[Heathkit] GB> DX40 Function Switch Mod - WAS: Help locating a heathkit part

[sbjohnston at aol.com]

 I'll send you scans of the DX-60 and DX60B schematics in a separate email...

Steve


 


 

-----Original Message-----
From: Bry Carling <bcarling at cfl.rr.com>
To: FLBOATANCHORS at yahoogroups.com; TampaBayTradersNet at yahoogroups.com; heathkit at mailman.qth.net; forsale-swap at mailman.qth.net; boatanchors at mailman.qth.net
Cc: glowbugs at piobaire.mines.uidaho.edu
Sent: Tue, 5 May 2009 4:25 am
Subject: GB> DX40 Function Switch Mod - WAS: Help locating a heathkit part



















There IS another method which has been used in many DX60s.






The DX60 seems to have suffered from this problem far worse than 






the DX40s did - looking at how many have burned out anyway...
















Maybe guys were more careful back in the DX40 era?
















Anyway, what a LOT of guys have done is to install a small relay 






to handle the HV switching which is the contact set that burns out 






on the function switch. The best that I remember it, there is another 






set of contacts which switches some lower voltage and you can tap 






off that to power a 12V or 6V relay to handle the HV switching chore.
















I have not seen this mod written up anywhere, but I HAVE seen it installed in 
at least two different DX60s. I expect the same scheme would work for a 
DX40 also.
















These things have become a little tougher with the removal of 






Heathkit manuals from the BAMA mirror site (sadly) after many years






- thanks to lawyers.
















Most (NOT all) web sites have r emoved Heathkit manuals. Many have 






even removed the modification information out of fear of the pests.
















I think I have a copy of the manual and schematic somewhere on 






a CD but finding it could be a challenge!
















Does anyone else have those modification details that they would like to 
share?
















http://www.heathkit-museum.com/ham/hvmdx-40.shtml
















http://www.qsl.net/la5ki/org/he/dx40.htm
















73 de AF4K, Bry






?






> A suggestion on the DX-40 function switch... 






> 






> I don't think you'll find an exact replacement anywhere except a parts-unit DX-40 or DX-35. So I'd 






> suggest one of two approaches: 






> 






> 1) Build your own from switch parts. This requires some circuit analysis, but from what I can see 






> on the schematic, a five-position five-pole switch could do the job 






> 






> 2) Change thecontrol system of the rig to use available switches.The original control system is 






> very hard on thefunction switch, and is obviously a cause of failures. 






> 






> I prefer 2). The existing control switch has to do things like switch the B+ to the 6146 plate, which 






> makes for a short life. 






> 






> 73 de Jim, N2EY






> 






> 






> 






> Remember Mom this Mother's Day! Find a florist near you now. 






> 






> __._,_.___ 






> 






> TELL YOUR HAM FRIENDS ABOUT FL BA.






> 






> Post a message: FLBOATANCHORS at yahoogroups.com






> Subscribe:FLBOATANCHORS-subscribe at yahoogroups.com






> Unsubscribe: FLBOATANCHORS-unsubscribe at yahoogroups.com






> List owner: FLBOATANCHORS-owner at yahoogroups.com






> 






> http://groups.yahoo.com/group/FLBOATANCHORS






> 






> 






> 






> 






> Your email settings: Individual Email|Traditional






> Change settings via the Web (Yahoo! ID required)






> Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured






> Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe 






> 






> __,_._,___ 














?