[Premium-Rx] Racal 3791 service Manual

[VK3XYZ]

Hi,
It's been a while since I looked at the RA379X stuff but this is what I can
recall (with a little help of popping the lid off again).
Depending on what options the receiver is fitted with will determine if you
have 2, 3 or 4 DSP fitted. All are the same part,  a DSP56002FC40. Either
one or both of DSP 3&4 may not be fitted ( the two socketed DSP). The pinout
of the PQFP and the PGA versions are different. To use the PQFP in place of
the PGA requires an adapter. Both the PGA and the adapter are hard to find
based on my previous attempts.

Fitting them will not necessarily give you any extra functions/capabilities.
It will depend on what firmware you have fitted and if  logic device PD6 is
fitted.

DSP 1: IC64 (furthest away when looking down with front panel aiming at
you). Audio input/output via CODEC 1.
DSP2: IC70 sigma delta ADC for the IF input and does AGC
DSP3: IC82 Does digital IF/AF for the RS422 interface
DSP4: IC91 (most forward when looking down with front panel aiming at you).
Connects to CODEC 2 (IC23) for audio in/out.
IC23: CODEC 2, TLC32044FCN. PLCC socket  top RH corner when looking down
with front panel aiming at you).
PD6:  KEY PLD (PLCC socket closest LH corner when looking down with front
panel aiming at you ), decryption  logic to allow certain features.

Having said all that if you have DSP1,2, and 4 with codec 2 then the
firmware I have on my data page,
http://members.iimetro.com.au/~gcd/data.html,  if I recall correctly - will
give you most of the options . I recall from the discussion that this
firmware is in most (all?)  379x post a certain date, I think it removed the
need for PD6 as well? There was some discussion on this a few years back,
you'll find it in the archives I'm sure.

If you fit DSP 3, note that the IF is only 32kHz bandwidth so it's not
really useful in my opinion.
Again from memory (check the archives) DSP 4 with CODEC 2 allow for ISB with
the above firmware.

Hope that helps somewhat.

Greg

-----Original Message-----
From: Premium-Rx [mailto:premium-rx-bounces at mailman.qth.net] On Behalf Of
premium-rx-request at mailman.qth.net
Sent: Saturday, 9 January 2016 6:50 AM
To: premium-rx at mailman.qth.net
Subject: Premium-Rx Digest, Vol 110, Issue 3


Today's Topics:

   1. Re: Utility Monitoring Receiver (David Schofield)
   2. Re: Utility Monitoring Receiver (sm0aom at telia.com)
   3. FS: DESKTOP RACK CABINET-HAMMOND RCBS1900717BK1 for premium
      receiver (Gilbert Harris)
   4. Re: Utility Monitoring Receiver (Clemens Paul)
   5. Racal 3791 service Manual (Mike Neese)

------------------------------

Message: 5
Date: Fri, 8 Jan 2016 13:49:39 -0600
From: Mike Neese <n46w726 at gmail.com>
To: premium-rx at mailman.qth.net
Subject: [Premium-Rx] Racal 3791 service Manual
Message-ID:
	<CAHTBMfB7oo7w5+2wB15Z4L5kW_HA+2tZq=m1Y3nLJKbZb-BVvQ at mail.gmail.com>
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hello all i recently purchased a Racal 3791 and I am looking for a service
Manual, I will pay what ever is a fair price!, my radio is complete except
for a Texas instrument processor chip that is used for the DSP noise
blanker. I would like to find out what that chip specifically is,and How to
get one to complete this radio. Any help will be highly appreciated thank
you!

73's Mike N.
N46w726 at gmail.com


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