[Collins] 32S-3 advice needed

[Robert Jefferis]

Whoops - stopped too soon. I should have mentioned to be sure that the PA load lever is near the 50 Ohm mark and that you put the PA Tuning pointer at least in the ballpark of the frequency you are tuning at. There are a few oddball combinations of exciter tuning and PA tuning that can send the TX into oscillation. Normal, correct operating practice will not inadvertently find one of these (hmmm, I wonder how I know this? chuckle).
Good luck.
Bob
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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