[R-390] Diode load

[Bob Camp]

Hi

Pulling off the weird mods is always a good idea. Once you get that done, think more and do less. Wholesale 
"replace all of this" and "re-do ever one of those" that is rarely a good idea on day one (if ever). Work your way from the speaker towards 
the antenna. Verify that each part of the radio is working, but don’t go crazy getting any one part “perfect” until 
the whole thing works to some degree. The bits and pieces interact with each other….

One example is running tubes through a tube tester. It will give you good data to think about, but unless you find one
that is just plain dead, it’s only food for thought. Note which one is which and how good/ bad they seem to be on the tester. 
If the tester *and* the circuit performance say the tube has issues, swap it out (swap out does not equal throw out ..). More 
thought, more analysis, more research in the manuals, less changing things around …

Bob


> On Mar 26, 2015, at 9:32 PM, K7iou1 <k7iou1 at gmail.com> wrote:
> 
> Hi Larry, just got done checking the 1st and 2nd oscillators and both are correct. Looks like a serious alignment is needed. Someone's been in there before as the transformer covers are reversed from 1st & 2nd oscillator circuits with notes in the manual.
> 15 MHz is dead on.
> 28 MHz 400k off
> 7.293 MHz 8.295 1.003 MHz off
> Other bands little or no receive.
> I will use Cramolin, Deoxit on all tube sockets & connections. Previously used it on module  harness plugs.
> Audio working. SSB rectifier removed.
> Thanks to all for your help.
> de k7iou
> 
> On Mar 26, 2015, at 4:31 PM, Larry H <dinlarh at att.net> wrote:
> 
> Hi David,  If the 2nd xtal osc is off a lot, check its switch alignment.
> 
> Regards, Larry
> 
> From: Larry H <dinlarh at att.net>
> To: K7iou1 <k7iou1 at gmail.com> 
> Sent: Thursday, March 26, 2015 1:23 PM
> Subject: Re: [R-390] Diode load
> 
> Hi David,  Good and BAD news.  As for the diode load Navy mod - Make sure that the center conductor of the coax does not touch anything.  It sounds like its ok now.
> 
> As for the off freq, check the 17mc osc frequency - you can disconnect the mini coax j221 and feed it to rx or counter.  If its very close its fine.  If good, try the 2nd osc at j415.  Since its been sitting for a while, you could be a victim of 'bad contacts' due to corrosion.  Wiggling and /or removing and replacing tubes and crystals can sometimes resolve these issues.  If you use a deoxit, be very careful in application - use a Q tip.  Spraying can be a problem.
> 
> Also,  you should check the filter killer cap c553 asap.
> 
> Regards, Larry
> 
> 
> 
> From: K7iou1 <k7iou1 at gmail.com>
> To: Larry H <dinlarh at att.net> 
> Sent: Thursday, March 26, 2015 12:58 PM
> Subject: Re: [R-390] Diode load
> 
> Yes, I did that and audio is now working but...,
> 
> Slow progress, I found it receiving on 11M with audio but signals received are low.
> Carrier Meter adjust full clockwise, top of chassis.
> Gain adjust full counter clockwise, top of chassis.
> 
> My Icom receive freq. 27.025 guy running excessive power as you could hear the transmitter grown and the ring when he PTT. Indicated receive Frequency R-390A was 28.985
> I then tried 40M Icom 7.293 and hit transmit while hunting for it and with BFO on I heard it ring at 8.805. With BFO off I would only heard a slight pass through.
> Ideas?
> 
> 
> 
> On Mar 26, 2015, at 12:50 PM, Larry H <dinlarh at att.net> wrote:
> 
> Hi David,  I looked at the mod schematic you posted and see no mention of changing the need for the 14-15 jumper for diode load.  The audio mod looks good to me.  I'd install the jumper and see.
> 
> And no I don't think the audio agc gadget could hurt anything if it shorted.
> 
> Regards, Larry
> 
> From: K7iou1 <k7iou1 at gmail.com>
> To: "R-390 at mailman.qth.net" <R-390 at mailman.qth.net> 
> Sent: Thursday, March 26, 2015 10:24 AM
> Subject: [R-390] Diode load
> 
> Previous owner did a audio mod.
> The jumper for diode load is out but with his mod I don't know if I can install the jumper. 
> I posted it here on AMfone
> http://amfone.net/Amforum/index.php?topic=38117.0
> Schematic of mod at bottom of my last post.
> 73
> de k7iou
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