[R-390] R-390 Digest, Vol 82, Issue 1

Wed Feb 2 03:28:44 EST 2011

Hallo Bob, it is always the same. The B+ voltage is way too high, after that 
modification in the power supply, I experienced this with an original 
Collins, which was field changed this way. You have to determine, which cap 
is gone, but before - please - restitute the 26Z5W's, they last for years! 
Mine are from 1967, still going strong, and the EAC R-390A never ever 
complained. Best regards, Johannes, Bavaria, Germany.
prof.johannes.fischer at t-online.de
----- Original Message ----- 
From: <r-390-request at mailman.qth.net>
To: <r-390 at mailman.qth.net>
Sent: Tuesday, February 01, 2011 6:00 PM
Subject: R-390 Digest, Vol 82, Issue 1


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> Today's Topics:
>
>   1. R390-A problem (Robert Young)
>   2. Re: query re ground loop (Tisha Hayes)
>   3. Re: R390-A problem (Robert Moses)
>   4. Re: R390-A problem (Robert Fish)
>   5. Re: R390-A problem (Shoppa, Tim)
>   6. Re: R390-A problem (Gord Hayward)
>   7. Re: R390-A problem (Robert Moses)
>   8. Re: R390-A problem (Barry Williams)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 31 Jan 2011 12:21:15 -0500
> From: Robert Young <youngbob53 at msn.com>
> Subject: [R-390] R390-A problem
> To: r-390 <r-390 at mailman.qth.net>
> Message-ID: <COL122-W429D3D8779262A1E48E189C6E20 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> Hello all,
>
> The radio works normally then after about a ten minute warm up the volume 
> jumps up maybe double (normal listing level with local gain on 0) and 120 
> cycle hum is audible. If I click it from AGC to standby or AGC to 
> calibrate and back it drops down to normal volume again for a few seconds 
> then goes back up, it's almost like something is not conducting and needs 
> a little voltage spurt to get going again. This was intermittent when it 
> first started a few years ago but is now predictable although it was 
> sometimes go back to normal by itself. Everything else is the same either 
> way, just the volume jumps up (I have to turn down the RF control to get 
> it silenced) AGC seems to be working normally. This radio was restored by 
> Chuck Ripple about 5 years ago and i have changed some tubes since then 
> but have pretty much left it alone besides tubes, it works great except 
> for this little annoyance. The power supply was solid stated by him. I'm 
> wondering if a cap in the audio chain is on it's
>  way out. I have another audio module but it's inaccessible right now. I 
> suspect something in the audio section, anyone have any ideas?
>
> Bob Young
> KB1OKL
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 31 Jan 2011 12:14:47 -0600
> From: Tisha Hayes <tisha.hayes at gmail.com>
> Subject: Re: [R-390] query re ground loop
> To: r-390 at mailman.qth.net
> Message-ID:
> <AANLkTikNYLAQMgsynj8dLsRUgnTuDbd_V4Mprvy0+xap at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> With the switchover to a two prong connector you have pretty much narrowed
> it down to a ground loop.
>
> In the circuit box the neutral (white) and ground (bare or green) wires 
> will
> be bonded together. It they are also bonded together in the radio chassis 
> it
> is a ground loop but not one that I would have expected to be noticeable.
>
> Ideally the hot and neutral conductor in the radio should go to the line
> filter, power switch and power transformer only. The ground wire should go
> to the chassis.
>
> If this problem recently appeared you may have "something" in the receiver
> that is leaking to chassis ground. Since you are getting by with a two 
> wire
> adapter the radio can function but it still is not a good thing. Try to 
> use
> a voltmeter to measure the potential between chassis ground and the
> grounding pin at the outlet.
>
> I will give an example on why you do not want to let this go on 
> unaddressed;
> My Dell laptop power supply was attached to the wall when I took a 
> lightning
> strike at the house. The laptop was not attached at the time and when I
> plugged it in things worked fine. One unpleasant experience was that the
> plug to my laptop suddenly had a partial AC potential on the barrel of the
> connector. It was not an issue unless I swapped laptops from my personal
> D800 (plastic case) to my work laptop with a metal case. If I was using 
> the
> laptop in my "lap" (on bare legs) it would give me an unpleasant shock.
