax88
https://www.youtube.com/@RadioPax88/videos

Offline ThaDood

  • DX Legend
  • ******
  • Posts: 1226
  • Likely, not where you are.
    • View Profile
    • Extreme Part #15!
    • Email
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #1 on: October 14, 2020, 1851 UTC »
Wow... Somethin' ain't right there. Well, open that up and look for, either an adjustment POT, or for cold solder joints by a Zener Diode, or an LM78##-like Voltage Regulator. Just for the heck of it, have you put it to a load, like a 12VDC light bulb, and measured the voltage under load? Not having that power supply myself, I'm just speculating, but hopefully enough to help.
I was asked, yet another weird question, of how I would like to be buried, when I finally bite the big one. The answer was actually pretty easy. Face-down, like a certain historical figure in the late 1980's, (I will not mention who, but some of you will get it, and that's enough.) Why??? It would be a burial that will satisfy everyone: (1) My enemies will say that it will show me where to go. (2) On the same point, I can have my enemies kiss my butt. (3) It will temporarily give someone a place to park a bicycle. See??? A WIN / WIN for everyone.

Offline alpard

  • Sr. Member
  • ****
  • Posts: 267
    • View Profile
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #2 on: October 14, 2020, 1937 UTC »
 I will open up the AD-55E, and see if I could see the voltage adjustment pot.
« Last Edit: October 15, 2020, 2237 UTC by alpard »
ICOM R71E, Lowe HF-225, YAESU FRG100, TECSUN PL-330, PL-320, XHDATA D-109, D-808, MSi001 SDR, AOR AR3030, Sangean ATS803, ATS-909X, Antenna= Random Wire+ATU, Active Miniwhip

https://twitter.com/RadioPax88
https://www.youtube.com/@RadioPax88/videos

Offline alpard

  • Sr. Member
  • ****
  • Posts: 267
    • View Profile
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #3 on: October 14, 2020, 2051 UTC »
Wow... Somethin' ain't right there. Well, open that up and look for, either an adjustment POT, or for cold solder joints by a Zener Diode, or an LM78##-like Voltage Regulator. Just for the heck of it, have you put it to a load, like a 12VDC light bulb, and measured the voltage under load? Not having that power supply myself, I'm just speculating, but hopefully enough to help.

Thank you for your advice.  I have opened up the AD-55E, and there was no pot to adjust the voltage. 

« Last Edit: October 15, 2020, 2232 UTC by alpard »
ICOM R71E, Lowe HF-225, YAESU FRG100, TECSUN PL-330, PL-320, XHDATA D-109, D-808, MSi001 SDR, AOR AR3030, Sangean ATS803, ATS-909X, Antenna= Random Wire+ATU, Active Miniwhip

https://twitter.com/RadioPax88
https://www.youtube.com/@RadioPax88/videos

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 31236
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #4 on: October 14, 2020, 2141 UTC »
Did you measure the AD-55 voltage under a load?
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline alpard

  • Sr. Member
  • ****
  • Posts: 267
    • View Profile
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #5 on: October 14, 2020, 2309 UTC »
No, haven't done it yet.  I wouldn't imagine the output voltage from the AD-55 would drop a lot under the load. Would you?
« Last Edit: October 15, 2020, 2233 UTC by alpard »
ICOM R71E, Lowe HF-225, YAESU FRG100, TECSUN PL-330, PL-320, XHDATA D-109, D-808, MSi001 SDR, AOR AR3030, Sangean ATS803, ATS-909X, Antenna= Random Wire+ATU, Active Miniwhip

https://twitter.com/RadioPax88
https://www.youtube.com/@RadioPax88/videos

Offline Stretchyman

  • Hero Member
  • *****
  • Posts: 657
    • View Profile
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #6 on: October 15, 2020, 0853 UTC »
A schematic would be useful!

However if it's a simple pass transistor linear jobbie then the smoothing cap may be shot and passing A.C. ripple, just a guess.

Put your meter on A.C. see anything? If you do it's the cap.

Str.
'It's better to give than receive' so why Rx when you can Tx!

                                              ;)

Offline alpard

  • Sr. Member
  • ****
  • Posts: 267
    • View Profile
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #7 on: October 15, 2020, 1511 UTC »
Great idea on reading AC from the output DC. If the smoothing cap is bad or diodes are bad, then it will show
solid AC voltage readings.  Will try that.

