[R-390] Delta ISB-1 SSB Converter

Tue Mar 7 10:17:51 EST 2006

Looking for any info on this unit. Aquired one with a broken meter. Would 
like to repair it,(need manual copy) and then use it with my non A to 
compare against my CV 591. I've run into a dead end on this. Apparently few 
made it into the civilian market. Rick K8PJQ CCA 11437 rdavis7 at comcast.net
----- Original Message ----- 
From: <r-390-request at mailman.qth.net>
To: <r-390 at mailman.qth.net>
Sent: Tuesday, March 07, 2006 4:01 AM
Subject: R-390 Digest, Vol 23, Issue 9


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> Today's Topics:
>
>   1. Bad resistors - the saga continues (n4buq at knology.net)
>   2. Leitch Meter-Matic VTVM? (n4buq at knology.net)
>   3. RE: 6BJ6/6BH6 sub (David Wise)
>   4. RE: 5 khz difference? (David Wise)
>   5. RE: Corrector plate PTO's, was Re: Another "Close to
>      Perfect"R-390a (David Wise)
>   6. Current Requirement for R-390 Regulated B+? (Tom Norris)
>   7. A bit more on my IF deck (Barry)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: 6 Mar 2006 15:32:07 -0000
> From: "n4buq at knology.net" <n4buq at knology.net>
> Subject: [R-390] Bad resistors - the saga continues
> To: R-390 at mailman.qth.net
> Message-ID: <20060306153207.9285.qmail at webmail1.knology.net>
> Content-Type: text/plain; charset=iso-8859-1
>
> While replacing the 27K resistors last night (and breaking one of those
> little two-pronged standoff which fortunately I had a replacement for but
> that's another story), I found R544 (2.7M in the AGC circuitry) to be
> completely open (or higher than the 30M my meter can detect).  I wonder
> what the effect this had on the operation of the radio?  I'm going to
> replace it, but was just wondering what function this resistor provides.
>
> V506A's plate resistor, R549, was on the high side of it's tolerance (82K
> gone to 90K), but it was easy to get to and since one end had to be lifted
> to replace one of the 27K's, it's getting replaced too.  I also wonder 
> what
> effect (if any) this would make on the operation of the radio.  Slight
> difference in AGC voltages?
>
> Thanks,
>
> Barry - N4BUQ
>
>
> ------------------------------
>
> Message: 2
> Date: 6 Mar 2006 19:18:24 -0000
> From: "n4buq at knology.net" <n4buq at knology.net>
> Subject: [R-390] Leitch Meter-Matic VTVM?
> To: R-390 at mailman.qth.net
> Message-ID: <20060306191824.10140.qmail at webmail1.knology.net>
> Content-Type: text/plain; charset=iso-8859-1
>
> I wonder if anyone on this list has ever seen or used a Leitch Meter-Matic
> VTVM?  It is an autoranging meter that looks to have been manufactured in
> the '50s.  Nice, big, big meter with little lamps to indicate the range
> that is selected.  It uses a stepper relay to determine the range.
>
> I haven't found any info on it on Google and wondered if any of you gents
> know anything about it.  BTW, it's a model 20-55.
>
> Leitch Engineering Corporation
> 326 Lincoln Street
> Manchester, New Hampshire, U.S.A
> Telephone 3-4773 (<- one indication of the age of this thing)
>
> Thanks!
>
> Barry - N4BUQ
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 6 Mar 2006 14:25:36 -0800
> From: "David Wise" <David_Wise at Phoenix.com>
> Subject: RE: [R-390] 6BJ6/6BH6 sub
> To: <r-390 at mailman.qth.net>
> Message-ID:
> <AE05136670F5E94999252FFD798B67AD02406B at hil-exch2k3.phoenix.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Affirmative, strong-signal performance will be suboptimal, with
> increased vulnerability to overload and cross-modulation.
> If it takes less AGC than normal to achieve a given gain (the
> case with a 6BH6 sub), then the front end is running hotter
> than intended, which means it takes less signal to drive them positive.
> Your carrier meter will also read low.
>
> The "3D" in your copy of my old post is the tilde character, meaning 
> "approximately".
> Most of those tubes can't be compared apples-to-apples from the specs,
> as some are tabulated for a given plate current, others for a given
> transconductance.  (It would be possible to get closer with many
> models of transconductance tube tester.)  I only meant to list all the 
> ones
> I could find that would operate, with no implication that they would do 
> well.