>
> Being naturally lazy I put it low on my priority list of things to 
> replace.
> I just learned to use something as an insulator between leg and laptop.
>
> The downside was that the problem in the power supply did not get better.
> Finally this last fall it went into a full fault and put 120 VAC on the
> laptop and blew out the motherboard on the laptop when I plugged into an
> external monitor.
>
> I suggest trying to figure out exactly what is causing the hum on the 
> radio
> before you (or your child, spouse, dog, etc..) completes the circuit to
> ground.
>
> -- 
> Ms. Tisha Hayes/ AA4HA
> ----------------
> "I'll be a diode, cathode, electrode
> Overload, generator, oscillator
> Make a circuit with me." -- The Polecats
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 31 Jan 2011 11:21:11 -0700
> From: Robert Moses <rhmoses at earthlink.net>
> Subject: Re: [R-390] R390-A problem
> To: R-390 at mailman.qth.net
> Message-ID: <4D46FD97.6070507 at earthlink.net>
> Content-Type: text/plain; charset=us-ascii; format=flowed
>
> It sounds like it's time for freeze spray.
>
> Robert Young wrote:
>
>>Hello all,
>>
>>The radio works normally then after about a ten minute warm up the volume 
>>jumps up maybe double (normal listing level with local gain on 0) and 120 
>>cycle hum is audible. If I click it from AGC to standby or AGC to 
>>calibrate and back it drops down to normal volume again for a few seconds 
>>then goes back up, it's almost like something is not conducting and needs 
>>a little voltage spurt to get going again. This was intermittent when it 
>>first started a few years ago but is now predictable although it was 
>>sometimes go back to normal by itself. Everything else is the same either 
>>way, just the volume jumps up (I have to turn down the RF control to get 
>>it silenced) AGC seems to be working normally. This radio was restored by 
>>Chuck Ripple about 5 years ago and i have changed some tubes since then 
>>but have pretty much left it alone besides tubes, it works great except 
>>for this little annoyance. The power supply was solid stated by him. I'm 
>>wondering if a cap in the audio chain is on it'
> s
>>  way out. I have another audio module but it's inaccessible right now. I 
>> suspect something in the audio section, anyone have any ideas?
>>
>>Bob Young
>>KB1OKL
>>
>>______________________________________________________________
>>R-390 mailing list
>>Home: http://mailman.qth.net/mailman/listinfo/r-390
>>Help: http://mailman.qth.net/mmfaq.htm
>>Post: mailto:R-390 at mailman.qth.net
>>
>>This list hosted by: http://www.qsl.net
>>Please help support this email list: http://www.qsl.net/donate.html
>>
>>
>>
>
>
>
> ------------------------------
>
> Message: 4
> Date: Mon, 31 Jan 2011 10:23:13 -0800
> From: Robert Fish <rwfish at comcast.net>
> Subject: Re: [R-390] R390-A problem
> To: Robert Moses <rhmoses at earthlink.net>, R-390 at mailman.qth.net
> Message-ID: <4D46FE11.90104 at comcast.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Technician in a can!
>
>> It sounds like it's time for freeze spray.
>>
>> Robert Young wrote:
>>
>>> Hello all,
>>>
>>> The radio works normally then after about a ten minute warm up the 
>>> volume jumps up maybe double (normal listing level with local gain on 0) 
>>> and 120 cycle hum is audible. If I click it from AGC to standby or AGC 
>>> to calibrate and back it drops down to normal volume again for a few 
>>> seconds then goes back up, it's almost like something is not conducting 
>>> and needs a little voltage spurt to get going again. This was 
>>> intermittent when it first started a few years ago but is now 
>>> predictable although it was sometimes go back to normal by itself. 
>>> Everything else is the same either way, just the volume jumps up (I have 
>>> to turn down the RF control to get it silenced) AGC seems to be working 
>>> normally. This radio was restored by Chuck Ripple about 5 years ago and 
>>> i have changed some tubes since then but have pretty much left it alone 
>>> besides tubes, it works great except for this little annoyance. The 
>>> power supply was solid stated by him. I'm wondering if a cap in the 
>>> audio chain is on i
> t'
>>   s
>>>   way out. I have another audio module but it's inaccessible right now. 
