[Collins] Re: collins 618T-3

kb6oks00 [email protected]
Tue, 8 Jul 2003 19:16:27 -0700


Sounds like you have the power requirments under control, the 516H-1
is only used with the 618T-1 and -1B

These radios are still in service on a few aircraft and flying every
day. Collins still maintains them in the Atlanta service center. If
you plan to keep one on the air you will need to be able to perform
all the maintainance yourself.  Just the labor alone to have someone
else service the rig will exceed the cost of a new rice box!  There
are ton's of adjustments in the radio and with out proper
documantation, experance, and a bench full of test equipment you will
quickly have a pile of junk and a radio that will not lock on
frequency.  

As for the TTL chips these were only used in the "B" versions
(618-1B,-2B,-3B). The VFO was removed from the A12 RF translator
assy. and the KC Stab was replaced with a synthesizer.  The "B" radio
will also tune in 100Hz steps with the proper 714-(x) control box.

Good luck in returning this radio to the air
Lynn KB6OKS
Collins Seattle service center.  

---- Original Message ----
From: [email protected]
To: [email protected]
Subject: Re: [Collins] Re: collins 618T-3
Date: Tue, 08 Jul 2003 15:49:43 -0500

>400 w PEP SSB takes at least 800 w PEP input to the PA plate. More 
>with
>the compact continuous tuning tank circuits in the 618T PA. 100 W
>carrier AM is 400 W PEP. That drawer full of 60's vintage TTL logic
>takes quite a few watts as do the servo amps and the RF driver 
>section.
>28 volts at 35 amps is 980 watts. Marginal at best with little room 
>for
>those necessities and the inverter inefficiency. I'd figure on 45 
>amps
>not 35 amps. Or just run it on a pair of well charged batteries and 
>let
>the current be supplied as it may.
>
>I had an opportunity to work with that MARS 618T, didn't see that it 
>was
>a benefit to my station or the program and let KD6E tackle it. He did
>get one on the air, but had to work unreasonably regularly to find 
>and
>replace failing flat pack TTL SUHL chips to keep it on the air.
>
>Besides the control cables, one needs the extender cables for each
>module and then the extender cards or cable for each subassembly or 
>the
>Collins module and subassembly test stands.
>
>73, Jerry, K0CQ, Technical Advisor to the CRA.
>-- 
>Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
>Reproduction by permission only.
>Sponsored by the Collins Radio Association
>http://www.collinsra.com
>