President 2510 NO FM RX just white noise

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ixphant0mxi
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President 2510 NO FM RX just white noise

Post by ixphant0mxi »

Radio Make and Model: President HR2510
PCB Number: PB-111AD 1980 Uniden ( or 1988 looks like 1980 on silk screened numbers )
PLL Number: UC1201
Test gear available: o-scope, v/ohm meter 7 digit cpi counter with probes and RF input SO 239 connectors
Symptoms: No FM RX just white noise, no RF gain control on FM Rx, NOTE : i can hear FM Rx signal if I transmit on a test radio on same bench with the 2510's RF gain wide open if turned down nothing but white noise also test radio has to be on same bench or right next to 2510 I don't think if some one across the street transmitted on FM on a test radio i would hear them i can see a little movement in the needle of a other signal if some one is on am mode but no am scratch or ssb scratch while in FM

What is working: TX: AM./SSB/CW/ FM RX: AM/SSB/ CW

What has been tried: Adjusted L401 on FM PC board as per 2510 service manual Alignment instructions just made things a bit cleaner on the lose up FM Rx with test radio but no improvement to anything else as far as non next to test radio on FM TX on bench still white noise and no normal FM Rx no RF Gain control in FM

Did it suddenly happen ?: No i got the radio this way
Anything else that may be of help?: this is President 2510 Version 1
amber display, factory talkback (i have since removed the talkback) the version that goes 26.000 Mhz to 29.999 mhz
Rick or Scott any ideas?
i love my 2510 everything else works super on it would just like the FM to also work as some of us here in the states use Fm mode
hakkeri2
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Re: President 2510 NO FM RX just white noise

Post by hakkeri2 »

Tarkista fm kortilta 47 uf / 10 v kondensaattori onko oikosulussa. Myös vastus 10 ohm voi olla palanut. Minulla on samanlainen ongelma, voimakas fm signaali kuuluu tosi hiljaa, am ja ssb toimivat hyvin.

English:
Check the fm card 47 uf / 10 v capacitor is it shorted. Also 10 ohm resistor can be blown. I have a similar problem, a strong FM signal is real quiet, :?: AM and SSB are working well.
ixphant0mxi
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Re: President 2510 NO FM RX just white noise

Post by ixphant0mxi »

not getting a reading on smd chip resistor on the bottom of the fm pcb UGH guess ill just leave it with out fm and use my Magnum 257
zodiac
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Re: President 2510 NO FM RX just white noise

Post by zodiac »

What hakkeri2 is saying is, that on the FM board you can see only one resistor on the component side of the FM board with the IC and the two filters, that is the 10ohm rasistor he's talking about.
On the other side of the board is an electrolytic capacitor that can cause the resistor to go faulty, if the resistor is reading 10ohm then that's not the problem but if not then you will have to take the FM board out and replace both of them whilst it's out.
The FM board will need handling with care when being removed as it's a tight fit in the board.
How far is it.
Twice it's length from halfway.
ixphant0mxi
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Re: President 2510 NO FM RX just white noise

Post by ixphant0mxi »

fm board pb-119AD
this is what i have from top left to right, , bottom left to right
component side:
top left: L402 can
top right : relay ft402 printed next to it
bottom left blue electrolytic cap
middle IC 401
bottom right : right crystal FT 401 printed where the 3 legs of crystal are soldered to solder side
no banded carbon resistor visible on component side no open holes for a missing component
back side traces and chip resistors and diode No visible banded carbon resistor
now unless im mistaken that is the correct fm board
just to the right there is a board with visible resistor on it
board is PB-117ac
has L203 on it
3 electrolytic caps 2 glass diodes and resistor and it is 100K
zodiac
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Re: President 2510 NO FM RX just white noise

Post by zodiac »

Board PB119 is the FM board and the FT402 is the .455 filter and FT401 if the 10.7 filter or it may have a crystal filter 10.695.
I have seen the crystal filter with a broken lead before today so make sure that's not your problem.
The 10ohm resistor is to the right of the .455 (FT402) filter and the capacitor is on the other side of the board, it's the only component that's not surface mounted.
How far is it.
Twice it's length from halfway.
ixphant0mxi
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Re: President 2510 NO FM RX just white noise

Post by ixphant0mxi »

no resistor there zodiac
how can i post pics on the fourm so i can show you the board ?
zodiac
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Re: President 2510 NO FM RX just white noise

Post by zodiac »

This is the FM board, I've cleaed it up a bit but you can now see the resistor.
Maybe the newer radios have it mounted on the other side of the board as the diagram is for the PB119AA board.
Dave.
Attachments
PB119.png
PB119.png (56.22 KiB) Viewed 6863 times
How far is it.
Twice it's length from halfway.
ixphant0mxi
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Re: President 2510 NO FM RX just white noise

Post by ixphant0mxi »

here is my fm board as you can see no resistor on it and non in the back every thing on the back side is surface mount
Attachments
fm board on my 2510
fm board on my 2510
fm board2.JPG (88.74 KiB) Viewed 6864 times
ixphant0mxi
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Re: President 2510 NO FM RX just white noise

Post by ixphant0mxi »

a drawing of the fm board
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ms paint of my board
ms paint of my board
FM BOARD 2510.JPG (22.06 KiB) Viewed 18453 times
zodiac
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Re: President 2510 NO FM RX just white noise

Post by zodiac »

You've got a slightly different board than what I'm looking at, yours has a capacitor on the side shown and no resistor.
The board I'm looking at is the 119AA, the first board used in the radio. If you do take the board out it might be worth changing the IC for what it would cost, you never know it just might be that that's faulty.
How far is it.
Twice it's length from halfway.
ixphant0mxi
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Re: President 2510 NO FM RX just white noise

Post by ixphant0mxi »

my board is PB119 AD so looks like there might be up to 4 versions or more of the fm board
Yequan
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Re: President 2510 NO FM RX just white noise

Post by Yequan »

The other side of the board electrolytic capacitors may result in resistance to wrong, that if the resistance is 10ohm not a problem to read, but if not, then you will want to take the FM board out, replace them both at the same time it was.
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