[R-390] R390-A Contract Choices. should be C227

[Bob Camp]

Hi

Well that last message really went out on the wrong thread ... sorry 
about that!

	Bob Camp
	KB8TQ

On Mar 29, 2005, at 7:16 AM, Bob Camp wrote:

> Hi
>
> To answer the second part of your question.
>
> The 47 pf cap is there to take care of the inductance of the chassis 
> mount cap that is on the cathode. Apparently they found that some of 
> the parts were not low enough impedance at the high end of the band. 
> Fixing the problem isn't quite as easy as it looks. You want to be 
> sure you don't create a parallel resonant circuit between the two 
> caps. Normal advice on bypass caps is not to worry to much about 
> values as long as they are higher than what is specified. This is one 
> place where the normal advice doesn't apply ..
>
> 	Take Care
>
> 		Bob Camp
> 		KB8TQ
>
>
> On Mar 28, 2005, at 11:04 PM, Flowertime01 at wmconnect.com wrote:
>
>> In a message dated 3/28/05 3:05:48 PM Eastern Standard Time, 
>> K4HCA at alltel.net
>> writes:
>>
>> I have been looking for an R-390A for last few months. Question; 
>> Apparently,
>> these fine receivers were manufactured by several (?) different 
>> companies.
>>> From those of you who have had experience with them, are receivers 
>>> manufactured
>> by one particular company more desirable as a restoration project than
>> another? Or, put more simply, if one had a choice, which one would 
>> you recommend?
>>
>> Many thanks,
>>
>> Harold
>>
>> __________________
>>
>> Back when (68-75) we had the receivers by the hundreds. We considered 
>> them
>> all equal. They were all alike inside and out side. There were 
>> differences (wire
>> harness, cosmo PTO). Some gear trains ran better than others but any 
>> and all
>> receivers would work to specifications.
>>
>> We did not go out of our way to swap modules around but it did 
>> happen. If you
>> get one that mostly matches inside, you make consider buying some 
>> lottery
>> tickets. Fair Radio is selling working receiver for $600.00.
>>
>> Watch the meters. Some receivers had glow in the dark paint on the 
>> meter
>> face. Some tree huggers though us fellows would be licking the paint 
>> on our meter
>> faces or throwing R390/A in the land fill. Many receivers had the 
>> meters
>> pulled before they went to salvage sale. The cost of replacement 
>> meters with
>> "acceptable" interior paint can drive the cost of a receiver up.
>>
>> The state of the tube set can increase the price. Consider what it is 
>> going
>> to cost to replace a set of tubes.
>>
>> The next real cost is the work that has been done on the receiver. A 
>> simple
>> semi annual preventive maintenance cleaning and alignment performed 
>> by a
>> skilled technician takes a minimum of 4 hours. Plan to spend all day 
>> Saturday twice
>> a year doing a cleaning, tube check and alignment on your receiver. 
>> Skilled
>> electronic techs are billing $20.00 $25.00 an hour for independent 
>> time. More if
>> they are supporting a commercial shop overhead. A real gear cleaning, 
>> panel
>> paint job, recap, audio deck rebuild (different cap values for better 
>> audio
>> sound) or other real repair can push the price of a receiver up over 
>> the 1,000
>> mark real easy.
>>
>> The 3 K item was a real stretch.
>>
>> Real deals are still being found real regular. Start shopping and do 
>> not pass
>> over any because of the perceived contract it come from. If its all 
>> there it
>> can be returned to full function. Some real care and it can out 
>> perform the
>> generic run. Super smooth gears trains are very doable. Better audio 
>> through
>> some audio deck changes. Better sensitivity through tube selection 
>> (not a lasting
>> change as tubes age). Better performance through some cap and resistor
>> changes.
>>
>> You may have to pay for work that has already been done. You can do 
>> the
>> needed work your self. There are several of us fellows on the 
>> reflector here who
>> will do work for you. Mostly you will select a local fellow to you as 
>> UPS can be
>> done but it cost. Crates and freight service is a pain to arrange and 
>> also
>> cost.
>>
>> You may already have an offer or two from the list for a receiver.
>>
>> Let us know what you find. Let us know what problems you find in the 
>> receiver.
>>
>> Happy Operating
>>
>> Roger KC6TRU
>>
>>
>>
>>
>>
>>
>>
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>