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 Post subject: HELP to fix broken finger on RF deck Hammarlund SP-600
PostPosted: Apr Sun 28, 2019 6:23 pm 
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Location: Prescott AZ
Hi,
I've decided to tackle my rather tatty Hammarlund SP-600 rebuild. This is labeled as a JX-21, ser no. 17790. I removed the RF deck to get at the 20 bumblebee caps (all quite leaky). Surprisingly this turned out to be a 7-wire RF deck, not 6-wire as expected.

My real problem is a broken finger on the bottom of the RF Deck (2nd RF tube V2).

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I know there is an unused finger on the local oscillator and that there is a way to remove it and replace my broken finger.
What I need is some CLEAR instructions on how to do it. The one instruction I found online left me baffled.

I sure would appreciate any help that could be provided since I will only get ONE shot at doing this correctly.

Thanks,
Mark

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 Post subject: Re: HELP to fix broken finger on RF deck Hammarlund SP-600
PostPosted: Apr Sun 28, 2019 7:23 pm 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 6481
Location: Liberty, Missouri
Don't know how you went about removing the deck, but to replace it you should remove one set of modules from the Turret.

Image

When it comes time to re-install the RF deck, rotate the "blank" position under where the RF deck will be installed. Then, when done, you can simply rotate the Turret and replace the modules.

Image

As I remember, only the modules for the bottom two bands have molded paper caps in them, so to minimize work, make sure one the sets you remove is for one of the bottom two bands.

Be real careful when removing/installing the spring clips, they can travel SEVERAL feet, and seem to assume a camouflaged appearance. :roll:

As for replacing the clip on the RF deck, haven't done that, but I'd think it would fairly straight forward.
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Last edited by Mikeinkcmo on Apr Sun 28, 2019 7:39 pm, edited 1 time in total.

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 Post subject: Re: HELP to fix broken finger on RF deck Hammarlund SP-600
PostPosted: Apr Sun 28, 2019 7:30 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Morris Plains, N.J. 07950
Mark, this article tells how to fix it.

https://www.radioblvd.com/sp600_rebuild.htm


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 Post subject: Re: HELP to fix broken finger on RF deck Hammarlund SP-600
PostPosted: Apr Sun 28, 2019 8:48 pm 
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Joined: Mar Thu 20, 2008 4:02 pm
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Thanks for your advice and help. I did see the instructions in the article that Joe pointed out but I'm having trouble getting the instructions to work for me. I'll keep trying.
Mark

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 Post subject: Re: HELP to fix broken finger on RF deck Hammarlund SP-600
PostPosted: May Thu 02, 2019 3:52 am 
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Joined: Jul Thu 29, 2010 5:35 am
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Location: Simonton, Texas
I have repaired my SP-600 with this problem and I have pictures but they are in a funny format and I can't resize them to post them here. Send me an email or private message with your email and I will send the pictures to you via email.

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 Post subject: Re: HELP to fix broken finger on RF deck Hammarlund SP-600
PostPosted: May Thu 02, 2019 7:39 pm 
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Joined: Feb Sun 17, 2008 11:36 pm
Posts: 2011
Location: Dayton, Ohio
A manual I use, says rotate the BANDSWITCH to in-between two adjacent bands, to disengage the contacts and avoid damaging them.

Model hobby shops sell brass stock of various thickness's, you might (if desperate) fashion a replacement contact and solder it in place. (good luck).

Charlie


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 Post subject: Re: HELP to fix broken finger on RF deck Hammarlund SP-600
PostPosted: May Thu 02, 2019 7:46 pm 
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e-mail sent to Koby for photos.
Thanks.
Mark

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 Post subject: Re: HELP to fix broken finger on RF deck Hammarlund SP-600
PostPosted: May Fri 03, 2019 1:56 am 
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Joined: Jan Mon 28, 2013 9:35 pm
Posts: 1453
Location: Santa Rosa, CA
I'm deep in the bowels of a very early SP-600 (JX) myself and today
was RF deck day. Ugh. Its been years and had forgotten how difficult
these are to get out and work on. Especially with failing eyesight.

I've always just removed one set of coils to make sure the fingers
don't get damaged. Easy to do.

Reviewing my notes I see where on one I had done years ago
there was a problem with one of the 100 pF micas in the RF deck. Yours should have
three of these, earlier versions had 4. The problem was sudden, small
shifts in either the VFO or the mixer pulling the VFO. Replacing
these mics solved the problem.

May be common knowledge now but if not swap these out.
Steve

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 Post subject: Re: HELP to fix broken finger on RF deck Hammarlund SP-600
PostPosted: May Tue 07, 2019 1:28 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Warner Robins, GA
What I did was to rotate the bandswitch to where it was between bands and i was able to remove and insert the RF deck without breaking or bending a finger.


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