> It seems odd to me that the 6DC6 is less than abundant; it was made for 
> TV's.
>
> 73,
> Dave
>
>> -----Original Message-----
>> From: r-390-bounces at mailman.qth.net
>> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of n4buq at knology.net
>> Sent: Tuesday, February 28, 2006 11:52 AM
>> To: r-390 at mailman.qth.net
>> Subject: Re: [R-390] 6BJ6/6BH6 sub
>>
>>
>> Okay.  I had them reversed.  I thought that didn't make
>> sense, but now it
>> does.
>>
>> Thanks!
>>
>> Barry
>>
>> On Tue, 28 Feb 2006 14:23:37 -0500, "Tim  Shoppa" <tshoppa at wmata.com>
>> wrote :
>>
>> > > Okay, now it's time to educate me on this issue.  If the 6BH6 is a
>> > remote
>> > > cutoff tube, then it won't go into cutoff as "early" as the sharp
>> > cutoff
>> > > 6BJ6, right?
>> >
>> > Other way around: 6BJ6 is remote cutoff, 6BH6 is sharp cutoff.
>> >
>> > The 6BJ6 was the original IF tube. 6BH6 is the sub.
>> >
>> > >  If that's the case, then why will you see distortion on strong
>> > > signals with the remote cutoff tube?
>> >
>> > Actually either will distort with very strong signals. And when
>> > you're subbing around it's likely that biases etc will be quite
>> > unoptimal for critical use.
>> >
>> > Tim.
>> > _____________________________________________________________
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>> >
>> >
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>
>
> ------------------------------
>
> Message: 4
> Date: Mon, 6 Mar 2006 14:49:54 -0800
> From: "David Wise" <David_Wise at Phoenix.com>
> Subject: RE: [R-390] 5 khz difference?
> To: <r-390 at mailman.qth.net>
> Message-ID:
> <AE05136670F5E94999252FFD798B67AD02406C at hil-exch2k3.phoenix.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Ahem.  8MHz and above does not use the 17MHz oscillator,
> so your frequency counter observation completely accounts
> for the discrepancy.  Maybe someone else can say whether
> 5kHz is small enough to be correctable and big enough to bother.
>
> 73,
> Dave
>
>> -----Original Message-----
>> From: r-390-bounces at mailman.qth.net
>> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of Masters Andy
>> Sent: Tuesday, February 28, 2006 2:55 PM
>> To: r-390 at mailman.qth.net
>> Subject: [R-390] 5 khz difference?
>>
>>
>> Good evening.  I have an EAC-67 series R-390A that I
>> am working through and learning about R-390A's in the
>> process.
>>
>> Using a recently cal'd counter, I was able to set my
>> BFO for top dead center on 455khz and it tracks +/- 3
>> khz nicely as indicated by the ticks on the panel. I
>> also adjusted the crystal calibrator by counting it on
>> frequency at 200 khz.  It stays put rather nicely as
>> well.
>>
>> Having done this, I then went through all the bands to
>> have a look at dial calibration and have discovered
>> that .5-8.0 mhz, the dial reads 5 khz low on each band
>> but on the higher bands it is relatively dead on. (or
>> it might be said it can be set dead on using the Zero
>> Adjust for the lower freqs and is actually 5khz high
>> on the higher ones).  In any event, what gives here
>> and why the disparity? I first thought it might be my
>> 17 Mhz oscillator.  When I count the 17 mhz oscillator
>> it indicates it is 4.790 khz low on all bands .5
>> through 8 mhz.  After 8 mhz, it changes, but I can't
>> get an accurate read on its error.  I don't see a way
>> to "warp" the 17 mhz crystal on but I am not convinced
>> that is the problem or that there is only one problem.
>>  Any suggestions?
>>
>> Thanks,
>>
>> Dutch Masters NU5O
>>
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>
>
> ------------------------------
>
> Message: 5
> Date: Mon, 6 Mar 2006 16:22:58 -0800
> From: "David Wise" <David_Wise at Phoenix.com>
> Subject: RE: [R-390] Corrector plate PTO's, was Re: Another "Close to
> Perfect"R-390a
> To: <r-390 at mailman.qth.net>
> Message-ID:
> <AE05136670F5E94999252FFD798B67AD024070 at hil-exch2k3.phoenix.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Caveat: I have linearized one Collins R-390A corrector plate PTO.
