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Spectra D37 A5 VCO unlock.

Posted: Wed Mar 23, 2011 10:22 pm
by PETNRDX
Here is my problem...
D37 A5 900 Mhz Spectra that has been in my possession for nearly 20 years.
Working fine and used a lot until about 7 years ago.
Last year or so I have only used it a little, now 900 activity is picking up a lot.
Started to get that "thump" in the speaker on mode or volume change.
So, today decided I better do the re-cap.
( I have been carefully inspecting the caps periodically, no leakage seen )
Changed all the electrolytics, very little leakage hidden under the caps when removed.
Cleaned per the usual.
Fired up the radio, Rx good, TX on DIRECT is good, but not Rpt. FAIL 001 instantly.
Opened the case, removed the RF board shield to take a look, radio worked fine for about two minutes.
VCO is around 4.3 v on RX, same on TX Direct.
VCO basically Zero ( .16 v ) when unlocked.
Freqs are all in the 902 range.
Again, this radio has worked fine for years.
Compared the voltages at all the new caps with a working "sister" radio on same freqs, and those voltages are nearly the same.
Same with OSC voltage.
Any body have an idea.
These have the resistor VCO mod ( 150 ohm )

Re: Spectra D37 A5 VCO unlock.

Posted: Thu Mar 24, 2011 1:00 am
by Will
You did not get the damage off the RF/IF board.

Re: Spectra D37 A5 VCO unlock.

Posted: Thu Mar 24, 2011 2:43 pm
by PETNRDX
Lets not be insulting.
I fixed the damage which was VERY minimal considering the age of my Spectras. They are 1990.
The problem was even dumberer than that...
In working on the radio, most of the time, I had the chassis oriented VCO/Rf board up, VCO towards me, RF board away.
In working on that side of the radio, I lifted the VCO board just enuf to pull the mating pins out of the RF board.
When putting the board back in, the last pin went OUTSIDE the little socket but apparently stayed in contact just enuf to work once in awhile.
On disassembling the radio again, I saw the bent pin.
Now fixed.

Re: Spectra D37 A5 VCO unlock.

Posted: Mon Mar 28, 2011 11:59 am
by RADIOMAN2002
Your lucky, I have broken more than a few pins by not paying attention.

Re: Spectra D37 A5 VCO unlock.

Posted: Mon Mar 28, 2011 1:24 pm
by PETNRDX
Yes, I am VERY lucky.
Those pins are fragile, and I know it.
I was tired and lucky I didn't ruin an otherwise good radio...

Re: Spectra D37 A5 VCO unlock.

Posted: Mon Mar 28, 2011 2:32 pm
by com501
'bout time you got on the local 900 repeaters..... :D

Re: Spectra D37 A5 VCO unlock.

Posted: Mon Mar 28, 2011 3:02 pm
by PETNRDX
I am on 927.35 all day.
And there is a new repeater going up VERY soon.
You and Paul need to get on there.
The Slide system is kind of noisy, but I heard from the owner that they plan to make that much better when snow allows...

Re: Spectra D37 A5 VCO unlock.

Posted: Mon Mar 28, 2011 3:27 pm
by com501
Working on it, but I don't have a handheld, I'm more of a mobile guy. Paul rarely brings his in, I'll remind him.