[Johnson] T/R relay

[Carl]

There arent enough parts in the switch to make it an involved fix. Id 
suspect a 6BL8 with H-K leakage to start. A leaky electrolytic followed by 
an arcover in the 6X4 to be an excellent cause of fried transformers.

Carl
KM1H


----- Original Message ----- 
From: "Charles Ring" <w3nu at roadrunner.com>
To: "Bill Cromwell" <wrcromwell at gmail.com>
Cc: <johnson at mailman.qth.net>
Sent: Wednesday, July 10, 2013 11:40 PM
Subject: Re: [Johnson] T/R relay


>
> On 7/10/2013 2326, Bill Cromwell wrote:
>> On 07/10/2013 11:00 PM, Charles Ring wrote:
>>> I have used the 250-39 Johnson T/R switch since 1967. I've had 3 of them 
>>> and the power transformer on two of those have failed. Since returning 
>>> to the air a year ago I've been using one with my Globe King 500A and 
>>> Drake R-4C.  It works, but unlike long ago, I can't get full QSK. The 
>>> receiver is being badly desensed. I don't remember if it did better then 
>>> with the R-4C or if that was only with the 2-C and the R-4B, both of 
>>> which are waiting for repairs. I am interested in changing to either a 
>>> fast relay or a PIN diode switch. I seldom do faster than 25WPM.
>>>
>>> 73 de W3NU
>> Hi Charles,
>>
>> My Johnson Ranger has an issue with a reduced but still present plate 
>> current flowing with the key up. Using the Johnson T-R switch I can hear 
>> the "diode noise" in the receiver. Right now I suspect a wiring change 
>> sometime in the past or a defective part allowing that plate current. I 
>> have been piecemeal reworking/refurbing the Ranger. The manual says there 
>> should be no plate current with the key up in the CW mode but there is. 
>> Up to me to find out why. I am using the open frame relay with the Ranger 
>> until I resolve that issue - and no QSK.
>>
>> Is your TX final amp cutoff with the key up? One possible source of your 
>> trouble.
>>
>> 73,
>>
>> Bill  KU8H
>>
>
> Nothing shows on the meter. I do sometimes get some diode noise but that's 
> a separate thing. When I key the transmitter the R-4C is so desensed that 
> I do not hear myself in the receiver (unless I detune the preselector 
> some) and have to rely on keyer sidetone. It recovers but not fast enough 
> for real QSK.
>
> -- 
> *Charles Ring W3NU*
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