[Premium-Rx] Collins 651S-1 advice sought

[Mac]

Most impressive Nick most,  i speak of your repair efforts and diligence 
to wade in and slog thru it all and yield the results you now have.. 
good job.

Nick i might have mentioned it in a private email,  but your web site 
and navy radio/speakers/receivers is superb.  i use it often to check 
out speakers and what i am trying to find and what you have, I like it 
..  thanx for being such a resource..

best:  mac/mc  w5mc

On 5/28/2019 5:56 AM, w3jn--- via Premium-Rx wrote:
> Nick, as you observe, troubleshooting these is pretty difficult without the extender cards - but it can be done and tacking test wires to the board is about the only way to do it.
> You may need both the DCU and DCFE cards, or at least one of them, because as I recall one of them replaces a board having a bunch of diodes and a few ICs that routes control lines around to account for different options, such as the VLF front end, filter daughterboard, squelch, ISB, etc.
> The boards should have those plastic levers on each edge, with the board nomenclature to aid in removal.  Card cage may have gotten a bit bent, not sure if you can loosen the front and back edges a bit so the cards slip in and out a bit easier.  I have not seen that problem (hard to extract cards) with any of those I've worked on.
> Your first step, since it has DCU and DCFE boards but the version number does not indicate remote control, is to go thru that big version table and verify you have the right version of *each* board for the radio.  Many of the cards have subtle differences to account for options.  This might be the issue with not tuning above 9.999 MHz.
> I have a bunch of 651S-1 boards, mostly unknown condition, but I can check them out IF the versions correspond to my 651S-1s and yours, and they're the right versions.  I also have a NOS S-meter, but yes there is a small light behind it and as I recall it's not all that easy to change (but neither is the meter!)
> Finally, the mod to disable the tuning mute is simple, there's a mute diode on the power supply board that you can lift one end, or cut the mute line trace.  It's strange that Collins routed the audio mute thru the PS board.
> Good luck, it's really a fantastic receiver, and I like it much better than my 51S-1.  It has outstanding audio, and just looks/feels "right".
> 73 John
>
>
> -----Original Message-----
> From: Nick England <navy.radio at gmail.com>
> To: Premium-Rx at mailman.qth.net <Premium-Rx at mailman.qth.net>
> Sent: Mon, May 27, 2019 8:28 pm
> Subject: [Premium-Rx] Collins 651S-1 advice sought
>
> In a fit of Xenia/Dayton sunstroke madness, I bought a 651S-1 receiver
> (Collins p/n 522-4836-152). Having heard about this receiver for years, I
> figured it would be interesting to have one and the price wasn't too
> outlandish.
> http://www.virhistory.com/ham/dayton-19/IMG_2584.JPG
>
> The seller said it worked and it does, mostly.
> Major issue so far - The 10's of MHz is stuck at 0 so it is fine up to 9.9999
> MHz. Both display and synth are stuck so the problem must be in the upper
> 2-bit counter circuit on the A14 board and I can probably figure that
> out with some scoping. I don't have an extender card, so I'll have to
> remove card, tack on a few wires, reinsert card, scope a bit, repeat as
> necessary.
> So - the questions -
> 1) What is the trick to pulling these cards out? I finally used a vise-grip at
> the corners of the A14 Freq Ctl Ckt Board, but I don't want to keep doing
> that and munge up the card.
> 2) What to my wondering eyes should appear but early flat-pack TTL and
> DTL logic.
> Is there any source for this stuff nowadays?
> 3) Is there any reason to keep the DCU and DCFE boards? I'm not going to ever
> try remote control and IF I get lucky, I might be able to rob a chip I need
> off them.
> Can I just pull these cards out or are there jumpers I need to fix? This is a
> -152 version receiver which the manuals say comes without DCU/DCFE
> 4) Does anyone have a junker A14 board? Want to trade for DCU/DCFE?
> 5) Does anyone have a spare cabinet? This is rack-mount unit with speaker, but
> no cabinet.
> 6) The meter is working but not lit - I assume there is a lamp inside there
> somewhere.
> 7) The USB signal is weak but working - so that's another board to scope
> out.
>
> All in all, it was a reasonable gamble and I think I'll have a good experience
> using it. The audio muting when changing frequency is odd, but I recall
> seeing a hint about defeating that. The fluorescent displays all work, but
> are dim. I may do the LED conversion some day but that's a future project.
>
> Cheers
> Nick