>>> I suspect something in the audio section, anyone have any ideas?
>>>
>>> Bob Young
>>> KB1OKL
>>>
>>> ______________________________________________________________
>>> R-390 mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:R-390 at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>>
>>>
>> ______________________________________________________________
>> R-390 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:R-390 at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>>
>
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Mon, 31 Jan 2011 13:35:34 -0500
> From: "Shoppa, Tim" <tshoppa at wmata.com>
> Subject: Re: [R-390] R390-A problem
> To: Robert Young <youngbob53 at msn.com>, r-390 <r-390 at mailman.qth.net>
> Message-ID:
> <B136EDE3DF5EC441B6F08E0A7AB872450BADD0B69D at EX2K7-CMS-1.wmata.local>
> Content-Type: text/plain; charset="us-ascii"
>
> Sounds like cathode to filament short (hum is the smoking gun but the gain 
> shift is telltale too). These are often intermittent. Switching to or 
> through standby interrupts B+.
>
> Most likely it's any of the 5814A's and I'm guessing somewhere after the 
> detector.
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net] 
> On Behalf Of Robert Young
> Sent: Monday, January 31, 2011 12:21 PM
> To: r-390
> Subject: [R-390] R390-A problem
>
>
> Hello all,
>
> The radio works normally then after about a ten minute warm up the volume 
> jumps up maybe double (normal listing level with local gain on 0) and 120 
> cycle hum is audible. If I click it from AGC to standby or AGC to 
> calibrate and back it drops down to normal volume again for a few seconds 
> then goes back up, it's almost like something is not conducting and needs 
> a little voltage spurt to get going again. This was intermittent when it 
> first started a few years ago but is now predictable although it was 
> sometimes go back to normal by itself. Everything else is the same either 
> way, just the volume jumps up (I have to turn down the RF control to get 
> it silenced) AGC seems to be working normally. This radio was restored by 
> Chuck Ripple about 5 years ago and i have changed some tubes since then 
> but have pretty much left it alone besides tubes, it works great except 
> for this little annoyance. The power supply was solid stated by him. I'm 
> wondering if a cap in the audio chain is on it's
>  way out. I have another audio module but it's inaccessible right now. I 
> suspect something in the audio section, anyone have any ideas?
>
> Bob Young
> KB1OKL
>
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
> ------------------------------
>
> Message: 6
> Date: Mon, 31 Jan 2011 13:44:16 -0500
> From: Gord Hayward <ghayward at uoguelph.ca>
> Subject: Re: [R-390] R390-A problem
> To: r-390 <r-390 at mailman.qth.net>
> Message-ID: <4D470300.9000308 at uoguelph.ca>
> Content-Type: text/plain; charset=us-ascii; format=flowed
>
>>
>>
>>Sounds like cathode to filament short (hum is the smoking gun but the gain 
>>shift is telltale too). These are often intermittent. Switching to or 
>>through standby interrupts B+.
>>
> I had that happen in the limiter (limiter switched off gave no problem).
> Swapping tubes is the best diagnostic as my tube tester didn't catch the
> fault.
> Cheers de Gord, VE3EOS.
>
> -- 
>
> Gordon L. Hayward, Ph.D., P.Eng.,
> Associate Professor, Biological Engineering,
> School of Engineering, University of Guelph,
> Guelph, Ontario, N1G 2W1.
>
>
>
>
> ------------------------------
>
> Message: 7
> Date: Mon, 31 Jan 2011 15:37:50 -0700
> From: Robert Moses <rhmoses at earthlink.net>
> Subject: Re: [R-390] R390-A problem
> To: R-390 at mailman.qth.net
> Message-ID: <4D4739BE.8090507 at earthlink.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> An insulated stick is also useful for poking around to find parts that
> are cracked or poorly soldered.
>
> Robert Fish wrote:
>
>> Technician in a can!
>>
>>> It sounds like it's time for freeze spray.