>
> I can't remember the range of correction.  There is a very real
> limit on rate of change of correction.  If there's a valley, it
> has to be wider than the follower, or it will never touch bottom.
> The plates slide individually quite well, as each pair is separated
> by a thin stationary finger.  A thumbnail is a pretty good tool
> for sliding individual plates.  Just thin enough and stiff enough,
> and always handy :)
>
> Dave
>
>> -----Original Message-----
>> From: r-390-bounces at mailman.qth.net
>> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of Tim Shoppa
>> Sent: Thursday, March 02, 2006 7:58 AM
>> To: r-390 at mailman.qth.net
>> Subject: [R-390] Corrector plate PTO's, was Re: Another "Close to
>> Perfect"R-390a
>>
>>
>> > The R-389 PTO is type 70H-1 (not 70H-2  or 70H-12).  It makes FIFTY
>> turns
>> > not 10 turns end to end. It is rumored to have been the
>> most difficult
>> PTO
>> > Collins ever made. I assume that they were all made at Collins, not
>> > contracted out.
>>
>> I just googled for "R-389" and PTO and found Don Reave's pictures
>> of the internals of a 70H-1. Except for the corrector plate stack
>> it looks a lot like the innards of my 390A Cosmos PTO's (some
>> of the parts look to be identical or at least the same series) and
>> elements of the chassis look very similar too (including those
>> dessicant packs even!)
>>
>> Silly questions about corrector plates (my very limited experience
>> is with Cosmos-style PTO's):
>>
>> What's the typical "range" of correction? It looks like a little
>> less than 1/4 of a turn is max (although typical seems to be far less
>> and obviously
>> you can't go too far from one correction plate to the other.)
>>
>> Are the plates "slidable" to the correction, or is each
>> correction plate
>> machined to provide exactly that correction? If they're slidable it
>> looks like it'd be tricky to slide one without disturbing
>> others in the
>> stack... If they're not slidable it would seem that re-linearizing
>> would require either a machine shop or a large supply of
>> assorted corrector plates.
>>
>> Tim.
>> __
>
>
> ------------------------------
>
> Message: 6
> Date: Mon, 6 Mar 2006 22:36:49 -0600
> From: Tom Norris <r390a at bellsouth.net>
> Subject: [R-390] Current Requirement for R-390 Regulated B+?
> To: r-390 at mailman.qth.net
> Message-ID: <1343CB0E-5244-468F-8EC5-7CF2E1E4E89A at bellsouth.net>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
> What is the max current required for the B+ in the R-390?  The 390A
> has had everything nice and mapped out over the past few years by
> bunches of us here on the list, not so it's pappy.
>
> Thanks and 73
>
> Tom NU4G
>
>
> ------------------------------
>
> Message: 7
> Date: Mon, 6 Mar 2006 22:43:40 -0600
> From: "Barry" <n4buq at knology.net>
> Subject: [R-390] A bit more on my IF deck
> To: "R-390-List" <R-390 at mailman.qth.net>
> Message-ID: <000f01c641a1$b4f2f800$6401a8c0 at knology.net>
> Content-Type: text/plain; charset="iso-8859-1"
>
> I got the resistors replaced and all seems fine.  I need to do a full IF
> alignment, but it seems to be behaving just a slight bit better.  I'm not
> sure, but I think it doesn't take quite as long for the system to dump the
> charge from SLOW AGC as it did.  Is that perhaps a function of that 2.7M
> resistor?
>
> I wanted to check the resistances and voltages around where I had worked.
> Everything looks pretty good except for pin 2 of V506.  According to the
> manual, I should have about -0.4V, but I'm getting nothing (HP410B used
> here).  Checking the resistance, the manual states I should be seeing 500K
> in AGC mode and I'm only seeing 400K here.  There are three resistors to 
> GND
> from V506, pin 2 and they add up to 500K.  Apparently I have something 
> else
> parallel to this that's pulling the resistance down a bit.  It's always
> something.  Any guesses why I don't see -0.4V here?
>
> Thanks,
>
> Barry - N4BUQ
>
>
>
> ------------------------------
>
> _______________________________________________
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>
> End of R-390 Digest, Vol 23, Issue 9
> ************************************ 


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