[Milsurplus] TCS Photo Page

[WA5CAB at cs.com]

Clare,

Mechanically, TCS through possibly TCS-4 have the loading coil scale 
information engraved on the front panel.  We're not dead certain when that change 
occurred as Collins used most of the same photos in the TCS-4 manual as they 
did in the base TCS manual.  TCS-5 has the more familiar removable plastic 
scale plate.  TCS through TCS-5 transmitter and receiver have a post 
sticking out of each corner or the front panel.  TCS-6 and later have handles 
instead.  As far as I recall, those are the only externally visible changes.  
Except that Collins built sets consistently use Phillips head screws.  Some of 
the other contractors use slotted head screws.  Specifically, Air King, who 
built TCS-14 and the Postwar TCS-15 uses slotted screws.  I keep forgetting 
to look at what I have on the shelf to see if I have any other examples of 
that.

Electrically, the only change I know of in the transmitters is that at 
Serial Number 9363 of TCS-12 production the electrical position of the RF 
ammeter was moved from the hot to the cold (ground) side of the output variometer 
to between the T/R relay and the antenna post.  TCS-13 and -14 production 
overlapped the TCS-12 and I think they are wired like the later -12's.

In the receivers, the only change I've ever seen mentioned is that the IF 
transformers changed from air core capacitor trimmed to iron core slug tuned. 
 I couldn't find it just now but I think I recall reading somewhere that 
TCS-7 and back have air core and TCS-9 on have iron core.  Collins didn't make 
TCS-8, I don't have a TCS-8 manual, and don't know which way it is.

So the short answer is that it's very hard to ID the model number of a 
radio that has no nameplate.  The only exception is probably TCS-5, because 
hardly any TCS-4's ever turn up, TCS-1, -2 and -3 all went to the Soviet Union 
and I've never heard of anyone ever finding a TCS.  Which means that if a 
receiver or transmitter has corner posts, it's almost certainly a -5.

In a message dated 2/16/2011 3:31:28 PM Central Standard Time, 
clare.owens at gmail.com writes: 
> Thank you Nick.  But that brings up a question:  Is there much electrical
> difference between the models?
> 
> I have a TCS in good condition - probably not modified at all - but it 
> came
> with no ID plates.  I later found a really badly stored TCS and bought it
> for its TCS-15 nameplates which had survived.  Bill Fizette of the AWA
> wanted the TCS that now had no plates so I sold it to him for a few bucks 
> at
> the AWA Spring meet/auction probably 15 years ago.
> 
> Are there any outstanding easy to notice differences between the models?
> 
> Thanks,
> 
> Clare
> 

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480