>>>
>>> Robert Young wrote:
>>>
>>>> Hello all,
>>>>
>>>> The radio works normally then after about a ten minute warm up the
>>>> volume jumps up maybe double (normal listing level with local gain
>>>> on 0) and 120 cycle hum is audible. If I click it from AGC to
>>>> standby or AGC to calibrate and back it drops down to normal volume
>>>> again for a few seconds then goes back up, it's almost like
>>>> something is not conducting and needs a little voltage spurt to get
>>>> going again. This was intermittent when it first started a few years
>>>> ago but is now predictable although it was sometimes go back to
>>>> normal by itself. Everything else is the same either way, just the
>>>> volume jumps up (I have to turn down the RF control to get it
>>>> silenced) AGC seems to be working normally. This radio was restored
>>>> by Chuck Ripple about 5 years ago and i have changed some tubes
>>>> since then but have pretty much left it alone besides tubes, it
>>>> works great except for this little annoyance. The power supply was
>>>> solid stated by him. I'm wondering if a cap in the audio chain is on
>>>> it'
>>>
>>>   s
>>>
>>>>   way out. I have another audio module but it's inaccessible right
>>>> now. I suspect something in the audio section, anyone have any ideas?
>>>>
>>>> Bob Young
>>>> KB1OKL
>>>>
>>>> ______________________________________________________________
>>>> R-390 mailing list
>>>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>> Post: mailto:R-390 at mailman.qth.net
>>>>
>>>> This list hosted by: http://www.qsl.net
>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>>
>>>>
>>>>
>>> ______________________________________________________________
>>> R-390 mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:R-390 at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>>
>>
>>
>>
>>
>
>
>
> ------------------------------
>
> Message: 8
> Date: Mon, 31 Jan 2011 20:29:44 -0600
> From: Barry Williams <ba.williams at charter.net>
> Subject: Re: [R-390] R390-A problem
> To: r-390 at mailman.qth.net
> Message-ID: <4D477018.7010503 at charter.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Bob,
>
> I'm certainly no expert but could it be the function switch? Mine has
> done the same thing as yours for more than 15 years. I've been too lazy,
> over worked, or unorganized to check it out. Mine will regain audio by
> going to any other switch position most of the time. The off function
> hasn't worked the whole time of this, but it works to get the audio
> strength back.
>
>
>
> Barry
>
>
>> An insulated stick is also useful for poking around to find parts that
>> are cracked or poorly soldered.
>>
>> Robert Fish wrote:
>>
>>> Technician in a can!
>>>
>>>> It sounds like it's time for freeze spray.
>>>>
>>>> Robert Young wrote:
>>>>
>>>>> Hello all,
>>>>>
>>>>> The radio works normally then after about a ten minute warm up the
>>>>> volume jumps up maybe double (normal listing level with local gain
>>>>> on 0) and 120 cycle hum is audible. If I click it from AGC to
>>>>> standby or AGC to calibrate and back it drops down to normal volume
>>>>> again for a few seconds then goes back up, it's almost like
>>>>> something is not conducting and needs a little voltage spurt to get
>>>>> going again. This was intermittent when it first started a few years
>>>>> ago but is now predictable although it was sometimes go back to
>>>>> normal by itself. Everything else is the same either way, just the
>>>>> volume jumps up (I have to turn down the RF control to get it
>>>>> silenced) AGC seems to be working normally. This radio was restored
>>>>> by Chuck Ripple about 5 years ago and i have changed some tubes
>>>>> since then but have pretty much left it alone besides tubes, it
>>>>> works great except for this little annoyance. The power supply was
>>>>> solid stated by him. I'm wondering if a cap in the audio chain is on
>>>>> it'
>>>>    s
>>>>
>>>>>    way out. I have another audio module but it's inaccessible right
>>>>> now. I suspect something in the audio section, anyone have any ideas?
>>>>>
>>>>> Bob Young
>>>>> KB1OKL
>>>>>
>
>
>
> ------------------------------
>
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> R-390 mailing list
> R-390 at mailman.qth.net
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>
> End of R-390 Digest, Vol 82, Issue 1
> ************************************