[Hammarlund] Info on acquiring an SP 600

[Rodger]

I missed the original message due to email issues but the only thing I 
can add is that some of the SP-600's have an issue with the power supply 
filter chokes.  For part of the production, Hammarlund (or its supplier) 
used a potting tar which becomes electrically leaky over time.  When the 
leakage becomes high enough it will drop the B+, overload the 
transformer and rectifier, etc.  One of the two chokes in my SP-600 
developed this problem and I ended up replacing both of them.  Others 
have insulated them and mounted them above ground but I don't like 
having things floating which one would expect to be grounded in a piece 
of equipment.

I don't know how widespread this problem is but when I reported the 
issue with mine 7 or 8 years ago I got a large number of emails from 
others who had the same experience.  This isn't an insurmountable 
problem but it is something to check for to avoid damaging the main 
power transformer.  In my case, the defective choke got noticeably warm 
in short order and testing showed significant leakage from the winding 
to the case.

The SP-600 is a great band cruiser and a nice sounding and performing 
radio.  I have mine mounted in a rack with a Racal RA-17 and an RCA 
AR-88 and all three get used quite a bit.  Mine is an earlier unit that 
needed recapping but it really wasn't a bad process.  As long as you 
follow the proper procedure for removing the turret the job will go 
quickly and without damage to the switches.

73, Rodger WQ9E

Bob Krassa wrote:
> There are people on this list who know a lot more than I 
> about the diferent models of the SP-600 but there is quite a 
> bit of info on the web that could help in selecting the best 
> for your interests.
>
> Late serial numbers - above around 15,000, seem to have 
> ceramic caps instead of deteriorating paper caps and so are 
> preferable unless you are willing to do major disassembly to 
> re-cap.  The electrolytics are easy to get to.
>
> Shipping damage is a big issue with these heavy units so if 
> you can find one that you can pick up in person you are a 
> lot better off.  
>
> If you can inspect it you can check out the gear train - 
> slippage may just be due to oil which can be removed with 
> alcohol but mechanical looseness may be harder to fix.
>
> Also if it works at all you will have some asurance that the 
> transformers are not toasted.
>
> They are great radios, hope you find one you like!
>
> 73 Bob Krassa AC0JL
>
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