[R-390] R389 and R390 faults

[Barry Hauser]

Hi Mark, Rob

Not sure what comes first logically, but here goes:

First -- the R-390A Y2K manual on my website is the original, not revised 
version.  If that's what you need, suggest you go to Al Tirevold's site for 
the later version.

Second -- Rob is asking primarily about the R-389 & R-390 (without the A) --  
apparently, as the '389 is related to the '390, not the A. The Y2K manual on 
my website and Al's is strictly for the R-390A.

I am not that familiar with the R-389, but if the power supply and AF 
deck -- which is mostly power supply/regulation components is the same, same 
applies to both:  The 6082's throw a lot of heat.  The AF deck is mounted 
upside down so the heat rises and tends to cook the components under the 
chassis.  In particular, it is recommended to replace the 47 ohm resistors 
(4 of them I think) as per Dave Medley's advice.  In addition, it's a good 
idea to use a small fan set up to exhaust the heat from that side of the 
mainframe. R-390/URR's -- the pre-cost reduced edition -- do not exhibit the 
same capacitor failure patterns as the R-390A/URR's.  Component and tube 
compliment are very different.

AS for the counter knob on the BFO, they are not vernier/gear reduction 
drives, just counters which were added to improve reset-ability of the 
BFO -- unless someone also added a 10-1 reduction drive as well, but it's 
not part of the counter-knob mechanism.

hope this helps,
Barry



----- Original Message ----- 
From: "Mark Huss" <mhuss1 at bellatlantic.net>
To: "Rob Filby" <robsr390a at btopenworld.com>
Cc: <R-390 at mailman.qth.net>
Sent: Tuesday, March 21, 2006 2:02 PM
Subject: Re: [R-390] R389 and R390 faults


> First, you may want to reference the R-390A manual at 
> http://www.hausernet.com/r390a/
> It should have everything you need.  Pay particular attention to the 
> Capacitor replacement listing.  AWlso, for some reason, 2.2K resistors in 
> the R-390A's seem to change value considerably.  Otherwise, just watch the 
> list.  Good Luck.
>
> The counter knob on the BFO was added to R-390A's used for RTTY reception. 
> Makes tuning the BFO to FSK tones much easier.
> Rob Filby wrote:
>
>>Hi.
>>     I have recently bought an R389 and a pair of R390 rxs. They are all 
>> complete and in good condition.
>>At first appearance it seems as the PSU, Audio stage and IF strip are 
>>interchangable. I have a few questions which I would to ask the group and 
>>perhaps somebody could help me please.
>>
>>1.Were any parts listings produced for the above rxs, ie detailing the 
>>wattage of resistors and the voltage
>>ratings of other components?
>>
>>2.Are there any common faults or other troublesome components that fail or 
>>give trouble that I need to be
>>aware of?
>>
>>3. I have a couple of R390A rxs which have a mechanical counter for the 
>>BFO, why was this used over the standard knob?
>>
>>Thanks for your help
>>
>>Rob.  _____________________________________________________________
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>>
>
>
> -- 
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> in UFOs. This proves that men will believe almost anything if it comes 
> with really great gadgetry.-- Captain Ed --
>
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