I don't have the schematic, and couldn't find it anywhere.
« Last Edit: October 15, 2020, 2235 UTC by alpard »
ICOM R71E, Lowe HF-225, YAESU FRG100, TECSUN PL-330, PL-320, XHDATA D-109, D-808, MSi001 SDR, AOR AR3030, Sangean ATS803, ATS-909X, Antenna= Random Wire+ATU, Active Miniwhip

https://twitter.com/RadioPax88
https://www.youtube.com/@RadioPax88/videos

Offline M0DOU

  • Newbie
  • *
  • Posts: 1
    • View Profile
    • Email
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #8 on: June 20, 2021, 2026 UTC »
Just found this post after measuring two acquired Icom AD-55 power supplies to check voltage and polarity was correct before using it on my Icom R75 receiver.

Both measure around 20V output. This does seem a bit high but might be by design, if you look at the circuit diagram for the R75, the input voltage goes straight into a couple of voltage regulators (14V and 5V).

Checking the datasheets for these shows they can handle up to 30V input which is well above the 20V input.

Still, I'm a little surprised and disappointed, I'd have expected the NS-55 to be properly regulated at 13.8V given it is manufactured by Icom and is labelled as such on casing.

I probably won't use them as it's only going to generate excess heat from the R75's regulators and reduce their lifetime.


Offline redhat

  • DX Legend
  • ******
  • Posts: 1587
  • USA
  • Music is my drug.
    • View Profile
    • Email
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #9 on: July 08, 2021, 1716 UTC »
Doesn't surprise me.  I've seen more than a few questionable designs come out of icom over the last few decades.  From filter boards that zorch and smoke, to things like this...no thanks.

+-RH
Somewhere under the stars...
Airspy HF+, MLA-30/Mini-whip/Chi-Town Loop
Please send QSL's and reception reports to xfmshortwave [at] proton [d0t] me

Offline Quin

  • Newbie
  • *
  • Posts: 1
    • View Profile
    • Email
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #10 on: April 04, 2024, 1143 UTC »
I discovered similar readings. My AD55A has 19.57V. Seems weird that ICOM would have that set since it is outside the +/-15% range they spec on most receivers and transceivers. I have moved to a SMPS I have built myself. Also working on two dual SMPS boxes for my other radios.

Offline ~SIGINT~

  • DXing Phenomena
  • *******
  • Posts: 4231
  • N.E. Canada (FN08)
  • .ılılı..ılılı..ılılı..ılılı..ılılı..ılılı.
    • View Profile
    • Milspec Communication Canada
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #11 on: April 04, 2024, 1433 UTC »
The instruction sheet can be found on the ICOM site: https://www.icomjapan.com/support/manual/1794/
and state an output of 15 VDC +/- 5% at 2 Amps.

I doubt that you will find any adjustments in this power supply. Photos at the link bellow.
https://www.dxengineering.com/parts/ico-ad-55ns

Offline RobRich

  • DX Legend
  • ******
  • Posts: 1771
  • Tampa, FL USA
    • View Profile
Re: ICOM AD-55 power supply output voltage adjustment
« Reply #12 on: April 04, 2024, 1601 UTC »
I have seen unregulated 12vDC wall warts at 17-18 volts unloaded, and some models can reportedly hit 20+ volts. o.0

Anyway, about the original AD-55(A), at least for the version shipped with earlier R75 models....

Quote
Alas, the linear "transformer" version of the AD-55A floor brick power supply (USA versions) is unregulated and provides way too much voltage even fully loaded (which we measured at 17.65 volts which is way over specs.). So the set runs very warm to near HOT after awhile as the internal voltage regulator has to burn this excessive voltage off.

Source: https://www.qsl.net/n9ewo/icr75.html

Later production R75 models shipped with the AD-55S-12 switching power supply.
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | KiwiSDR 2 | 2x Msi2500 Msi001 | 2x RTL-SDR V3 + NE602 | 2x RTL-SDR V4
148' Loop-on-Ground | 31' Vertical | 18' End-Fed Vertical | 9' NCPL | PA0NHC MiniWhip