Nato 2000

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Anonymous

Nato 2000

Post by Anonymous » Wednesday 23rd Mar 2005, 9:40

Hi all I Have Two!! Nato 2000 which both have no rx or tx,,both rx has squelch noise but no tx,, anyone know of any stock faults,, rgds

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The Defpom
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Post by The Defpom » Wednesday 23rd Mar 2005, 9:58

There is a diode that blows, I think it was D1, when it goes the radio stops transmitting.

zodiac
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Post by zodiac » Wednesday 23rd Mar 2005, 14:25

It could be the PLL, or Q30 back right hand side bolted to the chassis it's a darlington transistor 2SB837 or 11?? cannot remember the number, or Q36 it has a bit of aluminium bolted to it. if you look on the back (track side) of the board you will see the screen print for all the transistors and diodes, makes it easy to find them.
Does the relay klick when you key up or not, if not check D1 on the relay board, i think that that's the one scott was on about as it is a common fault on that radio. But my guess would be Q30 or 36.
Let us know how you get on with it.
73's
How far is it.
Twice it's length from halfway.

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Post by zodiac » Wednesday 23rd Mar 2005, 14:38

fastuart,
Just had a look at a scrap board,D1 on the main board is the zener diode for the PLL it's a 5.1volt device.
Check that out for 5v because without 5v the PLL wont work, no TX or RX.
How far is it.
Twice it's length from halfway.

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Post by The Defpom » Wednesday 23rd Mar 2005, 19:38

zodiac, yep, that is the diode I was thinking of, the PLL's zener, I had a nato 2000 about 13 years ago, had that diode go on me, it is a comon problem with that chassis, I spent so long tracking it down (13 years ago) that it eched itself into my brain, cant remember what I did last week but remember that bloody diode !!

Might be an idea to upgrade it to a 1W zener. instead of a 500mW

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Post by zodiac » Thursday 24th Mar 2005, 12:36

Scott,
Tell me about it, when i eprom a cybernet ssb radio that's the first thing i do,remove that diode and take 5v from the 7805 i fit for the eprom.
It dont go again.
How far is it.
Twice it's length from halfway.

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Post by zodiac » Thursday 24th Mar 2005, 14:35

Scott,
I think you'll find the answer is to turn the FM deviation down a bit and use a power mike. It may just solve the problem on AM as well.
As you know we don't use AM in the UK so i've never had that problem.
But i must say that type of radio the 125 and the 001 boards sound much better on all modes than the other cybernet boards IE 059 & 121, they sound s**t.
I take it you know what all the adjusters are for. Has your radio got the 4 CT6,7,8,9 adjusable capsitors in like the nato, there for spreading the lower channels power, that is channel 1 of each band. As you said the power on those radios is far too high for AM.
Other than that i'm sorry i can't help you on that one.
How far is it.
Twice it's length from halfway.

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Post by The Defpom » Thursday 24th Mar 2005, 16:19

Yeah, it has the extra capacitors to tune the cans on the lower (or was it higher, cant remember) frequencies, so it is very broadbanded, the VCO is pretty good too, gave it a couple of bands below normal and it still locked across all bands, old but nice radio.

Looks like aI may have to do some digging into the radio when I get the chance, as the AM mod is well down, FM is a bit weak, probably a bad capacitor somewhere.

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Post by cubwolf » Monday 18th Sep 2006, 4:20

Dragging an old topic from the dead lol
I always change R150 which is in line with the AF ALC.
In the 121 board i stick a 5.6k and the 125/natos around 3k and that helps the fm tx audio

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Re: Nato 2000

Post by bigpimp347 » Friday 4th Mar 2016, 4:13

10 years later, dragging this one up :)

Nato 2000, D1 ok,
D1 on relay board ok..
has RX ok..
TX relay clicks, no output and no TX lights,
also no voltage to TX light (so not switching in to TX..
Q36 shows voltages on all three pins (the darlington)
so am i thinking a switching transistor on the relay board ??
wasn't there a way to bypass the relay to force a Nato in to TX ??
I want to die asleep like my granddad did.
Unlike his passengers, Screaming and shouting..!

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Re: Nato 2000

Post by bigpimp347 » Monday 7th Mar 2016, 6:04

even further, lost RX,
all diodes and transistors seem fine (using an ESR)
TP3 next to VCO won't go below 4.5v needs to be 2.5v to lock the VCO
so any ideas why the voltage is so high ??
D1 is still ok :)
I want to die asleep like my granddad did.
Unlike his passengers, Screaming and shouting..!

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