[Collins] 32S-3 advice needed

[Robert Jefferis]

Frank,

You did not mention whether or not the TX was advertised as working when you purchased it. Let's assume it was working. Also, you did not mention what frequency you were trying to tune up on. For starters, section 2.1.1e can be a bit misleading, especially if you are trying to tune on 80M or 40M. If the TX alignment is fairly good the exciter tuning is very sharp on 80 and 40, becoming less sharp as you go up in frequency.  If the exciter tuning is sufficiently off resonance at your desired frequency you will indeed NOT see any grid drive indication with increasing MIC GAIN. I suggest you try 20M, go to "TUNE" mode, put the mic gain at about 12:00 O'clock and gently rock the exciter tuning through the entire "14" range while watching for signs of life (grid drive) on the meter in "P.A. Grid" position. If this is a no-go, try another frequency band. Keep your tuning attempts relatively short, less than 10-15 seconds in "TUNE".

Bob, KF6BC
On Dec 20, 2009, at 6:51 PM, frankshughes at aim.com wrote:

> Hi,
> I recently bought a 32S-3 and am trying to get it working.
> 
> This is the first Collins transmitter I have seen and so I'm taking it 
> slow,
> following the manual, trying to learn all I can.
> Might be nothing at all wrong with it, just simple novice errors on my 
> part as I learn (no Elmer
> available here)
> 
> Or possibly the problems found so far may be resolved by some repairs 
> that I can do, but I know my limits and will
> stop if my work yields no results.
> 
> I have bought a NOS all JAN tube set, so I have a way to try new tubes.
> I also have bought a capacitor replacement kit (C6, C8, C177, C143, 
> C176, C184, C185) which I will put in
> soon.
> 
> I'm using this manual:
> 32S-3-_7th-ed-06-69_.pdf
> 
> I have the unit grounded, a watt meter/SWR connected to the transmit 
> out, and that goes into a 50 ohm dummy load.
> 
> No other connections on the back panel.
> Collins SM-2 mic. connected to front panel.
> 
> SECTION 1
> Installation
> 1.3 Initial Checks
> 
> Result= BIAS adjusts fine
> 
> SECTION 2
> Operation
> 2.1 CW Tuning
> 2.1.1
> e.
> Turn the MIC GAIN control (12) clockwise until the meter needle just 
> moves....
> 
> Problem - no meter movement at any MIC GAIN control setting
> 
> f. Set METER switch to P.A. PLATE position, and adjust P.A. TUNING for 
> minimum plate current.
> 
> Result=There is a slight dip in the meter when I do this adjustment, OK.
> 
> g. Place the METER switch to P.A. GRID position and EMISSION switch to 
> LOCK KEY position.
> Advance the MIC GAIN control slowly until approximately 1/2 scale grid 
> current is indicated on the meter.
> 
> Problem - no meter movement at any MIC GAIN control setting
> 
> At this point, I stopped and went to the "Service Instructions" 
> section.
> 
> It points out that most problems are w/ tubes, and clean the 
> sockets/pins as first steps, before more advanced troubleshooting.
> 
> Tested all the tubes that could be tested in my TV-10.
> Could not find any TV-10 configuration info for the OA2, 6U8A, so these 
> were not tested.
> The 6CL6 shows shorts in TV-10 "short" test positions except 4.
> The TV-10 book does not say this is normal, but a new 6CL6 behaves the 
> same, so probably nothing wrong but I don't want to blow up my TV-10 so 
> I did not test this one.
> The 6146's overload the TV-10 current capacity so I did not test them 
> either.
> 
> Found one (V10, VOX/ANTI-VOX RECTIFIER) that barely moved the needle 
> for the diode test. (replaced it w/ 5726)
> 
> Cleaned all the pins/sockets on all the tubes w/ Hosa Caig DeoxIT 
> F100L.
> 
> The unit seems to have all the original capacitors, so I'm thinking the 
> next logical step is to replace the caps listed above and check 
> function again.
> 
> If that has no effect, I suppose I could just put in all new tubes and 
> see what happens.
> 
> If the electrolytic cap and tube replacement has no effect, I will stop 
> and sent the unit off for further troubleshooting and repairs.
> 
> What do you think of this approach?
> 
> Thanks,
> 
> Frank Hughes
> KJ4OLL
> Collins Radio Association member 1654
> 
> 
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