[Heath] LMO rebuilding....did I mess it up?

[Guy Giacopuzzi]

Glen,  and any other members of the Heathkit listserve,

I think I have a problem, and it's not in Houston....I got the 80 band 
tuned up on my SB-101, so I thought I'd try it on the air..I found an 80 
meter LSB group of hams talking ,and having tuned up the 101' into a 
dummy load, I turned it onto the antenna and called...they came right 
back and said I had a nice signal...no tuner...I asked "what frequency 
are you showing?" and he came back "3900khz".   Only one problem...I was 
tuned to 3691khz!!  I checked this again on 40 meters...same 
thing...when I transmit a signal using my Elecraft K2 on 7400khz, the 
101' is reading (and receiving) it on 7181khz...Did I do something wrong 
with the LMO?  I checked it's range of movement,and with the tuning unit 
dialed all the way counterclockwise, the  variable cap is almost closed; 
then, five turns to the right and the cap is fully opened, as I recall.  
I didn't check it on any other bands, but at the moment, it would seem 
the LMO's output is 219khz too low....right?   It's reading 219khz low 
exactly on both bands..... Help....

A bit of history.  I know virtually nothing about the history of this 
101'....I bought this one, with another 101' and two HP23 series power 
supplies from a nearby ham for $100.  He had bought them from another 
ham, hoping to get one working one out of the pair.  He never had time 
to delve into either of them....

Guy
WA6OQQ,
On of the hams at Heath


On 2/1/2016 1:40 PM, Glen Zook wrote:
> The LMO can be removed without removing the front panel.  You do have 
> to loosen the setscrew on the dial assembly, unsolder the wires to the 
> LMO, and remove the 4-nuts on the underside of the chassis.
>
> Remove the main tuning knob and loosen the large nut on the panel that 
> holds the shaft.  Move the shaft so that the slip drive is removed 
> from the dial.  Then, lift the LMO from the chassis and away from the 
> dial.
>
> After making the repairs, put the LMO back in place and reverse the 
> directions.
> Glen, K9STH
>
> Website: http://k9sth.net
>
>
>
> ------------------------------------------------------------------------
> *From:* Guy Giacopuzzi <gggdds at js-net.com>
> *To:* Glen Zook <gzook at yahoo.com>
> *Sent:* Monday, February 1, 2016 2:22 PM
> *Subject:* Re: LMO rebuilding....
>
> Glen,
> Thanks for your help....I followed some of your advice, and the advice 
> that I didn't follow came back to bite me.....I acquired a couple of 
> SB-101's for a song (well, a song plus $100, but it included two power 
> supplies....)....and I've been "bringing the 1st one 'back'" so to 
> say....cleaning, checking, going thru the tune up routine, etc......I 
> rebuilt the LMO on an SB-101....removed the front panel, etc to get to 
> it...had to do a lot of general cleaning as the entire dial assy was 
> all gummed up.   I took apart and cleaned the LMO...lubed it, removed 
> and cleaned the stops, but/I didn't do the braid thing/......I used a 
> high end light oil for the lube...from Kroil....I got it on the air 
> last night, loaded it into a 75 ft long wire w/ no tuner and joined a 
> group at about 3800kc or so but they kept reporting I was "jumping all 
> over the place"...as I listened, I heard them, but the frequency kept 
> changing...or "warbling" as you say. My signal was plenty powerful, 
> and the group was spread out all over the California coast up past San 
> Francisco...so the 6146B's were really kicking, so to say.  So, I 
> reread your email and this time, downloaded the file on LMO 
> rebuilding.  I'm going to attempt removal of the LMO w/o removing the 
> front panel--can I do that?  Maybe I'll have to remove the 
> "escutcheon" to set the dial on right...Anyway, now I think I've got 
> to do the braid....I was going to use a bit of "soldering" or maybe I 
> should say "de-soldering" braid...Is that ok?   Anyway, I should have 
> followed /all/ of your advice, not just some of it.  One other 
> interesting thing....when I tuned in the stations, my RF gain control 
> didn't work, and when I looked at it, the diode on the middle terminal 
> had let go...but wow, did the receiver/have a lot of gain/.  When I 
> hooked it back up, the gain seemed to back down a bit.  I thought I'd 
> play with that just a bit to see if the control is somehow hurting the 
> overall receiver gain...

-- 

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